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Weekend and Oral

Electronic Posters (no CME credit)

Electronic Power Pitch Poster (no CME credit)

### MRS/MRSI Aquisition

 Exhibition Hall 1271-1304 Monday 8:15 - 10:15

 1271 Metabolite cycled density-weighted concentric rings k-space trajectory (DW-CRT) enables 1H magnetic resonance spectroscopic imaging at 3 Tesla in a clinically feasible timeframe Adam Steel1,2, Mark Chiew3, Peter Jezzard4, Natalie Voets4, Puneet Plaha4, M. Albert Thomas5, Charlotte J Stagg4, and Uzay E Emir6 1Nuffield Department of Medicine, University of Oxford, Headington, United Kingdom, 2National Institute of Mental Health, National Institutes of Health, Bethesda, DC, United States, 3Nuffield Department of Clinical Neuroscience, University of Oxford, Headington, United Kingdom, 4Nuffield Department of Clinical Neurosciences, University of Oxford, Headington, United Kingdom, 5Department of Radiology, University of California Los Angelas, Los Angeles, CA, United States, 6School of Health Sciences, Purdue University, West Lafayette, IN, United States In this study, we demonstrate that a metabolite-cycled semi-LASER pulse localization with density-weighted concentric rings trajectory (DW-CRT) enables high-resolution MRSI to be acquired at 3 Tesla within a clinically feasible acquisition time.  High-resolution (5 x 5 x 10 mm3) DW-CRT feasibility at 3T was assessed in 6 healthy volunteers. Subsequently, the clinical utility of this approach was demonstrated by mapping the presence of 2-HG in a patient with a grade III oligodendroglioma tumor.

 1272 Standardized Parameterization of Echo-Planar Compressed Sensing MRSI Acquisition and Reconstruction Jason C. Crane1, Marram P Olson1, Yan Li1, Maryam Vareth1, Hsin-Yu Chen1, Zihan Zhu1, Sukumar Subramaniam1, Peder E.Z. Larson1, Duan Xu1, Daniel B. Vigneron1, and Sarah J. Nelson1 1Department of Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States Advanced MRSI acquisition strategies can be complex to implement and require customized reconstruction software, typically designed for a specific raw file format and that relies upon a priori knowledge of the specific implementation of the pulse sequence being applied. The ISMRMRD format1 has begun to address standardization in describing data acquisition parameters for different types of imaging data, but further development is needed. Here we build on this strategy by demonstrating XML encoding of parameters that describe flyback echo-planar, compressed sensing MRSI acquisitions being implemented on scanners from multiple vendors at UCSF that can be supported with generalized reconstruction software.

 1273 SNR and PSF Simulations for k-t Trajectories in MRSI: CSI, EPSI, Rosettes, and Concentric Rings Amir Seginer1 and Assaf Tal1 1Weizmann Institute of Science, Rehovot, Israel We compare, using numeric simulations, the point spread functions (PSF) and the SNR of different trajectories in k-t space for magnetic resonance spectral imaging (MRSI). This is a first step towards evaluating the trajectory of choice while balancing SNR efficiency, scan time, and localization of signal (resolution vs. bleed).

 1274 JSASSI: A B1 Insensitive Technique for J-Resolved 2D Magnetic Resonance Spectroscopy at 7T Judy Alper1,2, Rebecca E Feldman1, Francesco Padormo1, Priti Balchandani1, and Gaurav Verma1 1Radiology, Icahn School of Medicine At Mount Sinai, New York, NY, United States, 2Biomedical Engineering, City College of New York, New York, NY, United States Magnetic resonance spectroscopy (MRS) can be used to investigate metabolite concentration changes correlated to neurological and psychiatric diseases. Improved spectral resolution and metabolite quantification in these disorders would add to our understanding of neurodegenerative diseases. JSASSI is a novel technique for localized two-dimensional (2D) MRS, based in part on the JPRESS spectroscopic sequence while implementing pulses from the SASSI sequence. An incrementing Δt1 time delay is introduced for resolving J-coupled metabolites from overlapping resonances. JSASSI was applied in phantoms and in vivo. Metabolite peaks for NAA, Glx, Cr and others were clearly identified using JSASSI. Unambiguous detection and resolution of J-coupled metabolites could facilitate reliable quantification of metabolites such as GABA, with potential applications in characterization and treatment monitoring in psychiatric disorders.

 1275 Optimisations for ultra-high resolution MRSI of the brain at 7 T: Towards even higher resolutions and faster measurements Gilbert Hangel1,2, Bernhard Strasser3, Michal Povazan4,5, Eva Hečková1,2, Stephan Gruber1,2, Philipp Moser1,2, Lukas Hingerl1,2, Siegfried Trattnig1,2, and Wolfgang Bogner1,2 1High Feld MR Centre, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 4Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States Recently, ultra-high resolution (UHR-) MRSI of the brain at 7 T was successfully demonstrated, allowing metabolic mapping at near-anatomical resolution. With this work, we propose further optimised sequences, one for shorter measurement times of under 5 min and one for even higher in-plane resolutions down to 12 µL, which will allow a more flexible application of UHR_MRSI, and show their possibilities and limitations. Furthermore, the effects of slice thickness for UHR-MRSI were investigated with a second set of measurements.

 1276 Cross-vendor standardization of a 3 T MRS protocol with semi-LASER Adam Berrington1,2, Dinesh K Deelchand3, James Joers3, Michal Považan1,2, Michael Schär1, Joseph Gillen1,2, Peter B Barker1,2, and Gülin Öz3 1Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Center for Magnetic Resonance Reseach, University of Minnesota, Minneapolis, MN, United States Acceptance of 1H-MRS for clinical use is hindered by variability in methodology across platforms. Cross-vendor standardization is thus desirable for large-scale studies to be conducted. Here, we standardize a semi-LASER scheme (TE=30 ms) with identical pulses, inter-pulse durations and acquisition protocol in phantom and healthy volunteers on Philips and Siemens 3 T systems. The implemented method resulted in high quality spectra with matched SNR, linewidth and spectral patterns in phantom and similar estimated metabolite concentrations in vivo: between-subject CVs for NAA were (2.6-11.0)% and (3.3-10.2)% for Philips and Siemens, respectively. This method highlights the potential for pooling data across multiple sites.

 1277 Intrinsic inversion recovery-based macromolecular nulling in MEGA-PRESS 1H-MR brain spectra Alexander Gussew1, Andreas Masek1, Martin Krämer1, and Jürgen R. Reichenbach1 1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany The reliability of 1H-MRS MEGA-PRESS measurements of inhibitory neurotransmitter GABA in the human brain typically suffers from macromolecular (MM) contaminations of GABA resonances. In this work, we present a novel MM suppression approach, which relies on adiabatic inversion of the longitudinal magnetization of both metabolites and MMs prior to playing out the MEGA-PRESS editing scheme, which is applied after an inversion time delay (TI) corresponding to the zero-crossing of MM magnetization. As demonstrated in healthy subjects, this new approach ensures appropriate MM suppression and provides additional GABA signal gain compared to the commonly applied approach with symmetrical MM editing.

 1278 What is the optimal ROI size for single voxel MRS in global brain pathology? Maike Hoefemann1, Victor Adalid1, and Roland Kreis1 1Depts. Radiology and Biomedical Research, University of Bern, Bern, Switzerland The purpose of this study was to investigate optimal voxel size (VS) as a compromise between increasing SNR and decreasing linewidth under the side-constraint of minimal artifact levels and to investigate potential benefits from considering signals from single coil elements separately. Eight different VS were evaluated; hinting at optimal VS of 60 cm³ and indicating that lineshape information from unsuppressed water should be included in the fitting process. Differences in single coil elements show substantial impacts on spectral quality, indicating that individual processing and exclusion of certain channels is superior to the standard procedure of an indiscriminate weighted sum.

 1279 ISIS based Relaxation Enhanced MR spectroscopy (iRE-MRS) for downfield spectroscopy at short echo times Sonia I. Goncalves1 and Noam Shemesh1 1Neuroplasticity and Neural Activity Lab, Champalimaud Foundation, Lisbon, Portugal MRS is a versatile technique that allows for the non-invasive in-vivo exploration of tissue metabolism. In most MRS pulse sequences based on broadband excitation, the acquisition is preceded by water saturation pulses that suppress the water bulk signal and implicitly also exchangeable protons downfield of water. We introduce a new method for short-TE downfield MRS and show that it detects multiple peaks in-vivo that extend beyond 9 ppm.

 1280 Repeatability and reproducibility of GABA quantification using MEGA-PRESS  in anterior cingulate cortex as a biomarker for depression Daniel Alamidi1, Jan Weis2, Christine Nabuurs3, Mats Fredrikson4,5, Andreas Frick4,6, Fredrik Ahs4,5, Jakub Kraus5,7, Jonas Persson8, and Maarten Versluis3 1Philips, Stockholm, Sweden, 2Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden, 3Philips, Best, Netherlands, 4Department of Psychology, Uppsala University, Uppsala, Sweden, 5Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden, 6Department of Psychology, Stockholm University, Stockholm, Sweden, 7Centre for Neuroscience, Central European Institute of Technology, Masaryk University, Brno, Czech Republic, 8Department of Neuroscience, Psychiatry, Uppsala University, Uppsala, Sweden Proton MRS of the anterior cingulate cortex (ACC) is an attractive biomarker as it provides non-invasive methods to quantify GABA levels that are linked with several psychiatric disorders. This study validates a MEGA-PRESS sequence that combines phase cycling with real time frequency drift correction to measure GABA spectra in phantom and human brain. The GABA levels of the ACC were repeatable and reproducible at two different scanning sites. Consequently, the technique is appropriate for future longitudinal psychiatric studies.

 1281 Comparison of adiabatic and non-adiabatic inversion pulses for lipid suppression in human calf muscle Andreas Masek1, Alexander Gussew1, Martin Krämer1, and Jürgen R. Reichenbach1,2,3,4 1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 3Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 4Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany Overlapping signal contributions originating from different metabolites with similar molecular structure is a common problem of in vivo 1H-MR spectroscopy with magnetic field strengths of ≤ 3 T. One prominent example is the “contamination” of the resonances of lactate with fat signals in 1H-MR muscle spectra. The goal of this work was to implement a MRS sequence with inversion recovery based adiabatic/ nonadiabatic lipid suppression and to test this approach in vivo in two different human calf muscles.

 1282 Finger tapping induces lactate increase in the human motor cortex detected by J-edited 1H-MRS at 4T Yury Koush1, Robin A. de Graaf1, Lihong Jiang1, Douglas L. Rothman1, and Fahmeed Hyder1 1MRRC, Yale University, New Haven, CT, United States While functional MRI (fMRI) localizes regions of activation, functional MRS (fMRS) provides metabolic response to activation. fMRS, using short echo-time (TE) non-edited 1H-MRS protocols, has been shown to be capable of detecting a lactate increase in sensory-induced activations. Because short TE non-edited lactate spectra are susceptible to functional hyperemia and contamination from lipids/macromolecules, we posited if long TE J-edited 1H-MRS detection of lactate can reliably detect metabolic changes in the motor cortex (MC) during the standard finger-tapping paradigm. Our fMRS results at 4T showed significant physiological modulation of the MC lactate level.

 1283 Glycine quantification via S-PRESS difference editing of myo-inositol Thomas Lange1 and Michael Dacko1 1Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany The quantification of glycine (Gly) with in vivo MRS is challenging due to the strong spectral overlap with myo-inositol (mI) so that only the concentration sum mI+Gly can be accurately measured with standard MRS methods at clinical field strengths. In this work, the distinction and quantification of mI and Gly is demonstrated with S-PRESS difference editing, which enables unequivocal detection of the strongly coupled mI resonances through suppression of the overlapping uncoupled Gly resonance.

 1284 High resolution localized 1D homonuclear decoupled in phase MR spectroscopy via z-filtered 2D J-spectroscopy Lin Yanqin1, Bo Duan1, Dan Tian1, Qing Zeng1, and Zhong Chen1 1Department of Electronic Science, Xiamen University, Xiamen, China Proton 1D MR spectroscopy is an important tool in the study of a number of diseases. However, due to multiplet structure and narrow proton chemical shift range, 1D spectra become complicated for direct assignment and quantification. Homonuclear broadband decoupled spectra can be obtained by separating the chemical shift and J coupling information into orthogonal axes in the conventional JPRESS spectra. However, they suffer low resolution because of phase-twisted lineshape. Here, a J-resolved alike experiment with z-filtered module is introduced for the selection of in phase magnetization, and thus high resolution phase sensitive localized 1D spectra can be obtained.

 1285 Macromolecule-suppressed GABA acquisition at 7T with commonly available Gaussian editing pulses. Pallab K Bhattacharyya1 and Mark J Lowe1 1Imaging Institute, Cleveland Clnic, Cleveland, OH, United States Co-editing of macromolecule(MM) resonances is a major problem in J-difference based editing (e.g.  MEGA-PRESS) at 3T and lower field strengths. Symmetrical pulsing centered at the 1.7 ppm MM resonance alleviates this problem but results in loss of desired GABA signal, in addition to loss of unwanted MM signal, due to high bandwidth of frequency-selective editing pulses. Larger separation of editing pulses at 7T reduces the problem, but large chemical shift displacement errors, especially at low B1, make MEGA-PRESS non-viable at 7T. Using a low-power MEGA-LASER sequence, we measured macromolecule minimized GABA at 7T with editing pulses having bandwidths available in most scanners.

 1286 Simultaneous MRSI of GABA and glutathione using HERMES spectral editing at 3T Kimberly Chan1,2,3, Richard Edden2,3, Georg Oeltzschner2,3, Muhammad Saleh2,3, and Peter Barker2,3 1Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, 2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD, United States, 3F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States HERMES with single-voxel PRESS localization has been used to simultaneously edit multiple compounds.  It’s often desirable to measure spectra from multiple brain regions, using MR spectroscopic imaging (MRSI). This study examined the feasibility of HERMES editing of GABA and GSH with a PRESS-localized MRSI sequence at 3T, and compared it to conventional MEGA-edited MRSI acquisitions. It’s found that adding symmetrical lipid suppression pulses to HERMES allows the sequence to be used in vivo and has an editing efficiency equivalent to that of separate acquisitions of GABA and GSH using MEGA-PRESS MRSI without an increase in measurement variability relative to MEGA-PRESS.

 1287 High resolution mapping of GABA+ and Glx using motion-corrected, spiral-accelerated, edited 1D-semiLASER MRSI in the human brain at 7T Philipp Moser1,2, Bernhard Strasser3, Lukas Hingerl1, Michal Považan4,5, Gilbert Hangel1, Eva Heckova1, Borjan Gagoski6, Andre van der Kouwe7, Ovidiu C. Andronesi7, Siegfried Trattnig1,2, and Wolfgang Bogner1 1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 4Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 6Fetal-Neonatal Neuroimaging; Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States, 7Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States In vivo detection of gamma-aminobutyric acid (GABA) and glutamate (Glu), both major neurotransmitters in the human brain, benefits from the higher sensitivity and SNR at ultra-high field (7T) compared to lower field strengths. However, strong B1+ inhomogeneities and chemical shift displacement errors, as well as subject motion and carrier frequency drifts can significantly impair the experiment. We preliminarily propose the first high resolution full-slice in vivo mapping of GABA+ at 7T. Combining spatial-spectral spiral encoding for MRSI acceleration with B1-insensitive adiabatic pulses and real-time motion correction allows unprecedented high resolution J-difference editing at 7T in comparably short scan time.

 1288 Optimized Crusher Design for Magnetic Resonance Spectroscopy Karl Landheer1 and Christoph Juchem1,2 1Biomedical Engineering, Columbia University, New York, NY, United States, 2Radiology, Columbia University, New York, NY, United States Modern magnetic resonance spectroscopic (MRS) pulse sequences frequently overlook the issue of unwanted coherence pathways. A novel and robust algorithm which only requires input of the desired coherence(s) was developed to optimally crush all unwanted coherence pathways for any MRS pulse sequence. Experiments were performed on the GE BRAINO phantom comparing crusher schemes obtained from the literature with those obtained from the developed optimization algorithm for sLASER and MEGA-sLASER. The results demonstrate that the effects of unwanted coherences can be drastically reduced through the implementation of an optimized crusher scheme, without the need for additional or stronger crushers.

 1289 Improving time resolution in the imaging of metabolic dynamics using Compressed Sensing from 2D Heteronuclear Multiple Quantum Coherence Utako Yamamoto1, Hirohiko Imai1, Kei Sano1, Masayuki Ohzeki2, Tetsuya Matsuda1, and Toshiyuki Tanaka1 1Department of Systems Science, Kyoto University, Kyoto, Japan, 2Department of Applied Information Sciences, Tohoku University, Sendai, Japan We propose a compressed sensing reconstruction method with high time resolution for imaging fast metabolic dynamics from sequential data measured using 2D 1H-13C heteronuclear multiple quantum coherence (HMQC) MRSI. Optimization using the alternating direction method of multipliers (ADMM) is employed to incorporate prior knowledge about the substance distribution. The 2D-HMQC MRSI with pseudo-random undersampling is applied to tumor-bearing mice after the injection of [U-13C] glucose. From the resulting data, we successfully reconstruct time-series of the in vivo density of three substances (glucose, lactate, and fat) at a high time resolution of 2.25 min.

 1290 Fast In Vivo Metabolite T2 Quantification by RF-Driven Steady State Ningzhi Li1, Linqing Li1, Yan Zhang1, and Jun Shen1 1National Institute of Mental Health, Bethesda, MD, United States MARzss method is a novel method for brain metabolite T2 quantification without varying echo time. This study evaluates the feasibility of shortening the scan time of the MARzss method by more than 80% using minimum TR and two-FA measurements. Phantom and preliminary in vivo studies show that metabolite T2 quantifications using two-FA measurements agree well with T2 values obtained by the originally proposed seven-FA measurements. In addition, Monte Carlo simulations indicate that under the same total scan time, the two-FA measurements can significantly improve the precision of T2 quantification.

 1291 Test-retest reliability of real-time frequency and motion corrected Hadamard encoded spectral editing (CHASE) Anna Lind1, Vincent O. Boer1, Mads Andersen2, Esben T. Petersen1,3, and Anouk Marsman1 1Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2Philips, Copenhagen, Denmark, 3Center for Magnetic Resonance, Dept. Electrical Engineering, Technical University of Denmark, Lyngby, Denmark Inhibitory neurotransmitter GABA and antioxidant GSH are suggested to be implicated in psychiatric and neurological disorders. Because of their relatively weak signals, spectral editing is necessary to assess GABA and GSH in the human brain. Hadamard encoding can be applied simultaneously for spectral editing of GABA and GSH. As both small metabolite signals and Hadamard encoding are highly susceptible to frequency drift and motion, real-time frequency and motion correction significantly improves spectral quality. The data obtained in this study so far suggest good test-retest reliability of real-time frequency and motion corrected Hadamard encoded spectral editing (CHASE) for GABA and GSH.

 1292 Flip Angle Corrected Multi-TR, Multi-TE 1H MR Spectroscopy Gavin Hamilton1, Alexandra N Schlein1, and Claude B Sirlin1 1Liver Imaging Group, Department of Radiology, University of California, San Diego, La Jolla, CA, United States Multi-TR, multi-TE 1H MRS estimates T1 and T2 of fat and water and liver proton density fat fraction in a single breath-hold. This approach uses a steady state solution, which assumes a perfect 90° pulse is generated which is not guaranteed in vivo, possibly introducing T1 errors.  We introduce a flip angle corrected multi-TR, multi-TE 1H MRS sequence based on a non-steady state approach and demonstrate, in phantoms, that while the multi-TR, multi-TE MRS sequence estimates T1 dependent on the flip angle, the flip angle corrected multi-TR, multi-TE MRS sequence estimates T1 independent of flip angle.

 1293 Accuracy and Reproducibility of NAD+, NADH and Redox Ratio Measurement in Human Brain by LCModel Lijing Xin1, Ozlem Ipek1, Bernard Cuenoud2, Maurice Beaumont2, Maya Shevlyakova2, and Rolf Gruetter3,4 1Centre d'Imagerie BioMédicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Nestec Ltd, Avenue Nestlé 55, Vevey, Switzerland, 3Departments of Radiology, University of Lausanne, Lausanne, Switzerland, 4Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland The aims of this study were to test the feasibility of NAD+, NADH and redox ratio([NAD+/NADH]) measurement in vivo in the human brain at 7T using LCModel and to further evaluate the measurement accuracy and reproducibility. High 31P spectral quality was achieved and LCModel provides excellent fitting quality. Monte-Carlo simulations and test-retest experiments demonstrated good measurement accuracy and reproducibility with sufficient SNR achieved. The values are in agreement with those previously published. Therefore, LCModel can be used as an alternative tool to achieve automated and objective measurement of NAD+, NADH and redox ratio in human brain in vivo.

 1294 Accelerated Correlated Spectroscopic Imaging in Two Spectral-Three Spatial Dimensions with Slice-selective Adiabatic Refocusing Pulses in Human Calf Muscles Manoj K Sarma1, Andres Saucedo1, Christine H Darwin2, Neil Wilson1, Zohaib Iqbal1, Cathy C Lee2,3, Catherine Carpenter4, Theodore Hahn2,3, and M. Albert Thomas1 1Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 2Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 3Greater Los Angeles Veterans Affairs Medical Center, Los Angeles, CA, United States, 4School of Nursing, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States An optimized version of the five-dimensional (5D) echo-planar correlated spectroscopic sequence using an adiabatic full passage (AFP) RF pulse pair has been implemented on a 3T MRI/MRS scanner equipped with a 15-channel transmit/receive coil. The sequence was initially tested using a corn oil phantom. The calf muscle of twelve healthy subjects (age 27.5±3.1 years) and six diabetic type 2 subjects was studied (age 62.3±9.8 years). The AFP pulse pair enabled a sharper profile and minimal chemical shift misregistration. The localization of the volume of interest showed differential distribution of metabolites and lipids in human calf muscle and tibial marrow.

 1295 Uncovering Long Range J-coupled Lipid Resonances in Human Calf In-Vivo: Pilot Findings Using Localized Two Dimensional Total Correlated Spectroscopy Manoj K Sarma1, Andres Saucedo1, Christine H Darwin2, Cathy C Lee2,3, Ravinder R. Regatte4, and M. Albert Thomas1 1Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 2Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 3Greater Los Angeles Veterans Affairs Medical Center, Los Angeles, CA, United States, 4Center for Biomedical Imaging, New York University School of Medicine, New York, NY, United States Based on the same principle of localized correlated spectroscopy (L-COSY) of coherence transfer during mixing period, total correlated spectroscopy (TOCSY) is a powerful technique that can provide correlations for both direct and long range coupled spins via relayed coherence transfer.  Due to the SAR issue, the potential of TOCSY has not been fully exploited in-vivo and only few versions of TOCSY have been evaluated in brain. Here we have implemented a novel version of localized TOCSY technique for implementation in human calf muscle in-vivo, and compared results from three mixing strategies. Results are presented from a corn oil phantom, and in-vivo 2D spectra from 4 healthy volunteers and 1 diabetic patient obtained on 3T clinical platforms. We demonstrated that TOCSY can uncover the hidden relayed peaks, particularly that of IMCL/EMCL in calf muscle which can play an important role in better estimation of degree of unsaturation.

 1296 In vivo detection of NAD+ in human calf muscle at 7T using 28-channel knee volume coil Puneet Bagga1, Neil Wilson1, Catherine DeBrosse1, Hari Hariharan1, and Ravinder Reddy1 1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States Nicotinamide adenine dinucleotide (NAD+) is a ubiquitous molecule present in all cells and tissues of the body with an important role in the redox reactions and metabolism. Small changes in NAD+ levels may lead to oxidative stress and may be a cause for various disorders. NAD+ is usually be detected in vivo by 31P NMR spectroscopy. Recently, NAD+ measurement with 1H MRS in the human brain was demonstrated. In the present study, we show for the first time, in vivo single voxel localized 1H MRS detection of NAD+ from the human calf muscle at 7T.

 1297 Profiling lipid composition in whole breast tumours using two dimensional (2D) double quantum filtered (DQF) correlation spectroscopy (COSY) and multiple quantum coherence (MQC) magnetic resonance spectroscopy (MRS) Sai Man Cheung1, Ehab Husain2,3, Yazan Masannat3,4, Vasiliki Mallikourti1, Steven D Heys3,4, and Jiabao He1 1Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, United Kingdom, 2Pathology Department, Aberdeen Royal Infirmary, Aberdeen, United Kingdom, 3School of Medicine, University of Aberdeen, Aberdeen, United Kingdom, 4Breast Unit, Aberdeen Royal Infirmary, Aberdeen, United Kingdom Changes in lipid composition, such as polyunsaturated fatty acids (PUFA), have found to be potential biomarker of breast cancer. It has been shown that PUFA has a role in breast cancer initiation. The relationship in human between lipid composition and breast tumour grading warrants urgent investigation, as a pathway towards improved treatment. Conventional MRS suffers from overlap of nearby lipid and water peaks, and is insufficient for lipid composition measurement. We conducted double quantum filtered (DQF) correlation spectroscopy (COSY) to resolve lipid composition from the whole breast tumour, and multiple quantum coherence (MQC) MRS for further close investigation of PUFA.

 1298 High Quality Magnetic Resonance Spectroscopy Reconstruction with Vandermonde Factorization on Low Rank Hankel Matrix Xiaobo Qu1, Jiaxi Ying1, Di Guo2, Jian-Feng Cai3, Gongguo Tang4, and Zhong Chen1 1Department of Electronic Science, Xiamen University, Xiamen, China, 2School of Computer and Information Engineering, Xiamen University of Technology, Xiamen, China, 3Department of Mathematics, Hong Kong University of Science and Technology, Hong Kong, China, 4Department of Electrical Engineering & Computer Science, Colorado School of Mines, Golden, CO, United States Magnetic resonance spectroscopy (MRS) is commonly converted from its free induction decay (FID) data with Fourier transform. How to reconstruct high quality spectra is one of the fundamental problems for MRS. In this work, a reconstruction method is proposed to explore the general exponential property of FID. Each exponential function of FID is explicitly enforced with the Hankel matrix Vandermonde Factorization (HVaF). This model is then applied to spectrum reconstruction of sparsely sampled FID in fast MRS. Results on synthetic and realistic MRS show that the new approach requires fewer data to allow successful reconstruction and provides better reconstruction on low-intensity signals than the state-of-the-art low rank Hankel matrix method. Thus, the new approach would be useful for faster data acquisition or recovery of weak spectral peaks in MRS applications.

 1299 Indirect Detection and Spin Amplification of Non-Proton MRS and MRI by Solvent Proton Signals Zhao Li1 and Yung-Ya Lin1 1Chemistry and Biochemistry, UCLA, Los Angeles, CA, United States A general indirect-detection and spin-amplification scheme has been developed to enhance the sensitivity of heteronuclear MRS and MRI based on dynamic instability of the solvent proton magnetization under collective feedback fields of radiation damping and the distant dipolar field. The heteronuclear solute spins are first detected by the solvent proton spins through various magnetization transfer mechanisms and serve as small “input” signals to perturb the solvent proton magnetization, which is prepared in an unstable state. The weakly detected signal is then amplified through subsequent nonlinear evolution of the solvent proton magnetization to achieve 10x SNR improvement for 13C MRS and MRI.

 1300 Reproducibility of the measurement of hepatic lipid composition with 1H MRS at 3T Pandichelvam Veeraiah1,2, Kay H.M Roumans2, Joachim E Wildberger1, Patrick Schrauwen2, Vera B Schrauwen-Hinderling1,2, and Lucas Lindeboom1,2 1Department of Radiology, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands, 2Department of Human Biology and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, Netherlands The total intrahepatic lipid (IHL) content can reliably be determined with 1H-MRS, but measuring lipid composition (saturated, mono- and poly-unsaturated fatty acids) is very challenging. At 3T the allylic peak is contaminated with the alpha-carbonyl methylene resonance, which hampers accurate measure of lipid composition. Recently, we developed a new approach to determine the lipid composition using prior knowledge to correct the signal intensity for alpha carbonyl group using methyl resonance. Here, we determined the in vivo reproducibility of our approach and robust quantification of lipid composition in a group of subjects with a wide range of total liver fat content.

 1301 Preliminary study of proton magnetic resonance spectroscopy with multi-echo-time for simultaneous quantification and T2 measurement of glutamate. Chi-Hyeon Yoo1,2, Kyu-Ho Song1, Song-I Lim1,2, Dong-Choel Woo2, and Bo-Young Choe1 1Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea, 2Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea This study presents our preliminary concept of multi-echo-time (TE) in vivo proton magnetic resonance spectroscopy (1H MRS) for the simultaneous quantification and T2 measurement of the brain metabolites, particularly glutamate. The feasibility of the proposed method was verified by comparing metabolite concentrations to that of conventional short-TE, and T2 relaxation times to that of conventional T2 measurement. Although TE points must be further optimized, the multi-TE in vivo 1H MRS could be used to simultaneously investigate the changes of brain metabolism and microenvironments in a scan time comparable to that of the conventional method.

 1302 Feasibility of Echo Time Optimization for Glutamate and Myoinositol Detection using TE-Averaged PRESS Spectral Editing Technique in Human Brain at 3T. Gokce Hale Hatay1 and Esin Ozturk Isik1 1Biomedical Engineering Institute, Bogazici University, Istanbul, Turkey This study aims to investigate the feasibility of echo time (TE) optimization for TE-averaged PRESS for faster detection of glutamate (Glu) and myoinositol (mI) in human brain at 3T. Proton MR spectroscopic imaging (1H-MRSI) data of a brain phantom and a healthy volunteer were acquired at 3T using 10 different TEs, which were selected based on prior Monte Carlo simulation results. TE-averaged PRESS spectra were created with best TE combinations, and metabolites were quantified in MATLAB. Our results indicated that TE-averaged PRESS with upto 5 TE’s could reliably detect separate Glu and mI metabolites.

 1303 1H-localised 13C DEPT measurement of glutamate and glutamine turnover in human frontal lobe using [1-13C]glucose infusion at 7T Bernard Lanz1, Chen Chen1, Carolina Campanha Fernandes1, Liz Simpson2, Adriana Anton3, Mohammad Katshu4, Mohan Rathnaiah4, Andrew Peters1, Ian Macdonald2, Stephen Williams5, Bill Deakin3, Peter Liddle4, and Peter Gordon Morris1 1Sir Peter Mansfield Imaging Centre, The University of Nottingham, Nottingham, United Kingdom, 2School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom, 3Neuroscience and Psychiatry Unit, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom, 4Institute of Mental Health, The University of Nottingham, Nottingham, United Kingdom, 5Centre for Imaging Science, University of Manchester, Manchester, United Kingdom Human 13C MRS has recently shown its further potential in understanding neurological disorders. In the field of schizophrenia, 1H MRS has been applied with findings of abnormal concentrations of glutamate ﴾Glu﴿ and glutamine ﴾Gln﴿ in anterior cingulate cortex ﴾ACC﴿. It is therefore of interest to measure glutamate metabolism with 13C MRS in this brain region to get deeper understanding of these changes. In the present study, we applied localized 13C MRS at 7T upon [1-13C]glucose infusion, using a 13C/1H volume coil and polarisation transfer (DEPT) to test the feasibility of measuring glutamate turnover in ACC.

 1304 Iterative Reconstruction of 23Na Multi-Channel Breast Data Using Compressed Sensing Combined with Anatomical 1H Prior Knowledge Sebastian Lachner1, Olgica Zaric2, Matthias Utzschneider1, Lenka Minarikova2, Stefan Zbyn3, Bernhard Hensel4, Siegfried Trattnig2, Michael Uder1, and Armin M. Nagel1,5 1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 3Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, 4Center for Medical Physics and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 5Division of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), Heidelberg, Germany An iterative reconstruction algorithm for sodium magnetic resonance imaging (23Na MRI) with multi-channel receiver coils is implemented and compared to a conventional gridding reconstruction. Based on compressed sensing (CS) it utilizes a total variation (TV(2)), combined with anatomical weighting factors (AnaWeTV(2)) to preserve known tissue boundaries. Simulated and measured 23Na multi-channel data sets of the female breast were reconstructed. The TV(2) and in particular the AnaWeTV(2) lead to an improved image quality, due to effective noise reduction and the highlighting of structure. The presented CS reconstruction is beneficial especially for high undersampling factors.

### MRS/MRSI Reconstruction & Quantification

 Exhibition Hall 1305-1335 Monday 8:15 - 10:15

 1305 Evaluation of different postprocessing-based B0 inhomogeneity correction methods for application in 7T FID-MRSI Stanislav Motyka1, Philipp Moser1,2, Bernhard Strasser3, Lukas Hingerl1, Michal Považan4,5, Gilbert Hangel1, Eva Heckova1, Stephan Gruber1, Siegfried Trattnig1,2, and Wolfgang Bogner1 1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 4Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States The information from B0 maps can be used to improve the spectral quality in MRSI. Two post-processing methods, SPREAD and odMRSI, were implemented and evaluated on: i) simulation model, ii) phantom data, and iii) high-resolution in vivo data acquired by 2D FID-MRSI with CAIPIRINHA acceleration at 7T. Both methods were capable to improve the spectral quality, however, the SPREAD only in high SNR situations which are not present in clinical reality. The spectral quality improvement brought by odMRSI was equivalent to the averaging of 6 averages but this improvement could not be directly translated into the same metabolic map quality.

 1306 MOSAIC - a generalized multi-channel coil combination for 1H-MRSI via interleaved calibration scans Philipp Moser1,2, Bernhard Strasser3, Lukas Hingerl1, Michal Považan4,5, Gilbert Hangel1, Eva Heckova1, Stephan Gruber1, Siegfried Trattnig1,2, and Wolfgang Bogner1 1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 4Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States The optimal combination of signals from all receive elements is a prerequisite in MRSI especially at high field (≥7T), not only for SNR-efficient acquisition, but also for good parallel imaging reconstruction [1,2]. Phantom and in vivo experiments showed superior performance of MOSAIC including higher SNR, smaller FWHM and anatomically detailed metabolic maps compared to Brown and WSDV coil combination. MOSAIC is a flexible and robust approach for efficient MRSI coil combination under challenging conditions (B0≥7T, many coil elements, no reference coil, low SNR, possible spectral artifacts, motion/instability related artifacts, 1st-order phase error), especially with an outlook on parallel-imaging non-Cartesian MRSI.

 1307 3D EPSI Hadamard spectral editing of GABA and GSH at 7T Vincent Oltman Boer1, Nam Gyun Lee1, Anouk Marsman1, and Esben Thade Petersen1,2 1Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2Center for Magnetic Resonance, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark A 3D MRSI sequence was developed for simultaneous editing of GABA and GSH using a Hadamard editing scheme at 7T. 3D MRSI was performed using a 1D echo planar spectroscopic readout (EPSI). Volume selection was perfomed using a sLASER volume selection box using adiabatic refocusing pulses.

 1308 Dictionary-Learning Compressed Sensing Reconstruction for an Anisotropic 3D Density-Adapted Radial Acquisition Sequence Matthias Utzschneider1,2, Nicolas G. R. Behl 3, Sebastian Lachner1, Andreas Maier2,4, Michael Uder1, and Armin M. Nagel1,3 1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 3Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Erlangen Graduate School in Advanced Optical Technologies, Erlangen, Germany Sodium magnetic resonance imaging requires dedicated acquisition techniques and reconstruction approaches due to the low in-vivo signal and ultra-short relaxation times. For this purpose a compressed sensing reconstruction technique using dictionary learning is applied to raw data acquired with an anisotropic 3D density-adapted radial acquisition sequence. The anisotropic acquisition allows an adjustment of projections in different directions to increase the in-plane resolution. In the following evaluation the possible benefits of the compressed sensing reconstruction using the increased in-plane resolution are shown for in-vivo sodium magnetic resonance imaging and quantification of 23Na.

 1309 Accelerated in vivo Phosphorus Magnetic Resonance Spectroscopic Imaging combining flyback-EPSI and Compressed Sensing Alejandro Santos Diaz1 and Michael Noseworthy1,2 1School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada, 2Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada Long acquisition time is still a major limitation in performing clinical 31P MRSI studies. To overcome this limitation we implemented and tested a pulse sequence that combines flyback EPSI readout and compressed sensing (CS). Our results, in human skeletal muscle, show the feasibility of performing 31P MRSI using this combined approach.

 1310 Optimization of Radial Echo Planar Spectroscopic Image Reconstruction for Hyperpolarized [1-13C]-Pyruvate Imaging Joshua Niedzielski1, Chang-yu Sun1, Keith Michel1, Christopher Walker1, Samuel Einstein1, and James Bankson1 1Imaging Physics, Univ. of Texas-MD Anderson Cancer Center, Houston, TX, United States Radial echo planar spectroscopic imaging (EPSI) is an efficient method for imaging hyperpolarized (HP) substrates. However, symmetric data sampling between even/odd echo components can lead to ghost artifacts that can interfere with spectral undersampling strategies that enhance SNR. The purpose of this study was to optimize the acquisition and reconstruction of a symmetric radial EPSI sequence for dynamic HP [1-13C]-pyruvate imaging. In this work, we show that the generalized Fourier transform technique preserves spectral bandwidth, reduces ghost and aliasing artifacts, and improves SNR compared to alternative strategies that separately consider even and odd echo subsets.

 1311 In vivo validation of OVS-localized navigator for prospective frequency correction in MRSI Chu-Yu Lee1, In-Young Choi1,2,3, and Phil Lee1,3 1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, United States, 2Department of Neurology, University of Kansas Medical Center, Kansas City, KS, United States, 3Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States Data acquisition for MRS and MRSI requires a stable scanner frequency during the relatively long scan time. However, gradient heating and subject motion during the scan result in drifts of the scanner frequency. The effects of frequency drifts include reduced SNR, broad linewidth, and errors in spatial encoding and metabolite quantification. We had recently proposed a new navigator approach: outer volume suppression (OVS)-localized navigator, to prospectively correct frequency drifts without introducing SNR losses, overcoming the shortcomings of previous PRESS-localized navigator. The purpose of this study is to validate the OVS-localized navigator approach through the comparison with non-localized navigator and the quantitative evaluations of spectral quality and metabolite concentrations in 10 healthy subjects.

 1312 Reconstruction of motion affected prostate MRSI data using navigators and compressed sensing Rashmi Reddy1, Ryan Kalmoe2, Greg Metzger2, and Sairam Geethanath1,3 1Dayananda Sagar Institutions, Bangalore, Karnataka, India, 2Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 3Department of Radiology, Columbia University Medical Centre, New York, NY, United States This work focuses on reconstruction of 2D prostate in vitro and in vivo MRSI data. Motion affected phase encodes are tracked using a free induction decay navigator. The proposed work utilizes Compressed Sensing (CS) reconstruction technique to compensate for the loss of motion affected information. Comparison between data without motion considered as ground truth (GT) is performed with data with motion and CS reconstructed data. Qualitative and quantitative performance measures indicate improvement in spectral quality with the application of the navigator led CS MRSI reconstruction. Current and future work involves the application of this method on an increased sample size.

 1313 Quantitative evaluation of systematic bias in clinical MRS introduced by the use of metabolite basis sets simulated with ideal RF pulses Maike Hoefemann1, Jan Willem van der Veen2, and Roland Kreis1 1Depts. Radiology and Biomedical Research, University of Bern, Bern, Switzerland, 2NIH, NIMH, Magnetic Resonance Spectroscopy Core, Bethesda, MD, United States The purpose of this study was to quantitatively evaluate biases caused by the use of ideal PRESS simulations. Metabolite basis spectra were simulated for an ideal PRESS sequence as well as with real shaped RF-pulses. Theoretical ground truth spectra were constructed for different TE and shim settings. They were fitted using both basis sets. It is shown that the fitting accuracy decreases when using ideal simulations and they depend on TE and metabolite. Therefore, simulation of basis sets should include the effects of the real pulse shapes even for the presented case of short TE and fairly large B1 amplitude.

 1314 Toward Absolute Quantification Using External Reference Standards at 3T and 9.4T Andrew Martin Wright1,2, Sahar Nassirpour1,2, Paul Chang1,2, and Anke Henning1,3 1Biological Cybernetics, Max Planck Institute, Tübingen, Germany, 2IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tübingen, Tübingen, Germany, 3Institute of Physics, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany Absolute quantification is a challenge with many paths to reach the final goal of quantifying metabolites in absolute units (e.g. Molarity and molality). Utilizing an external reference standard (ERF) is an attractive method for quantifying in vivo metabolites due to the ability for direct comparison between a known concentration of a metabolite and the in vivo data. A major concern in utilization of an ERF is the differences in coil loading between in vivo and in vitro measurements. To that end, this work describes a method to calibrate and adjust the transmitter voltage in order to maximize signal detection independently of coil load.

 1315 On the exploitation of slow macromolecular diffusion for baseline estimation in MR spectroscopy using 2D simultaneous fitting André Döring1, Victor Adalid1, Chris Boesch1, and Roland Kreis1 1Depts. Radiology and Biomedical Research, University of Bern, Bern, Switzerland The slow diffusivity of macromolecules was exploited in 2D signal modeling with FiTAID to estimate the macromolecular baseline in MRS of human brain. Two approaches were used for baseline modeling: (i) a predefined model derived from high-field and T1-based baseline determination and (ii) a model-free description by equally spaced Voigt resonances. Inspection of fit residues and comparison with literature reveals that the second model is more appropriate.

 1316 Simultaneous modeling of sum and difference spectra improves quantitative outcomes for edited MRS Daniel Luc Rimbault1, Georg Oeltzschner2,3, Ali Alhamud1,4, Ernesta Meintjes1,4, and Richard A. E. Edden2,3 1Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa, 2Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 4Cape Universities Body Imaging Centre (CUBIC-UCT), Cape Town, South Africa J-difference-edited MR spectroscopy allows for the detection of several low-concentration compounds at 3T, but suffers from long acquisition times. Multiplexed editing experiments provide simultaneous detection of two or three metabolites by differentially modulating the spin systems of interest, and separating edited signals into distinct sum or difference spectra. For a novel multiplexed experiment (HERCULES), with simulated metabolite basis functions we demonstrate that simultaneously modeling the sum and difference spectra results in comparable metabolite levels with lower coefficients of variation, compared to separate modeling of the sum and difference spectra.

 1317 The Effect of  B0 and B1+ Inhomogeneities on Spinal Cord MRS Nicholas Maurice Simard1, Aimee J Nelson2, and Michael D. Noseworthy1,3 1School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada, 2Department of Kinesiology, McMaster University, Hamilton, ON, Canada, 3Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada Spinal cord 1H MR Spectroscopy (1H-MRS) is a promising method for musculoskeletal research. However, due to the spine’s anatomical location there is a significant degradation of signal quality due to magnetic field inhomogeneities, rendering most MRS approaches inaccurate. Although there has been measurement of ΔB0 in spinal cord MRS, there are no comprehensive assessments of temporal changes in B0 and B1+ relating physiological disturbances with MRS accuracy. Thus our goal was to continually measure temporal changes in B0 and B1+ during the length of a typical MEGA-PRESS scan (10min).

 1318 Quantification of Glutamate and Glutamine in the healthy brain via 1H in-vivo CSI MRS using LCModel is not reliable. Simon Maennlin1, Rupert Kolb1, Anja Stierl1, and Uwe Klose1 1Departement of Diagnostic and Interventional Neuroradiology, University Hospital Tuebingen, Tuebingen, Germany Glutamate and glutamine play an important role in CNS. Both are quantifiable via 1H in-vivo MRS, although a correct, separate quantification of both metabolites is often very challenging. In this study, 1H in-vivo CSI MRS was performed on ten healthy subjects, using the CSI sequences PRESS and Semi-LASER with TE=40ms,60ms,80ms,100ms and 135ms at 3T. The inner 64 spectra of each CSI matrix at each TE were averaged to a single spectrum. Averaged spectra were analysed using LCModel. The quantification of glutamate and glutamine, using this method, which is also a popular approach in MRS research, was shown to be inconsistent.

 1319 Novel methodology for processing, quality assessment, and artifact mitigation of raw 2D Correlation Spectroscopy data Laura J Mariano1, Marcia Sahaya Louis2, Benjamin Rowland3, Huijun Liao4, Kristin Heaton5, John Irvine1, and Alexander P Lin3,6 1The Charles Stark Draper Laboratory, Inc., Cambridge, MA, United States, 2Electrical and Computer Engineering, Boston University, Boston, MA, United States, 3Center for Clinical Spectroscopy, Brigham and Women's Hospital, Boston, MA, United States, 4Psychiatric Neuroimaging Laboratory, Brigham and Women's Hospital, Boston, MA, United States, 5US Army Institute of Environmental Medicine, Natick, MA, United States, 6Harvard Medical Institute, Boston, MA, United States 2D Correlation Spectroscopy (COSY) can be used to identify and study coupled resonances that cannot be observed or distinguished in 1D NMR spectra. However, resources and literature on best practices for processing raw 2D COSY data are limited. In this work, we describe a novel pipeline of signal processing algorithms and visualizations for quality assessment and artifact mitigation designed specifically for raw 2D COSY data, including detection of residual H2O and lipid contamination, correction for drift across averages, and peak location correction to enable more accurate comparisons of metabolites across subjects.

 1320 NMRScopeB – an open-source simulator for metabolite quantitation and pulse sequence development Zenon Starčuk1 and Jana Starčuková1 1Magnetic Resonance and Cryogenics, Institute of Scientific Instruments of the CAS, Brno, Czech Republic The architecture and function of the release version of a spectroscopic simulator NMRScopeB is described. It includes the jMRUI-related GUI and an open-source calculation server communicating with the kernel via sockets. While standard metabolite set simulations needed for quantitation by jMRUI or LCModel can be prepared in a few steps, more complex research task can be handled as well. The operation is described by control and data flow charts. After a period of beta-testing, the simulator is released as part of the recent jMRUI package.

 1321 Implications of magnetic susceptibility difference between grey and white matter for spectroscopy quantification at 7T. Donghyun Hong1, Jack JA van Asten2, Seyedmorteza Rohani Rankouhi1, Jan-Willem Thielen1, and David G. Norris1,3 1Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany, 2Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, Netherlands, 3Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, Netherlands Magnetic susceptibility differences between grey matter (GM) and white matter (WM) can potentially affect lineshapes and chemical shifts in single voxel spectroscopy. Hitherto, analytical techniques such as LCModel assumed a single lineshape per voxel. Separated GM and WM signals using multi-echo GRE image sequence in combination with literature values for the metabolite distribution between GM and WM enable to construct a realistic basis set for LCModel. With this information we can test how magnetic susceptibility induced lineshape modification affects metabolic quantification, which uses spectral prior knowledge.

 1322 Spectral denoising for MR Spectroscopy using orthogonal polynomials Mathieu Naudin1,2,3, Benoit Tremblais1, Carole Guillevin2, Rémy Guillevin2, and Christine Fernandez-Maloigne1 1Univ. Poitiers, XLIM, CNRS UMR 7252, Poitiers, France, 2Univ. Poitiers, LMA, CHU Poitiers, CNRS UMR 7348, Poitiers, France, 3Siemens Healthineers, Saint-Denis, France We propose a new methodology to denoise MRS spectrum with a focus on the acquisition time diminution. Using a discrete orthogonal polynomials, we detect two types of areas : homogenous and non-homogenous (metabolite peaks). Once these areas detected, we compute the Noise Level Function (NLF). Then, using the NLF, we use orthogonal polynomials to reconstruct a signal with a strategy for each type of area. As results, a denoising method is provided and it helps to correct the noise due to the acquisition time diminution with a good metabolite peaks conservation.

 1323 Metabolite quantitation using water-scaling corrected with Magnetic resonance fingerprinting Ryan J Larsen1, Joseph L. Holtrop1,2, and Brad P. Sutton1,2 1Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States Quantitation of MRSI data using water-scaling requires correction of the water signal for relaxation and CSF partial volume effects. We demonstrate the use of a rapid MRF sequence to characterize the water signal used to quantify MRS data, which we call WAter-scaling Quantification using MRF (WAQ-MRF) scan.  WAQ-MRF provides subject-specific corrections of partial volume and relaxation effects for water-scaled data. By adding a one minute scan to a standard MRSI acquisition it is possible to eliminate the need for assuming literature values of relaxation and proton density to correct the water signal.

 1324 Spectral Quantification for Multiple-TE Spectroscopy Using Spectral Priors and Measured Lineshape Distortion Function Fan Lam1, Yudu Li1,2, and Zhi-Pei Liang1,2 1Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States This work presents a new method for quantifying multiple-TE/two-dimensional spectroscopy data, characterized by the use of spectral priors obtained by quantum mechanical simulations and an experimentally measured lineshape distortion function derived from a set of multi-TE water spectroscopic data. Results from in vivo J-resolved spectroscopy data demonstrated the excellent fitting produced by the proposed method, and improved robustness over a standard parametric-model-based method. With further developments, such as extensions to different sequences and Cramer-Rao bound analysis, the proposed method should prove useful for a range of 2D spectroscopy experiments.

 1325 Classification of brain tumors by 1H MRSI and MRI using convolutional neural networks Jacopo Acquarelli1,2, Arend Heerschap3, Geert J. Postma2, Twan van Laarhoven1, Jeroen J. Jansen2, Elena Marchiori1, and Lutgarde M.C. Buydens2 1Data Science, Radboud University Nijmegen, Nijmegen, Netherlands, 2Analytical Chemistry, Radboud University Nijmegen, Nijmegen, Netherlands, 3Radiology and Nuclear Medicine, Radboud University Nijmegen, Nijmegen, Netherlands Several machine learning approaches have been used to classify brain tumors using MR images and spectra. Here we explore the specific properties of convolutional neural networks (CNN) for this task. We designed a CNN that could be trained on combined MR image and spectroscopic image data by exploiting their specific properties (spatial and spectral locality). Using a ‘leave-one-out’ validation, we demonstrate that our method outperforms state-of-the-art classification methods to distinguish tumor grades. These results demonstrate that CNNs are a powerful approach for tumor classification using MRSI data.

 1326 Highly Accelerated Simulation of Model Spectra for TE-Averaged Spectral Fitting Yan Zhang1 and Jun Shen1 1National Institute of Mental Health, Bethesda, MD, United States One-dimensional projection method was applied to the simulation of spatially localized J-resolved magnetic resonance spectroscopy with real RF pulses. As a comparison, the same pulse sequence was simulated using non-localized ideal RF pulses. The resultant TE-averaged spectra of glutamate were compared with phantom experiment at 3T. Conspicuous differences between ideal pulse simulated spectrum and phantom spectrum were found. For vivo comparisons, metabolite quantification was performed with real RF pulse basis set and ideal pulse basis set, respectively. Real RF pulse generated basis set significantly improved the reproducibility of glutamate quantification in vivo.

 1327 How does inclusion of different macromolecular baseline models affect reproducibility of 1H-FID MRSI in the brain at 7T? Eva Heckova1, Ursel Antpusat1,2, Michal Považan3,4, Bernhard Strasser5, Gilbert Hangel1, Lukas Hingerl1, Philipp Moser1, Stephan Gruber1, Siegfried Trattnig1,6, and Wolfgang Bogner1,6 1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Hamm-Lippstadt University of Applied Sciences, Hamm, Germany, 3Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 5Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 6Christian Doppler Laboratory for Clinical Molecular Molecular MR Imaging, Vienna, Austria The goal was to investigate how the use of different macromolecular baseline models affects both the accuracy and test-retest reproducibility of metabolite quantification for clinically attractive FID-MRSI scan with in-plane resolution of 3.4 x 3.4 mm2 and acquisition time of 5 min. We confirmed that our 1H-FID-MRSI sequence provides information about abundance and spatial distribution of several neurometabolites with high accuracy. Including the information about the macromolecular background into the quantification process does not decrease its reproducibility.

 1328 Highly Accelerated (R=14) Water Reference Acquisition for High Resolution 1H MRSI using Compressed Sensing Paul Chang1,2, Sahar Nassirpour1,2, and Anke Henning1,3 1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tuebingen, Tuebingen, Germany, 3Department of Physics, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany In this study, the acquisition of a high resolution (64x64) water reference MRSI data is accelerated by a factor of R=14 using compressed sensing. The results show that this highly accelerated water reference can reliably be used for eddy current and phase correction purposes, as well as internal referencing and quantification. This enables the acquisition of the high resolution water reference MRSI data in 80 seconds at 9.4T.

 1329 MRF in Single Voxel Spectroscopy: Signal to Noise Ratio or Dictionary Length - Which is more important? Alexey Kulpanovich1 and Assaf Tal1 1Weizmann Institute of Science, Rehovot, Israel We use MR spectroscopic fingerprinting (MRSF) to quantify T1,T2 and concentration addressing the tradeoff between fingerprint lengths and averaging. Methods. MRSF using 25, 50 and 100 fingerprint lengths were compered to inversion recovery (IR) and multi-TE using Monte-Carlo simulations and in-vivo experiments. Bias and variance were estimated for NAA, Creatine and Choline. Results. Simulations of all MRSF sequences show better accuracy and bias over IR. In-vivo experiments show improved T1 and concentration estimation. Conclusion. The low SNR emphasizes the tradeoff between fingerprint length and averaging. The In-vivo results show clear advantage using shorter fingerprint and increasing the SNR.

 1330 Estimation of T2 Relaxation Times of Downfield Peaks in Human Brain at 9.4 T Saipavitra V. Murali Manohar1, Tamas Borbath1, Nicole Fichtner2,3, Ioannis Angelos Giapitzakis1, Daniel Zaldivar1, Roland Kreis3, and Anke Henning1,4 1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Institute for Biomedical Engineering, UZH and ETH Zurich, Zurich, Switzerland, 3Depts. Radiology and Biomedical Research, University of Bern, Bern, Switzerland, 4Institute of Physics, Ernst-Moritz Arndt University Greifswald, Greifswald, Germany T2 relaxations times for the downfield metabolites in human brain 1H MR spectra were estimated at 9.4 T. A possible new peak at 8.35 ppm with rapid T2 decay is reported. Due to the use of a non-water suppressed MRS method, the T2 of slowly exchanging peaks could be assessed. The shorter T2 relaxation times in the downfield compared to the upfield spectral areas leads us to suspect a macromolecular contribution, while also exchange effects may contribute to the short apparent T2s.

 1331 Multivariate Analysis of Developmental-Dependent Differences in Metabolites in White and Gray Matter: An Ultra-Short TE 1H MRS Study at 3T Jack Knight-Scott1 1Radiology, Children's Healthcare of Atlanta, Atlanta, GA, United States Application of multivariate analysis of variance (MANOVA) to a developmental data set of 1H spectra from white and gray matter brain tissue shows not only significant tissue differences but also significant gender and age differences. By specifically controlling for metabolite correlations, MANOVA results show higher sensitivity and power than individual ANOVAs.

 1332 A comparison of reference-based methods for removing artifacts in non-water-suppressed 1H MRSI data Zhengchao Dong1,2, Feng Liu1,2, Min Li2,3, Matthew Milak2, and Sachin Jambawalikar4 1New York State Psychiatric Institute, New York, NY, United States, 2Psychiatry, Columbia University, New York, NY, United States, 3Collage of Internet of Things, Hohai University, Changzhou, China, 4Radiology, Columbia University, New York, NY, United States Sideband artifacts is the major obstacle to 1H MRSI without water suppression. To remove the sideband artefacts, several reference-based methods have been proposed, in which the reference signals are acquired from a water phantom with identical experimental parameters as those of in vivo scan are acquired. The reference-based methods do not suffer scan time penalty and they are compatible with any accelerated sequences such as SENSE-SI. The aim of the present work is to improve and compare the performance of two kinds of reference-based methods, namely, the phase compensation method and the artifact subtraction method.

 1333 Conditions for extracting statistical descriptors from MR spectra characteristic of heterogeneous materials such as biological tissue Norbert W Lutz1 and Monique Bernard1 1CRMBM, Aix-Marseille University, Marseille, France Materials such as biological tissue are often characterized by considerable heterogeneity. This can manifest itself in significant variability of certain physicochemical parameter values across the measured volume. If the chemical shift of a particular MR resonance varies systematically with such a parameter, the resulting lineshape can be used to quantitatively characterize the heterogeneity with respect to this parameter. This is achieved by transforming the MRS lineshape into a curve representing the statistical distribution of the parameter values in question, followed by the derivation of a histogram. We study here two important conditions for the statistical evaluation of such spectrum-derived histograms.

 1334 Effects of non-linearity correction on statistical descriptors of pH heterogeneity, obtained from 3-APP and inorganic phosphate resonances of tumor 31P MR spectra Norbert W Lutz1 and Monique Bernard1 1CRMBM, Aix-Marseille University, Marseille, France We recently presented a method for extracting statistical descriptors of pH heterogeneity from  lineshapes of pH-sensitive 31P MRS resonances. The first step in this analysis is the conversion of the resonance in question into the corresponding pH profile. The latter is then corrected for non-linearity between chemical shift and pH. However, this procedure is insufficient since the unequal spacing of the digital points making up such pH profiles needs to be compensated for by appropriate weighting. Exact statistical descriptor values are of importance in quantification of tissue pH heterogeneity, an issue that has received major attention in recent cancer research.

 1335 Restoration of truncated FID by machine learning Hyochul Lee1 and Hyeonjin Kim1,2 1Department of Biomedical Sciences, Seoul National University, Seoul, Republic of Korea, 2Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea The potential applicability of a recurrent neural network (RNN) in the reconstruction of spectra from truncated FIDs was explored. A RNN was trained on a set of simulated full FIDs with varying metabolite concentrations. Then, the performance of the trained RNN was tested on severely truncated FIDs (~95% truncation). Our preliminary study suggests that RNNs may be used in the restoration of truncated FIDs and thus reconstruction of spectra including tiny multiplets. A well trained RNN may be applicable to the situations where data sampling is highly limited such as in cardiac MRS and spectroscopic magnetic resonance fingerprinting (sMRF).

### Spectroscopy: NMR & Other

 Exhibition Hall 1336-1345 Monday 8:15 - 10:15

 1336 Time-domain EPR imaging with slice selection Ayano Enomoto1, Ken-ichiro Matsumoto2, Shun Kishimoto1, Shingo Matsumoto3, Murali C Krishna1, and Nallathamby Devasahayam1 1National Cancer Institute, National Institutes of Health, Bethesda, MD, United States, 2Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, Chiba, Japan, 3Graduate school of Information Sicence and technology, Hokkaido University, Sapporo, Japan The slice selection imaging has advantages of reducing imaging time and obtaining optimum dynamic range in image for EPR imaging as well as for MRI. However, the slice selection using a selective pulse, which is used in MRI, is difficult to implement in EPR imaging because of ultra-fast relaxation time compared to gradient settling time. Therefore, we used a modulated gradient field to achieve slice selection in pulsed EPR imaging in this study. We demonstrated the slice selection imaging with tubes and a living mouse to show the effect of slice selection in pulsed EPR imaging.

 1337 Metabolic characteristics of oncogenically transformed mouse neural progenitor cells using one dimensional 1H NMR Magretta Adiamah1, Liam Mistry2, Andrew Houlton2, Elizabeth Stoll3, and Ross Maxwell4 1Northern Institute for Cancer Research, Newcastle University, Newcastle, United Kingdom, 2School of Natural and Environmental sciences, Newcastle University, Newcastle, United Kingdom, 3Institute of Neuroscience, Newcastle University, Newcastle, United Kingdom, 4Northern Institute for cancer research, Newcastle University, Newcastle, United Kingdom Metabolic profiles of oncogenically transformed neural progenitor cells (NPCs) derived from 3 and 12 month old mice were evaluated using one dimensional 1H NMR spectroscopy. Principal component analysis revealed two distinct clusters which corresponded to the differently-aged NPCs. Metabolites identified in these cell lines were similar but differed in their relative abundance. The 3 month NPCs were characterised by high lipid CH2, creatine and choline. The metabolic signature of 12 month NPCs featured high levels of taurine, myo-inositol and branched-chain amino acids. This data suggests alterations in metabolic phenotype of aged NPCs which may arise from differences in enzymatic capacity.

 1338 Gene Expression Profiling to Understand the 1H MRS Characterization of the VEGF Metabolic Secretome from a Triple Negative Human Breast Cancer Xenograft Santosh Kumar Bharti1, Balaji Kirshnamachary1, Louis Dore-Savard2, Brett Stark1, Aleksander S. Popel3, and Zaver M Bhujwalla1,4 1Division of Cancer Imaging Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 2McGill University Health Centre and RI-MUHC, Montreal, QC, Canada, 3Systems Biology Laboratory, Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 4Department of Oncology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States Vascular endothelial growth factor (VEGF A) is a potent regulator of angiogenesis, invasion, and metastasis, especially in breast cancer. Secreted VEGF that forms a part of the interstitial milieu along with other metabolites shapes the microenvironment. Here, using 1H MR spectroscopy and microarray, we have characterized the metabolic and gene signature of the tumor tissue derived from MDA-MB-231 cells that stably overexpressed VEGF gene. Metabolic changes supported by gene array data provide new insight into the role played by VEGF in breast cancer progression

 1339 1H MRS Reveals Major Changes in Brain Metabolites Induced by Human Pancreatic Cancer Xenografts Santosh Kumar Bharti1, Paul T Winnard Jr.1, Yelena Mironchik1, Marie-France Penet1, Anirban Maitra2, and Zaver M Bhujwalla1,3 1Division of Cancer Imaging Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 2Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 3Department of Oncology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States Our ongoing efforts are focused on understanding systemic metabolic changes that occur during cancer-induced cachexia using human pancreatic ductal adenocarcinoma (PDAC) xenografts, since the syndrome occurs with the highest frequency and severity in PDAC. We used 1H MRS to analyze brain metabolite levels in mice with and without cachexia inducing human PDAC xenografts. Spectra revealed depletion of several metabolites, including neurotransmitters, in cachectic mice. These findings provide new insights into disruption of brain metabolism that may compromise central nervous system (CNS) function. Identifying alterations of brain metabolism may provide novel interventions to prevent or reduce CNS injury and cachexia.

 1340 Effect of sampling method on HR-MAS NMR spectra of caprine brain biopsies Annakatrin Häni1, Gaelle Diserens2, Anna Oevermann3, Peter Vermathen2, and Christina Precht1 1Department of Clinical Veterinary Medicine, University of Bern, Bern, Switzerland, 2DBMR, University of Bern, Bern, Switzerland, 3DCR-VPH, University of Bern, Bern, Switzerland Metabolic profiling of tissue biopsies using HR-MAS NMR has potential diagnostic and prognostic value, but alterations in the biochemical profile due to factors such as sampling method may lead to misinterpretation. Therefore we investigated the effect of two different sampling methods in normal caprine brain tissue, in vivo sampling by stereotactic biopsy and direct post mortem surgical sampling. We found significant differences between the two biopsy types with elevated lactate and creatine, and altered choline-containing compounds. We conclude that metabolite alterations depend on sampling methods and suggest the use of in vivo biopsy in animal models.

 1341 13C-NMR to study cancer cell metabolic plasticity following PDK inhibition. Influence of dichloroacetate and long-term exposure to acidic environment on glucose and glutamine metabolic pathways. Céline Schoonjans1, Nicolas Joudiou1, Cyril Corbet2, Olivier Feron2, and Bernard Gallez1 1Biomedical Magnetic Resonance Group (REMA), Louvain Drug Research Institute, Catholic university of Louvain, Bruxelles, Belgium, 2Pharmacotherapy Group (FATH), Institute of Experimental and Clinical Research, Catholic university of Louvain, Bruxelles, Belgium Many cancer cells present an exacerbated glycolytic flux that provides advantage for growth and leads to extracellular acidosis. Dichloroacetate (DCA), a PDK inhibitor, shifts metabolism from glycolysis to glucose oxidation and decrease various cancer cells lines proliferation. However, as tumor cells are presenting metabolic plasticity, PDK inhibition may lack efficacy. To measure metabolic adaptations of cancer cells to acidic environment and in response to DCA, we studied metabolic fluxes using 13C-NMR spectroscopy. With this technology, we measured differences in metabolic profiles between parental cancer cells line and acidic clones and we quantified specific changes in metabolism following DCA treatment.

 1342 Non-invasive mapping  of glutathione levels in mouse brains by electron paramagnetic resonance (EPR) imaging Miho C Emoto1, Hirotada G Fujii1, and Hideo Sato-Akaba2 1Sapporo Medical University, Sapporo, Japan, 2Osaka University, Toyonaka, Japan Glutathione (GSH) is an important antioxidant that can protect cells under oxidative stress. Thus, a non-invasive method to measure GSH levels in live animals is needed. To map the levels of GSH in mouse brains, a new method using electron paramagnetic resonance (EPR) imaging with nitroxide imaging probes was developed. By analyzing the relationship between reduction rates for nitroxides in brains measured by EPR and brain GSH levels measured by biochemical assay, pixel-based mapping of brain GSH levels was successfully obtained. The newly developed method was applied to a kindling mouse model of epilepsy to clarify the role of GSH.

 1343 Comparing the Reproducibility of Commonly Used Magnetic Resonance Spectroscopy Techniques to Quantify Cerebral Glutathione at 3 T Andrea Wijtenburg1, Jamie Near2, Stephanie Korenic1, Frank Gaston1, Hongji Chen1, Mark Mikkelsen3,4, Robert McMahon1, Peter Kochunov1, Elliot Hong1, and Laura Rowland1,5 1Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States, 2Centre d’Imagerie Cérébrale, Douglas Mental Health Institute, Montreal, QC, Canada, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 5Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States Cerebral glutathione (GSH), a marker of oxidative stress processes, has been quantified in neurodegenerative diseases and psychiatric disorders using proton magnetic resonance spectroscopy. However, no studies to date have compared the reproducibility of the most commonly used magnetic resonance spectroscopy techniques for GSH quantification. Here, we scanned ten healthy adults twice and acquired spectroscopic data using PRESS, PR-STEAM, SPECIAL, and MEGA-PRESS at 3 Tesla. We assess reproducibility via mean coefficients of variation (CV) and mean absolute difference (AD).

 1344 On spectrally selective measurements of irreversible and reversible transverse relaxation rates from single voxel, single echo time PRESS acquisitions Robert Mulkern1 and Mukund Balasubramanian1 1Radiology, Children's Hospital, Boston, Boston, MA, United States We developed a methodology to measure the reversible and irreversible transverse relaxation rates R2' and R2, respectively, of multiple spectral peaks from spectroscopic sampling of both sides of a single spin echo. The methodology was applied to resonances in muscle and brain and the irreversible relaxation rates R2 were compared with conventional measurements made from right side only spectra acquired at multiple PRESS echo times.

 1345 Aberrant Glutamatergic Neurotransmission in the Left Dorsolateral Prefrontal Cortex in Patients with Mild Cognitive Impairment: Preliminary Evidence from Task-Based Proton Magnetic Resonance Spectroscopy Anupa A Vijayakumari1, Bejoy Thomas1, Ramshekhar N Menon2, and Chandrasekharan Kesavadas1 1Imaging Sciences and Interventional Radiology, Sree Chitra​ Tirunal Institute for Medical Sciences and Technology, Trivandrum, India, 2Neurology, Sree Chitra​ Tirunal Institute for Medical Sciences and Technology, Trivandrum, India Much less is known about the changes in glutamate during working memory (WM) in patients with mild cognitive impairment (MCI).  In this study, we aimed to understand the glutamatergic response to functional activation in patients with MCI and healthy subjects (HS) during WM. The changes in glutamate were examined before, during, and after the WM task in both groups using point resolved spectroscopic sequence. We observed increased glutamate in HS during the task which was absent in MCI. This suggests the disruption in the glutamatergic neurotransmission, which may be a part of the underlying pathophysiology in MCI.

### MRS Human Applications

 Exhibition Hall 1346-1360 Monday 8:15 - 10:15

 1346 Tracking changes in glutamate using dynamic MRS in response to an acutely painful stimulus. Jessica Archibald1,2, Erin L Macmillan3,4,5, Carina Graf2,6, Cornelia Laule2,6,7, and John L.K Kramer1,2 1Kinesiology, University of British Colombia, Vancouver, BC, Canada, 2International Collaboration on Repair Discoveries (ICORD), Vancouver, BC, Canada, 3Radiology, University of British Colombia, Vancouver, BC, Canada, 4ImageTech Lab, SFU, Simon Fraser University, Vancouver, BC, Canada, 5Philips Healthcare Canada, Philips, Vancouver, BC, Canada, 6Physics and Astronomy, University of British Colombia, Vancouver, BC, Canada, 7Pathology and Laboratory Medicine, University of British Colombia, Vancouver, BC, Canada Current treatment and diagnosis of pain conditions are dependent on self-reported measures. The objective of this study was to establish the feasibility of determining changes in excitatory neurotransmitter concentrations (glutamate) in the anterior cingulate cortex (ACC) as an objective measure of pain using dynamic single voxel magnetic resonance spectroscopy (MRS). Glutamate levels can accurately be detected with this paradigm, although a general trend in relation to pain was not observed across subjects. This is the first study to report dynamic levels of glutamate in the ACC in relation to pain in healthy individuals using optimized MRS acquisition and processing methods.

 1347 Hippocampal metabolite changes in response to chronic corticosterone exposure: in vivo magnetic resonance spectroscopy at 9.4T Song-I Lim1,2,3, Kyu-Ho Song1, Chi-Hyeon Yoo1, Hyeon-Man Baek3, and Bo-Young Choe1 1The Catholic University of Korea College of Medicine, Seoul, Republic of Korea, 2Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea, 3Lee Gil Ya Cancer & Diabetes Institute, Gachon University School of Medicine, Incheon, Republic of Korea The purpose of the study is to investigate neurochemical changes in a mouse model using proton magnetic resonance spectroscopy. Animals received 1% of ethanol drinking water solution or 100μg/mL of corticosterone dissolved in 1% of ethanol drinking water for 4 weeks. MRS spectra were acquired at the end of the experiment. Mice that ingested corticosterone show elevated glutamate, glycerophosphocholine and taurine levels in the hippocampus compared with those shown by the control group. Increased corticosterone levels are considered a sign of stress or metabolic disturbance. Therefore we suggest that chronic corticosterone exposure can affect the hypothalamic-pituitary-adrenal dysregulation and neurochemical alteration.

 1348 [Asp], [Glu] and [NAA] changes following traumatic brain injury revealed by J-edited 1H MRS. Petr Menshchikov1,2, Natalia Semenova1,2,3, Andrei Manzhurtsev2,3, Maxim Ublinskii2,3, Ilya Melnikov2, and Tolib Akhadov2 1Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russian Federation, 2Clinical and Research Institute of Emergency Pediatric Surgery and Trauma, Moscow, Russian Federation, 3Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation For the first time new method based on MEGA-PRESS pulse sequence for simultaneous aspartate (Asp), glutamate (Glu) and N acetyl aspartate (NAA) cerebral in vivo concentrations quantification were used for monitoring important metabolic changes after severe traumatic brain injury. Revealed Glutamate and Aspartate decrease is associated with excititoxicity (rapidly release of Glu and Asp from vesicles). In addition, Asp reduction might result from reduced availability of Glu.[NAA], marker of neuronal activity, reduction may be associated with synthesis disruption due to reduction of major NAA precussor (Asp).

 1349 Magnetization transfer among non-aqueous species and between them and water in spinal cord Uzi Eliav1, Peter J. Basser2, and Gil Navon1 1School of Chemistry, Tel Aviv University, Tel Aviv, Israel, 2SQITS/NICHD, NIH, Bethesda, MD, United States Previous publications demonstrated that the intensity of white matter (WM) images of spinal cord stem from aqueous and non-aqueous protons (having a peak at 3.5ppm). The peak of the non-aqueous protons was analyzed to be a superimposition of signals with a distribution of T2* (10-1000μs). Questions unanswered by these studies are whether the peaks with short and long T2* exchange magnetization among themselves, and whether they transfer magnetization (MT) to water. In the present publication these questions are addressed by combining double quantum filtering with magnetization transfer. The results demonstrate exchange between non-aqueous species and between them and water.

 1350 Multi-channel signal combination algorithms for polyunsaturated fatty acids (PUFA) using multiple quantum coherence (MQC) MRS in breast cancer Vasiliki Mallikourti1, Sai Man Cheung1, Yazan Masannat2,3, Ehab Husain3,4, Steven D Heys2,3, and Jiabao He1 1University of Aberdeen, Aberdeen, United Kingdom, 2Breast Unit, Aberdeen Royal Infirmary, Aberdeen, United Kingdom, 3School of Medicine, University of Aberdeen, Aberdeen, United Kingdom, 4Pathology Department, Aberdeen Royal Infirmary, Aberdeen, United Kingdom Polyunsaturated fatty acid (PUFA) is associated with malignant transformation of breast cancer and can be extracted from overwhelming background signals using multiple quantum coherence (MQC) MRS. Since MQC loses half of the signal, SNR enhancement through effective combination of signals acquired from multi channel coils holds significant potential. Investigations so far focused on conventional brain MRS, with drastically different metabolites and cluttered appearance compared to MQC MRS in breast. We therefore acquired PUFA spectra from 17 fresh breast tumour specimens and a patient on a clinical 3T scanner, and current algorithms of adaptively optimised combination (AOC), S/N2, S/N, Signal evaluated.

 1351 Detection of acute changes in glutamate with MR Spectroscopy using an N-acetylcysteine challenge Ruth Tuura1, Geoffrey Warnock2, Alfred Buck2, Valerie Treyer2, Ralph Noeske3, and Michael Sommerauer2 1University Children's Hospital, Zurich, Switzerland, 2University Hospital, Zurich, Switzerland, 3GE Healthcare, Potsdam, Germany We examined acute changes in MRS-visible glutamate and glutamine after stimulation with N-acetylcysteine (NAC), since NAC reportedly decreases synaptic glutamate via activation of inhibitory metabotropic glutamate receptors. In 10 healthy adults, NAC significantly reduced Glx in the basal ganglia and prefrontal cortex. In the basal ganglia, the changes in Glx were driven by changes in Gln, suggesting that Gln might represent a proxy marker for synaptic glutamate. In the frontal lobe, the MEGAPRESS edited spectra showed greater sensitivity to changes in Glx than short TE PRESS or the edit OFF subspectra. Acute compartmental shifts in glutamate are detectable with MRS.

 1352 Characterizing altered glucose and glutamine metabolism in castration-resistant prostate cancer using high-resolution NMR Jinny Sun1, Renuka Sriram2, Robert Bok2, Romelyn Delos Santos2, Mark Van Criekinge2, Daniel Vigneron2, and John Kurhanewicz2 1UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA, United States, 2Department of Radiology and Biomedical Imaging, University of California, San Fracisco, San Francisco, CA, United States This study demonstrates significant increases in flux through aerobic glycolysis, oxidative phosphorylation, and glutaminolysis with development of therapeutic resistance to androgen deprivation therapy using patient-derived cell lines and a transgenic murine model. Based on these metabolic differences between androgen-sensitive and insensitive prostate cancer, a combination of hyperpolarized [1-13C]pyruvate, [2-13C]pyruvate and  [5-13C]glutamine can be used to noninvasively predict therapeutic resistance in future patient studies using HP 13C MRI.

 1353 Increase in Glutamate concentration during motor activation measured using functional Magnetic Resonance Spectroscopy (fMRS) at 3T. Osnat Volovyk1 and Assaf Tal1 1Chemical Physics, Weizmann Institute of Science, Rehovot, Israel In the presented study we've demonstrated that small changes in Glutamate concentration associated with performing simple motor task can be reliably detected with 3T system using functional 1H MR spectroscopy. Comparison between two differently timed paradigms for motor activation revealed a clear preference for longer-block designs.  This suggests that motor activity-induced changes in Glutamate concentration are of minutes-long time-scale.

 1354 A 1H/31P MRS study of ATP and GABA modulation induced by anodal transcranial direct current stimulation in primary motor cortex of healthy subjects Harshal Jayeshkumar Patel1, Chang-Hoon Choi2, N. Jon Shah2,3, and Ferdinand Binkofski1,2 1Division of Clinical Cognitive Sciences, Department of Neurology, RWTH Aachen University Hospital, Aachen, Germany, 2Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich GmbH, 52425, Juelich, Germany, 3Faculty of Medicine, Department of Neurology, RWTH Aachen University, JARA, Aachen, Germany Transcranial direct current stimulation (tDCS) modulates cerebral energy and cortical inhibition. In this study we investigated long-term effects of anodal stimulation on inhibitory neurotransmitter and energy phosphate concentration using proton and phosphorous magnetic resonance spectroscopy. Our results indicate immediate GABA reduction following anodal tDCS and further maintaining the decreased state until the end of the experiment. ATP/Pi and PCr/Pi show initial reduction following anodal tDCS and further sign of recovery by the end of the experiment.

 1355 7T Magnetic Resonance Spectroscopy in the Hippocampus of MRI Normal Temporal Lobe Epilepsy Patients John Adams1,2, Simona Nikolova3,4,5, Suzan Brown6, Robert Bartha1,2, and Jorge Burneo6,7 1Department of Medical BioPhysics, University of Western Ontario, London, ON, Canada, 2Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, ON, Canada, 3Department of Physics and Astronomy, University of California, Irvine, CA, United States, 4Department of Neurobiology and Behavior, University of California, Irvine, CA, United States, 5Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, United States, 6Epilepsy Program, London Health Sciences Centre, London, ON, Canada, 7Department of Clinical Neurological Studies, University of Western Ontario, London, ON, Canada The utility of magnetic resonance spectroscopy for studying temporal lobe epilepsy (TLE) has been limited by magnetic field inhomogeneities. Using a 7T head-only MR system, we have successfully measured a number of metabolites which are challenging to measure in the hippocampus, including glutamate and glutathione, and we have observed a trend suggesting a decrease in creatine between contralateral and ipsilateral hippocampi in patients with unilateral, 1.5T MRI normal TLE.

 1356 Exploring metabolite profiling of patients with secondary progressive multiple sclerosis Anita Monteverdi1, Bhavana Shantilal Solanky2, Floriana De Angelis2, Domenico Plantone2, Jonathan Stutters2, Nevin John2, Letizia Casiraghi1,3, Ian Marshall4, Sue Pavitt5, Gavin Giovannoni6, Christopher Weir7, Nigel Stallard8, Clive Hawkins9, Basil Sharrack10, Siddharthan Chandran4, Jeremy Chataway2, and Claudia Angela Gandini Wheeler-Kingshott1,2,11 1Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 2Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 3Brain Connectivity Center, C.Mondino National Neurological Institute, Pavia, Italy, 4Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom, 5Dental Translational and Clinical Research Unit, School of Dentistry, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom, 6Department of Neurology, Barts and the London NHS Trust, London, United Kingdom, 7Edinburgh Clinical Trials Unit, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom, 8Division of Health Sciences, University of Warwick, Coventry, United Kingdom, 9Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom, 10Academic Department of Neuroscience, Royal Hallamshire Hospital, Sheffield, United Kingdom, 11Brain MRI 3T Research Centre, C. Mondino National Neurological Institute, Pavia, Italy Proton magnetic resonance spectroscopic imaging (MRSI) quantifies brain metabolism in vivo and has the potential of uncovering the mechanism of action of therapeutic drugs. In this study, we assessed the baseline metabolic profile of 161 patients with secondary progressive multiple sclerosis (SPMS) against a control population by applying a short TE PRESS MRSI protocol at 3T. Based on the results the SPMS population could be divided into different groups (normal/biochemically abnormal) suggesting biochemical heterogeneity within SPMS patients.

 1357 Anterior cingulate cortex glutathione decreases with age - faster in women than in men? Adriana Anton1, Catherine Gregory1, Richard Smallman1, Silke Conen1, Faezeh Sanaei-nezhad2, Bill Deakin1, and Steve Williams2 1Neuroscience and Psychiatry Unit, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom, 2Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom The anti-oxidant glutathione (GSH) may protect against ageing.  Significantly lower GSH in the occipital cortex has been reported in elderly compared to young healthy volunteers. Here we show that GSH is also decreased in middle-aged (N=8, 39-54y) compared to young (N=8, 22-32y) healthy subjects in the anterior cingulate but not the occipital cortex using GSH-edited MEGA-PRESS at 3T.  This significant difference is driven by the women in the middle-age sub-group (significantly lower GSH than in men). This suggests that age-related oxidative stress begins earlier in women compared to men and sex composition of a studied group could influence results.

 1358 Higher apparent diffusion coefficients in the older human brain Dinesh K Deelchand1, J. Riley McCarten1,2, Laura S Hemmy1,2, Edward J Auerbach1, and Małgorzata Marjańska1 1University of Minnesota, Minneapolis, MN, United States, 2Veterans Affairs Health Care System, Minneapolis, MN, United States The goal of this study was to compare the apparent diffusion coefficients (ADC) of the five major metabolites between young and older adults. Three brain regions were studied at 3 T using STEAM: prefrontal, posterior cingulate and occipital cortices. This study shows that the diffusivities of total N-acetyl aspartate, glutamate and myo-inositol are higher (7% on average) in the posterior cingulate cortex in older adults while no significant differences in ADC for the five major metabolites are observed in the other two brain regions studied. The ADCs of water are also higher in older adults in all three brain regions.

 1359 Contribution of Intramyocellular Lipids to the Decrease in Muscle Density with Age Nicholas A. Brennan1, Kenneth W. Fishbein1, David A. Reiter2, Richard G. Spencer1, and Luigi Ferrucci3 1Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States, 2Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 3Longitudinal Studies Section, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States Muscle density has been shown to decrease with age. However, the basis for this decrease remains unclear. We hypothesize that this decrease is associated with increased IMCL, and evaluated this relationship using localized 1H MRS of the vastus medialis muscle. We find that increased IMCL and decreased muscle density are strongly correlated across a large age range, even after controlling for multiple potential confounding variables.

 1360 13C Magnetic Resonance Spectroscopy: Study of sperm metabolism under a hypoxic atmosphere. Nurul Fadhlina Ismail1,2, Steven Reynolds1, Sarah Calvert3, Martyn Paley1, and Allan Pacey3 1Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom, 2Faculty of Health Science, Universiti Sultan Zainal Abidin, Terengganu, Malaysia, 3Academic Unit of Reproductive & Developmental Medicine, University of Sheffield, Sheffield, United Kingdom Studying energy metabolism in sperm may be helpful in understanding the relationship between motility and infertility. To understand sperm metabolism, we acquired 13C MR spectra during incubation with 13C-glucose in a normal and hypoxic atmosphere. Studies suggested that glycolysis is the main pathway for energy metabolism in sperm but whether glycolysis or oxidative phosphorylation(OXPHOS) dominates varies among species. This study examined the effect of hypoxia on sperm energy metabolism, with a secondary aim to observe Krebs cycle intermediates in the MR spectrum. Lactate signal in the hypoxia group was significantly higher than in the normoxia group. No Krebs cycle intermediate was detected.

### MRS Animal Studies

 Exhibition Hall 1361-1368 Monday 8:15 - 10:15

 1361 Opto-functional Magnetic Resonance Spectroscopy (O-fMRS): investigating brain energetics under optogenetic and sensory stimulation Nathalie Just1 and Cornelius Faber1 1AG Experimentelle Magnetische Kernresonanz Translational Research Imaging Center (TRIC) Institut für, University Hospital Münster, Germany, Münster, Germany For a better understanding of metabolic processes underlying neurovascular mechanisms, fMRS  represents a suitable technique. The combination of fMRS and optogenetics (O-fMRS)  should allow targeting  the metabolism of  specific cell populations  during their activation. Our study aims at developing O-fMRS methodology in rat to provide further insight into brain energetics during activation. Here we establish a comparison between O-fMRS and sensory-fMRS in the rat forepaw cortex to investigate whether energetic demands are similar.

 1362 Comparison of in vivo MRS and ex vivo HR-MAS MRS for assessment of metabolite content in the GOT1 small intestine neuroendocrine tumour model Mikael Montelius1, Johan Spetz2, Diana Bernin3, Oscar Jalnefjord1,4, Maria Ljungberg1,4, and Eva Forssell-Aronsson1,4 1Dept. of Radiation Physics, University of Gothenburg, Gothenburg, Sweden, 2University of Gothenburg, Gothenburg, Sweden, 3Swedish NMR Center, University of Gothenburg, Gothenburg, Sweden, 4Dept. of medical physics and biomedical engineering, Sahlgrenska University hospital, Gothenburg, Sweden In vivo characterisation of tumour metabolism using MRS would facilitate tumour therapy response assessment, but in vivo conditions may obscure the metabolic information acquired. In this study we investigate the information contained in in vivo MRS spectra of a neuroendocrine tumour model by correlating it to ex vivo HR-MAS MRS on excised tumour samples. Effects of post-mortem tissue degradation and tumour sample site on in vivo–ex vivo correlations are evaluated, and interpretation of in vivo data is discussed.

 1363 A neuroimaging study of the effects of early vs. late anti-inflammatory treatment in a rodent model of Alzheimer’s disease Caitlin Fowler1, Dan Madularu2, John Breitner3, and Jamie Near3 1Engineering, McGill University, Montreal, QC, Canada, 2McGill University, Montreal, QC, Canada, 3Douglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, QC, Canada Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with no effective treatments or known biomarkers for definitive diagnosis, substantiating the need for early detection of AD and early intervention. This project employs Magnetic Resonance Spectroscopy (MRS) to measure changes in neurometabolites as compared to behavioural measures of cognitive function, in a transgenic rat model of AD under treatment conditions. Preliminary results suggest that changes in metabolite levels are present before the onset of cognitive impairment, and between treatment and control groups, with some of these changes being sexually dimorphic.

 1364 Longitudinal follow-up of brain metabolism in rat models of progressive Parkinson's disease using Magnetic Resonance Spectroscopy Imaging. Carine Chassain1, Christophe Melon2, Guilhem Pages3, Yann Le Fur4, Pascal Salin2, Lydia Kerkerian-Le Goff2, and Franck Durif5,6 1MRI department, CHU Clermont-Ferrand, Clermont-Ferrand, France, 2IBDM, UMR 7288 CNRS / Aix-Marseille Université, Marseille, France, 3AgroResonance-UR370 QuaPA, Saint Genes Champanelle, France, 4Centre de Résonance Magnétique Biologique et Médicale UMR 7339 CNRS / Aix-Marseille Université, Marseille, France, 5Neurology department, CHU Clermont-Ferrand, Clermont-Ferrand, France, 66Université Clermont Auvergne (UCA), EA7280 NPSY-Sydo, Clermont-Ferrand, France The development of animal models that reproduce the selective and progressive loss of nigral dopamine neurons characterizing Parkinson’s disease has opened new possibilities to study the disease evolution. Here magnetic resonance spectroscopy imaging was used to follow up the distributions of metabolites in key basal ganglia components in two rat models of progressive parkinsonism at three time points over a period of 120 days following injury. First results on overtime changes in NAA and glutamate repartition will be presented. Completion of this project may provide novel insights onto the pathological alterations associated with the progression of the neurodegenerative process.

 1365 Metabolic Consequences in the Heart and Skeletal Muscle of Human Pancreatic Cancer Xenograft Growth Santosh Kumar Bharti1, Paul T Winnard Jr.1, Yelena Mironchik1, Marie-France Penet1, and Zaver M Bhujwalla1,2 1Division of Cancer Imaging Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 2Department of Oncology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States To understand the metabolic events that occur during cancer-induced cachexia, here we analyzed the effects of human pancreatic cancer xenografts on heart and skeletal muscle metabolites using 1 H MRS.  Studies were performed with cachexia-inducing Pa04C and non-cachexia inducing Panc1 human pancreatic cancer xenografts, since cachexia occurs most frequently in pancreatic cancer.  1H MR spectra identified differences in heart and skeletal muscle metabolites of cachectic and non-cachectic mice, as well as between normal mice and cachectic as well as non-cachectic mice.  Our data highlight the systemic metabolic changes that occur with tumor growth and provide new insights in cancer-induced cachexia.

 1366 Metabolic imaging of glioblastoma using hyperpolarized 13C-MRI - glycolytic metabolism in cancer stem cell-like cells. Tatsuya Kawai1, Jeffery Brender2, Kevin Camphausen1, and Murali C Krishna2 1Radiation Oncology Branch, National Cancer Institute, NIH, Bethesda, MD, United States, 2Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD, United States Dynamic nuclear polarization-MRI along with hyperpolarized [1-13C] pyruvate was conducted to evaluate the difference in glycolytic profile between a glioblastoma cell line and cancer stem-like cells using the orthotopic xenograft mouse model.

 1367 Does maternal swimming during gestation protects the neonatal brain from hypoxic-ischemic injury? Yohan van de Looij1,2,3, Eduardo Sanchez1, Petra S Hüppi1, and Stéphane V Sizonenko1 1Service développement et croissance, Université de Genève, Geneva, Switzerland, 2Laboratoire d'imagerie fonctionnelle et métabolique, Ecole polytechnique fédérale de Lausanne, Lausanne, Switzerland, 3Institut translationnel d'imagerie moléculaire, Université de Genève, Geneva, Switzerland There are growing evidences that swimming during gestation has a neuroprotective effect on offspring perinatal brain injuries. The aim of this work was to assess this neuroprotective effect on P3 hypoxic-ischemic model by 1H-MRS and diffusion MRI (DTI and NODDI) at 9.4T. A moderate, but real effect of swimming during gestation on the neurochemical profile 24h after HI was observed. Difference in neurochemical profile between sedentary and swimming rats may lead to a different response to the injury. At long-term, diffusion MRI derived parameters changes following HI were restored in the swimming HI group, providing evidence of a neuroprotective effect.

 1368 Differences between neurochemical profiles of male and female C57BL/6 mice Sarah N Larson1 and Ivan Tkac1 1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States The purpose of this study was to demonstrate whether neurochemical profiles of male and female C57BL/6 mice were affected in a sex-related manner. In vivo 1H MRS data were acquired from four different groups of mice, each group consisting of 10 male and 10 female mice. Highly significant differences between male and female groups were consistently observed in each group. These results have serious implications for appropriate quantification referencing (water vs. creatine, male or females in treated vs. control group) for avoiding bias in data interpretation.

### Cartilage

 Exhibition Hall 1369-1393 Monday 8:15 - 10:15

 1369 Ability of MRI to Predict the Severity and Location of Chondral and Labral Pathology at Arthroscopy Alissa J. Burge1, Stephen Lyman1, Matthew F. Koff1, Hollis G. Potter1, Sydney Kersten1, Bin Lin1, Kara Fields1, and Bryan Kelly1 1Hospital for Special Surgery, New York, NY, United States Preoperative MRI and intraoperative arthroscopic images were independently reviewed in a cohort of 24 hips with femoroacetabular impingement with respect to severity and location of chondral, labral, and osseous pathology. Initial calculation of agreement between MRI and arthroscopic findings demonstrated fair to near perfect agreement for the severity of pathology; however, agreement for the location of pathology was highly variable. MR images were subsequently re-scored utilizing the indirect head of the rectus femoris as an anatomic landmark, in accordance with the system used by the operating surgeon, resulting in overall increased agreement across position-dependent variables.

 1370 Correlation time mapping is associated with permeability of articular cartilage Mikko T. Nissinen1,2, Nina Hänninen3, Petri Tanska1, Olli Nykänen1, Mithilesh Prakash1, Matti Hanni2,3,4, Juha Töyräs1,5, Rami K. Korhonen1, Mikko J. Nissi1, and Miika T. Nieminen2,3,4 1Applied Physics, University of Eastern Finland, Kuopio, Finland, 2Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland, 3Research Unit of Medical Imaging, University of Oulu, Oulu, Finland, 4Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland, 5Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland Correlation time τc is a parameter that describes the relaxation properties of soft tissues. In this study, articular cartilage from human cadaver patellae was studied using MR imaging and biomechanical testing and modeling. The statistical analysis revealed an association between the permeability, as revealed by mechanical modeling, and the correlation time measured for articular cartilage.

 1371 T2* Enhancement for Multi-Echo Data Image Combination -- Using least squares for echo prediction Zhang Qiong1, Chen Shi1, Wei Binyan2, and Kang Yuanyuan1 1Siemens Shenzhen Magnetic Resonance Ltd, Shen Zhen, China, 2Siemens Healthcare China Ltd, Shang Hai, China This work provides a virtual echo prediction method for Multi Echo Data Image Combination (Medic) based on least square estimation. The strong dependences between multi-echoes in Medic sequences are used to predict virtual echoes with assumed echo times, and then such predictions are combined with real acquired echoes for heavier T2* contrast enhancement.

 1372 Comparison of Conventional and Synthetic MRI for Quantitative Cartilage T2 Mapping of the Patella Le Roy Chong1, Gideon Ooi1, Jia Hui Ng1, and Hafiz Bin Abu Hassan1 1Department of Radiology, Changi General Hospital, Singapore, Singapore Synthetic MRI has been shown to be of comparable performance to conventional MRI in the assessment of intracranial abnormalities. This study compares synthetic MRI with conventional T2 mapping for quantitative assessment of cartilage T2 relaxation times. T2 values acquired via synthetic MRI are highly correlated with but not equivalent to conventional T2 mapping. Synthetic MRI could be a potential alternative in the quantitative assessment of chondral abnormalities, without the need for prolonged scan times and providing the benefit of dynamic tissue contrasts from a single acquisition.

 1373 Associations between Osteoarthritis Molecular Biomarkers and MR-based cartilage composition and Knee Joint Morphology: Data from the Osteoarthritis Initiative Gabby B Joseph1, Michael C Nevitt2, Charles E McCulloch2, Jan Neumann1, John A Lynch2, Ursula Heilmeier1, Nancy E Lane3, and Thomas M Link1 1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States, 3Department of Rheumatology, University of California, Davis, Davis, CA, United States This study assessed the relationships of serum/urine biomarkers for osteoarthritis with MR imaging measures of joint structure and composition, using data from the Osteoarthritis Initiative (OAI). Significant positive correlations between the serum/urine biomarkers (sHA, sMMP3) and MRI cartilage T2 relaxation time measurements, compositional markers of early cartilage degeneration were observed. However, no significant associations were found with cartilage morphology or Kellgren-Lawrence (KL) grade.  Therefore, serum biomarkers and cartilage T2 composition may reflect similar features of the pathophysiology of cartilage matrix degenerative disease.

 1374 Detailed T2-mapping analysis reveal disc characteristics that may be of significance for low back pain patients Christian Waldenberg1, Hanna Hebelka2, Helena Brisby3, and Kerstin Magdalena Lagerstrand1 1Dept. of Medical Physics and Techniques, Sahlgrenska University Hospital, Gothenburg, Sweden, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Gothenburg, Sweden, 2Dept. of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Gothenburg, Sweden, 3Dept. of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden., Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Gothenburg, Sweden In this study, we address the lack of studies comparing intervertebral disc characteristics between symptomatic and asymptomatic individuals. Based on quantitative T2-mapping, small but relevant differences between low back pain patients and a control cohort were found on a global and regional level.

 1375 Magnetization Transfer Ratio (MTRNOE) as a Biomarker of Hip Osteoarthritis Hatef Mehrabian1, Jasmine Rossi-Devries1, Alan L Zhang2, Richard B Souza3, and Sharmila Majumdar1 1Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States, 3Physical Therapy, University of California, San Francisco, San Francisco, CA, United States Loss of cartilage collagen, proteoglycans (PG), glycosaminoglycans (GAG) are responsible for osteoarthritis (OA). MRI biomarkers T2 (sensitive to collagen), magnetization transfer (MT) and T1ρ, (sensitive to PG), and GAGCEST (sensitive to GAG) can detect OA at early stages. Similar to GAGCEST, CEST signal of Nuclear Overhauser Effect (NOECEST) at -1.6ppm also changes with OA. However, unlike GAGCEST, this NOECEST is measurable at 3T which is suitable for hip. MT ratio at this -1.6ppm (MTRNOE) represents the combination of MT, T2, NOECEST effects. OA-related changes in these three parameters result in decreased MTRNOE making it a reliable biomarker for OA.

 1376 T2 and T1rho mapping of ankle cartilage of female and male ballet dancers Saya Horiuchi1, Hon J. Yu1, Alex Luk1, Adam Rudd1, Jimmy Ton1, Edward Kuoy1, Jeff Russell2, Kelli Sharp3, and Hiroshi Yoshioka1 1Radiological Sciences, University of California, Irvine, Irvine, CA, United States, 2Science and Health in Artistic Performance, Ohio University, Athens, OH, United States, 3Department of Dance, The Claire Trevor School of the Arts, University of California, Irvine, Irvine, CA, United States This study demonstrated T2 and T1rho profiles of talar dome and tibial plafond cartilage from male and female ballet dancers using angular-segmentation methodology for quantitative assessment of cartilage in vivo. The results in this study showed both T2 and T1rho relaxation time indicated the lowest value over the central weight-bearing portion, while they indicated relatively higher values in the anterior and posterior portion. These findings can be due to the combination of the magic angle effect which has higher influence on T2 value and early cartilage degenerative changes which are more sharply detected by T1rho value.

 1377 Analysis of the Local Associations between Morphology and Biochemical Composition of the Articular Cartilage after Anterior Cruciate Ligament Injury and Reconstructive Surgery using Voxel-Based Relaxometry Onyekachi Ezinna Nnabue1,2, Hatef Mehrabian1, Valentina Pedoia1, Berk Norman1, Benjamin C. Ma2, and Sharmila Majumdar1 1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States This study uncovered new insights on the local associations between cartilage thickness and T1ρ relaxation time (a marker of cartilage proteoglycan content). Using Voxel-based relaxometry, this study quantified the longitudinal and cross-sectional thickness changes that occur in both the ACL-injured knee and the healthy contralateral in the lateral femoral condyle, medial femoral condyle, trochlea, medial tibia, lateral tibia, and patella and examined compartment-specific associations with relaxometry at various time points.

 1378 CS+SENSE for Fast UTE Knee Imaging: Technical Feasibility Yongxian Qian1, Li Feng1, Tiejun Zhao2, Richardo Otazo1, and Fernando E. Boada1 1Radiology, New York University, New York, NY, United States, 2Siemens Healthineers USA, New York, NY, United States Ultrashort echo time (UTE<1ms) imaging has advantages over traditional long TE (>10ms) imaging to detect asymptomatic (subclinical) cartilage damages in the knee joint, such as fissuring, fracturing and collagen fiber breakdown. To advance UTE imaging toward clinical use, its long scan time needs to be reduced to meet clinical requirement of short protocols. Compressed sensing (CS) and sensitivity encoding (SENSE) parallel imaging have the potential to do so. However, individual use of them has limitations. A combined use of both techniques has been shown in dynamic imaging to be able to achieve higher acceleration factor without SNR loss. This study explores the technical feasibility to extend CE+SENSE to static UTE imaging.

 1379 Quantitative evaluation of knee cartilage after anterior cruciate ligament reconstruction using UTE-T2* mapping in a rabbit model Yiwen Hu1 and Jianxun Qu2 1Fudan University affiliated Huashan Hospital, Shanghai, China, 2GE Healthcare, CHINA, Beijing, China Our study is a prospective longitudinal study conducted to find outcome of anterior cruciate ligament reconstruction in rabbit model. We evaluated degenerative changes of cartilage by UTE-T2* mapping. ACLR knees shows cartilage matrix degeneration at early stage of "ligamentization", though rabbit tibiofemoral cartilage is definitely thin.

 1380 Comparison of T2 Relaxation Times in Knee Cartilage Between Breaststroke and Nonbreaststroke Swimmers James Yoder1, Feliks Kogan1, and Garry E. Gold1,2,3 1Radiology, Stanford University, Stanford, CA, United States, 2Bioengineering, Stanford University, Stanford, CA, United States, 3Orthopaedic Surgery, Stanford University, Stanford, CA, United States While MRI has been widely used to examine the effects of translational forces on cartilage matrix structure, studies looking at rotational forces are limited. Breaststroke swimmers are a population of interest since the repeated use of the breaststroke kick has been cited as a source of knee pain. However, the cartilage of breaststrokers has not been quantitatively measured to investigate possible differences and the potential increased risk of cartilage degeneration and osteoarthritis development. This study compares the T2 relaxation times of various compartments for patellar, femoral, and tibial cartilage at the superficial, deep, and aggregate levels between breaststrokers and nonbreaststrokers.

 1381 Grey-Level Co-Occurrence Matrix Texture Analysis of T2, Adiabatic T1ρ, Adiabatic T2ρ and Dual-Echo Steady-State Magnetic Resonance Imaging Contrasts in Osteoarthritic Knee Articular Cartilage Ines Barros1,2, Arttu Peuna2, Victor Casula1,3, Marianne Haapea1,2, Eveliina Lammentausta2, and Miika T. Nieminen1,2,3 1Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, 2Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland, 3Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland Grey-level co-occurrence matrix (GLCM) based texture analysis is a sensitive image processing tool for the evaluation of cartilage in knee osteoarthritis (OA). Texture analysis of T2, Adiabatic T1ρ (AdT1ρ), Adiabatic T2ρ (AdT2ρ) relaxation time maps as well as Dual-Echo Steady-State (DESS) images showed the ability to distinguish OA patients and asymptomatic volunteers. Moreover, texture analysis turned out to be more sensitive to cartilage degeneration than mean relaxation time values. Texture analysis can therefore supplement existing quantitative MRI techniques of articular cartilage.

 1382 Simulated 1H-1H residual dipolar couplings of collagen-associated water Jouni Karjalainen1, Mikko J. Nissi2, Miika T. Nieminen1,3,4, and Matti Hanni1,3,4 1Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, 2Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, 3Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland, 4Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland Residual dipolar couplings have been suggested as the cause of the orientational dependence of relaxation times in anisotropic tissues, such as articular cartilage. We use molecular dynamics simulations to compute the residual dipolar couplings of water protons associated with a model collagen molecule. The results suggest that significant residual dipolar couplings appear without strong binding between the water and the collagen.

 1383 Quantitative GagCEST MRI in Juvenile Bovine Articular Cartilage Exhibit Correlations between 3T and 7T Lauren Watkins1, Feliks Kogan2, Marianne Black3, Marc Levenston1,2,3, and Garry Gold1,2 1Bioengineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3Mechanical Engineering, Stanford University, Stanford, CA, United States GagCEST is a quantitative MR technique that shows promise at 7T to specifically detect cartilage glycosaminoglycan content; however, its potential at 3T is still uncertain. This study utilizes a new optimized 3D GagCEST sequence to maximize SNR and GagCEST contrast at 3T. Comparison of GagCEST asymmetry maps obtained at 3T and 7T suggest that GagCEST can be used to distinguish zonal differences in cartilage composition at both 3T and 7T. This work demonstrates potential for whole joint GagCEST knee imaging at 3T with improved dynamic range.

 1384 Automated segmentation of the cartilage from high-resolution isotropic T1rho MRI Henry Rusinek1, Rahman Baboli2, Artem Mikheev2, Azadeh Sharafi2, and Ravinder R Regatte2 1Radiology, New York University School of Medicine, New York, NY, United States, 2Radiology, New York Unversity School of Medicine, New York, NY, United States We analyze the accuracy of atlas-based cartilage segmentation from isotropic T1ρ MRI and compare it to semi-automated "seed and blanket" method and manual segmentation (ground truth). Reference 3D cartilage masks were taken as the consensus of two human experts. For patella, our implementation of template matching yielded the root mean square volume measurement error RMSE of 0.66 cm3, with interclass correlation coefficient (ICC) = 0.765 and sufficient precision to detect the gender effect. Over two-fold improvement in accuracy, RMSE = 0.25 cm3 and ICC = 0.960 was achieved with a fast, semi-automated algorithm. Similar results hold for the accuracy of the average thickness of segmented masks.

 1385 The novel and quantitative MRI technique: Q-space imaging for evaluating intervertebral disc degeneration: basic and clinical study. Daisuke Nakashima1, Nobuyuki Fujita2, Junichi Hata3,4, Takeo Nagura2, Kanehiro Fujiyoshi5, Hideyuki Okano3, Masahiro Jinzaki2, Morio Matsumoto2, and Masaya Nakamura2 1Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan, 2Keio University School of Medicine, Tokyo, Japan, 3Central Institute for Experimental Animals, Kawasaki, Japan, 4Department of Physiology, Keio University School of Medicine, Tokyo, Japan, 5Murayama Medical Center, Tokyo, Japan The conventional qualitative classification of intervertebral disc (IVD) degeneration: Pfirrmann classification on T2 weighted imaging does not have the enough sensitivity for the evaluation of IVD degeneration. In the present study, probability at zero displacement  obtained from Q-space imaging (QSI) has a high sensitivity of IVD degeneration in both basic and clinical study compared with the conventional method: T2 mapping. In particular, probability at zero displacement made it possible to observe the effect of the regenerative drug: N-Acetyl Cystaine on IVD degeneration which could not be observed by using T2 mapping. Probability at zero displacement obtained from QSI has the possibility to be a novel biomarker of IVD degeneration.

 1386 Effect of Fat-contamination and Fat-suppression on T2 Quantitation of Knee Articular Cartilage In Vivo Petri Paakkari1, Stefan Zbyn1,2, Mikko J Nissi3, Eveliina Lammentausta4, Miika T Nieminen1,2,4, and Victor Casula1,2 1Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, 2Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland, 3Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, 4Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland This study aims to investigate the effect of fat contamination and fat suppression (FS) on in vivo T2 mapping of knee cartilage. Four volunteers were imaged on a 3T MRI scanner and T2 values were calculated in several regions of tibiofemoral cartilage using a MSME sequence with and without FS. The use of FS improved repeatability of cartilage segmentation in several regions and reduced the chemical shift artifacts. However, the regional heterogeneity in FS sequence introduced further uncertainties in T2 measurements.

 1387 T1 Relaxation Time Mapping of Articular Cartilage for Femoroacetabular Impingement (FAI) - A Clinical Pilot Study Jutta Ellermann1, Douglas Martin2, Casey P Johnson3, Robert Gao4, Luning Wang1, and Patrick Morgan5 1Radiology, CMRR, University of Minnesota, Minneapolis, MN, United States, 2Radiology, Stanford University, Palo Alto, CA, United States, 3Radiology, University of Minnesota, Minneapolis, MN, United States, 4University of Minnesota, Minneapolis, MN, United States, 5Orthopaedics, University of Minnesota, Minneapolis, MN, United States In this pilot study we demonstrate the clinical utility of quantitative T1 relaxation time mapping to assess acetabular cartilage damage in patients with Femoroacetabular Impingement (FAI).

 1388 Analysis of Knee Cartilage using Magnetization Transfer and Multi-exponential T2* Fitting Sooyeon Ji1, Se-Hong Oh2, Young-Han Lee3, Dongmyung Shin1, Doohee Lee1, Taehyun Hwang1, Woojin Jung1, Hyeong-Geol Shin1, and Jongho Lee1 1Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea, 2Department of Biomedical Engineering, Hankuk University of Foreign Studies, Seoul, Republic of Korea, 3Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Republic of Korea In this study, we explored the combined use of magnetization transfer (MT) weighting and bi-exponential T2* fitting as a potential tool to analyze the composition and microscopic geometry of the knee cartilage. The analysis results of deep cartilage areas showed that the MT ratio of the short T2* component had significantly larger values than that of the long T2* component. This observation may be explained by the geometry of collagen fibrils and proteoglycans.

 1389 T1-T2 correlation of site-specific changes and zone-dependent anisotropy of osteoarthritic cartilage using multi-resolution MRI Farid Badar1 and Yang Xia1 1Physics, Oakland University, Rochester Hills, MI, United States Topographical and zonal based studies of healthy and OA canine tibial cartilage are shown to be essential for the early detection of osteoarthritis. A high-resolution T1-T2 correlation with the low-resolution imaging of depth-dependent T2 profiles shows a more detailed and sensitive method of measuring the early sign of cartilage degradation, beneficial to human OA MRI.

 1390 Effect of spin-lock field direction on chemical exchange spin-lock (CESL) and evaluate its feasibility of glycosaminoglycan (GAG) detection at 3.0T Baiyan Jiang1 and Weitian Chen1 1Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, Hong Kong Chemical exchange spin-lock (CESL) is sensitive to fast exchange metabolites. CESL is performed across a range of resonance frequency offsets. At any frequency offset, either anti-parallel or parallel spin-lock directions can be used. However, different directions can affect the z-spectrum and the magnetization transfer ratio asymmetry analysis. We used simulations and in vivo experiments to demonstrate this effect and provided theoretical analysis. We also presented preliminary results of CESL for imaging of chemical exchange associated with glycosaminoglycan (GAG) in human knee at 3.0T.

 1391 Macromolecular fraction from magnetization transfer ultrashort echo time (MT-UTE) modeling proportionally correlates with applied mechanical load on the cadaveric knee joint Saeed Jerban1, Yajun Ma 1, Wei Zhao1, Michael Carl2, Eric Y Chang1,3, and Jiang Du1 1Radiology, University of California, San Diego, San Diego, CA, United States, 2GE Healthcare, San Diego, CA, United States, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States Ultrashort echo time (UTE) MRI is able to assess long T2 tissues such as articular cartilage (AC) and short T2 tissues such as meniscus. Early stage of osteoarthritis is hypothesized to affect the mechanical properties of AC, sooner and quicker than its morphology. This study focused on the application of UTE imaging, including UTE magnetization transfer (UTE-MT) modelling, adiabatic T1r, T1 and T2* measurements in cadaveric human knee joints subject to sequential mechanical loading. Compression load application resulted in significant increases in macromolecular fraction estimated in AC and meniscus, obtained by two-pool MT modeling. T1, T1ρ and T2* biomarkers did not show consistent trends.

 1392 Quantitative DCE-MRI perfusion imaging of the subchondral bone in knee osteoarthritis Bas A. de Vries1, Joost Verschueren1, Dirk H.J. Poot2, Gabriel P. Krestin1, and Edwin H.G. Oei1 1Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands, 2Medical Informatics, Erasmus MC, Rotterdam, Netherlands Changes in subchondral bone in knee osteoarthritis could be a marker of altered fluid dynamics. Perfusion can be visualized and quantified with MRI using dynamic contrast enhanced MRI (DCE-MRI). Using quantitative analysis of DCE-MRI, we compared perfusion in the affected compartment with the non-affected compartment in patients with unicompartmental knee osteoarthritis. We also evaluated the perfusion in subchondral bone marrow lesions (BMLs). Perfusion of the subchondral bone measured with DCE-MRI is not significantly different between the affected and non-affected compartment. Subchondral BMLs are significantly associated with increased perfusion parameters compared to subchondral bone regions without BMLs.

 1393 Low-field MRI of osteoarthritis in humans: correlations between load-dependent cartilage properties and relaxation parameters Erik Roessler1, Carlos Mattea1, Miika Nieminen2, Sakari Karhula2, Simo Saarakkala2, and Siegfried Stapf1 1Ilmenau University of Technology, Ilmenau, Germany, 2University of Oulu, Oulu, Finland At low magnetic fields, T1 variation within cartilage is a robust parameter that is employed to quantify the layered structure in the tissue and is sensitive to factors such as enzymatic degradation, external load, and diseases such as osteoarthritis. Variable-field relaxometry provides access to the content and local order of glycosaminoglycans and collagen via proton-nitrogen quadrupolar dips. In this study on 20 human cartilage samples, load-dependent low-field and variable-field techniques were combined for the first time to correlate NMR parameters with the severity of osteoarthritis.

### Muscle

 Exhibition Hall 1394-1411 Monday 8:15 - 10:15

 1394 Impact of Rate of Cuff Inflation on the Post-Ischemia Hyperemic Response Rajiv S Deshpande1, Erin K Englund2, and Felix W Wehrli2 1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States The ischemia-reperfusion paradigm can be used to evaluate skeletal muscle and peripheral vascular function. To induce ischemia, a cuff is inflated to a suprasystolic pressure, which leads to occlusion of the blood vessels, and reactive hyperemia results upon cuff deflation. This study was done to determine whether the rate at which the cuff inflates affects the hyperemic response. MRI data were acquired using the ischemia-reperfusion paradigm under slow and fast cuff inflation rates with PIVOT and projection velocity mapping in eight healthy subjects. The results suggest that there were no significant differences between hyperemic responses from slow and fast inflations.

 1395 Simultaneous magnetic resonance elastography of the supraspinatus and the trapezius muscles Daiki Ito1,2,3, Tomokazu Numano1,3, Koichi Takamoto4, Kazuyuki Mizuhara3,5, and Hisao Nishijo6 1Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan, 2Office of Radiation Technology, Keio University Hospital, Tokyo, Japan, 3Health Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan, 4Department of Judo Neurophysiotherapy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan, 5Department of Mechanical Engineering, Tokyo Denki University, Tokyo, Japan, 6Department of System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan Palpation is difficult to distinguish stiffness of the supraspinatus and trapezius muscles. Magnetic resonance elastography (MRE) can measure stiffness of tissues quantitatively only if vibrations reach the tissues. We developed simultaneous MRE of the supraspinatus and trapezius muscles by adjusting the shape of a wave transducer and vibration frequency. MREs were performed using self-made wave transducer at 50-150 Hz, with a 25 Hz step. Both wave images of the supraspinatus and trapezius muscles showed clear wave propagation at 50 and 75 Hz. The results demonstrated that our techniques allow simultaneous MRE of the supraspinatus and trapezius muscles at 75 Hz.

 1396 Multi-centric evaluation of stability of quantitative outcome measures in healthy calf muscles Lara Schlaffke1,2,3, Alberto De Luca4, Louise Otto5, Robert Rehmann1, Marlena Rohm1, Jedrzej Burakiewicz3, Celine Baligand3, Jithsa Monte6, Chiel den Harder6, Aart Nederveen6, Hermien Kan3, and Martijn Froeling2 1Neurology, BG UK Bergmannsheil gGmbH, Bochum, Germany, 2Radiology, Universitiy Medical Center Utrecht, Utrecht, Netherlands, 3C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands, 4Image Science Institute, Universitiy Medical Center Utrecht, Utrecht, Netherlands, 5Brain Centre Rudolf Magnus, Neurology, Universitiy Medical Center Utrecht, Utrecht, Netherlands, 6Radiology, Academic Medical Center Amsterdam, Amsterdam, Netherlands Clinical feasible, comparable muscle MR-techniques are crucial for monitoring disease progression and therapy in patients with neuromuscular diseases. We developed and evaluated a multi-modal quantitative MR protocol at 3T. Diffusion parameters, water T2 relaxation time and fat-fraction were measured and tested for temporal stability, multicenter reproducibility and covariate influence. Diffusion parameters stabilized after 15 minutes and were comparable between centers. Water T2 decreased 1ms within 1 hour. In dorsal muscles fat-fraction increased slightly, due to a decrease in muscle size. Temporal stability of quantitative parameters was shown and showed that T2 decrease needs to be considered when planning protocols.

 1397 Exploring the Textural Differences between Diseased and Normal Muscle on T1 Weighted MRIs of the Mid-calf and Mid-thigh Chang Tung Harold Yip1, Phua Hwee Tang2, and Kein Meng Wendy Liew3 1Duke-NUS Medical School, Singapore, Singapore, 2Department of Diagnoistic and Interventional Imaging, KK Women's And Children's Hospital, Singapore, Singapore, 3Paediatric Neurology, KK Women's and Children's Hospital, Singapore, Singapore Textural analysis is a non-invasive objective method to characterize MRIs of subjects with muscular disorders. It has the potential to characterize muscle abnormalities that are not visible to the human eye. This allows the detection of muscle abnormalities earlier hence aiding early diagnosis and prognostication. This also allows textural analysis to be a potential quantitative outcome measure for clinical trials of drug treatments for muscular disorders. This study shows that the textural parameter entropy remains stable as age increases and can distinguish between diseased and normal muscle tissue.

 1398 Fully automatic segmentation of all lower body muscles from high resolution MRI using a two-step DCNN model Anudeep Konda1, Katherine Crump1, Daniel Podlisny1, Craig H Meyer1, Silvia S Blemker1, Joe Hart1, and Xue Feng1 1Springbok, Inc., Charlottesville, VA, United States Lower limb skeletal muscles play an essential role in athletic performance as wellas muscular health in patients with dystrophies. Quantitative mapping of all 35 lower body muscles from high resolution MRI has the potential to improve power and agility in athletes and assist the diagnosis and follow-up for certain musculardystrophies in medical applications. However, due to the weak contrast and insufficient boundary information, the accurate segmentation of each individual muscle is challenging. In this study we developed a fully automatic segmentation framework using a two-step DCNN model and showed accurate segmentation for all muscles.

 1399 Robust multi-atlas MRI segmentation with corrective learning for quantification of local quadriceps muscles inflammation changes during a longitudinal study in athletes Hoai-Thu Nguyen1, Pierre Croisille1,2, Magalie Viallon 1,2, Charles de Bourguignon2, Rémi Grange2, Sylvain Grange1,2, and Thomas Grenier3 1Univ Lyon, UJM-Saint-Etienne, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, F-42023, Saint-Etienne, France, 2Department of Radiology, Centre Hospitalier Universitaire de Saint-Etienne, Université Jean-Monnet, Saint-Etienne, France, 3Univ Lyon, INSA‐Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69621, Villeurbanne, France This study propose an improved automatic segmentation of longitudinal MRI dataset of mountain ultra-marathon runners’ upper thighs acquired during the Tor des Géants 2014 by using a multi-atlas segmentation strategy with corrective learning with a small number of training set. Our highly accurate and robust segmentations allow us to locally study the inflammation of each quadriceps head induced by the extreme conditions of the race, a method that is of high interest to monitor the impact of eccentric efforts during the race, identify local physiopathology changes in patients, and benefits of eventual therapy or intervention.

 1400 Using texture analysis based on T2WI, DWI and delayed T1-enhanced imaging to differentiate benign and malignant soft tissue tumors Nan Sun1, Cuiping Ren1, Ying Li1, Jingliang Cheng1, and Zhizheng Zhuo2 1Dept. of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Philips Healthcare, Beijing, China With the popularity of magnetic resonance technology in recent years, the detection rate of soft tissue tumors has been greatly improved. The soft tissue tumors in MR images show various signal intensity distribution in different modalities. This work investigated and evaluated the role of texture analysis on T2WI, DWI and delayed T1-enhanced images to characterize the soft tissue tumors, and then evaluate the textures by support vector machine classifiers (SVM) to differentiate benign and malignant soft tissue tumors. Results showed that the application of texture analysis in T2WI, DWI and T1-enhanced imaging is helpful to distinguish benign and malignant soft tissue tumors by SVM.

 1401 Measurement of skeletal muscle extraceullar volume (ECV) in the healthy thigh: determination of the time to contrast equilibrium Alex F Goodall1, Dr David A Broadbent1, Dr Raluca B Dumitru2,3, Prof David L Buckley4, Prof Maya Buch2,3, Dr Ai Lyn Tan2,3, and Dr John D Biglands1,2 1Department of Medical Physics & Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom, 2NIHR Leeds Biomedical Research Centre, Leeds, United Kingdom, 3Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, United Kingdom, 4Department of Biomedical Imaging Science, University of Leeds, Leeds, United Kingdom Five healthy volunteers were scanned at 3 T to determine the time to contrast equilibrium in skeletal leg muscle to establish whether extracellular volume (ECV) mapping is clinically feasible for skeletal muscle (as it has proved to be for myocardium). Time to contrast equilibrium was 13 minutes, and native T1 values were validated against the literature. It was also found that the difference in measurement of ECV using the aorta compared to the femoral artery was small. It is hoped that advancements in this technique could aid in the diagnosis and treatment of scleroderma patients with muscle involvement.

 1402 Multi-parametric MRI-based classification for generating muscle percentage index in muscular dystrophy Aydin Eresen1, Noor E. Hafsa2, Lejla Alic2, Sharla M. Birch1, Jay F. Griffin1, Joe N. Kornegay1, and Jim X. Ji1,2 1Texas A&M University, College Station, TX, United States, 2Texas A&M University at Qatar, Doha, Qatar Imaging biomarker for muscular dystrophies, such as muscle percentage index (MPI), successfully differentiates between healthy and dystrophic muscles. However, the current methods to generate this biomarker are not well defined and therefore lack robustness and reproducibility. This study imaged ten Golden Retriever Muscular Dystrophy (GRMD) pectineus-muscle samples at a 4.7T MRI scanner. To facilitate estimation of MPI and to validate the results, we use trichrome-stained histology images. These images were registered accurately to multi-parametric quantitative MRI (qMRI). We use local gradient and texture information to classify qMRI into muscle and non-muscle with respective accuracies of 0.86 and 0.71.

 1403 MRI characterization of skeletal muscles of two dystrophic mouse models Ravneet Singh Vohra1, Joshua Park1, Philip Kramer1, David Marcinek1, Jeffrey Chamberlain2,3, and Donghoon Lee1 1Department of Radiology, University of Washington, Seattle, WA, United States, 2Department of Neurology, University of Washington, Seattle, WA, United States, 3Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Washington, Seattle, WA, United States The mdx mouse model is one of the most commonly used animal model for Duchenne muscular dystrophy (DMD). However, it has a milder phenotype compared to patients with DMD. Evidence has demonstrated the presence of genetic modifiers that lead to phenotypic variability even with an identical gene mutation in both human and animal models of muscular dystrophy. We performed multi-parametric, high resolution MRI to demonstrate severity of disease progression in dystrophic mouse models on two different genetic backgrounds.

 1404 Application of MR Elastography to Transvertebral Psoas Major Muscle Tomokazu Numano1,2, Daiki Ito1,2,3, Koichi Takamoto4, Kazuyuki Mizuhara5, and Hisao Nishijo6 1Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan, 2Health Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan, 3Office of Radiation Technology, Keio University Hospital, Tokyo, Japan, 4Department of Judo Neurophysiotherapy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan, 5Mechanical Engineering, Tokyo Denki University, Tokyo, Japan, 6Department of System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan The aim of the present work was to develop the vibration techniques for the psoas major muscle (PM) MR elastography (MRE). The results indicated that the PM well vibrated, due to transmission of vibration from the lumbar spine. These findings suggest that placement of a narrow vibration pad under the supine body, along the lumbar spine, would allow PM MRE. The present techniques for the PM MRE provide a quantitative diagnostic tool for LBP-associated changes in the muscles, since increased stiffness of the muscle due to continuous contraction is suggested to be an important cause of LBP.

 1405 Improved Spontaneous Activity Maps of Resting Skeletal Musculature by surface EMG-based Contraction Pattern Classification Martin Schwartz1,2, Günter Steidle1, Petros Martirosian1, Michael Erb3, Bin Yang2, Klaus Scheffler3,4, and Fritz Schick1 1Section on Experimental Radiology, University Hospital of Tübingen, Tübingen, Germany, 2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, 3Biomedical Magnetic Resonance, University Hospital of Tübingen, Tübingen, Germany, 4High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany Reliable assessment and analysis of spontaneous mechanical activities in musculature (SMAM) visible in repetitive DWI is a relatively new technique for non-invasive characterization of skeletal musculature. To correct for data corrupted by intentional contractions, a surface electromyography-based contraction state analysis was investigated to reject undesired DWI data. It is demonstrated that the presented method enables a more reliable quantification of SMAMs and improved spontaneous activity maps.

 1406 Validation of an Osirix Plugin for automatic fat infiltration measurements in Paraspinal muscles using T2 weighted images Cristobal Arrieta1, Julio Urrutia2, Pablo Besa2, Ignacio Osorio1, Cristian Montalba1, Daniel Hasson3, Marcelo E Andia4, and Sergio Uribe4 1Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile, 2Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile, 3Department of Radiology, Universidad del Desarrollo, Santiago, Chile, 4Department of Radiology, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile Paraspinal muscle fat infiltration has been related with low back pain. This measurements are typically evaluated using T2w images, however, the accuracy of this method needs a proper validation, since inhomogeneities may produce severe signal changes. In this work, we developed and validated an OsiriX plugin which allows to segment infiltrated fat in T2w images. This tool also allowed us for validating the use of T2w images, considering Dixon fat images as gold-standard. To validate our plugin, we evaluated 5 cross sectional areas (L1-S1) of 4 paraspinal muscle groups  for T2w images of 37 patients. To validate T2w images, we analyzed 10 healthy volunteers and 10 patients. We found that T2w segmentation with our OsiriX plugin is a reliable and an accurate method to evaluate the fat infiltration in paraspinal muscles.

 1407 Ex vivo MRS evaluation of severe burn injury in mice shows metabolic changes in skeletal muscle Leo L. Cheng1, Bailing Li1,2, Lindsey. A. Vandergrift1, Jiake Chai3, and Zhongcong Xie4 1Pathology, Massachusetts General Hospital, Boston, MA, United States, 2Burns and Plastic Surgery, First Affiliated Hospital of General Hospital of PLA, Beijing, China, 3Burn and Plastic surgery, First Affiliated Hospital of PLA General Hospital, Beijing, China, 4Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, United States Patients of severe burn injury often suffer from sepsis, which results in multiple organ failure and prolonged metabolic derangement, leading to higher mortality. Accurate measurements of burn injury-associated metabolic changes may provide the burn clinic with quantitative tools to assess patient status. We tested the efficacy of High-Resolution Magic Angle Spinning (HRMAS) magnetic resonance spectroscopy (MRS) in evaluation of tissue metabolic changes with mouse skeletal diaphragm and gastrocnemius muscles after burn injury. HRMAS measurements indicated that IMTG and plasma FFA levels were increased after severe burn injury, with more pronounced differences detected in diaphragm muscle than in gastrocnemius muscle.

 1408 Sensitivity of Quantitative Texture Metrics to Variations in Image Acquisition Parameters Bruce Damon1, Yuan Xie2, Ke Li1, Susan Kroop1, and Jane Park1 1Vanderbilt University School of Medicine, Nashville, TN, United States, 2Vanderbilt University, Nashville, TN, United States The purpose of this study was to examine the dependence of a quantitative texture metric, the high gray level run length emphasis (HGRE) in T2-weighted images, on common variations in image acquisition parameters. We studied 13 muscle disease patients with quantitative fat/water MRI and contrast-based images.  The ability of the HGRE was unaffected by image matrix size. We also measured the dependence of the regression parameters on TR and TE. The results support the use of quantitative texture analysis to study clinically acquired MR images in muscle disease patients.

 1409 Assessment of perfusion-metabolism matching in exercising muscle from dynamic contrast-enhanced MRI and T2 mapping Gwenael Layec1, christopher Conlin2, Jiawei Dong2, Stephen Decker3, Corey R Hart3, Nan Hu2, Mariya A Chadovich2, Michelle A Mueller2, Lillian Khor3, Christopher Hanrahan2, Vivian S Lee2, and Jeff L Zhang2 1VA Medical Center GRECC 182, 1D23A 500 Foothill Drive, University of Utah, Salt Lake City, UT, United States, 2Radiology, University of Utah, Salt Lake City, UT, United States, 3University of Utah, Salt Lake City, UT, United States Using an MR approach combining DCE-MRI and T2 mapping, this study revealed that unlike PAD patients, muscle tissue perfusion was tightly correlated to exercise-induced changes in R2 in the lower leg muscles of healthy individuals. These findings suggest Q/Met mismatch following exercise in the skeletal muscle of PAD patients. The combination of DCE-MRI and T2 mapping opens a new avenue of research to investigate perfusion-metabolism heterogeneity in normal physiological conditions and muscle-related pathologies.

 1410 Effects of PDE5A inhibition on skeletal muscle 1H2O T2 following an acute bout of downhill running and endurance training in dystrophic mice Abhinandan Batra1, Ravneet Vohra2, Steve Chrzanowski1, Donovan J Lott1, Glenn A Walter1, Krista Vandenborne1, and Sean C Forbes1 1University of Florida, Gainesville, FL, United States, 2University of Washington, Seattle, WA, United States This study examined the effects of phosphodiesterase 5A inhibition with sildenafil citrate on skeletal muscle 1H2O T2 in dystrophic mice (mdx) following downhill running and during four weeks of low-intensity treadmill training.  Skeletal muscle 1H2O T2 was measured from spectra acquired with a single voxel 1H-MRS STEAM sequence.  Our findings showed less altered T2 after downhill running with sildenafil citrate treatment indicating less muscle damage and improved running performance during endurance training.  Collectively, the results support the use of sildenafil citrate when combined with acute and chronic bouts of exercise as a potential therapeutic intervention in muscular dystrophies.

 1411 Multi-Parametric MRI characterization for damaged dystrophic muscle Joshua Park1, Ravneet Vohra1, Jeffrey S Chamberlain2,3, and Donghoon Lee1 1Radiology, University of Washington, Seattle, WA, United States, 2Neurology, University of Washington, Seattle, WA, United States, 3Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, Seattle, WA, United States Muscular dystrophy is a family of inherited diseases characterized by progressive muscle weakness that leads to muscle damage and wasting. Clinical measures of muscular dystrophy rely on surgical biopsy, which is invasive and limited. Magnetic resonance imaging (MRI) can provide valuable information pertaining to tissue characteristics of this disease noninvasively. We performed multi-parametric MRI to assess the changes due to muscle damage and subsequent recovery over 3 weeks starting at 12 weeks of age in disease affected mice. The differences observed through MRI measurements demonstrate MRI can be used effectively to track disease progression and responses to future therapy.

### MSK: Other

 Exhibition Hall 1412-1437 Monday 8:15 - 10:15

 1412 A Prospective, Longitudinal Assessment of Adverse Local Tissue Reactions in Resurfacing Hip Arthroplasty Versus Primary Total Hip Arthroplasty Jacqui C. Zhu1, Matthew F. Koff1, Bin Lin1, Kara Fields1, Danyal G. Nawabi1, Edwin Su1, Douglass Padgett1, and Hollis G. Potter1 1Hospital for Special Surgery, New York, NY, United States The purpose of this prospective study was to compare the prevalence of magnetic resonance imaging detected adverse local tissue reactions (ALTRs) in metal-on-metal hip resurfacing arthroplasty (HRA) and ceramic-on-poly (COP) total hip arthroplasty subjects. Images acquired at 4 time points with a 1-year interval showed a higher prevalence of ALTRs in the HRA than COP subjects. The self-assessed symptomatology scores did not significantly differ between the two groups at follow-up, indicating that ATLRs can be clinically silent. This study will permit better understanding of the natural history and follow up of ALTRs complicating hip arthroplasty.

 1413 Dynamic contrast enhanced MR imaging in early stage knee osteoarthritis: A test-retest repeatability study Faezeh Sanaei Nezhad1,2, James MacKay3, Josh Kaggie3, Martin Graves3, Fiona Gilbert3, Andrew McCaskie4, Rob Janiczek5, Geoff JM Parker1,2, Alexandra R Morgan5, and Jose Ulloa1,2 1Bioxydyn, Manchester, United Kingdom, 2Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom, 3Department of Radiology, University of Cambridge, Cambridge, United Kingdom, 4Department of Trauma & Orthopaedics, University of Cambridge, Cambridge, United Kingdom, 5GSK, Stevenage, United Kingdom Dynamic contrast-enhanced MRI (DCE-MRI) has proven to be an effective method for qualitative and quantitative measurement of synovitis in the knee. Here we evaluate the test-retest repeatability of DCE-MRI measurements in the knee at 3 T. Eight patients with mild/moderate knee osteoarthritis (OA) were scanned twice, 4 weeks apart. DCE biomarkers from the extended Tofts model were measured. This is the first demonstration of the repeatability of DCE-MRI in knee OA. This evaluation provides data to enable sample size calculations for further longitudinal and interventional studies using DCE-MRI as a biomarker of inflammation in OA.

 1414 Analysis of the Orientation-Dependent Frequency of Tendon via Ultrashort Echo Time (UTE) MRI Adrienne G. Siu1, Luca Biasiolli1, and Matthew D. Robson1 1Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom Tendon exhibits changes in T2, T2*, and resonant frequency as a function of its orientation with respect to B0. An ultrashort echo time (UTE) sequence was employed to characterize the frequency of fresh bovine digital flexor tendon at angles of 0⁰ to 90⁰ relative to B0, causing a maximal frequency shift of 1.0 ppm. Factors that could influence the frequency of tendon were evaluated. It was found that the frequency of tendon was affected by the enclosing container, but not the geometry of the tendon.

 1415 Cartilage and Meniscus T2 Relaxation Time in Subjects With and Without Meniscus Tears Richard Kijowski1, Shivhumar Kambhampati1, Joshua Bunting1, Benjamin Beduhn1, Kaitlin Woo1, and Fang Liu1 1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States This study was performed to compare cartilage T2 between subjects with and without meniscus tears.  T2 mapping was performed on the knees of 30 control subjects without meniscus tears and 93 subjects with meniscus tears.  Medial and lateral compartment cartilage T2 was measured.  Radiographic osteoarthritis severity was assessed using the Kellgren-Lawrence (KL) grading scale.  The 30 KL-0 control subjects without meniscus tears had significantly lower (p<0.001) medial compartment cartilage T2 than KL-0 (n=46), KL 1 (n=27), and KL-2 (n=20) subjects with meniscus tears and significantly lower (p<0.01) lateral compartment cartilage T2 than KL-1 and KL-2 subjects with meniscus tears.

 1416 Accuracy of MRI-based measurements of aponeurosis dimensions Lachlan Bird1,2, Arkiev D'Souza1,3, Iain Ball4, Caroline Rae1,3, Robert Herbert1,3, and Bart Bolsterlee1,3 1Neuroscience Research Australia, Randwick, Australia, 2Sydney University, Camperdown, Australia, 3University of New South Wales, Kensington, Australia, 4Philips Electronics Australia, Sydney, Australia Aponeuroses are the thin, sheet-like tendons that cover substantial parts of muscles. We validated measurements of the dimensions of aponeuroses from T1, mDixon and ultrashort echo time (UTE) scans by comparing to direct measurements from dissection and digitisation. We used sequences that are feasible for human studies. Aponeurosis widths and lengths, measured on 20 lamb muscles, were substantially underestimated from mDixon scans. More accurate measurements were obtained from T1 and UTE scans, which had root mean square errors of 8-10% and 5-13% of the aponeurosis width and length, respectively, and did not systematically underestimate or overestimate aponeurosis width or length.

 1417 Elevated conversion of hyperpolarized [1-13C]pyruvate to [1-13C]lactate is not associated with tissue acidosis, as measured with hyperpolarized [13C]bicarbonate, in a murine model of rheumatoid arthritis. Alan J. Wright1, Zoé M. A. Husson2, De-en Hu1, Gerard Callejo2, Kevin M. Brindle1,3, and Ewan St. John Smith2 1CRUK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, 2Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom, 3Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom Measurements of synovial fluid pH in patients with rheumatoid arthritis suggest acidosis can occur at inflamed joints. A widely used model of rheumatoid arthritis is produced by injecting complete Freund’s adjuvant into the hind paw of a mouse. We have investigated whether inflammation is associated with acidosis in this model using Magnetic Resonance Spectroscopic Imaging of injected hyperpolarised [1-13C]pyruvate, to detect the metabolic changes associated with inflammation, and hyperpolarised [13C]bicarbonate to measure extracellular pH. A significant increase in the [1-13C]lactate/[1-13C]pyruvate was observed throughout the inflamed tissue, but there is no apparent acidosis

 1418 Is the anterolateral ligament affected by the rupture of anterior cruciate ligament? A tentative investigation based on magnetic resonance imaging qian wang1, Cuiping Ren1, Jingliang Cheng1, and Zhizheng Zhuo2 1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Clinical Science, Philips Healthcare, Beijing, China This study aimed to demonstrate the incidence of injured of ALL following ACL rupture, as well as observe the characteristics of thus injury based on MRI. In the study, we used the high resolution 3D TSE-based sequences including the optimized T1W-VISTA and T1W-VISTA-SPAIR to evaluate the 43 knees of patients who have ligament ruptured through clinical test. Chi-square test was performed to analyze the categorical variables. Binary logistic regression was performed to investigate the main cause. It indicated that ACL injuries has closer association with ACL injuries but less association with LM injuries, and the femoral portions of ALL were easily ruptered

 1419 3D high resolution MR imaging of anterolateral ligament qian wang1, Cuiping Ren1, Jingliang Cheng1, and Zhizheng Zhuo2 1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Clinical Science, Philips Healthcare, Beijing, China This study aimed to demonstrate the feasibility of optimized 3D high resolution MR imaging for scanning anterolaterl ligament, as well as provide more accurate imaging technique for patient with ACL and ALL injured. In the study, we used the high resolution 3D TSE-based sequences including the optimized T1W-VISTA, PDW-VISTA, and T1W-VISTA-SPAIR to evaluate the 60 knees of thirty healthy volunteers. There was significant difference between the three techniques for both the radiologists, and there was high consistency between the scores of two radiologists. 3D T1W-VISTA imaging technique has a high superiority in the three techniques, which may provide more information for clinical diagnosis.

 1420 A machine learning method for tissue characterisation in the human thigh Terence Jones1,2, Sarah Wayte3, Abhir Bhalerao4, Nicola Gullick5, and Charles Edward Hutchinson1,2 1Medical School, University of Warwick, Coventry, United Kingdom, 2Radiology, University Hospitals Coventry & Warwickshire NHS Trust, Coventry, United Kingdom, 3Medical Physics, University Hospitals Coventry & Warwickshire NHS Trust, Coventry, United Kingdom, 4Computer Science, University of Warwick, Coventry, United Kingdom, 5Department of Rheumatology, University Hospitals Coventry & Warwickshire NHS Trust, Coventry, United Kingdom Inflammatory idiopathic myositis is a debilitating inflammatory muscle condition. Diagnosis relies on a battery of tests, but monitoring of disease severity can be challenging. We present a novel machine learning approach to classifying tissues using multi-parametric analysis of routine MRI sequences. A logistic regression model was trained to predict tissue type based on T1 and STIR signal intensity and 10-fold cross-validated. The system attained 93.8% sensitivity and 96.9% specificity overall (ROC area 0.991). Testing of this model showed a low level of ostensible muscle inflammation in 9/11 asymptomatic controls – likely due to misclassification of vessels.

 1421 Usefulness of PETRA imaging for frozen shoulder patients Ryuji Nojiri1, Yasuaki Tsurushima1, Hiroko Fukushima1, Masaaki Hori2, Murata Katsutoshi 3, Nobuhisa Shinozaki 4, Yasui Kenji 5, Kazuhiro Maeda5, and Ken Okazaki 5 1Radiology, Tokyo medical clinic, Tokyo, Japan, 2Radiology, Jyuntendou University Hospital, Tokyo, Japan, 3SIEMENS Healthcare Co., Tokyo, Japan, 4Orthopedics, Tokyo-kita medical center, Tokyo, Japan, 5Orthopedics, Tokyo Women’s Medical University, Tokyo, Japan Pointwise encoding time reduction with radial acquisition (PETRA) has made it possible to visualize those tissues which have a short T2* value such as ligaments and tendons as high signal images by using ultra-short echo time (TE). In this study, we evaluated the significant difference of the thickness of the joint capsule in the axillary pouch, depending on the stage or the symptom of patients with frozen shoulder.

 1422 MRI Cytography: a biomarker of microstructural myofiber damage in Amyotrophic Lateral Sclerosis Natenael B Semmineh1, Alberto Fuentes1, David Medina1, Rachael Sirianni1, and C Chad Quarles1 1Barrow Neurological Institute, Phoenix, AZ, United States For patients diagnosed with Amyotrophic Lateral Sclerosis (ALS), the clinical heterogeneity of disease presentation and progression continues to confound the identification of robust outcome measures and biomarkers that can be used as surrogates of progression to provide faster and improved decision-making during clinical trials. To overcome this limitation we developed a non-invasive imaging strategy, termed MRI Cytography (MRC) that is uniquely sensitive to abnormal muscle cytoarchitecture. In a preclinical model of ALS, MRC was able to reliably differentiate between normal and degenerated muscle microstructure.

 1423 Preliminary study of BOLD fMRI for the differentiation of musculoskeletal benign and malignant tumors Nan Sun1, Cuiping Ren1, Ying Li1, Jingliang Cheng1, and Zhizheng Zhuo2 1Dept. of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Philips Healthcare, Beijing, China This work investigated and evaluated the role of Blood Oxygenation Level-Dependent (BOLD) based functional MRI in characterizing the musculoskeletal tumors, and furtherly evaluate the ability of the power calculated from the fMRI time series  to differentiate benign and malignant tumors, which might be helpful for clinical diagnosis and studies.

 1424 MRI findings in Early Rheumatoid Arthritis, their clinical correlate and method of assessment Fan Xiao1, Jacky Ka Long Ko1, Jason Chi Shun Leung2, Ryan Ka Lok Lee1, David Ka Wai Yeung1, Lai-Shan Tam3, and James Griffith1 1Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong, 2Jockey Club Centre for Osteoporosis Care and Control, The Chinese University of Hong Kong, Hong Kong, Hong Kong, 3Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, Hong Kong This study investigated the correlation between MRI parameters and clinical assessment in 106 treatment naïve patients presenting with early rheumatoid arthritis (ERA) i.e. symptoms < 24 months. The degree of synovial and tenosynovial proliferation, bone marrow oedema and bone erosions were semi-quantitatively and quantitatively measured on MR imaging. Quantitative MRI parameters showed better correlation with clinical assessment than semi-quantitative methods. Only quantitative MRI methods showed significant change after treatment for one year.

 1425 MR based changes in normal ACL hamstring graft over two years following reconstruction Fan Xiao1, Jacky Ka Long Ko1, Alex Wing Hung Ng1, Jason Chi Shun Leung2, David Ka Wai Yeung1, Patrick, Shu Hang Yung3, and James Griffith1 1Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong, 2Jockey Club Centre for Osteoporosis Care and Control, The Chinese University of Hong Kong, Hong Kong, Hong Kong, 3Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, Hong Kong This study investigates that normal changes seen on MRI of the ACL graft over first two years after reconstruction. The graft and perigraft tissues were assessed on serial MRI examinations addressing features such as graft size, signal intensity and perfusion. MR changes were compatible with the histological process known as changes in the ACL graft, usually called ‘ligamentization of the graft’ seems to have stabilized by 24 months.

 1426 Anisotropic analysis and decay characteristics of T2* relaxation of the human Achilles tendon studied with 7 T MR-microscopy Benedikt Hager1,2, Vladimir Juras1,2,3, Martin Zalaudek1,2, Joachim Friske1,2, Xeni Deligianni4, Oliver Bieri4, Lena Hirtler5, Andreas Berg6, Markus Schreiner1,7, Sonja Walzer7, and Siegfried Trattnig1,2 1High-Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3Department of Imaging Methods, Institute of Measurement Science, Bratislava, Slovakia, 4Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland, 5Center for Anatomy and Cell Biology, Department for Systematic Anatomy, Medical University of Vienna, Vienna, Austria, 6Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 7Department of Orthopaedic Surgery, Medical University of Vienna, Vienna, Austria The fiber-to-field angle dependence and the T2* characteristics of a human Achilles tendon were investigated. The results show an increase of approx. factor 20 in T2* values when the long axis of the tendon is change from 0° to 55°, which is much higher than previously reported. Moreover, in contrast to previous findings we found no homogenous biexponential decay behavior for the tendon on a small sized voxel basis. The results reported here are to our knowledge the first MR-microscopy evaluations of the orientational dependence of T2* relaxation in the Achilles tendon.

 1427 MRI Methods for Exercise-based Perfusion Assessment of Diabetic Feet with Ulcers Masoud A Edalati1, Mary K Hastings1, Zayed Mohamed1, David Muccigrosso1, Ran Li1, Michael J Mueller1, and Jie Zheng1 1Washington Univesity in St Louis, Saint Louis, MO, United States The purpose of this study was to develop MRI methods for comprehensive evaluation of foot muscle perfusion and perfusion reserve in patients with diabetes and foot ulcers. Healthy controls and patients with diabetic foot ulcers were scanned with a non-contrast MRI protocol at rest and during a standardized foot flexion exercise. Ischemic regions around foot ulcers were clearly identified with quantitative perfusion data during the exercise.

 1428 T1ρ, T2, and RAFF are Sensitive to Acute Ischemic Injury to the Femoral Head in a Piglet Model of Legg-Calvé-Perthes Disease Casey P. Johnson1,2, Cathy S. Carlson3, Ferenc Toth3, Harry K. W. Kim4,5, and Jutta M. Ellermann1,2 1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Radiology, University of Minnesota, Minneapolis, MN, United States, 3Veterinary Population Medicine, University of Minnesota, Saint Paul, MN, United States, 4Texas Scottish Rite Hospital for Children, Dallas, TX, United States, 5Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, TX, United States We demonstrate that quantitative T1ρ, T2, and RAFF relaxation time maps are highly sensitive to bone/marrow and cartilage changes within 48 hours following ischemic injury to the growing femoral head. This work has important implications for the diagnosis and treatment of diseases associated with avascular necrosis of bone and cartilage.

 1429 Impact of Respiratory Triggering in 3T Sub-Millimeter High Resolution Brachial Plexus MRI Darryl B Sneag1, Jacqui C Zhu1, Susan Lee1, Tina Jeon1, Bin Lin1, and Maggie M Fung2 1Radiology, Hospital of Special Surgery, New York, NY, United States, 2Applications & Workflow, GE Healthcare, New York, NY, United States This study’s purpose was to compare non-respiratory and respiratory- triggered proton density and T2-weighted DIXON fat suppression sequences for high-resolution brachial plexus MRI. In a cohort of 5 volunteers and 20 patients, we were able to demonstrate that respiratory triggering substantially reduced ghosting artifact and improved delineation of nerve fascicular architecture with acceptable increased scan time.

 1430 Advanced Knee Imaging Study in NCAA Division 1 Basketball: Protocol Development and Preliminary Results Katherine A Young1, Feliks Kogan1, Robert D Peters2, Matthew F. Koff3, Valentina Pedoia4, Marc Safran5, Ben Ma4, Riley Williams3, Tom Wickiewicz3, Marianne S Black1, John M Sabol2, Kimberly K. Amrami6, Hollis Potter3, Sharmila Majumdar4, and Garry Gold1 1Radiology, Stanford, Stanford, CA, United States, 2GE Healthcare, Waukesha, WI, United States, 3Hospital of Special Surgeries, New York City, NY, United States, 4University of California San Francisco, San Francisco, CA, United States, 5Stanford, Redwood City, CA, United States, 6Radiology, Mayo Clinic, Rochester, MN, United States Chronic knee injuries are especially common in jumping athletes, and in particular high-level basketball players. In this work, we developed an advanced quantitative MRI protocol to longitudinally study early degenerative changes in high-level basketball players across multiple sites. Studying these changes, between high and low impact athletes, within one season as well as over three seasons for a cumulative effect, will help provide better insight into these changes. In developing this protocol for a multi-center study, we use a common phantom to assess biases in quantitative measurements across study scanners.

 1431 Ultra-short echo-time (UTE) imaging of the knee with curved surface reconstruction-based extraction of the patellar tendon Martin Krämer1, Marta B Maggioni1, Christoph von Tycowicz2, Nick Brisson3, Stefan Zachow2, Georg N Duda3, and Jürgen R Reichenbach1,4,5,6 1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Zuse Institute Berlin, Berlin, Germany, 3Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité – Universitätsmedizin Berlin, Berlin, Germany, 4Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 5Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 6Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany Due to very short T2 relaxation times, imaging of tendons is typically performed using ultra-short echo-time (UTE) acquisition techniques. In this work, we combined an echo-train shifted multi-echo 3D UTE imaging sequence with a 3D curved surface reconstruction to virtually extract the patellar tendon from an acquired 3D UTE dataset. Based on the analysis of the acquired multi-echo data, a T2* relaxation time parameter map was calculated and interpolated to the curved surface of the patellar tendon.

 1432 Analysis of collagen fibrillogenesis of a caprine patella tendon with magic angle imaging Karyn Elizabeth Chappell1, Catherine Van Der Straeten1, Donald McRobbie2, Wladyslaw Gedroyc1, Mihailo Ristic3, and Djordje Brujic3 1Medicine, Surgery and Cancer, Imperial College London, London, United Kingdom, 2University of Adelaide, Adelaide, Australia, 3Mechanical Engineering, Imperial College London, London, United Kingdom It is known that our collagen fiber alignment changes as we develop, reach maturity and then age: the crosslinking of collagen is considered one of the best biomarkers of aging. This study used magic angle imaging to visualise the collagen fiber changes between development and skeletal maturity in caprine knees. Immature tendons are less aligned during development, becoming more aligned as skeletal maturity is reached. This method has great potential to non-invasively improve our understanding of the development and degeneration of collagen rich structures.

 1433 Feasibility of monosodium urate assessment using multi-echo gradient echo based quantitative imaging Seung hee Han1, Yoonho Nam1, Joon-Yong Jung1, and Won-Hee Jees1 1Seoul St.Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea Gout is a common disease caused by monosodium urate (MSU) accumulation in joints. Although conventional MR imaging well describes generic features of inflammation, sensitivity of MSU is relatively low compared to dual energy CT. Because MSU has diamagnetic susceptibility, high sensitivity can be expected in magnetic susceptibility related contrast imaging. However, calcium is another diamagnetic material existing in joints. Therefore, distinguishing MSU and calcium is an essential step for imaging MSU. In this context, we investigate the feasibility of multi-echo gradient echo based quantitative imaging for MSU assessment.

 1434 The role of susceptibility weighted imaging (SWI) in musculoskeletal radiology as an alternative to computed tomography (CT). Akshaykumar Nana Kamble1 and Gaurav Gangavani2 1Radio-diagnosis, Institute of Nuclear Medicine and Allied Sciences (INMAS), Delhi, India, 2Sir Ganga Ram Hospital, New Delhi, India SWI has been used for detection of calcification and hemosiderin deposits in diagnosis of the neurological disorders, hemorrhagic disorders and neuroinfectious conditions. Our study tries to answer the question that whether the susceptibility weighted MR imaging can provide alternative to the CT scan and thus decreasing our dependency on the modality which has significant drawback of having radiation dose especially to our young patients. We compared SWi and CT for the characterization of lesion calcification and hemorrhage and we found there was no significant difference in detection rate of these characteristics between two modalities, thus proving SWI as equally sensitive.

 1435 T1 and T2 Mapping of Delayed Gadolinium Enhancement in Osteoarthritis with MR Fingerprinting Joshua D Kaggie1,2, James MacKay1,2, Guido Buonincontri3, Fiona J Gilbert1,2, Rolf F Schulte4, Alexandra R Morgan5, Robert L Janiczek5, Michela Tosetti3, Andrew McCaskie2,6, and Martin J Graves1,2 1Radiology, University of Cambridge, Cambridge, United Kingdom, 2Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom, 3IRCCS Stella Maris and IMAGO7 Foundation, Pisa, United Kingdom, 4GE Healthcare, Munich, Germany, 5Experimental Medicine Imaging, GlaxoSmithKline, London, United Kingdom, 6Division of Trauma and Orthopaedic Surgery, University of Cambridge, Cambridge, United Kingdom Mapping of quantitative MRI relaxation values is promising for improving the assessment of MSK disease. Magnetic Resonance Fingerprinting (MRF) is a new method that enables fast quantitative MRI by exploiting the transient signals caused by the variation of pseudorandom sequence parameters.   This proof-of-concept work demonstrates the utility of MR Fingerprinting in the knee. Seven participants, four of which had Kellgren-Lawrence (KL) grade 2 or 3, were imaged eighty minutes after gadolinium injection with MRF on a 3.0T MRI. The mean T1 relaxation times were shorter  in cartilage by 5-20% in KL=2,3 subjects when compared to normal subjects.

 1436 Significant Metabolic Differences Between Benign Lipomatous Lesion and  Liposarcoma Identified by High-Resolution 1H and 31P MRS: A Pilot Study Santosh Kumar Bharti1, Brett Shannon2, Adam Levin2, Carol D Morris2, Laura Fayad3, and Zaver M Bhujwalla1,4 1Division of Cancer Imaging Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 2Department of Orthopaedic Surgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 3Musculoskeletal Radiology, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 4Department of Oncology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States Adipocytic tumors present a spectrum of neoplastic disease including benign lipomas and their variants, atypical lipomatous tumors, and malignant liposarcomas. Distinguishing areas of malignant dedifferentiation from benign and atypical lipomatous tumors is a diagnostic challenge due to overlapping magnetic resonance imaging characteristics, and pre-operative diagnostic accuracy is poor. Here we have identified dramatic differences in the metabolic profile of water-soluble and lipid extracts of adipocytic tumors, suggesting that magnetic resonsance spectroscopy may have the potential to improve diagnostic accuracy. Our data may also lead to potential metabolic targets for treatment.

 1437 Automated Seed Points Selection Based Radial-Search Segmentation Method For Sagittal and Coronal View Knee MRI Imaging Sandeep Panwar Jogi1,2, Rafeek T.1, Sriram Rajan3, Krithika Rangarajan3, Anup Singh1, and Amit Mehndiratta1 1Centre of Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2BME, ASET, Amity University Haryana, Gurgaon, India, 3Mahajan Imaging Centre, New Delhi, India Knee disorders are generally marked in tibio-femoral bone junction. Most of available segmentation techniques use time consuming semi-automatic approach as radial search method, in sagittal view only. However, coronal view MRI Knee images are clinically equal important. Proposed approach automates seed points selection process for the radial search method, which work equally good on both sagittal and coronal view for identification of tibio-femoral junction.

### Bone

 Exhibition Hall 1438-1450 Monday 8:15 - 10:15

 1438 Does chemical shift imaging offer a biomarker for the diagnosis and assessment of disease severity in multiple myeloma? Miyuki Takasu1, Takayuki Tamura1, Yuji Akiyama1, Chihiro Tani1, Yoko Kaichi1, Shota Kondo1, and Kazuo Awai1 1Department of Diagnostic Radiology, Hiroshima University Hospital, Hiroshima, Japan We investigated whether chemical shift imaging (CSI) is useful for differentiating multiple myeloma infiltration from hematopoietic bone marrow and for quantitatively assessing disease severity. For those myeloma patients with relatively high cellularity in the bone marrow, a lower signal drop on oppose phase images indicated a higher tumor burden. For bone marrow with relatively low cellularity, disease severity was not reflected on CSI. CSI did not prove useful for differentiating myeloma infiltration from hematopoietic bone marrow, which implies that differentiation between regrowth of hematopoietic bone marrow and minimal residual disease or relapse after chemotherapy might be difficult with CSI.

 1439 Towards Whole-Skeleton Fat Fraction Mapping: The Impact of Parallel Imaging Vruti Dattani1, Tim Bray2, Alan Bainbridge3, and Margaret A Hall-Craggs2 1Royal Free Hospital, London, United Kingdom, 2Centre for Medical Imaging, University College London, London, United Kingdom, 3Department of Medical Physics, University College London Hospitals, London, United Kingdom Whole body MRI (WB-MRI) is increasingly used to image the skeleton in haematological diseases such as multiple myeloma (MM) and inflammatory disorders such as spondyloarthritis. WB-MRI can be used to acquire fat fraction (FF) maps, which can assess disease severity and treatment response. However, patients with bone pain find it difficult to lie in the scanner for long periods, necessitating the use of parallel imaging to accelerate the acquisition. The aim of this study was to determine the extent to which parallel imaging causes noise artifacts and fat-water swaps in FF maps, and to assess their impact on FF measurements.

 1440 Fat Fraction Thresholds for Defining Bone Marrow Edema and Fat Metaplasia in Spondyloarthritis: More Objective than ‘A Tiny Bit of White’ Timothy J P Bray1,2, Alan Bainbridge3, Corinne Fisher2, Debajit Sen2, and Margaret A Hall-Craggs1,2 1Centre for Medical Imaging, University College London, London, United Kingdom, 2Arthritis Research UK Centre for Adolescent Rheumatology, University College London, London, United Kingdom, 3Department of Medical Physics, University College London Hospitals, London, United Kingdom MRI is now widely used to diagnose spondyloarthritis, but existing methods for image analysis rely on qualitative visual analysis by radiologists, and suffer from poor reproducibility between observers. Here, we show that proton density fat fraction (PDFF) measurements can be used as an objective, quantitative alternative to visual analysis. Using receiver operating characteristic (ROC) analysis, we find that PDFF measurements enable accurate separation of bone marrow edema (active inflammation) and fat metaplasia (structural damage) from normal marrow. The described approach is more objective than looking for 'a tiny bit of white' on fat-suppressed images, which is the current clinical standard.

 1441 Measure for Measure: Machine Learning Models for Osteoporosis MRI data Uran Ferizi1, Harrison Besser1, Chamith S Rajapakse2, Punam K Saha3, Stephen Honig1, and Gregory Chang1 1New York University School of Medicine, New York, NY, United States, 2University of Pennsylvania School of Medicine, Philadelphia, PA, United States, 3University of Iowa College of Medicine, Iowa City, IA, United States We examine how Machine Learning can be used to identify novel risk factors of osteoporotic bone fracture. Using measurements from patient MRI scans at five anatomical sites, we sought to find which specific regions are best for stratifying the risk of osteoporotic fracture. Further studies on these models and other data will help improve clinicians’ ability to accurately diagnose Osteoporosis, so that patients at risk for bone fracture may be caught and treated earlier.

 1442 Performance of different classifiers in the diagnosis of benign and malignant bone tumors based on MR diffusion kurtosis imaging Zhizheng Zhuo1, Ying Li2, Cuiping Ren2, and Jingliang Cheng2 1Clincial Science, Philips Healthcare, Beijing, China, 2Radiology Department of First Affiliated Hospital of Zhengzhou University, Zhengzhou, China Recently, the AI (Artificial Intelligence) is popular in the clinical diagnosis based on medical imaging. The major target is to identify or classify the disease condition through the features extracted from the clinical images. Different algorithms (or classifiers) can be applied to classify the disease and the performance might be different for a specific clinical issue. In this work, we tried to investigate the performance of different classifiers in the diagnosis of benign and malignant bone tumors based on MRI diffusion kurtosis imaging.

 1443 Chemical Shift Quantitative Magnetic Susceptibility Study of Ex-vivo Human Cortical Bone Specimen with three-dimensional Cones ultra-short echo time (UTE) imaging Xing Lu1,2, Saeed Jerban1, Michael Carl3, Yajun Ma1, Annette von Drygalski4, Eric Y Chang5, and Jiang Du1 1Department of Radiology, University of California, San Diego, San Diego, CA, United States, 2Institute of Electrical Engineering, Chinese Academy of Science, Beijing, China, 3GE Healthcare, San Diego, CA, United States, 4Department of Medicine, Division of Hematology/Oncology, University of California, San Diego, San Diego, CA, United States, 5Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States Bone mineral density (BMD) evaluation is crucial for the diagnosis of osteoporosis and related fractures. The purpose of this pilot study was to use a chemical-shift QSM method based on a 3D UTE-Cones sequence to assess the susceptibility values of human cortical bone specimens with consideration of gender and donor age, ranging over 5 decades. Significant differences between QSM values were observed for the different genders. A decaying trend between the minus QSM value and advancing age exists, which suggests a relationship between QSM values and BMD.

 1444 Study of mono-exponential and intravoxel incoherent motion models in differentiation of metastasis from myeloma Xiaoying Xing1, Ning Lang1, and Huishu Yuan1 1Peking University 3rd Hospital, Beijing, China This study aimed to evaluate the diagnostic performance of diffusion weighted imaging (DWI) to differentiate metastasis from myeloma using the apparent diffusion coefficient (ADC) and parameters derived from the intravoxel incoherent motion (IVIM) theory. 40 patients with metastasis and 12 with myeloma underwent diffusion-weighted magnetic resonance (MR) imaging and dynamic contrast enhanced MRI (DCE-MRI). ADC, diffusion coefficient(D), pseudodiffusion coefficient(D*), and perfusion fraction (f) were calculated.Through our study it is feasible to d ifferentiate metastasis from myeloma by mono-exponential and IVIM models . IVIM-derived D and D* values showed significantly better diagnostic performance than ADC values in differentiating metastasis from myeloma.

 1445 Clinical value of semi-quantitative and quantitative MR perfusion imaging in distinguishing malignant from benign bone tumors Ying Li1, Cuiping Ren1, Jingliang Cheng1, and Zhizheng Zhuo2 1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Philips Healthcare, Beijing, China The dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) is a common scanning technology which contains semi-quantitative and quantitative perfusion information. This work investigated and evaluated the ability of semi-quantitative and quantitative perfusion information in characterizing the bone tumors, and furtherly evaluate the ability of semi-quantitative and quantitative parameters to differentiate benign and malignant tumors.

 1446 Proton Density Zero Echo Time(ZTE) Imaging for Evaluating the Bone Involvement in the Femoral Tumor Xin Lou1, Jinfeng Li1, Lin Xu1, Xigang Zhao2, Jianxun Qu2, and Lin Ma1 1Radiology and Imaging, China Army General Hospital, Beijing, China, 2General Electric Healthcare, Beijing, China MRI can display the compositions of different tissues and adjacent involvements. In the patients of bone tumors, the integrity of cortical bone needed to be assessed for the preoperative planning. This study used proton density ZTE to display the bone involvement in patients of femoral tumors. Substantial agreement was found between CT and ZTE (r=0.98-0.99) and there was not statics significance between the measured diameters from CT and ZTE MRI (p=0.34-0.99). further development of ZTE may obviate the need of CT in evaluating the bone involvement of femoral tumors.

 1447 Preliminary study of T1rho imaging technique in assessment of early intervertebral disc degeneration in asymptomatic pilots at 3.0T magnetic resonance XiuLan Zhang1, Yongmin Bi2, and Lizhi Xie3 1Radiology Department, The First Affiliated Hospital of Yangtze University, JingZhou, China, 2Department of CT&MRI, Air Force General Hospital, Beijing, China, 3GE Healthcare, China, Beijing, China T1rho MRI in the lumbar spine may provide a tool for the diagnosis of early degenerative changes in the disc. In this study, the mean T1rho value of pilots was significantly lower than that of the control group. The degenerative grades of pilots mainly were grade III and IV, but control group were grade I and II. There were significant differences in T1rho values at each age group between pilots and control group. And overload on spine column of pilots may be the important reason in degeneration and accelerate the degeneration process.

 1448 Utility of ZTE for the Characterization of Acute Ankle Fractures Alissa J. Burge1, Ryan E Breighner1, Megan Sahr1, Matthew F. Koff1, Ogonna K Nwawka1, Darryl B. Sneag1, Gabrielle Konin1, Bin Lin2, David Helfet1, and Hollis G. Potter1 1Hospital for Special Surgery, New York, NY, United States, 2Department of Radiology and Imaging - MRI, Hospital for Special Surgery, New York, NY, United States ZTE MRI provides CT-like tissue contrast, facilitating evaluation of mineralized bone. The utility of ZTE for evaluation of acute ankle fractures was evaluated in a series of 14 patients who underwent preoperative clinical MRI with an additional ZTE sequence, and subsequently underwent surgical fracture fixation. Fractures were characterized in a blinded fashion utilizing ZTE and CT, with subsequent operative confirmation. ZTE provided accurate characterization of fractures relative to both CT and surgery, with excellent inter- and intra-observer reliability.

 1449 Analysis of the relationship between mandibular joint motion trajectory and masticatory muscle properties (volume, shape, T1&T2 value) with MR dynamic imaging Ryusuke Nakai1,2, Takashi Azuma3, Toshihiro Togaya4, and Hiroo Iwata2 1Kokoro Research Center, Kyoto University, Kyoto, Japan, 2Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan, 3The Graduate School of Engineering, Kyoto University, Kyoto, Japan, 4Osaka Dental University, Osaka, Japan For the diagnosis of temporomandibular joint disease, it is important to analyze with complete accuracy the range of mandibular motion and the tissue properties of the masticatory muscle in individual patients. In this study, we explored the parameters for accurate imaging of the mandibular motion trajectory using MR dynamic imaging, and then analyzed the relationship between the range of mandibular motion and the tissue properties of the masticatory muscle. As a result, we successfully identified the optimal imaging parameters and clarified that the range of side-to-side motion of the mandibular joint correlated with the tissue properties of the masticatory muscle.

 1450 Macromolecular and water pools distribution maps in bovine cortical bone using ultrashort echo time (UTE) MRI combined with magnetization transfer (MT) modeling Saeed Jerban1, Yajun Ma 1, Wei Zhao1, Xing Lu1, Michael Carl2, Eric Y Chang1,3, and Jiang Du1 1Radiology, University of California, San Diego, San Diego, CA, United States, 2GE Healthcare, San Diego, CA, United States, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States Collagenous matrix, bound and pore water pools are main responsible components for viscoelastic properties of the cortical bone. Quantitative ultrashort echo time MR imaging (UTE-MRI) has been shown to be able to assess bound and pore water components as indexes for bone microstructure. UTE magnetization transfer (UTE-MT) modelling can evaluate the macromolecular (MM) components of the bone (collagen). Pixel mapping of MR properties of collagen and water components in cortical bone helps to localize pathologic or traumatic bone defects. This study focused on deriving the pixel maps of MR properties of these key bone components on seven bovine bone specimens.

### MR Safety

 Exhibition Hall 1451-1475 Monday 13:45 - 15:45

 1451 Assessment of Peripheral Nerve Stimulation due to MR gradient induced Electric Field around Implantable Device Xiyao Xin1, Xi Lin Chen1, Xin Huang1, and Shiloh Sison1 1Abbott, Sylmar, CA, United States Time varying magnetic gradient fields can induce electric field (E-field) in the human body and may cause peripheral nerve stimulation (PNS) during MR scan. As metallic implant may cause local E-field enhancement, there is speculation that it may increase risk of PNS. In this study, gradient coil modeling is used to investigate induced E-fields around implantable devices. The maximum E-field in the proximity of implants is compared to the whole body maximum E-field of the human body without implant. The result shows that the local enhanced E-field near implants does not exceed the whole body maximum E-field in human body.

 1452 Impacts of 3.0 Tesla magnetic resonance imaging noise on hearing function in neonates with hearing protection Huifang Zhao1, Chao Jin1, Xinyu Li1, Heng Liu1, Xiaoyu Wang1, Xingxing Tao1, Yannan Cheng1, and Jian Yang1 1Department of Diagnostic Radiology, the First Affiliated Hospital of Xi'an Jiaotong University, Xian', China Loud acoustic noise generated from magnetic resonance (MR) imaging remains the great concern for neonatal exams. This study therefore aims to clarify whether this noise would cause the hearing loss to neonates who underwent MRI exam by auditory brainstem response (ABR). Results indicated that there was no significant difference in all the six ABR indices (waves I, III, V amplitudes and wave I-III, III-V, I-V intervals) between before and after the MRI examinations. Our findings may suggest the rarely temporary impact of MRI noise on ABR in neonates who underwent a 3.0T MRI.

 1453 The transfer function for implanted wires when a second wire is near. Peter R.S. Stijnman1, Janot P. Tokaya1, Cornelis A.T. van den Berg1, and Alexander J.E. Raaijmakers1 1Center for Image Sciences, UMC Utrecht, Utrecht, Netherlands Lead wires of medical implants can pose a severe safety risk due to RF-induced heating. Risk assessment typically involves determination of the transfer function. This study shows that the transfer function may drastically change if a second wire is located close to the lead wire. An explorative simulation study has been performed investigating the impact of inter-wire spacing and wire length on the alteration of the transfer function by the second wire. Results reveal that in particular insulated wires may show very strong enhancements (>100%) in induced currents if a second wire is present.

 1454 Analysis and Design of Lead Wires with Metallic Shielding for Reduction of RF Heating during MRI for Active Implants Krishna Singhal1 and John A. Nyenhuis1 1Purdue University, West Lafayette, IN, United States The purpose of this work is to provide a quantitative understanding of how a conducting metallic shield over a lead will reduce RF heating at the electrode during MRI scans. A physical model and equations for reduction of RF heating by a shielded lead are presented. Temperature rise were calculated for different lengths of shielded and unshielded leads. Confirming measurements were made for a quarter wavelength coaxial cable model of the lead. Measured temperature rise and transfer function depended on terminations conditions, with the open lead exhibiting a temperature rise approximately 10 times greater than the shorted lead.

 1455 MRI compatible neural electrodes for simultaneous deep brain stimulation and fMRI mapping Siyuan Zhao1,2,3, Gen Li1, Wenjing Chen4, Zhifeng Liang4, and Xiaojie Duan1,2,3 1Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China, 2Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 3Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Peking University, Beijing, China, 4Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China Functional magnetic resonance imaging (fMRI) under deep brain stimulation (DBS) provides important insights into understanding the connection of the neural networks. However, such research has been limited by incompatibility of common electrode in the MR environment. To address such issue, we fabricated a novel graphene based neural microelectrode, which exhibited excellent charge storage capacity and MRI compatibility. Using such microelectrode, we successfully demonstrate deep brain stimulation of subthalamic nucleus (STN) evoked robust BOLD activation in cortex and basal ganglia nucleus of the Parkinsonian rats with minimal image artifact. Therefore, MR-compatible graphene microelectrode could provide unique opportunity for simultaneous DBS-fMRI studies.

 1456 RF-induced heating of a conducting wire entering into a dielectric medium along right-left axis on the presence of another wire during MRI Pallab K Bhattacharyya1,2, Tanvir Baig3, Bhumi Bhusal3, Mark J Lowe1, Michael Martens3, and Stephen Jones1 1Imaging Institute, Cleveland Clnic, Cleveland, OH, United States, 2Radiology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, United States, 3Physics, Case Western Reserve University, Cleveland, OH, United States RF-induced heating of stereo encephalography (SEEG) electrodes during MRI scans could be of concern. The change in heating pattern of an electrode in the presence of another electrode was investigated by measuring the heating at the tip of a conducting and insulated (bare at tip) wire parallel to B0-field and entering a poly-acrylic gel phantom along left-right axis in the presence of another wire. While the resonance length for maximum heating of the wires did not depend on the number of wires, the temperature rise at the wire tips depended on the relative lengths (resonance / anti-resonance) of the wires.

 1457 Safety of MRI scans of partially implanted entirely insulated conducting wire with spine matrix coil at 3T Pallab K Bhattacharyya1,2, Bhumi Bhusal3, Anna Crawford1, Thomas Masaryk1, and Mark J Lowe1 1Imaging Institute, Cleveland Clnic, Cleveland, OH, United States, 2Radiology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, United States, 3Physics, Case Western Reserve University, Cleveland, OH, United States RF-induced heating of an entirely insulated partially implanted conducting wire in a gel phantom was measured at two different 3 tesla systems with a receive-only spine matrix coil. Presence of inner spiral-wound stainless steel helix in Arrow AK-05502 intrathecal catheters raises concern about possible RF-induced heating during MRI. Temperature of the catheter was measured by using fiber optic sensors with fluoroptic monitoring with the catheter inserted into an ASTM gel phantom.  Different configurations representing in vivo settings were tested at different E-fields in the phantom. No significant heating was observed in any of the configurations.

 1458 Transmit Coil impedance measurements to estimate radiofrequency induced currents on wires in MRI Brandon J Coles1, Kevan J Anderson2, Greig C Scott3, Christopher W Ellenor3, and Graham A Wright1,2 1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Sunnybrook Research Institute, Toronto, ON, Canada, 3Electrical Engineering Department, Stanford University, Stanford, CA, United States MRI introduces a safety risk when performing imaged guided interventions caused by induced currents on interventional devices that potentially lead to dangerous temperature increases near their tip. This safety issue can be reduced using parallel RF transmission approaches, although it is difficult to ensure safety when device motion is involved. In this work, impedance changes of a transmit coil are used to estimate the coil’s induced current on a device, and this is extended to a two coil array to determine individual transmit signals needed to reduce the total induced current on a device with simple device geometry.

 1459 The feasibility study about the protection circuit for unplugged local transceiver coil in MRI bore Seunghoon Ha1, Adam Morris1, Jay Berres1, and Jonathan Nass1 1Philips Healthcare, Pewaukee, WI, United States The local transceiver coil such as a birdcage coil has still been equipped for local extremity or brain MRI in clinical study. By accident, the local transceiver coil is disconnected from an MRI system and inadvertently leaves linked to strong MRI RF fields during imaging procedures using other RF coils. It makes the local transceiver coil damaged such as components burnt as well as worse plastic housing melt and even causes patients’ skin to burn during clinical scanning. To prevent from these damages, we propose a new protection circuit to prevent the unplugged local transceiver coil in MR bore from RF power radiated by the whole body transmitter coil.

 1460 The effect of fetal dielectric properties, position and blood-flow in maternal tissues on fetal temperature for fetal MRI at 3T Shaihan J Malik1, Jeffrey W Hand1, and Joseph V Hajnal1 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom Effects of age adjusted dielectric properties for fetal tissues compared to adult values, fetal position, and blood-flow in maternal tissues on fetal temperature in a model of a 7 month pregnant woman within a 3T birdcage coil were investigated numerically.  Age adjusted properties resulted in small increases in peak and mean fetal temperatures and reduced time to reach a peak fetal temperature of 39°C. Changes in fetal position produced a greater effect on peak and mean fetal temperatures. Temperature dependent blood-flow in maternal superficial tissues had little effect on fetal temperature.

 1461 T2 Relaxation in Evaluating Gd deposition: comparison between MultiHance and Magnevist Ning HUA1, Pedro V. Staziaki2, Mohamad Assayuri2, Vanesa Carlota Andreu Arasa2, Hernan Jara1, and Osamu Sakai2 1Boston University, Boston, MA, United States, 2Boston Medical Center, Boston, MA, United States Purpose: To evaluation quantitative T2 mapping in exploring the effects of prior Gd exposure. Methods: Dual-echo MRI was performed in three groups of subjects; 1) without prior Gd exposure history, 2) only with prior exposure to MultiHance®, and 3) only with prior exposure to Magnevist®. T2 relaxation times were measured in pons, dentate nuclei, globus pallidi and thalami.  Results: T2 relaxation time decrease was observed for both contrast agents in dentate nuclei and globus pallidi. Conclusion: Quantitative T2 mapping is a valuable tool in the investigation of Gd deposition in the brain.

 1464 The impact of altering MRI equipment and scanning parameters on phantom signal intensity ratio measurements – possible implications for interpreting Gadolinium signal changes within the brain Laura Kate Young1, Shona Matthew1, Stephen Gandy2, Lukasz Priba2, and John Graeme Houston1,3 1Division of Molecular and Clinical Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee, United Kingdom, 2Medical Physics, NHS Tayside, Ninewells Hospital and Medical School, Dundee, United Kingdom, 3Clinical Radiology, NHS Tayside, Ninewells Hospital and Medical School, Dundee, United Kingdom Signal hyper-intensities within brain regions have been attributed to the deposition of gadolinium following repeat administrations of MR contrast agents. These have been mainly investigated retrospectively, but acquisition parameters may have varied. We investigated the impact of altering imaging parameters when measuring phantom signal intensity ratios (SIR). By changing parameters from a baseline, it was established that the application of filters, number of coil receiver channels, and changes to TR and TE resulted in percentage signal fluctuations of similar magnitude to hyper-intensities. It is recommended that imaging parameters are standardised where possible when interpreting SIR data in longitudinal brain studies.

 1465 Estimated Measurement Uncertainty (EMU) in Calorimetrically-Determined Whole Body SAR Values for Medical Device Evaluation Using Benchtop Radiofrequency Exposure Systems Krzysztof Wawrzyn1, Jack Hendriks1, William B. Handler1, and Blaine A. Chronik1 1The xMR Labs, Department of Physics and Astronomy, Western University, London, ON, Canada The in vitro assessment of true radiofrequency whole body averaged specific absorption rate (WB-SAR) is described in the technical specification standard of ASTM F2182-11a, by direct measure of RF-induced heating within a standardized phantom centered inside the RF birdcage coil. F2182-11a does not address uncertainty assessment of the heating experiment.  In this study, we present our measured values for short-term measurement repeatability and long-term measurement reproducibility. These measurements support the conclusion that RF-induced WB-SAR measurements made with bench-top RF exposure systems can be made with a total estimated measurement uncertainty of approximately 7% (k=1).

 1466 Impact of tissue image segmentation errors on SAR Asha Singanamalli1, Matthew Tarasek1, Qin Liu2, Desmond Yeo1, and Thomas Foo1 1GE Global Research, Niskayuna, NY, United States, 2GE Healthcare, Waukesha, WI, United States In this study, we evaluate the sensitivity of peak and global SAR to false positive (FP) and false negative (FN) errors in segmentation for three major brain tissue types: Gray Matter (GM), White Matter (WM) and Cerebrospinal Fluid (CSF). Voxel probability maps of GM, WM and CSF are thresholded at various intervals to generate multiple anatomical head models from a simulated T1w MRI dataset. FP and FN errors in segmentation are evaluated for each anatomical model with respect to the ground truth. Electromagnetic simulations are performed to relate these errors to peak and global SAR values at 3T.

 1467 Safety and EEG Data Quality of Concurrent High-Density EEG and High-Speed fMRI at 3 Tesla Mette Thrane Foged1,2, Ulrich Lindberg3, Kishore Vakamudi4,5, Henrik BW Larsson2,3, Lars Pinborg1,2, Troels W Kjær2,6, Martin Fabricius6, Claus Svarer1, Brice Ozenne7, Carsten Thomsen2,8, Sándor Beniczky6,9,10, Olaf Bjarne Paulson1,2, and Stefan Posse4,5,11 1Neurobiology Research Unit, Department of Neurology, Rigshospitalet, Copenhagen, Denmark, 2Dept. of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark, 3Functional Imaging Unit, Dept. of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark, 4Department of Neurology, University of New Mexico, Albuquerque, NM, United States, 5Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, United States, 6Dept. of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark, 7Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark, 8Dept. of Radiology, Rigshospitalet, Copenhagen, Denmark, 9Danish Epilepsy Centre, Dianalund, Denmark, 10Aarhus University, Aarhus, Denmark, 11Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, United States Using concurrent high-density EEG and different high-speed fMRI methods, we investigate safety of RF heating, effect on image SNR and assess EEG data quality. RF related electrode heating during a 30-minute scan did not exceed 1.0o C with any of the pulse sequences. No significant differences in the EEG data quality were found between high-speed fMRI and conventional EPI (p=0.78). Residual ballistocardiographic artifacts resulted in 58% of EEG data being rated as poor quality. This study demonstrates that high-density EEG can be safely implemented in conjunction with high-speed fMRI and that high-speed fMRI does not adversely affect EEG data quality.

 1468 Active Implantable Medical Device – Can its Radio Frequency Radiation be a Potential Source of MR Image Artifact? Xi Lin Chen1, Perry Li1, and Shiloh Sison1 1Abbott Laboratories, Sylmar, CA, United States To assess if an active implantable medical device (AIMD) may unintentionally generate radio frequency signals near the receiver band of an MRI RF coil and cause image artifact, a method is proposed in this study to quantify the maximum AIMD radiated signal strength near the MR Lamor frequencies at 1.5T and 3T. Three commercially available AIMDs were investigated and the maximum radiated signal level was found to be around -120 dBm at the 64 and 128 MHz range. Such information can be utilized in conjunction with MR RF receiver specifications to determine the potential impact on image artifacts

 1469 Implantable Lead MRI RF Heating in-vivo Transfer Function Modeling to Determine Suitable Test Medium Xi Lin Chen1, Shi Feng1, Xiyao Xin1, Xin Huang1, Ruoli Jiang1, and Shiloh Sison1 1Abbott Laboratories, Sylmar, CA, United States This abstract presents a novel technique to determine the suitable tissue simulating medium (TSM) conductivity for MRI lead electrode RF heating transfer function (TF) determination. The proposed method utilizes validated numerical lead model in conjunction with tissue models extracted along lead trajectories in anatomical models to produce in-vivo transfer function models. When combined with in-vivo incident electric fields, the power deposition or temperature rise predicted by the in-vitro and in-vivo TFs can be compared to assess the suitability and conservativeness of the selected TSM conductivity.

 1470 Comparison of RF Induced Device Heating at 0.35T and 1.5T Jessica A. Martinez1,2, Kévin Moulin1, Yu Gao1, Peng Hu1, and Daniel B. Ennis1,2 1Radiological Sciences, UCLA, Los Angeles, CA, United States, 2Bioengineering, UCLA, Los Angeles, CA, United States RF induced heating is a safety concern for patients with implanted electronic devices (IEDs). At lower field strengths (0.35T) heating is expected to be lower than at higher field strengths (1.5T). However, little experimental data has been acquired at field strengths below 1.5T. The purpose of this work is to compare the effects of field strength on RF induced heating by applying the same RF power in a metallic rod at 0.35T and 1.5T. We found that heating was substantially lower at 0.35T than 1.5T, which may be substantially beneficial for patients with IEDs.

 1471 Resonant heating study of a partially immersed implant in ASTM phantom and Human Model Bhumi Bhusal1, Tanvir Baig1, Pallab Bhattacharyya2, Stephen Jones2, and Michael Martens1 1Physics, Case Western Reserve University, Cleveland, OH, United States, 2Imaging Institute, Cleveland Clinic, Cleveland, OH, United States The RF heating of partially immersed implants in homogenous phantoms is reported to be highest for conductors at the resonant length. When addressing RF safety concerns, it is important to understand if these results apply to the heterogeneous structure within the human head.  In this study, numerical simulations of RF heating of a partially immersed wire in an ASTM phantom are compared to an IT’IS virtual human model (Duke) for a head-only RF transmit coil in a 3 T MRI. We find that the resonant lengths are the same in both cases but the peak SAR changes slightly.

 1472 Evaluation of RF-related heating of an MR-compatible catheter using MR-Thermometry Marylène DELCEY1,2,3,4, Pierre BOUR1,2,3,5, Valery OZENNE1,2,3, and Bruno QUESSON1,2,3 1IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France, 2Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France, 3INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France, 4Siemens Healthineers, Saint-Denis, France, 5Image Guided Therapy SA, Bordeaux, France This study presents a fast MR-thermometry sequence interleaved with a tunable SAR deposition module to simulate energy deposition of any clinically relevant MR-acquisition sequence. Validation of the method was performed on a 1.5T scanner using an MR-compatible catheter inserted into an agar-agar gel. Maximal temperature increase measured during equivalent SAR of a cardiac cine sequence was 41.8°C for a 90° flip angle. This sequence may help quantifying the maximal acceptable SAR for any patient wearing implanted device and/or for volumetric imaging of local heating in multi-transmit technology at high field.

 1473 MRI RF Safety of Active Implantable Medical Devices (AIMDs): Experimental Study of the Effect of Conductivity of Tissue Simulating Media Jingshen Liu1, Krishna Kurpad2, Paul Stadnik2, Jeffrey VonArx2, Larry Stotts2, Wolfgang Kainz3, and Ji Chen1 1University of Houston, Houston, TX, United States, 2Micro Systems Engineering Inc., Lake Oswego, OR, United States, 3Food and Drug Administration, Silver Spring, MD, United States Experimental study of the effect of conductivity of tissue simulating media is performed for MRI RF safety of active implantable medical devices. The influence of medium surrounding the implantable lead tip, and the influence of medium surrounding implantable pulse generator are analyzed.

 1474 Electro-Optic E-field Mapping of Medical Implants with High Spatial Resolution: Resonant Excitation of Metallic Stents Simon Reiss1, Thomas Lottner1, Ali Caglar Özen1, Michael Bock1, and Andreas Bitzer1,2 1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2BIOLAB Technolgy AG, Zürich, Switzerland Electrically conducting implants with small and complex geometrical structures such as stents require electric field measurements with high spatial resolution to assess local MRI safety. So far, E-fields have been measured with dipole antennae that are limited in spatial resolution to several millimeters. In this study, we present an optical setup for 2D spatially resolved E-field measurements of medical implants with high spatial resolution. Resonant excitation of metallic NiTi stents with varying lengths is assessed and the sub-millimeter spatial resolution of the setup is demonstrated.

 1475 Development and evaluation of a single-phase alloy with magnetic susceptibility equivalent to that of mammalian tissue for coil embolization of a cerebral aneurysm Ryusuke Nakai1,2, Takashi Azuma3, Mitsuaki Toda2, Tomonobu Kodata4, and Hiroo Iwata2 1Kokoro Research Center, Kyoto University, Kyoto, Japan, 2Institute for Frontier and Medical Life Sciences, Kyoto University, Kyoto, Japan, 3Graduate School of Engineering, Kyoto University, Kyoto, Japan, 4Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan Relatively less invasive MRI has recently been increasingly used for examination after coil embolization of a cerebral aneurysm, but there is a risk of misdiagnosis due to magnetic susceptibility artifacts. In this study, we developed a device composed of a highly biocompatible alloy with magnetic susceptibility equivalent to that of mammalian tissue, and evaluated it using both an in vitro model and rabbits. We found that this alloy markedly reduced magnetic susceptibility artifacts and can be used as a device in the body. We are planning to develop various implantable medical devices using this alloy.

### MR-Guided Interventions

 Exhibition Hall 1476-1508 Monday 13:45 - 15:45

 1476 Evaluation of 2D simultaneous multi-slice EPI for high resolution thermometry in the brain at 3T. Valéry Ozenne1,2,3, Pierre Bour1,2,3,4, Mathieu Santin5,6, Romain Valabrègue5,6, Charlotte Constans7, Aurélien Trotier8, Sylvain Miraux8, Jean-Francois Aubry7, and Bruno Quesson1,2,3 1IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France, 2Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France, 3INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France, 4Image Guided Therapy SA, Bordeaux, France, 5CENIR, Centre de NeuroImagerie de Recherche, Paris, France, 6ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, Paris, France, 7Institut Langevin Ondes et Images, ESPCI ParisTech, CNRS 7587, UMRS 979 INSERM, Paris, France, 8Centre de Résonance Magnétique des Systèmes Biologiques, UMR5536, CNRS, Univ. Bordeaux, Bordeaux, France MR-guided HIFU in the brain currently lacks from insufficient spatial and temporal monitoring of the effect of ultrasound. In this study, we combine simultaneous multi-slice (SMS) echo planar imaging (EPI) technique with in-plane parallel imaging to achieve high spatial resolution with large volume coverage and/or short acquisition time during temperature mapping at 3T. The sequence was tested in vivo in a human brain with different multiband (MB) factors. SMS reconstruction and temperature mapping were computed using the Gadgetron framework. Then, validation was performed on an ex vivo chicken muscle during HIFU sonication to validate the method.

 1477 Accelerated imaging for visualizing interventional devices using parallel acquisition and compressed sensing reconstruction Samira Vafay Eslahi1, Caiyun Shi2, Haifeng Wang2, Yifeng Ye3, Hanwei Chen3, Guoxi Xie4, and Jim Ji1 1Electrical and Computer Engineering, Texas A&M university, College Station, TX, United States, 2Shenzhen Institutes of Advanced Technology, Lauterbur Research Center for Biomedical Imaging, Shenzhen, China, 3Department of Radiology, Panyu Central Hospital, Guangzhou, China, 4Department of Biomedical Engineering, Guangzhou Medical University, Qingyuan, China Visualizing implanted and/or surgical devices is crucial for interventional radiology. Conventional MRI shows the devices as dark voids or with metal artifacts. Recent methods based on susceptibility mapping using fast spin-echo sequences can offer positive contrast visualizations, but they are relatively slow. In this work, parallel acquisition and compressed sensing reconstruction are integrated to accelerate the phase-sensitive acquisition and reconstruction. Applications in brachytherapy, biopsy and stent placement are demonstrated with simulations from real data. The proposed method can increase the acquisition speed by four while preserving the images quality.

 1478 Proton resonance frequency based MR thermometry using shifted-echo bSSFP Seohee So1, Jaejin Cho1, Kinam Kwon1, Byungjai Kim1, Wonil Lee1, and Hyunwook Park1 1School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea Magnetic resonance thermometry provides noninvasive temperature measurements for thermal therapy. In this abstract, we exploit linear phase relation generated by echo shifting in the bSSFP acquisition to measure PRF change. Echo-shifting from TE=TR/2 in bSSFP provides a linear relation between phase of transverse magnetization and phase evolution in TR. This linearity enables frequency prediction from the phase information, which makes temperature measurement with PRF shift possible. The performed simulations show shifted-echo bSSFP of TE=TR/4 well estimates frequency change.

 1479 Dependence of Focused-Ultrasound Induced Blood-Brain Barrier Opening Effect with Exposure Time: Evaluation via Dynamic Contrast-Enhanced Magnetic-Resonance Imaging Wen-Yen Chai1,2, Po-Chun Chun3, Sheng-Kai Wu4, Chih-Hung Tsai2, Hsin-Yi Lai5, and Hao-Li Liu2 1Department of Diagnostic Radiology and Intervention, Chang-Gung Memorial Hospital, Taoyuan, Taiwan, 2Department of Electrical Engineering, Chang-Gung University, Taoyuan, Taiwan, 3Department of Research and Development, NaviFUS corp., Taipei, Taiwan, 4Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 5Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University, Hangzhou, China FUS exposure with presence of microbubbles can transiently open the BBB at targeted brain tissues. The study purpose is to investigate the dependency of the BBB opening effect with ultrasound exposure time by DCE-MRI. Our result showed extending exposure time can effectively increase FUS-induced BBB opening degree without causing tissue damage. We also proposed a strategy by adjusting exposure time during the multiple exposures to overcome the effects that microbubbles concentration dynamic changed after IV bolus injection. This approach of control FUS exposure time may bring technology advances of FUS-induced BBB opening to deliver drug for CNS disease treatment.

 1480 Correction of Motion-Induced Artifacts in PRFS MR Thermometry During Mild Hyperthermia in the Pelvis Mingming Wu1, Paul Baron2, Hendrik T. Mulder2, Eduardo Coello1,3, Marion I. Menzel3, Gerard C. Van Rhoon2, and Axel Haase1 1Munich School of Bioengineering, Garching bei München, Germany, 2Erasmus Medical Center, Rotterdam, Netherlands, 3GE Research Center, Garching bei München, Germany Digestive motion including gas is the predominant source of artifacts for PRFS MR Thermometry monitored RF hyperthermia inside the pelvis. Gastrointestinal motion of gas introduces large field variations inside the pelvis, thus significantly hampers PRFS based MR temperature reading. The estimation of these dipolar field disturbances from a changing susceptibility distribution is very exact in case we know the mask of Δχ, as shown with a phantom experiment. But using the PDF method, which allows a heterogeneous distribution of Δχ-values in the background, the temperature error could be reduced to noise level for in-vivo data in presence of susceptibility artefacts as well.

 1481 Marker-less co-registration of MRI data to a subject’s head via a mixed reality device Christoph Leuze1, Grant Yang1, Gordon Wetzstein1, Mahendra Bhati1, Amit Etkin1, and Jennifer McNab1 1Stanford, Stanford, CA, United States Many medical applications such as brain surgery or stimulation require the clinician to identify an internal target location. Mixed reality see-through displays that enable a holographic visualization of brain MRI superimposed on a subject’s head can help clinicians identify internal target locations but require tracking methods that keep the holographic brain MRI aligned with the subject’s head as they move.  We present a method for marker-less tracking of a subject’s using a depth-sensing camera, which tracks facial features and sends location and rotation information to a see-through display to update the location in space of the MRI holograms.

 1482 Inertial Cavitation Induced Magnetic Resonance Signal Changes in a Rat Model Cheng-Tao Ho1, Chen-Hua Wu1, Po-Hung Hsu2, Hao-Li Liu3, Chih-Kuang Yeh1, Ching-Hsiang Fan1, Wen-Shiang Chen4,5, and Hsu-Hsia Peng1 1Department Of Biomedical Engineering And Environmental Sciences, National Tsing Hua University, Hsinchu City, Taiwan, 2Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan city, Taiwan, 3Department Of Electrical Engineering, Chang-gung University, Taoyuan city, Taiwan, 4Department Of Physical Medicine And Rehabilitation, National Taiwan University Hospital, Taipei city, Taiwan, 5Division Of Medical Engineering Research, National Health Research Institutes, Miaoli city, Taiwan We aim to real-time monitor the inertial cavitation (IC)-induced signal intensity (SI) changes in the presence of microbubbles and explore the correlation between the extent of IC-induced SI changes and the location of blood–brain barrier opening in a rat model. The computed |slope| map illustrated the territory of tissue with substantial SI changes and was consistent with the difference map (calculated from T1WI with and without Gd) and Evens Blue dyed region. In conclusion, we verified the feasibility of using FLASH sequence to distinguish the location of BBB-opening through the computed |slope| map in a rat model.

 1483 MR imaging simulator and optimized multi-echo z-shimmed sequence for temperature mapping near metallic ablation probes Megan E Poorman1,2, Yue Chen3, Robert J Webster III3,4, Eric J Barth3, and William A Grissom1,2 1Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 3Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, United States, 4Department of Neurological Surgery, Vanderbilt University, Nashville, TN, United States Signal loss near metallic ablation probes can prevent quality MR thermometry guidance of treatment. Previously we proposed an orientation-independent multi-echo Z-shimmed sequence that could recover the lost signal and improve temperature precision near the probe. However, this method was not feasible for online implementation due to the need to acquire high resolution off-resonance maps around the ablator followed by a computationally-intensive optimization. Here we present an MR imaging simulator that calculates images near metallic ablation probes and successfully use it for offline optimization of the multi-echo Z-shimmed pulse sequence.

 1484 Development of a Tissue Mimicking Phantom for Focal Laser Ablation of the Prostate Rory Geoghegan1,2, Alan Priester2,3, Alvaro Santamaria3, Le Zhang4, Samantha Mikaiel4, Holden Wu4, Warren Grundfest1,2, Leonard Marks3, and Shyam Natarajan1,2,3 1Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States, 2Center for Advanced Surgical & Interventional Technology, University of California, Los Angeles, Los Angeles, CA, United States, 3Department of Urology, University of California, Los Angeles, Los Angeles, CA, United States, 4Department of Radiology, University of California, Los Angeles, Los Angeles, CA, United States There is a need to further develop real-time feedback systems for monitoring focal laser ablation (FLA). Here we have developed a tissue mimicking phantom to facilitate research on the use of magnetic resonance thermometry (MRT) and interstitial thermal probes as feedback systems. The tissue mimicking phantom was designed to match the optical and thermal properties of prostatic tissue at 980nm. The thermal response of the phantom to FLA was then compared to previously acquired clinical data and found to be qualitatively and quantitively similar to prostatic tissue. MRT and real-time quantification of damage zone progression are also demonstrated.

 1485 Monitoring and Guidance on High-Intensity Focused Ultrasound Treatment by Multiple Fast Field Echo at 3.0 T MRI: Ex-Vivo Studies with Multiparametric Mapping Jong-Min Kim1,2, Chulhyun Lee3, Young-Seung Jo1, Han-Jae Chung1,2, Seong-Dae Hong1,2, You-Jin Jeong1,2, Jeong-Hee Kim4, and Chang-Hyun Oh1,2 1Department of Electronics and Information Engineering, Korea University, Seoul, Republic of Korea, 2ICT convergence technology for Health&Safety, Korea University, Sejong, Republic of Korea, 3Bioimaging Research Team, Korea Basic Science Institute, Chungbuk, Republic of Korea, 4Research Industrial for Advanced Industrial Technology, Korea University, Sejong, Republic of Korea Because the multiple Fast Field Echo (mFFE) is rich in contrast manipulation, such as, in water-fat, susceptibility, conductivity, and temperature imaging, it is well suited to guide the thermal treatment. In this study, we sought to investigate the feasibility of the mFFE for monitoring and guidance of HIFU treatment in ex-vivo swine tissue. To demonstrate this study, we present the conductivity, temperature, and susceptibility mapping results. We have shown that the mFFE is very useful for guidance and monitoring of the HIFU treatment. Simultaneous temperature, conductivity, and susceptibility mapping has been tried using the mFFE sequence and its utility has been shown in this paper.

 1486 Temperature Induced Susceptibility Correlation in Adipose Tissues for MR-Guided Microwave Ablation Yongyu Lin1, Kexin Deng1, Jinchao Wu2, Bingyao Chen3, Jiafei Yang3, Xing Wei3, and Kui Ying2,4 1Department of Biomedical Engineering, Tsinghua University, Beijing, China, 2Department of Engineering Physics, Tsinghua University, Beijing, China, 3Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, Beijing, China, 4Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Medical Physics and Engineering Institute, Tsinghua University, Beijing, China Microwave ablation requires high temperature measurement accuracy to monitor the curative effect of the lesions. PRFS-based MR thermometry is the most commonly used temperature monitoring technique. However, PRFS is hampered by temperature-dependent magnetic susceptibility changes. It has been proved in the Quantitative Susceptibility Mapping(QSM) that susceptibility can be measured from the phase changes ,which is derived from Maxwell’s Equation. In this work, we proposed a practical method to calculate the errors caused by temperature-induced susceptibility changes based on the method in QSM. Both Simulation studies and microwave heating experiments validated the accuracy of the method.

 1487 The effect of transducer position on signal-to-noise ratio in magnetic resonance guided focused ultrasound Emilee S. Minalga1, Robb Merrill1, Dennis L Parker1, Allison H Payne1, and J. Rock Hadley1 1Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, United States Hardware requirements can be a roadblock to implementing procedure-specific coils in magnetic resonance guided focused ultrasound. In order to more effectively implement coils in the system, the effects of the focused ultrasound transducer’s position on SNR needs to be considered. This work characterizes the SNR and noise correlation variability of the RF coils by evaluating the SNR tradeoffs and noise correlation as a function of device orientation and transducer position and report such variances.  Understanding the SNR tradeoffs of system placement during treatment can aid in increased SNR within the treatment volume and can be a factor to consider in treatment planning.

 1488 A hardware and algorithm framework for focal spot and slice positioning in MRgFUS treatments Robb P Merrill1, J Rock Hadley1, Katelynn R Stroth1, Dylan E Palomino1, Dennis L Parker1, and Allison H Payne1 1Utah Center for Advanced Imaging Research (UCAIR), University of Utah, Salt Lake City, UT, United States MRgFUS systems can be designed with a high degree of transducer positioning variability for precise focal point placement during tissue ablation procedures.  This study evaluates hardware design and complementary algorithmic adaptations that predict the focal spot location and MRI slice orientation as a function of transducer adjustment settings.  These design features were evaluated by comparing the physical focus of a mock transducer to the computed focus location from the prediction algorithm.  The mean error between the measured and predicted point position was found to be 2.9±1.8mm (N=20).  Predicted slice orientation parameters also showed good agreement with hardware adjustment measurements.

 1489 Self-adaptive Bio-heat Transfer Model Modified Hybrid for Monitoring Temperature in Microwave Therapies Jinchao Wu1, Shihan Qiu2, Bingyao Chen3, Jiafei Yang3, Xing Wei3, and Kui Ying1,4 1Department of Engineering Physics, Tsinghua University, Beijing, China, 2Department of Biomedical Engineering, Tsinghua University, Beijing, China, 3Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, Beijing, China, 4Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Medical Physics and Engineering Institute, Tsinghua, Beijing, China A BHT model was introduced to modify the penalty term of hybrid method for monitoring microwave ablation. Simulation results demonstrate that the proposed method is robust with the BHT model and can reconstruct more accurate temperature maps with different regularization parameters. Ex vivo experiment shows that the proposed method can achieve improved performance for rapid background shifting.

 1490 Detection of Acoustic Radiation Force-Induced Aggregated Bubbles by Velocity and Vorticity Maps Che-Wei Wu1, Po-Hung Hsu2, Hao-Li Liu3, Chen-Hua Wu1, Ching-Hsiang Fan1, Chih-Kuang Yeh1, Wen-Shiang Chen4,5, and Hsu-Hsia Peng1 1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, 2Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan, Taiwan, 3Electrical Engineering, Chang-gung University, Taoyuan, Taiwan, 4Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan, 5Division of Medical Engineering Research, National Health Research Institutes, Miaoli, Taiwan The aim of this study was to real-time localize the occurrence of secondary ARF and the aggregated bubbles by velocity and vorticity maps.  During FUS transmission, the flow velocity and vorticity downstream to the FUS focus increased substantially. By observing the pixel-wise flow behavior in a scatter plot with information of velocity and vorticity, the position of aggregated bubbles could be localized in the regions with decreased velocity and vorticity. In conclusion, we verified the feasibility of using phase-contrast MRI to real-time detect secondary ARF and aggregated bubbles by combining pixel-wise velocity and vorticity information.

 1491 Evaluate Acoustic Radiation Force Induced Displacement of High Velocity Core by Phase-contrast MRI Che-Wei Wu1, Po-Hung Hsu2, Hao-Li Liu3, Chen-Hua Wu1, Ching-Hsiang Fan1, Chih-Kuang Yeh1, Wen-Shiang Chen4,5, and Hsu-Hsia Peng1 1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, 2Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan, Taiwan, 3Electrical Engineering, Chang-gung University, Taoyuan, Taiwan, 4Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan, 5Division of Medical Engineering Research, National Health Research Institutes, Miaoli, Taiwan We hypothesized that the aggregated bubbles could be seen as a barrier, which might alter the flow pattern by shifting the high velocity core of flowing fluid. The aim was to assess the secondary acoustic radiation force and the size of aggregated bubbles, and thereby to estimate the amount of delivered drug in the targeting tissue. We found that larger displacement generally occurred with higher acoustic pressure, higher microbubble concentration, and slower flow velocity. In conclusion, we verified the feasibility of using phase-contrast MRI to evaluate the displacement of high velocity core in a phantom with flow microbubbles.

 1492 Volumetric and rapid MR-acoustic radiation force imaging using simultaneous multi-slice imaging Pierre Bour1,2,3,4, Valéry Ozenne1,2,3, Stanislas Rapacchi 5, Marylène Delcey 1,2,3,6, Rainer Schneider7, Wadie Ben Hassen6, and Bruno Quesson 1,2,3 1IHU-LIRYC, PESSAC, France, 2Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France, 3INSERM U1045, Bordeaux, France, 4Image Guided Therapy, Pessac, France, 5Center for Magnetic Resonance in Biology and Medicine - UMR 7339, Marseille, France, 6Siemens Healthcare, Saint-Denis, France, 7Siemens Healthcare, Erlangen, Germany The local tissue displacement induced by acoustic radiation force impulses (ARFI) during MR guided HIFU can be used to localize the focal spot position before thermal ablation and to monitor qualitative changes in tissue elasticity during ablation. However current MR-sequence implementations lack of spatial coverage, for a temporal resolution in the order of the timescale (<1Hz) of displacement changes during sonication. To address this limitation, we developed a simultaneous multislice MR-ARFI sequence with a slice acceleration factor up to 3. Displacement estimations measured with accelerated sequences are compared to reference values using a non-accelerated sequence.

 1493 Application of hybrid MR-ultrasound imaging to multi-baseline thermometry Pei-Hsin Wu1, Cheng-Chieh Cheng1, Frank Preiswerk1, and Bruno Madore1 1Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States MR thermometry, and more specifically the proton resonance frequency (PRF) shift method, has been widely employed for monitoring temperature change. However, breathing motion tends to corrupt the image phase that PRF relies upon. An existing free-breathing method called ‘multi-baseline thermometry’ was improved here by including a small ultrasound-based sensor fixed to the abdomen of the volunteer, to further help monitor and handle breathing motion. Utilizing both morphology (as in multi-baseline thermometry) and sensor information, better estimates of temperature changes could be achieved during breathing.

 1494 Hybrid Proton Resonance Frequency Shift and Variable Flip Angle T1 Temperature Mapping using a Golden-Angle 3D Stack-of-Radial Technique Le Zhang1, Tess Armstrong1,2, Samantha Mikaiel1,2, Alan Priester3, Rory Geoghegan4, Shyam Natarajan3,4, and Holden Wu1,2,4 1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 2Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, CA, United States, 3Urology, University of California Los Angeles, Los Angeles, CA, United States, 4Bioengineering, University of California Los Angeles, Los Angeles, CA, United States Proton resonance frequency shift (PRF) is widely used for MR temperature mapping, but is not applicable in adipose tissues. T1 measurement is an alternative MR temperature mapping method that can be applied in adipose tissues. Combined PRF-T1 mapping has been evaluated for Cartesian MRI, but there is a lack of research for non-Cartesian techniques. In this work, we propose a new multi-echo 3D stack-of-radial technique that combines PRF and variable-flip-angle T1 measurement for MR temperature mapping. Preliminary results from laser ablation in phantoms demonstrate good agreement between temperature derived from both PRF and T1 compared to readings of temperature probes.

 1495 Detecting T1-based signal reduction in focused ultrasound heating of bone at 1.5T using a 3D spiral ultra-short echo time sequence Helen Sporkin1, Yekaterina K Gilbo1, Sam W Fielden2, John P Mugler3, G. Wilson Miller3, Josef Pfeuffer4, Berthold Kiefer4, and Craig H Meyer1,3 1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Autism and Developmental Medicine Institute, Geisinger Health System, Danville, PA, United States, 3Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States, 4Application Development, Siemens Healthcare, Erlangen, Germany MR-guided Focused Ultrasound (MRgFUS) is used transcranially to ablate brain tissue for the treatment of essential tremor and Parkinson's disease symptoms. Proton resonance frequency shift MR thermometry detects changes in temperature in tissues with sufficiently long T2, but fails to detect heating in the cortical bone of the skull. T1-based MR thermometry uses T1 mapping to observe a linear increase in T1 with temperature but requires long acquisitions. We demonstrate a thermometry method using the linear relationship between signal magnitude from a T1-weighted 3D Spiral Ultra-short Echo Time sequence and temperature in focused ultrasound heated bone with improved temporal resolution.

 1496 Radiofrequency applicator concepts for RF hyperthermia treatment and MR imaging of glioblastoma multiforme at 7.0 T (298 MHz) Eva Oberacker1, Andre Kuehne2, Helmar Waiczies2, Jacek Nadobny3, Mirko Weihrauch3, Sebastian Zschaeck3, Pirus Ghadjar3, Peter Wust3, Thoralf Niendorf1,2,4, and Lukas Winter1 1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2MRI.TOOLS GmbH, Berlin, Germany, 3Clinic for Radiation Oncology, Charite University Medicine, Berlin, Germany, 4Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany Glioblastoma multiforme is the most frequent and most aggressive malignant brain tumor with de facto no prognosis of long-term survival by the use of current multimodal therapeutic approaches. RF heating at ultrahigh fields (B0=7.0T, f=298MHz) has the potential of delivering sufficiently large thermal dosage for hyperthermia of relatively large tumor areas. This work focuses on EMF simulations and compares RF applicator designs tailored for simultaneous RF heating and MRI. Our results suggest that RF power can be focused to small tumor areas and to large clinical target volumes derived from segmented patient data.

 1497 Bio Heat Transfer Model Based Temporally Constrained Reconstruction for Accelerated MR Temperature Imaging Shihan Qiu1, Jinchao Wu2, Bingyao Chen3, Jiafei Yang3, Xing Wei3, and Kui Ying2,4 1Department of Biomedical Engineering, Tsinghua University, Beijing, China, 2Department of Engineering Physics, Tsinghua University, Beijing, China, 3Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, Beijing, China, 4Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Medical Physics and Engineering Institute, Tsinghua University, Beijing, China Thermal therapies require accurate and real-time temperature monitoring to guide the treatment. To achieve higher temporal resolution in MR temperature imaging, we introduced bio heat transfer model to predict temperature maps, which are combined with previous image to act as constraints in the reconstruction of under-sampled data. An inverse optimization is also included to make the BHT model self-adaptive. Through robustness verifying experiment and heating simulation, the ability of the proposed method to provide accurate reconstruction at a high reduction factor is demonstrated in this study.

 1498 Accelerated MR-Thermometry Using Gradient Echo Keyhole for Focused Ultrasound Radhika Tibrewala1, Viola Rieke1, and Eugene Ozhinsky1 1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States MRgFUS treatments require rapid imaging to visualize the temperature and accurately determine thermal dose. We propose accelerated gradient echo keyhole trajectories for MR-thermometry, which acquire the middle of k-space densely (keyhole) while interleaving the outer k-space data. The trajectory acquisitions were synchronized to the ultrasound pulse to increase temperature accuracy. Different combinations of the keyhole size and number of interleaves were created and their accuracy was tested in a MATLAB simulation that uses the Bioheat Transfer Equation as a gold standard for temperature. The trajectories were implemented in RTHawk and results validated in a phantom experiment during focused ultrasound.

 1499 Passive Marker Tracking with Phase-Only Cross Correlation (POCC) in Highly Undersampled Radial Images: Improvements by Point-Spread-Function Considerations Andreas Reichert1, Michael Bock1, and Axel Joachim Krafft1 1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany Passive tracking with the phase-only cross correlation (POCC) algorithm can be used to accurately detect the position of MR-markers for needle procedures. The POCC tracking sequence continuously visualizes the planned needle trajectory during movement, however, image acquisition is interleaved with the measurement of two tracking images which degrades the temporal resolution. Here, it is shown that highly undersampled radial imaging together with the incorporation of the point-spread-function into the POCC algorithm can track the marker at substantially shorter acquisition times. This is an important step to improve the overall temporal resolution and might help to reduce durations of percutaneous procedures.

 1500 Mechanism of Stable Cavitation Induced Signal Intensity Changes in Fast Spin Echo Images Cheng-Tao Ho1, Chen-Hua Wu1, Po-Hung Hsu2, Hao-Li Liu3, Chih-Kuang Yeh1, Ching-Hsiang Fan1, Wen-Shiang Chen4,5, and Hsu-Hsia Peng1 1Department Of Biomedical Engineering And Environmental Sciences, National Tsing Hua University, Hsinchu City, Taiwan, 2Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Taoyuan city, Taiwan, 3Department Of Electrical Engineering, Chang-gung University, Taoyuan city, Taiwan, 4Department Of Physical Medicine And Rehabilitation, National Taiwan University Hospital, Taipei city, Taiwan, 5Division Of Medical Engineering Research, National Health Research Institutes, Miaoli city, Taiwan The purpose of this study was to comprehend the mechanism of stable cavitation (SC)-induced signal intensity (SI) changes by fast spin-echo images in a phantom with flowing MBs. We postulated that the different patterns of SI changes might be related to transmitting FUS pulses at different timing of k-line acquisitions. The SC-induced microstreaming and shear force could generate hypo- and hyper-SI changes, respectively. In conclusion, the illustration of the mechanism could be helpful for designing experiments in monitoring SC-induced SI changes.

 1501 Simultaneous displacement and T2 mapping of High-intensity focused ultrasound therapy Yangzi Qiao1, Chao Zou1, Zongwei Xu1,2, Chuanli Cheng1,3, Qian Wan1, Changjun Tie1, Xin Liu1, and Hairong Zheng1 1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Zhengzhou University, Zhengzhou, China, 3University of Chinese Academy of Sciences, Beijing, China In this work, a hybrid ARFI sequence based on segmented SE-EPI is proposed to simultaneously monitor the displacement and T2 change of tissue during HIFU therapy. The reliability of this sequence was validated first. The quantified displacement and T2 show good consistence with the reference ARFI and SE results. The hybrid sequence was then applied before and after HIFU therapy to evaluate the treatment effects. With the occurrence of ablative lesion, T2 relaxation time decreased in the lesion center and increased in the boundary. While the displaced region (region with obvious displacement) and the maximal displacement at focus both enlarged. In general, this hybrid ARFI is a potentially useful HIFU monitoring method in clinical application.

 1502 Monitoring of Acute Thermal Coagulation in Muscle Using PSIF Sequence in MRI-Guided High-Intensity Focused Ultrasound Therapy Changjun Tie1, Chao Zou1, Qian Wan1,2, Yangzi Qiao1, Chuanli Cheng1,2, Xin Liu1, and Hairong Zheng1 1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, GuangDong, China, 2University of Chinese Academy of Sciences, Beijing, China MR-guided high intensity focused ultrasound (MRgHIFU) is a new noninvasive approach for thermal ablation of focal lesions with clinical applications in uterus, bone, prostate, brain, breast, and liver.Traditionally, the volume of tissue coagulation is evaluated through contrast enhanced T1-weighted images (CET1). However, there are several limitations for CET1 used for thermal lesion detection. In this study, acute thermal damage following HIFU ablation in muscle was assessed using a PSIF images. this preclinical study demonstrates that PSIF sequence offers a good T2 contrast for visualizing acute thermal damage in muscle tissue during HIFU treatment, and has an obvious advantage in acquisition time, making PSIF a suitable sequence for real-time monitoring tissue changes during thermotherapy at high field system.

 1503 Feasibility Study for Off-Center Targets using ExAblate transcranial MR Guided Focused Ultrasound (tMRgFUS) System Sijia Guo1, Jiachen Zhuo1, and Rao P. Gullapalli1 1Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Medical Center, Baltimore, MD, United States Recent approval by the FDA for treating essential tremors has created increased interest in targeting other critical regions within the brain. Relatively low frequency 220kHz tMRgFUS system has the potential to reach off-center targets compared to the 670kHz system used for essential tremor treatment.  In this work, we assess the feasibility of the 220kHz reaching targets such as the central lateral thalamus (CL) due to its role in neuropathic pain and the more laterally located temporal lope for the role it plays in temporal lobe epilepsy.  Results suggest that temporal lobe interventions are possible but may require a careful optimization.

 1504 MR-HIFU setup for preclinical treatment of a mouse model of pancreatic ductal adenocarcinoma Joshua Park1, Ravneet Vohra1, Mark Mathis1, Ari Partanen2, Cecil Hayes1, Yak-Nam Wang3, Stella Whang4, Joo Ha Hwang4, and Donghoon Lee1 1Radiology, University of Washington, Seattle, WA, United States, 2Clinical Science MR Therapy, Philips, Andover, MA, United States, 3Applied Physics Laboratory, University of Washington, Seattle, WA, United States, 4Gastroenterology, University of Washington, Seattle, WA, United States Preclinical studies using animal disease models on clinical MR-HIFU systems are important for human clinical translations but are often very challenging.  We developed and tested a set of hardware components to treat a transgenic mouse model of pancreatic ductal adenocarcinoma on our clinical MR-HIFU system.  The hardware components include an optimized RF coil, filter, RF switches and coil/animal holder.  A gel phantom and a fixed mouse body were sonicated using the developed devices and a mild hyperthermia protocol on a 3T MR-HIFU system.  Pulse sequences for multi-parametric MRI were also tested to acquire optimum signal-to-noise ratio on the samples.

 1505 Intra-operative MRI with MR detectable endoscope using tunable lens filled with MR contrast agent Je-Seok Ham1, Sang-In Bae1, Won-Joon Do1, Ki-Hun Jeong1, and Sung-Hong Park1 1Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea During brain surgery, location of lesions can change in real-time due to leakage of cerebrospinal fluid. Therefore, navigating an MR-Endoscope probe with real-time intraoperative MRI is important in clinical application. However, conventional tracking system attached to the endoscope probe induces severe artifacts and is expensive and bulky. In this study, we propose a technique for navigating the endoscope probe without additional tracking system through segmentation of signals from tunable lens filled with gadolinium contrast agents. We also demonstrated tunable liquid-filled lens endoscope for intraoperative MRI. The proposed system/approach would be a good alternative as a tracking system for intraoperative MRI.

 1506 Improved MR thermometry for laser-induced thermal therapy – tradeoffs between imaging approaches Henrik Odéen1 and Dennis L Parker1 1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States MR thermometry is often used to monitor thermal therapies such as focused ultrasound and laser induced thermal therapies (LITT). As in MRI in general, there is an inherent tradeoff between measurement accuracy, precision, and spatial and temporal resolution in MR thermometry. In this work we present improved acquisition protocols for 2D and 3D MR thermometry for LITT applications. We investigate and compare image quality and temperature precision for 8 different 2D and 3D GRE, and 3D segmented EPI protocols. Experiments are performed in a healthy volunteer (non-heating) and tissue-mimicking gel (with heating).

 1507 ­MRI biomarkers for focused-ultrasound treatment of pancreatic ductal adenocarcinoma Ezekiel Maloney1, Ravneet Vohra1, Yak-Nam Wang1, Tatiana Khokhlova1, Stella Whang1, Kayla Gravelle1, Joshua Park1, JooHa Hwang1, and Donghoon Lee1 1University of Washington, Seattle, WA, United States Pancreatic cancer is a devastating disease with poor prognosis. Pancreatic tumor therapy has been ineffective in part because pancreatic tumors have high interstitial fluid pressure (IFP), driven by high hyaluronan concentration and a dense desmoplastic stroma that inhibit penetration of drugs into the tumor. We performed multi-parametric MRI at high resolution to non-invasively assess tumor response in a KPC mouse model to pulsed focused ultrasound treatments. T1 and T2 relaxation as well as diffusion, magnetization transfer, and chemical exchange saturation transfer methods were used to characterize the tumors before and after focused ultrasound treatment.

 1508 Performance evaluation of a B0-shim multi-coil system for small animal temperature mapping at 3T Qiaoyan Chen1,2, Jo Lee1,2, Jianghong Wen1,2, Chao Zou1,2, Xiaoliang Zhang3,4, Xin Liu1,2, and Ye Li1,2 1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Shenzhen Key Laboratory for MRI, Shenzhen, China, 3Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 4UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States The magnetic field variation is a critical factor affecting the accuracy of temperature measurement in MRT. In this study, a 5-channel B0-shim coil was constructed for small animal temperature mapping in the MRI guided high intensity focused ultrasound (HIFU) at 3T. Firstly, the shimming ability was evaluated by the phantom study with a result that the standard deviation (STD) value of the offset magnetic field has reduced to 69% after currents optimized. Secondly, the relationship between T2* and SNR improvement has been studied. The results demonstrate that the temperature measurement accuracy is improved by 8% with the local multiple B0-shim coils.

### Cancer Imaging

 Exhibition Hall 1509-1553 Monday 16:15 - 18:15

 1509 Using MRI to assess sonic hedgehog pathway inhibition in a genetically-engineered mouse model of adamantinomatous craniopharyngioma Jessica K.R. Boult1, Gabriela Carreno2, John R. Apps2, Laura S. Danielson3, Laura M. Smith3, Alexander Koers3, Louis Chesler3, Juan Pedro Martinez-Barbera2, and Simon P. Robinson1 1Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom, 2Developmental Biology and Cancer Research Programme, Birth Defects Research Centre, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 3Division of Clinical Studies, The Institute of Cancer Research, London, United Kingdom Expression of sonic hedgehog (SHH) pathway components is enriched in adamantinomatous craniopharyngiomas (ACPs) arising in Hesx1Cre/+;Ctnnb1lox(ex3)/+  mice compared to control pituitaries. An MRI-embedded trial of smoothened inhibitor vismodegib in this genetically-engineered mouse model was undertaken to assess SHH pathway inhibition in ACP. Longitudinal MRI identified accelerated solid tumour growth in response to 28 days vismodegib treatment, which was associated with increased tumour cell proliferation, and resulted in shorter survival.  7 days of treatment induced early tumoural lesions in Hesx1Cre/+;Ctnnb1lox(ex3)/+ pituitaries, resulted in a more undifferentiated and proliferative phenotype, and was associated with an elevated number of cells with clonogenic potential.

 1510 MRI-based radiomic to assess lipomatous soft tissue tumors malignancy: a pilot study Benjamin Leporq1, Amine Bouhamama2, Fabrice Lame2, Catherine Bihane2, Michaël Sdika1, Jean-Yves Blay3, Olivier Beuf1, and Frank Pilleul1,2 1Laboratoire CREATIS (CNRS UMR 5220, Inserm U1206, INSA-Lyon, UCBL Lyon 1), Université de Lyon, Lyon, France, 2Department of radiology, Centre de lutte contre le cancer Léon Berard, Lyon, France, 3Department of oncology, Centre de lutte contre le cancer Léon Berard, Lyon, France Aim of this study was to develop a MRI-based radiomic method to assess lipomatous soft tissue tumors malignancy. 105 subjects with lipomatous soft tissue tumors whose histology was known and with fat-suppressed T1w contrast enhanced MR images available were retrospectively enrolled to constitute a database. Based on histology, three groups were constituted according to malignancy from lipomas to high grade liposarcomas. A decisional algorithm based on 2 multivariate radiomic models was built to distinguish between these groups. Results demonstrate that the evaluation of lipomatous tumor malignancy is feasible using a routinely used MRI acquisition in clinical practice.

 1511 Magnetic resonance fingerprinting on a 1.5T MRI-Linac for tumor response monitoring Tom Bruijnen1, Bjorn Stemkens1, Jan J W Lagendijk1, Cornelis A T van den Berg1, and Rob H N Tijssen1 1Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands Magnetic resonance fingerprinting (MRF) is the ideal tool for rapid daily tumor response monitoring on a MRI-Linac (MRL). The 1.5T MRL used in our institution has a modified gradient coil and magnet coil design that potentially complicates the parameter quantification in MRF. In this work we are the first to demonstrate the feasibility of 2D MRF in phantoms and in-vivo on a 1.5T MRL. Moreover, we investigate the accuracy and precision of the parametric maps.

 1512 MRI-compatible intravital imaging window for longitudinal imaging of orthotopic mouse ovarian and pancreatic tumor stroma Filip Bochner1, Vishnu Mohan1, Inbal Biton2, and Michal Neeman1 1Biological Regulation, Weizmann Institute of Science, Rehovot, Israel, 2Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel Longitudinal multi-modal imaging of abdominal organs remains a challenge. In cancer research, where data acquired at multiple spatial and temporal scales is especially valuable, combination of powerful microscopic methods with MRI can yield complementary information about ECM and vascular components of the tumor stroma, both constituting a hallmark of pancreatic and ovarian tumors. Here we present the MRI compatible optical imaging window for longitudinal imaging of ovary and pancreas.

 1513 Exploring the use of MR Elastography to probe immune cell-stromal interaction in tumour microenvironment Ralph Sinkus1, Rachel Evans2, Fabian Flores-Borja3, and Tony Ng2 1Department of Radiological Imaging, King's College London, London, United Kingdom, 2School of Cancer and Pharmaceutical Sciences, King’s College London, London, United Kingdom, 3School of Cancer and Pharmaceutical Sciences King's College London, London, United Kingdom There is great, unmet need in understanding and monitoring non-invasively the immune cell changes within the tumour stromal microenvironment during cancer treatment. However there is as yet no reliable non-invasive method of identifying at very early time points patients who are most likely to benefit from this relatively expensive class of treatments which generally are only associated with a clinical response in 25-30% of patients1. We show here in a mouse model that changes 11 days after implantation in the liquid-to-solid ratio (phase angle y) of the tumour biomechanics are indicative for successful immune cell – stromal cell interactions.

 1514 DKI can early detect radio-insensitive human nasopharyngeal carcinoma xenograft in nude mice Xiang Zheng1, Yunbin Chen1, Youping Xiao1, and Dechun Zheng1 1Fujian Provincial Cancer Hospital, Fuzhou, China In order to evaluate feasibility of DKI sequence in early differentiating radio-insensitivity of nasopharyngeal carcinoma xenografts, Seventy-two nude mice were implanted with CNE-1(low radiosensitivity) and CNE-2(high radiosensitivity) and the xenografts were obtained. MRI scanning was performed after fractional irradiation. There are differences of the changes of DKI parameters (both D and K) between CNE-1 and CNE-2 before tumor volumes changed. Therefore, Both D and K can early (before volumes changed) distinguish radio-insensitive NPC xenografts from others.

 1515 Adult eye segmentation in MRI using active shape model: towards a personalized eye model for radiation treatment of uveal melanoma Huu-Giao Nguyen, PhD1,2,3, Raphael Sznitman, Prof. 2, Marta Peroni, PhD1, Jan Hrbacek, PhD1, Damien C. Weber, Prof. MD1, Alessia Pica, MD1, and Meritxell Bach Cuadra, PhD3,4 1Proton therapy Center, Paul Scherrer Institut (PSI), ETH Domain, Villigen, Switzerland, 2Ophthalmic Technology Laboratory, ARTORG Center of the University of Bern, Bern, Switzerland, 3Radiology Department, Centre d’Imagerie BioMédicale, Lausanne University Hospital, Lausanne, Switzerland, 4Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland We aim to construct a 3-dimensional patient-specific eye model from MRI data in order to later be integrated into proton radiation treatment planning. Our major challenge is the presence of motion, as subjects are awake and physiologically blink eyes. Additionally,  fixing a point during acquisition might be challenging for some patients with ocular tumors. As such, in this study we evaluated an Active Shape Model (ASM) segmentation on a data set of 31 subjects, including 3 uveal melanoma (UM) patients. Quantitative evaluation in comparison with manual delineations shows good accuracy, even for images with the presence of UM and tantalum clips.

 1516 Automatic classification between high grade gliomas and brain metastasis using Bag-Of-Features in comparison to statistical and morphologic features Moran Artzi1,2, Gilad Liberman1,3, and Dafna Ben Bashat1,2,4 1Functional Brain Center, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, 2Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel, 3Department of Chemical Physics, Weizmann Institute, Rehovot, Israel, 4Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel This study suggests a clinical decision-support tool for automatic classification of brain tumors. Classification was performed on 179 MRI patients: 81 patients with high grade-gliomas (HGG) and 98 patients with brain metastases (MET, 55 breast, 43 lung, cancer origin). The input data were Bag-Of-Features (BoF) and statistical-&-morphologic features extracted from T1WI+Gd. Classification was performed using five ensemble classifiers and results were evaluated using five-fold cross-validation. Best classification results produced accuracy=83%, sensitivity=87%, and specificity=81% for discriminating between HGG and MET using Statistical-&-morphologic features, and accuracy=79%, sensitivity=76%, and specificity=80% for discriminating between breast and lung MET using BoF + Statistical-&-morphologic features.

 1518 Investigating the effect of macromolecular cross-linking and increasing fiber density on the diffusion and viscoelastic properties of extracellular matrix materials using multiparametric MRI Hannah Macdonald1,2, Jeffrey Bamber1, David Collins1, Mihaela Rata1, Maxim Ryadnov2, and Nandita deSouza1 1Institute of Cancer Research, London, United Kingdom, 2National Physical Laboratory, London, United Kingdom Synthetic polymer polyvinylpyrrolidone and fibrous protein collagen were used to investigate the effect of macromolecular cross-linking and increasing fiber density on the physicochemical properties of extracellular matrix models using clinical MRI parameters and torsional rheometry. T1 and T2 decreased with increasing viscoelastic moduli of both materials. Covalent cross-linking of macromolecules by irradiation affected stiffness, but had a smaller effect than polymer concentration on T1, T2 and ADC. Collagen at increasing concentrations sufficient to substantially affect tissue stiffness (reflecting increasing fiber density) affected the structure of water within tissue, (changes in T1 and T2), but did not hinder water diffusion.

 1519 Assessment of Approximated Analytical B1+ Correction Method for prostate DCE-MRI with Multiple Noise Levels and in 3.0 T Systems Xinran Zhong1,2, Thomas Martin1,2, Steve Raman1, Holden H Wu1,2, Krishna Nayak3, and Kyunghyun Sung1,2 1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Physics and Biology in Medicine IDP, University of California, Los Angeles, Los Angeles, CA, United States, 3Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, United States B1+ correction is essential for quantitative prostate DCE-MRI. A simplified approximated analytical B1+ correction method was proposed previously, and we assess this method on a digital reference object (DRO) with various SNR levels and on 110 in-vivo cases from two 3.0 T systems. We find that the approximated analytical B1+ correction method achieves comparable performance to conventional correction method with substantially reduced computation. The approximated analytical correction method is simple and practical for application in the clinic.

 1520 Characterization of endometrioid adenocarcinoma microcirculation using distributed parameter model in DCE MRI Zhi Jun Ye1, Gang Ning1, Hui Zhu Chen1, and Yan Song1 1West China Second University Hospital, Chengdu, China Objective: To clarify the features of vascular proliferation and permeability in endometrioid adenocarcinoma. Methods: The DCE-MRI was applied to 55 women who confirmed as endometrioid adenocarcinoma with postoperative pathology. The receiver operating characteristic (ROC) analysis was employed using parameters derived with the DP model to differentiate tumor and normal myometrium and assess the diagnostic efficiency of these parameters. Results: E and PS in tumor was lower. F in tumor was faster. Vp and Ve in tumor were lower. Areas under ROC curve (AUCs) for E and PS attained values of 0.906 and 0.844. AUCs for F attained value of 0.548. Vp and Ve in tumor with AUC values of 0.796 and 0.871. Conclusion: The permeability of vascular wall was significantly lower in endometrioid adenocarcinoma, and the vascularity was moderately lower, suggestive of very different cell growth environment in endometrioid adenocarcinoma in comparison with most solid tumours.

 1521 Repeatability of intravoxel incoherent motion diffusion-weighted MRI during chemoradiation therapy in head and neck cancers Ramesh Paudyal1, Nadeem Riaz2, Vaios Hatzoglou3, Xie Peng2,4, Jonathan Leeman2, David Aramburu Nunez1, Yonggang Lu5, Joseph O. Deasy1, Nancy Lee2, and Amita Shukla-Dave1,3 1Medical Physcis, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 3Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 4Radiation Oncology, Shandong Cancer Hospital & Institute, Jinan, China, 5Radiology, Medical College of Wisconsin, Milwaukee, WI, United States The aim of this study is to determine the repeatability of pre- treatment (TX) and intra- TX week 1 imaging metrics derived from intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) in head and neck (HN) cancer patients during chemoradiation therapy. ADC, D, and D* imaging metrics showed better repeatability measurement than f in the metastatic node of HN cancer patients.

 1522 Brain metastases developing pseudoprogression have poor vascular function and supply Ingrid Digernes1, Endre Grøvik1, Line B. Nilsen1, Cathrine Saxhaug2, Oliver Geier1, Edmund Reitan2, Dag Ottar Sætre3, Birger Breivik4, Kari Dolven Jacobsen5, Åslaug Helland5, and Kyrre Eeg Emblem1 1Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway, 2Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway, 3Department of Radiology, Østfold Hospital Trust, Kalnes, Norway, 4Deptartment of Radiology, Hospital of Southern Norway, Kristiansand, Norway, 5Department of Oncology, Oslo University Hospital, Oslo, Norway Stereotactic radiosurgery of brain metastases can cause pseudoprogression. In this study, we use Vessel Architectural Imaging, based on dual echo DSC, to investigate the course of vascular function of brain metastases, both prior to and after pseudoprogression have occurred. Our results show that pseudoprogressing metastases were characterized by underperfused and oxygen-deprived tissue, and micro- and macrovessel pruning in the peritumoral regions. This was in contrast to peritumoral regions of responding metastases as well as normal-appearing brain tissue.

 1523 Grading of gliomas using Neurite orientation dispersion and density imaging (NODDI) on a clinical scanner Arush Honnedevasthana Arun1, Aarthi Deepesh2, Dhritiman Chakrabarti2, and Jitender Saini2 1Dayananda Sagar Institutions, Bangalore, India, 2National Institute of Mental Health and Neuroscience, Bangalore, India Diffusion tensor imaging is sensitive to movement of water molecules but not specific as a biomarker in evaluating the highly complex microstructural environment of gliomas. Neurite orientation dispersion and density imaging (NODDI) uses different strengths of diffusion gradients to provide more specific indices of tissue microstructure than DTI. Patients with grade IV gliomas exhibited significant increase in both neurite density and orientation dispersion index as compared to grade III and II glioma cases. This study demonstrates clinical feasibility of using NODDI as a biomarker to grade tumors.

 1524 Convolution-Difference Method for Feature Segmentation of Low-Resolution Images Andrew A Maudsley1 1Radiology, University of Miami, Miami, FL, United States Automated lesion segmentation of clinical imaging studies is of potential value for treatment monitoring and radiation treatment planning. With low spatial resolution imaging systems, such as MR Spectroscopic Imaging, segmentation based on image intensity variations must take into consideration the broad spatial response function. In addition, the relative lesion-to-background intensity variation and the object size must be considered. In this report a new automated image segmentation method is presented that accounts for these factors, which is based on a subtraction of a smoothed version of the MRSI maps from the original data.

 1525 A comparison of pseudo continuous arterial spin labeling perfusion MRI (pCASL) and permeability imaging with dynamic contrast-enhanced MRI (DCE-MRI) in human rectal cancer Yuichi Kumagae1, Yoshihiko Fukukurra1, Koji Takumi1, Hiroto Hakamada1, Tomoyuki Okuaki2, and Takashi Yoshiura1 1Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan, 2Philips Electronics, Tokyo, Japan Our purpose was to investigate potential correlations between the blood flow (BF) measured by pCASL and dynamic contrast-enhanced (DCE) MRI-derived pharmacokinetic parameters in rectal cancer. There were significant positive correlations between BF and Ktrans (p = 0.006, r = 0.579) or Kep (p = 0.002, r = 0.644). These results suggested that pCASL may have the potential to be a noninvasive alternative to DCE MRI.

 1526 Surveillance in Germline TP53 Mutation Carriers Utilizing Whole-Body Magnetic Resonance Imaging Kate Moodie1, Nick Ferris2, David Thomas3, Mandy Ballinger3, Emma Galligan1, Marion Harris4, Paul James1, Gillian Mitchell1, Eveline Niedermayr1, Bimal Parameswaran5, Deborah Schofield3, Sue Shanley6, Alison Trainer1, and Mary-Anne Young1 1Peter MacCallum Cancer Centre, Melbourne, Australia, 2Monash Imaging, Monash Health, Melbourne, Australia, 3Garvan Institute of Medical Research, Sydney, Australia, 4Monash Health, Melbourne, Australia, 5Eastern Health, Melbourne, Australia, 6Peter MacCallum Cancer Institute, Melbourne, Australia Germline TP53 mutations are associated with Li-Fraumeni syndrome (LFS). Mutation carriers ascertained on family history have an extremely high lifetime risk of cancers arising from one or more of many possible sites. There is no established screening strategy for early detection and treatment of these cancers. Herein, we report preliminary data from a prospective study of a whole-body screening program that includes whole-body. Five new malignancies (3 de novo, 2 recurrent) have been identified in five of the first 30 participants, suggesting potentially significant benefits from screening in this population.

 1527 Assessment of micronecrotic tumor tissue using dynamic contrast-enhanced magnetic resonance imaging Olga Schimpf1, Stefan Hindel1, and Lutz Lüdemann1 1Strahlenklinik, Med. Physik, Universitätsklinikum Essen, Essen, Germany Compartmental models for evaluation of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) datasets assume a homogeneous interstitital volume distribution and homogeneous contrast agent (CA) distribution within each compartment, neglecting effects of CA diffusion within the compartments. When necrotic or micronecrotic tumor tissue is present, these assumptions may no longer be valid. Therefore, the present study investigates the validity of three compartmental models in assessing tumors with necrotic components.

 1528 Early biomarkers of response to neoadjuvant chemotherapy in lung cancer: preliminary data from a multicenter international study Dominic Carlin1,2, Alexander Weller1,2, Joost Kuijer3, Gerbrand M Kramer3, Arturo Chiti4, Mary E. R. O'Brien5, Sanjay Popat5, Yan Liu6, and Nandita M deSouza1,2 1CRUK Imaging Centre, Institute of Cancer Research, London, United Kingdom, 2MRI Unit, The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom, 3VU University Medical Center, Amsterdam, Netherlands, 4Humanitas University, Milan, Italy, 5The Lung Unit, The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom, 6European Organisation for Research and Treatment of Cancer Headquarters, Brussels, Belgium Whole tumor ADC histogram parameters were assessed as early response biomarkers to platinum-based neo-adjuvant chemotherapy in 14 patients with non small cell lung cancer. On completion of treatment, 3 of 11 patients with DW-MRI at baseline and day 14 were classed responders by RECIST criteria.   At Day 14 of treatment, there was a significant reduction in ADC metrics in responders (2 of 3 beyond limits of agreement) compared to non-responders (2 of 11 beyond limits of agreement). An increase in ADC 75th centile (indicating more voxels with higher ADC values), was consistent with necrosis; non-responders did not show this change.

 1529 Developing a Halbach Array for Brain Tumor Targeting Areej Alghamdi1, Munitta Munitta Muthana1, and Martyn Paley2 1Oncology and Metabolism, University of Sheffield, Sheffield, United Kingdom, 2Academic Radiology, University of Sheffield, Sheffield, United Kingdom Steering magnetic nanoparticles (MNPs) in a desired trajectory has been proposed for guiding magnetically labelled drugs to clinical targets1. In order to steer MNPs to a desired location, a strong magnetic field and field gradient is necessary and the deeper the location, the stronger the magnetic force required. External permanent magnets can provide a strong magnetic field and gradient. We hypothesise that external magnetic field/field gradient arrays of 1.1T can be designed to capture MNPs into tumors. Brain tumors are one of the most difficult cancers to treat due to the complex anatomy of the brain. Therefore, we are developing a 3D printed brain tumor model to investigate trapping of MNPs into a tumor using Halbach arrays.

 1530 ­Lentiviral shRNA-mediated targeting of GDPD5 and GDPD6 in Orthotopic Human Breast Cancer Xenograft Models: A Metabolomics Study Kanchan Sonkar1, Marina Stukova2, Caitlin M. Tressler1, Balaji Krishnamachary1, Zaver M. Bhujwalla1,3, and Kristine Glunde1,3 1The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2San Juan Bautista School of Medicine, Caguas, PR, United States, 3The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States Activated choline phospholipid metabolism is a hallmark of cancer. Aggressive breast cancers are characterized by high tumoral phosphocholine and glycerophosphocholine. In our ongoing efforts of evaluating the glycerophosphodiesterases GDPD5 and GDPD6 as cancer treatment targets, we have systemically injected mice growing orthotopic triple-negative MDA-MB-231 breast tumors with lentiviral vectors that silence the GDPD5 or GDPD6 genes as compared to mice injected with control viruses. We have analyzed extracted tumor tissue by means of high-resolution 1H MRS-based metabolomics. Differences in tumor growth and metabolic profiles were observed following silencing of GDPD5 and GDPD6 genes when compared to control mice.

 1531 Development of a 3D radial MP2RAGE sequence for free-breathing T1 mapping of the mouse abdomen Thibaut L Faller1, Aurélien J Trotier1, Sylvain Miraux1, and Emeline J Ribot1 1CRMSB UMR5536, CNRS-Univ.Bordeaux, Bordeaux, France T1 mapping could be useful to quantify the evolution of metastases over time and evaluate therapy efficiencies. The MP2RAGE sequence enables to obtain 3D T1 maps in reasonable scan time. Nevertheless, the standard sequence is too sensitive to respiratory motion, preventing its use at the abdominal level. Consequently, a 3D radial MP2RAGE sequence has been developed. The accuracy of the T1 measurements was evaluated in vitro and on the mouse brain. Then, abdominal 3D T1 maps were obtained without motion artifact while free breathing. Finally, the radial MP2RAGE sequence was used for the early detection and characterization of hepatic metastases.

 1532 Co-registration of MRI and histological habitats in pre-clinical tumor models Bruna Victorasso Jardim-Perassi1, Suning Huang1, William Dominguez-Viqueira1, Epifanio Ruiz1, Mikalai Budzevich1, Jan Poleszczuk2, Marilyn Bui3, Robert Gillies1, and Gary Martinez1 1Cancer Imaging and Metabolism, Moffitt Cancer Center, Tampa, FL, United States, 2Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland, 3Pathology Anatomic, Moffitt Cancer Center, Tampa, FL, United States Tumor heterogeneity, may give insight into natural selection through detection of tumor sub-regions, referred as imaging habitats. We used statistical clustering of multiple pixels based on multiple MRI parameter maps to identify tumor habitats in pre-clinical models of sarcoma and breast cancer using T2, T2*, ADC and three model free parameter maps determined from dynamic contrast enhanced images. MRI-derived habitat maps were determined by clustering multidimensional voxels using a Gaussian mixture model. 3D-printed tumor molds were used to successfully co-register MR imaging slices with their histological habitat-counterparts. Four distinct tumor habitats were detected by MRI and biologically corroborated by histology.

 1533 The Immune Checkpoint PD-L1 and Choline Kinase-α are inversely related in triple negative human breast cancer cells Jesús Pacheco-Torres1, Marie-France Penet1,2, Yelena Mironchik1, Balaji Krishnamachary1, and Zaver M Bhujwalla1,2 1Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States Immune checkpoint inhibition to activate the immune system has emerged as an exciting treatment option for several cancers.  Programmed death-ligand 1 (PD-L1) plays a major role in immune suppression.  We investigated the relationship between the aberrant choline metabolism observed in most cancers and PD-L1 expression in triple negative human MDA-MB-231 breast cancer cells. Using siRNA to downregulate choline kinase-α (Chk-α) or PD-L1 or both, we identified a close inverse interdependence between Chk-α, PD-L1 and phosphocholine. These results have significant implications for treatments that decrease Chk-α expression as these may drive up PD-L1 expression allowing escape of cancer cells from immune surveillance.

 1534 The relationship of R1rho to aqueous pH and macromolecular density Petros Fessas1, Syed Omar Ali1, Joshua Kaggie1, Martin Graves1, Scott Reid1, Gavin Houston1, and Ferdia Gallagher1 1University of Cambridge, Cambridge, United Kingdom We investigated the sensitivity of R1rho MRI to pH and macromolecular density in in vitro phantoms and in brains of volunteers to assess its suitability as an imaging modality for detecting and assessing the response of brain tumours. We find the dependence of R1rho signal on pH in the presence of macromolecules, but a lack of pH dependence in their absence.  We confirm R1rho sensitivity to macromolecular density at constant pH.

 1535 Multiparametric MR approach for monitoring the pathological response of breast cancer patients to neoadjuvant chemotherapy Naranamangalam R Jagannathan1, Uma Sharma1, Khusbhu Agarwal1, Rani G Sah1, Sandeep Mathur2, Vurthaluru Seenu3, Siddhartha D Gupta2, and Rajinder Parshad3 1Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Department of Pathology, All India Institute of Medical Sciences, New Delhi, India, 3Department of Surgery, All India Institute of Medical Sciences, New Delhi, India A multiparametric MR approach using total choline (tCho), apparent diffusion coefficient (ADC) and tumor volume was undertaken for prediction of pathological response in 42 locally advanced breast cancer (LABC) patients undergoing neoadjuvant chemotherapy (NACT). 24 were pathologically responders (complete and partial) while 18 were non-responders. Percentage change in tCho, ADC and volume was higher in pathological responders than in non-responders after III NACT. Individually, all three parameters showed equal sensitivity (66.7%) with specificity in the range 64.7% to 70.6% for pathological response prediction. Combination of all three MR parameters yielded 66.7% sensitivity and a specificity of 64.7%.

 1536 Functional MRI at ultra-high field strength (11.7 T) for evaluation of rectal cancer stromal heterogeneity ex vivo: correlation with histopathology Trang Thanh Pham1,2,3,4,5, Timothy Stait-Gardner6, C. Soon Lee3,4,5,7, Michael B. Barton 1,3,4, Gary Liney1,3,4, Karen Wong1,3,4, and William S. Price5,6 1Radiation Oncology, Liverpool Cancer Therapy Centre, Liverpool Hospital, Sydney, Australia, 2Sydney West Radiation Oncology Network, Westmead, Blacktown and Nepean Hospitals, Sydney, Australia, 3Faculty of Medicine, University of New South Wales, Sydney, Australia, 4Ingham Institute for Applied Medical Research, Sydney, Australia, 5School of Medicine, Western Sydney University, Sydney, Australia, 6Nanoscale Organisation and Dynamics Group, Western Sydney University and National Imaging Facility, Sydney, Australia, 7Anatomical Pathology, Liverpool Hospital, Sydney, Australia Diffusion Tensor Imaging (DTI) MRI at ultra-high field (11.7 T) was used to examine the stromal ultrastructure of malignant and normal rectal tissue ex vivo, and findings were correlated with histopathology. DTI was able to distinguish tumour from desmoplasia: tumour was found to have isotropic diffusion, whereas desmoplastic reaction or fibrous tissue had moderately anisotropic diffusion. DTI was useful in assessing depth of tumour infiltration into rectal wall: tumour was able to be distinguished from muscularis propria which was highly organised and anisotropic. This study showed that DTI-MRI can assist in more accurately defining tumour extent in rectal cancer.

 1537 Assessment of treatment response of lymphoma in an animal model with in vivo MR elastography Jing Guo1, Animesh Bhattacharya2, Gergely Bertalan1, Jürgen Braun3, Clemens A. Schmitt2,4,5, and Ingolf Sack1 1Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 2Medica Department of Hematology, Oncology, and Tumor Immunology, and Molecular Cancer Research Center (MKFZ), Charité - Universitätsmedizin Berlin, Berlin, Germany, 3Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany, 4Berlin Institute of Health (BIH), Berlin, Germany, 5Max-Delbrück-Center for Molecular Medicine (MDC), Berlin, Germany In this feasibility study, we have characterized the mechanical properties of lymphoma directly in the cervical lymph nodes with in vivo multifrequency MRE for the first time. Both MRE and diffusion weighted imaging were used to investigate the tumor's response to chemotherapy. We found that lymphomas stiffened 24 hours after chemotherapy which was accompanied by increased apparent diffusion coefficient (ADC) and reduced tumor volume. Wave speed obtained from MRE is sensitive in detecting the mechanical response of lymphoma to chemotherapy. Observed tumor stiffening post treatment needs to be validated by larger group size and should be explained by histological analysis.

 1538 Assessment of Tumor Hypoxia Using Tissue Oxygen Level Dependent in a Rabbit VX2 Liver Tumor model Xinming Li1, Shuping Qin1, Wen Liang1, Yingjie Mei2, Yangguang Yuan1, and Xianyue Quan1 1Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, China, 2Philips Healthcare, Guangzhou, China There is attractive focus in developing non-invasive methods that assess tumor hypoxia. We applied tissue oxygen level dependent (TOLD) MRI to explore tumor oxygenation using VX2 liver tumor xenografts in a rabbit model. In this study，we demonstrated alteration in tumor oxygen inhalation and correlation in different hypoxia levels.

 1539 Dual-modality molecular imaging of choline kinase expression in lung cancer Sofya A Osharovich1, Anatoliy V Popov1, David Holt2, Sunil Singhal3, and E. Jim Delikatny1 1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States, 3Surgery, University of Pennsylvania, Philadelphia, PA, United States MR spectroscopy of tumors show elevated tCho resonances, reflecting increased levels of phosphocholine.  This arises from overexpression of choline kinase (ChoK), which can be detected in breast tumor models using targeted near-infrared (NIR) probes and fluorescence optical imaging.  This study translates these findings into lung cancer models, measuring elevated ChoK expression and activity in murine and human lung cancer cells and elevated ChoK levels in spontaneous canine adenocarcinomas. Dual modality molecular imaging could be employed using MRI and MRS for tumor staging, followed by NIR imaging for intraoperative surgical guidance, margin detection, and residual tumor removal, increasing patient survival.

 1540 MP2RAGE-Compressed Sensing for fast metastasis detection and characterization in mice Aurélien Trotier1, Stanislas Rapacchi2, Thibaut Faller1, Sylvain Miraux1, and Emeline Ribot1 1CRMSB UMR5536, CNRS-Univ.Bordeaux, Bordeaux, France, 2CRMBM UMR7339, CNRS/Aix-Marseille Univ., Marseille, France In order to detect and characterize metastases in preclinical studies, 3D T1 maps can be obtained with the MP2RAGE sequence. As high spatial resolution is required, the acquisition duration becomes prohibitive for the monitoring of metastases. Thus, acceleration via Compressed Sensing technique was achieved, necessitating a new undersampling scheme. T1 maps of the mouse whole brain were obtained in <1min. The T1 of brain metastases was not affected by CS acceleration. Then, ultra-high spatially resolved maps (130x125x141μm) were acquired without lengthening scan time, to detect early-growing metastases and accurately measure their volumes.

 1541 Tumor Metabolism, Diffusion, and Perfusion in Head and Neck Cancer: Pretreatment Multimodality Imaging with DCE-MRI, IVIM DW-MRI, 18F-FMISO PET/CT, and 18F-FDG PET/CT David Aramburu Nunez1, Milan Grkovski1, Nancy Lee2, Vaios Hatzoglou3, Heiko Schoder3, Ramesh Paudyal1, Nadeem Riaz2, Joseph O Deasy1, John Humm1, and Amita Shukla-Dave4 1Medical Physics, Memorial Sloan-Kettering Cancer Center, New York City, NY, United States, 2Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York City, NY, United States, 3Radiology, Memorial Sloan-Kettering Cancer Center, New York City, NY, United States, 4Medical Physics and Radiology, Memorial Sloan-Kettering Cancer Center, New York City, NY, United States The aim of this study is to understand the correlation of pretreatment quantitative imaging metrics obtained from multimodality imaging (MMI) techniques, such as DCE-MRI, IVIM DW-MRI, 18F-FMISO PET/CT, and 18F-FDG PET/CT giving us a comprehensive characterization of the tumor in head and neck cancer (HNC) patients. The results show complementary, rather than competitive, information about tumor metabolism, diffusion, and per­fusion.

 1542 MRI exploration of the subventricular region of the third ventricle and its association with neurofibromatosis type-1 and white matter integrity in children with optic pathway glioma Natalie R Boonzaier1, Patrick W Hales1, Felice D’Arco2, Kshitij Mankad2, Darren Hargrave3, and Christopher Clark1 1Developmental Imaging and Biophysics Section, Developmental Neurosciences, University College London Great Ormond Street Institute of Child Health, London, United Kingdom, 2Radiology Department, Great Ormond Street Children's Hospital, London, United Kingdom, 3Haematology and Oncology Department, Great Ormond Street Children's Hospital, London, United Kingdom The lateral subventricular zone has been explored in association with high-grade gliomas, both in-vivo and with MRI. The third ventricle subventricular zone (TVZ) has been explored in-vivo, using immunohistochemistry and microarray analysis, with regard to neurofibromatosis type-1-associated low-grade optic pathway gliomas. This remains unexplored with MRI. This study examined diffusion MRI features of the TVZ and its association with NF1-status and peri-tumour white matter integrity. TVZ features correlated with NF1-status, and peri-tumour white matter integrity. These results suggest that the state of the TVZ environment can potentially indicate whether a sporadic tumour might behave like its less disruptive NF1-associated counterpart.

 1543 Creating patient-specific computational head models for the study of tissue-electric field interactions using deformable templates Noa Urman1, Shay Levi1, Avital Frenkel1, Ariel Naveh1, Doron Manzur1, Gitit Lavy-Shahaf1, Hadas Sara Hershkovich1, Cornelia Wenger2, Ofir Yesharim1, Eilon Kirson1, and Ze'ev Bomzon1 1Novocure, Haifa, Israel, 2Novocure GbmH, Root, Switzerland Tumor Treating Fields (TTFields) are electric fields at an intermediate frequency approved for treatment of Glioblastoma Multiforme.  Understanding how TTFields distribution in the brain influences disease progression can be studied using numerical simulations. Creation of computational patient models involves accurate segmentation of patient MRIs, a task that cannot be performed automatically, and is therefore time-consuming. We present a method for rapidly creating patient head models using a  healthy head model  as a deformable template. The method is robust even when MRI data quality is low. It is enabling a study correlating the spatial distribution of TTFields and patient outcome.

 1544 Dose reduction in myxoid liposarcomas: Initial descriptive results in the evaluation of response using multiparametric MRI. Evanthia Kousi1, Maria A Schmidt1, Shane Zaidi2, Khin Thway 3, Cyril Fisher 3, Myles Smith4, Dirk Strauss4, Andrew Hayes4, Eleanor Moskovic5, Nicos Fotiadis5, Elizabeth Barquin2, Komal Amin6, Rick Haas7, Christina Messiou5, and Aisha Miah2 1CR-UK and EPSRC Cancer Imaging Centre, Royal Marsden NHS Foundation Trust & Institute of Cancer Research, Sutton, United Kingdom, 2Sarcoma Unit, Royal Marsden NHS Foundation Trust, London, United Kingdom, 3Pathology, Royal Marsden NHS Foundation Trust, London, United Kingdom, 4Academic Surgery, Royal Marsden NHS Foundation Trust, London, United Kingdom, 5Radiology, Royal Marsden NHS Foundation Trust, London, United Kingdom, 6Radiotherapy, Royal Marsden NHS Foundation Trust, London, United Kingdom, 7Radiotherapy, Neetherlands Cancer Institute, Amsterdam, Netherlands Compared to other soft tissue sarcomas (STSs), myxoid liposarcomas (MLSs) are exquisitely radiosensitive. The clinicopathological response following pre-operative radiotherapy at 50 Gy/25# in MLS might be due to radiation induction vascular damage. Here we report initial results in using multiparametric MRI (diffusion-weighted imaging, pharmacokinetic modelling and T2* measurements) to evaluate MLS response during and after preoperative RT. Dynamic contrast-enhanced examinations demonstrated both heterogeneous and homogeneous enhancement patterns. The tissue enhancement curve was monotonically-increasing in all cases, suggesting a distinct vascular pattern. Permeability and perfusion decreases from baseline in responders show Ktrans and IAUGC60 can potentially predict response.

 1545 Superpixels-based Segmentation and Automated Identification of Active Tumour and Necrotic regions in Bone Tumor using T1 and Diffusion Weighted Imaging Amit Mehndiratta1, Esha Baidya Kayal1, Sneha Patil Kulkarni1, Raju Sharma2, Devasenathipathy Kandasamy2, and Sameer Bakhshi3 1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Department of Radiology, All India Institute of Medical Sciences, New Delhi, India, 3Department of Medical Oncology, IRCH, All India Institute of Medical Sciences, New Delhi, India Proper Delineation of the tumour boundary and assessment of tumour size can take crucial part in treatment planning and monitoring treatment response. We investigate a fully automated Simple linear iterative clustering (SLIC) superpixel-based method for detection and segmentation of pathological tissues like oedema, tumour and necrosis associated with Osteosarcoma. Experimental results provide a close match to expert delineation and was able to estimate areas of active tumor and necrosis with good accuracy.

 1546 Prostate MR Elastography: a comparison of image acquisitions strategies in healthy volunteers Kay Pepin1, Kevin Glaser1, Yi Sui1, Roger Grimm1, Arvin Arani1, Phillip Rossman1, Richard Ehman1, Michael Herman1, and Lance Mynderse1 1Mayo Clinic, Rochester, MN, United States The purpose of this study was to compare image acquisition strategies for prostate MRE using external drivers. Additionally, to assess the normal heterogeneity of prostate mechanical properties in an age-matched cohort to the prostate cancer population. Improved resolution using higher MRE vibration frequencies, larger acquisition matrices, and distortion-reduction techniques, may help advance the clinical application of prostate MRE.

 1547 Liver metabolomic investigation of lentiviral targeting of GDPD5 and GDPD6 for breast cancer treatment in a preclinical model Kanchan Sonkar1, Marina Stukova2, Caitlin M. Tressler1, Balaji Krishnamachary1, Zaver M. Bhujwalla1,3, and Kristine Glunde1,3 1The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2San Juan Bautista School of Medicine, Caguas, PR, United States, 3The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States High-resolution 1H MRS is a powerful technique for metabolomics studies of tissues, cells, and body fluids. Here we have used this technique to explore metabolomic changes in the livers of mice that have been treated with lentiviral particles that silence either of the two glycerophosphodiesterase GDPD5 (GDPD5-shRNA) or GDPD6 (GDPD6-shRNA). We systemically administered lentiviral shRNA in mice with orthotopic breast tumor xenografts. We identified distinct increases in leucine, valine, glutathione, creatine, glucose, tyrosine, and histidine in the GDPD5-shRNA treated group, whereas cholesterol, isoleucine, beta-hydroxy butyrate, alanine, glutamate, glutamine, aspartate, fumerate, phenylalanine, and formate were elevated in the GDPD6-shRNA treated group.

 1548 Vascular-induced spin dephasing in real vascular networks reveals useful decay characteristics to differentiate glioblastoma from healthy brain tissue Artur Hahn1, Thomas Kruewel2, Julia Bode2, Lukas Reinhold Buschle1,3, Björn Tews2, Sabine Heiland1, Martin Bendszus1, Christian Herbert Ziener1,3, and Felix Tobias Kurz1,3 1Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany, 2Molecular Mechanisms of Tumor Invasion (V077), German Cancer Research Center (DKFZ), Heidelberg, Germany, 3E010 Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany The transverse relaxation attributed to spin dephasing, caused by microscopic field inhomogeneities throughout a single imaging voxel, induced by the BOLD-mechanism, is studied using realistic three-dimensional microvascular structures, attained with fluorescence ultramicroscopy from mouse brains, and custom-written simulations to uncover differences between glioblastoma and healthy brain tissue. The signal attenuation is weaker and more heterogeneous in tumor tissue. Relaxation rates scale differently with varying field strengths or blood properties and the relaxation processes exhibit strong deviations from Lorentzian decay. The results are important for the development of signal processing methods for tumor diagnosis without contrast agents.

 1549 Effect of corrections for image distortion and gradient nonlinearity on longitudinal DTI tumor measurements in breast patients receiving neoadjuvant chemotherapy Lisa J Wilmes1, Ek-Tsoon Tan2, Evelyn Proctor1, Wen Li1, Jessica Gibbs1, Nola Hylton1, and David C Newitt1 1University of California San Francisco, San Francisco, CA, United States, 2GE Global Research, Niskayuna, NY, United States Diffusion weighted imaging has shown promise for assessing tumor response to treatment, but suffers from gradient nonlinearity and image distortion that may adversely affect quantitative accuracy. This work evaluates corrections for image distortion (susceptibility-induced and eddy current) and bias from gradient non-linearity (GN) on breast tumor DTI metrics prior to treatment (T0) and at an early-treatment time point (T1), in six breast cancer patients undergoing neaoadjuvnt chemotherapy. Both GN and distortion correction had significant effects on tumor ADC and FA values at T0 and T1. The addition of distortion correction also improved the alignment of DTI and DCE-MRI tumor ROIs.

 1550 18F-FDG PET/MRI in Children with Oncologic Diseases: Initial Experience Hansel Javier Otero1, Carolina L Maya1, Sabah E Servaes2, Jeffrey P Schmall1, and Lisa J States1 1Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, United States, 2Raidology, Children's Hospital of Philadelphia, Philadelphia, PA, United States We describe our initial experience with integrated whole-body Fluor-18-Fluordesoxyglucose-PET/MR imaging in children in a retrospective study of all 18F-FDG-PET/MR at our institution. 51 studies were carried out in 41 children (34 girls, 17 boys) with a mean age of 10.16 years (10 months-24 years). Primary diagnosis included rhabdomyosarcoma (n=18) and Osteosarcoma (n=5). The majority of studies (n=29, 57.9%) were performed for treatment response/restaging. All studies were diagnostic (technical success rate 100%). The mean effective dose was 5.25 mSv (2.1-11.5 mSv). Mean total imaging time was 80 minutes (42-138 minutes). Thirty-eight (74.5%) cases had an average of 2.2 additional MR sequences. 18F-FDG PET/MR is technically feasible for the evaluation of oncologic processes in children at a fraction of the radiation dose.

 1552 Effect of Stereotactic Body Radiotherapy on Perfusion and Diffusion in Prostate Tumor and Benign Tissue Kristen Zakian1, Hebert Vargas Alvarez1,2, Andreas Wibmer2, Aditi Iyer2, Neelam Tyagi2, Aditya Apte2, Marissa Kollmeier2, Boris Mychalczak2, Karen Borofsky2, Oren Cahlon2, Yousef Mazaheri Tehrani2, Margie Hunt2, and Michael Zelefsky2 1Memorial Sloan Kettering Cancer Center, New York, NY, United States, 21275 York Avenue, Memorial Sloan Kettering Cancer Center, New York, NY, United States Multimodality MRI including DCE-MRI and DW-MRI were performed in patients prior to and following hypofractionated stereotactic body radiotherapy (SBRT).  Diffusion and perfusion related parameters in both tumor and non-tumor benign tissue were calculated at 3, 6, and 12 months after SBRT. Radiation-induced changes were observed in perfusion and diffusion related parameters in tumors. In the non-tumor transition zone, SBRT induced changes in perfusion-related parameters. Multimodality MRI has potential for treatment effect monitoring in the prostate after SBRT.

 1553 An integrated, semi-automated 3D printed Breast DCE-MRI phantom solution to generate diverse pharmacokinetic curves Nithin N Vajuvalli1, Amaresha Shridhar Konar1, Shivaprasad Ashok Chikop1,2, Ramesh Venkatesan2, and Sairam Geethanath1,3 1Medical Imaging Research Centre, Dayananda Sagar Institution, Bangalore, India, 2Wipro GE healthcare, Bangalore, India, 3Department of Radiology, Columbia University Medical Centre, New York, NY, United States In vitro phantoms play a critical role in the assessment of novel Dynamic Contrast Enhanced MRI (DCE-MRI) methods related to acquisition and reconstruction, among other advantages such as repeatability and reproducibility.  In this work, we demonstrate a 3D printed breast DCE-MRI phantom that is capable of producing diverse kinetic curves as those seen in human patients. The wash-in and wash-out characteristics were controlled through user controlled  Ktrans values and the geometry of the phantom respectively. The phantom demonstrated in this work is 3D printed, cost effective, user interface controlled, and integrated with a peristaltic pump to obtain different kinetic curves.

### Fiber Orientation & Fiber Tracking

 Exhibition Hall 1554-1573 Tuesday 8:15 - 10:15

 1554 Damped Richardson-Lucy deconvolution for multi-shell diffusion MRI Fenghua Guo1, Alexander Leemans1, Max Viergever1, Flavio Dell'acqua2, and Alberto De Luca1 1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2NATBRAINLAB, Department of Neuroimaging and NIHR Biomedical Research Centre, Institute of Psychiatry, King's College London, London, United Kingdom The damped Richardson-Lucy (DRL) algorithm is a popular spherical deconvolution technique to quantify fiber orientation distributions from single-shell brain diffusion MRI (dMRI) data. Thanks to the progress of acquisition hardware, it is becoming increasingly common to acquire multi-shell dMRI data, which has the potential, to deliver additional information on the microstructure of tissues. In this work we extended the DRL framework to accommodate multi-shell data while accounting for multiple tissue types in the brain, to reduce partial volume contamination on the main FODs. The approach was tested on two dataset and proved to be stable over different acquisition schemes.

 1555 Bundle-specific tractography using voxel-wise orientation priors Francois Rheault1, Etienne St-Onge2, Quentin Chenot3, Laurent Petit3, and Maxime Descoteaux2 1Computer Science, Université de Sherbrooke, Lac-Etchemin, QC, Canada, 2Computer Science, Université de Sherbrooke, Sherbrooke, QC, Canada, 3Groupe d'Imagerie Neurofonctionnelles, Institut des Maladies Neurodégénératives (GIN-IMN) - UMR 5293, CNRS, CEA, Université de Bordeaux, Bordeaux, France Diffusion tractography allows the investigation of white matter (WM) pathways of interest. However, to cover the full spatial extent of the desired bundles, tractography requires a large amount of streamlines (millions) to be generated. In this work, we developed a bundle-specific tractography algorithm using voxel-wise orientation priors. Our method aims to be more efficient than a classical whole brain tractography and increase the quality of virtual WM dissection.

 1556 Exploring Local Geometric Structure of Fiber Tracts Using Tract-Based Director Field Analysis Jian Cheng1,2, Tao Liu3, Feng Shi4, Ruiliang Bai5, Jicong Zhang3, Haogang Zhu3, Dacheng Tao2, and Peter J. Basser1 1National Institutes of Health, Bethesda, MD, United States, 2University of Sydney, Sydney, Australia, 3Beihang University, Beijing, China, 4Cedars Sinai Medical Center, Los Angeles, CA, United States, 5Zhejiang University, Hangzhou, China Inspired by distortion analysis of liquid crystals [1], we propose a novel mathematical framework, called tract-based director field analysis (TDFA), to explore the local geometric structure of fiber tracts after tractography. TDFA provides 6 scalar indices along tracts to quantify local orientational dispersion and orientational distortion (splay, bend, and twist) of fiber tracts. To our knowledge,  this is the first work to quantify "splay", "bend" and "twist" of fiber tracts, although the three terms have been widely used to qualitatively describe the complexity of fiber tracts for about 20 years [2]. Synthetic and real data experiments demonstrate the effectiveness of the proposed scalar indices.

 1557 ERFO: Improved ODF estimation by combining machine learning with linear estimation theory Divya Varadarajan1 and Justin P. Haldar1 1University of Southern California, Los Angeles, CA, United States Hiqh-quality diffusion tractography depends on the accurate estimation of orientation distribution functions (ODFs).  Existing estimation methods often use modeling assumptions that are violated by real data, lack theoretical characterization, and/or are only applicable to a narrow class of q-space sampling patterns. As a result, existing approaches may be suboptimal. This work proposes a novel ODF estimation approach that learns a linear ODF estimator from training data. The approach can be applied to arbitrary q-space sampling schemes, has strong theoretical justification, and it can be shown that the trained estimators will generalize to new settings they weren’t trained for.

 1558 Investigating the streamline count required for reproducible structural connectome construction across a range of brain parcellation resolutions Chun-Hung Yeh1, Robert Elton Smith1, Xiaoyun Liang1, Fernando Calamante1,2, and Alan Connelly1,2 1The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2The Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia This study systematically investigates a fundamental question for tractogram-based connectomics research: for a given resolution of brain parcellation, how many streamlines are required for reproducible connectome construction? We incorporate state-of-the-art tractography techniques with surface parcellation schemes of multiple granularities to investigate the influence of streamline count on the connectome variability. Our results suggest that selecting an appropriate number of streamlines is crucial for global and per-edge variability of the connectome, revealing important implications for subsequent network analysis and inferences. Methods that investigate structural connectivity with different brain parcellation resolutions should benefit from the experimental workflow and outcomes of this study.

 1559 Spherical deconvolution of diffusion MRI data with tensor-valued encodings Ben Jeurissen1 and Filip Szczepankiewicz2,3 1imec-Vision Lab, Dept. of Physics, University of Antwerp, Antwerp, Belgium, 2Clinical Sciences, Lund, Lund University, Lund, Sweden, 3Random Walk Imaging AB, Lund, Sweden Multi-tissue constrained spherical deconvolution (MT-CSD) exploits the characteristic b-value dependency of each tissue type to estimate both the apparent tissue densities and the full white matter (WM) fiber orientation distribution function from diffusion MRI data. In this work, we extend the MT-CSD approach to account for data acquired with nonlinear and multiple b-tensor shapes and show that multiple b-tensor shapes can provide a new means of contrast between tissue types, in particular between gray matter and WM. Our approach provides high-quality apparent tissue density maps and high-quality fiber tracking from data with multiple b-tensor shapes, even with sparse q-space samplings.

 1560 Free Water Elimination Improves Tractography Through Multiple Sclerosis Lesions Brittany Gilchrist1,2, Sidong Liu1,3,4, Chenyu Wang3,4, Ofer Pasternak5, Yuyi You1,2, and Alexander Klistorner1,2,3 1Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, Australia, 2Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia, 3Brain and Mind Centre, University of Sydney, Sydney, Australia, 4Sydney Neuroimaging Analysis Centre, Sydney, Australia, 5Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States Axonal loss within chronic MS lesions is typically accompanied by increase of extra-cellular space. Reduction of anisotropy caused by this excessive extra-cellular water may limit the ability of tractography techniques to accurately detect fibre bundles. The aim of this study was to examine if application of free water elimination (FWE) algorithm may improve deterministic tractography through MS lesions. We show that elimination of free water markedly increases detection of lesional fibre bundles. While this effect was observed in the majority of lesions, it was more apparent in lesions with small initial number of fibres and in lesions categorised as severely damaged.

 1561 Is removal of weak connections necessary for dense weighted structural connectomes? Oren Civier1, Robert Elton Smith1,2, Chun-Hung Yeh1, Alan Connelly1,2, and Fernando Calamante1,2 1Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia Recent advances in tractography enable the generation of weighted structural connectomes where connection strengths are biologically meaningful. However, use of probabilistic tracking algorithms leads to dense graphs with many low-strength connections, many of which may be considered erroneous. Historically, the existence of such false positives necessitated thresholding of weak connections; this was especially relevant when constructing binary connectomes. Here we show that in dense weighted structural connectomes, the contribution of weak connections to network metrics is negligible and, thus, their removal is not necessary; indeed, the confounds introduced by an arbitrary cut-off value may in fact render this process undesirable.

 1562 Angular versus spatial resolution in tractography for deep brain stimulation in psychiatry Luka Liebrand1,2, Guido van Wingen1,2, Damiaan Denys1,2,3, and Matthan Caan2,4,5 1Dept. of Psychiatry, Academic Medical Center - University of Amsterdam, Amsterdam, Netherlands, 2Amsterdam Neuroscience, Amsterdam, Netherlands, 3Netherlands Institute for Neuroscience, Amsterdam, Netherlands, 4Dept. of Radiology, Academic Medical Center - University of Amsterdam, Amsterdam, Netherlands, 5Spinoza Centre for Neuroimaging, Amsterdam, Netherlands Deep brain stimulation of the ventral part of the anterior limb of the internal capsule (vALIC) could potentially benefit from tractography-guided targeting, since it contains two major fiber bundles. In order to develop a diffusion-weighted sequence that has the greatest bundle specificity within the vALIC, we compared tractography results from a single-shell 3T sequence with multi-shell 3T and high-resolution 7T sequences. Although the multi-shell sequence showed superior SNR, it did not allow increased bundle discernibility in the vALIC. The high-resolution sequence showed more anatomical detail, with more radially constrained tractography, and proved superior for separating the two bundles.

 1563 A preliminary application of the diffusion tensor imaging in estimating the functional and structural recovery of the visual pathway in Dysthyroid Optic Neuropathy patients after intravenous methylprednisolone pulse therapy. ping liu1 and jing zhang1 1department of radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, wu han, China The management of DON (dysfunction optic neuropathy) is complex, an effective method to reflect the response of treatment is indispensable. We use the MRI-DTI combine d with DtiStudio software to assess the visual pathway changes in DON patients pre and post intravenous methylprednisolone pulse therapy. The results did demonstrate the improvement of visual pathway. The DTI can be regarded as a reliable tool to assess and follow up DON patients during therapy.

 1564 A multi-shell self-calibrating Richardson-Lucy deconvolution approach for the simultaneous quantification of ODF and tissue properties of different diffusion domains in the kidneys. Alberto De Luca1, Martijn Froeling2, and Alexander Leemans1 1Image Sciences Institute, UMC Utrecht and University Utrecht, Utrecht, Netherlands, 2Department of Radiology, UMC Utrecht, Utrecht, Netherlands The advent of multi-shell diffusion MRI (dMRI) offers a viable substrate to apply deconvolution profiles in tissues characterized by partial volume of multiple diffusion domains, as the kidneys. In this work we present a modified damped Richardson-Lucy (mdRL) algorithm to perform spherical deconvolution over multiple diffusion domains. This method does not need to define a prior response function, which is dynamically estimated for each voxel, and allows to compute a fiber orientation distribution as well as relevant scalar metrics, as mean diffusivity and fractional anisotropy, for each diffusion domain. Applicability on two sample datasets is demonstrated as proof of concept.

 1565 Automatic reconstruction of cortico-striato-thalamo-cortical loops with application to obsessive-compulsive disorder Dogu Baran Aydogan1, David Sean Thylur2, Junyan Wang1, Yuchun Tang3, Janet Sobell1, James Knowles4, and Yonggang Shi1 1Keck School of Medicine of USC, Los Angeles, CA, United States, 2Emory University, Atlanta, GA, United States, 3Shandong University Cheeloo College of Medicine, Shandong, China, 4SUNY Downstate Medical Center, Brooklyn, NY, United States Cortico-striato-thalamo-cortical (CSTC) loops are thought to play critical roles in the pathophysiology of several brain disorders. Despite the widespread evidence of CSTC circuits' crucial roles in brain disorders, a systematic approach to map their fiber pathways is missing. In order to advance our understanding on these critical circuits and how they are related to brain disorders, we propose a fully automatic approach for the in-vivo reconstruction based on diffusion MRI tractography. To demonstrate our approach, we studied MRI data from 19 patients with obsessive-compulsive disorder and 15 controls. Our approach enables in-dept analysis of the individual connections and also the full CSTC networks of the motor and lateral orbitofrontal loops.

 1566 Predictive Value of Two-tensor Unscented Kalman Filter Tractography in the Reconstruction of the Arcuate Fasciculus (AF) in Patients with Gliomas Involving Eloquent Language Areas Jing Yan1, Jingliang Cheng1, Shaoyu Wang2, and Xianzhi Liu3 1Department of MRI, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Siemens Healthcare, Scientific marketing, Beijing, China, 3Department of Neurosurgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China This study aimed to preliminarily investigate the postoperative changes of AF in glioma patients detected by two-tensor UKF tractography from the perspective of the usefulness as a reference for postoperative recovery of language functions. The postoperative changes of AF were evaluated chronologically in relation to postoperative changes in language functions after surgery. Our study preliminarily shows that postoperative changes in the long segment of the left AF detected by two-tensor UKF tractography may be a predicting factor for postoperative language functional outcomes. Postoperative changes in the long and posterior segment of the left AF may be related with the language comprehending and repeating ability in glioma patients.

 1567 Clustering of tractography datasets based on streamline point distribution Alexis Sánchez1, Cecilia Hernández1, Cyril Poupon2, Jean-François Mangin2, and Pamela Guevara1 1Faculty of Engineering, University of Concepción, Concepción, Chile, 2Neurospin, I2BM, CEA, Gif-sur-Yvette, France We propose a fiber clustering algorithm composed by several steps, with the objective of representing the whole dataset by a small set of cluster centroids. First, a clustering is performed separately for a subset of points within the streamlines. The obtained point clusters are then used to regroup the fibers having common point clusters. Next, fiber clusters are filtered out by size and finally regroup using a quick merge based on a maximum Euclidean distance. A reduced set of regular and thin clusters is finally obtained. In contrast to previous works, the proposed method is only based on streamline structure.

 1568 Mitigating the effects of imperfect fixel correspondence in Fixel-Based Analysis Robert Elton Smith1,2 and Alan Connelly1,2 1The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia A requisite step in performing a Fixel-Based Analysis (FBA) is the determination of "fixel correspondence", which defines how discrete fibre elements (fixels) for a particular subject map to the fixels defined in each voxel in template space. The method used thus far for this purpose - simply selecting the subject fixel that best aligns with the template fixel - fails to take into consideration the possibility for substantial variations in fixel segmentation across subjects. We propose a more sophisticated algorithm for determining fixel correspondence, which better accounts for differences in fixel segmentation, and demonstrate how this reduces the variance observed in fixel data across healthy controls.

 1569 Accuracy of response function estimation algorithms for 3-tissue spherical deconvolution of diverse quality diffusion MRI data Thijs Dhollander1, David Raffelt1, and Alan Connelly1,2 1The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2The Florey Department of Neuroscience, University of Melbourne, Melbourne, Australia Multi-shell multi-tissue constrained spherical deconvolution (MSMT-CSD) and single-shell 3-tissue CSD (SS3T-CSD) resolve white matter (WM) fibre orientation distributions and grey matter (GM) and CSF tissue compartments by deconvolving WM, GM and CSF response functions from the diffusion MRI data.  To estimate these response functions from the data itself, a T1-based method was originally proposed.  Recently, an unsupervised DWI-based method that doesn't rely on a co-registered T1-weighted image was also introduced.  We evaluated the performance of both methods on high-quality HCP-data and clinical-quality single-shell data of an elderly patient with extensive lesions.  The DWI-based method was more accurate in both scenarios.

 1570 Tissue-Encoded Colour Fluid-Attenuated Inversion Recovery (TEC-FLAIR) map: contrast fusion designed for improved characterisation of white matter lesion heterogeneity Thijs Dhollander1, Remika Mito1,2, and Alan Connelly1,2 1The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2The Florey Department of Neuroscience, University of Melbourne, Melbourne, Australia FLAIR MR images feature striking contrast, allowing easy identification of white matter hyperintense lesions.  While such lesions have been explained by a range of microstructural characteristics, FLAIR itself doesn't provide specificity to distinguish these heterogeneous origins. 3-tissue CSD techniques resolve white matter (WM), grey matter (GM) and CSF compartments.  In lesions, GM-like and CSF-like diffusion-weighted signals have been hypothesised to be related to certain origins, e.g. gliosis or increased interstitial fluid.  We propose a fusion of 3-tissue encoded colours and FLAIR via panchromatic sharpening techniques, designed for improved characterisation of white matter lesion heterogeneity.

 1571 Linking neurocognitive measures with whole brain structure using Diffusion ODFs in the HCP dataset Steven H. Baete1,2, Ying-Chia Lin1,2, Jingyun Chen1,2,3, Ricardo Otazo1,2, and Fernando E. Boada1,2 1Center for Advanced Imaging Innovation and Research (CAIR), NYU School Of Medicine, New York, NY, United States, 2Center for Biomedical Imaging, Dept of Radiology, NYU School Of Medicine, New York, NY, United States, 3Dept of Psychiatry, NYU School Of Medicine, New York, NY, United States Higher dimensional diffusion protocols are now routinely acquired in large-scale studies. While these diffusion data sets contain a wealth of information about white matter architecture, this information is not fully exploited when their dimensionality is reduced to simplify statistical correlations with neurocognitive markers over the whole brain. To overcome this limitation, we analyze the full Orientation Distribution Function (ODF) at each voxel using a Low-Rank plus Sparse decomposition to identify key ODF features. We use this approach to link neurocognitive measures to brain structure in a cohort of healthy Human Connectome Project volunteers.

 1572 7T DIFFUSION MRI DATA QUALITY FROM 3T SCANNER DATA Suheyla Cetin Karayumak1,2, Marek Kubicki1,2, and Yogesh Rathi1,2 1Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital, Boston, MA, United States Diffusion MRI (dMRI) data obtained from a 7T scanner has novel and improved microstructural tissue information missing from data acquired on 3T scanners. In this work, we propose to use deep Convolutional Neural Networks (CNN) that use rotation invariant spherical harmonic (RISH) features to map the dMRI data (the raw signal) between scanners without changing the fiber orientation. We validate our algorithm on 40 Human Connectome Project (HCP) subjects with scans on both 3T and 7T (10 training + 30 test). Our preliminary results on 30 test subjects shows that CNN can indeed reliably obtain 7T dMRI data quality from 3T scans.

 1573 Pipeline for post-processing peripheral nerve DTI Tina Jeon1, Jerome J Maller2, Maggie M.K. Fung3, and Darryl B Sneag1 1Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States, 2General Electric Healthcare, Melbourne, Australia, 3General Electric Healthcare, New York, NY, United States The purpose of the study is to evaluate and formalize a post-processing pipeline for DTI of the peripheral nerves using existing open source software suites. Our method integrates image registration, nerve segmentation, and DTI fiber tracking using the FMRIB software library (FSL) and MRtrix3, two popular software suites primarily used in the brain. 6 normal volunteers/patients and 9 nerves were analyzed and image quality was assessed. Using this protocol, image quality significantly improved in addition reducing processing time to 10 minutes using a semi-automated method.

### Diffusion MRI: Signal Reconstruction & Representation

 Exhibition Hall 1574-1612 Tuesday 8:15 - 10:15

 1574 Investigating noise distribution changes after motion correction and its effects on subsequent diffusion MRI processing Samuel St-Jean1, Alberto De Luca1, Max A. Viergever1, and Alexander Leemans1 1Image Sciences Institute, Department of Radiology, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands The quantification of diffusion MRI assumes the absence of motion and anatomical correspondence between diffusion sensitizing factors. To investigate the impact of processing order between motion correction and two denoising methods, we evaluated DKI and NODDI derived maps. Using repeated scans acquired with and without voluntary motion, three processing orders were compared. Results show that processing order moderately influences NODDI maps. However, two of the three denoising strategies can reduce outliers in mean kurtosis between 28% and 59% when compared to motion correction only.

 1575 Optimal b-value selection for IVIM-DWI: identification of pancreastic lesions based on entire-tumor Jiali Li1, Daoyu Hu1, and Zhen Li1 1Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China The purpose of this paper is to explore the successful b-value combination of IVIM-DWI that maximizes the diagnostic efficiency of parameters in differenting pancreatic cancer and normal tissues. IVIM parameters were measured by different b value combinations, and then the diagnostic performance of each significant parameter in identificating tumors and normal tissues was calculated and compared between different combinations. The results show that in different b value combinations, the diagnostic efficiency of the parameters are also different. The final conclusion is that b value combination of 0-1700 may be the best selection in clinical practice.

 1576 Voxel-wise Mahalanobis Distance (MaD-Vox): a multivariate approach to single subject analysis Jose M Guerrero1, Douglas C Dean III2, Nagesh Adluru2, and Andrew L Alexander3 1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 2Waisman Center, University of Wisconsin - Madison, Madison, WI, United States, 3Medical Physics, Psychiatry, University of Wisconsin - Madison, Madison, WI, United States A voxel-wise multivariate analysis based on the Mahalanobis distance is presented. Upon implementation on simulated DTI data, the method demonstrates the ability to detect regions of pathology at an individual level with respect to a reference healthy control group. This multivariate approach could enhance the clinical value of diffusion weighted MRI in the assessment of individual patients with highly spatially heterogeneous brain conditions such as traumatic brain injury or autism spectrum disorder.

 1577 Anatomical atlas of MAP MRI-derived 3D diffusion propagators and microstructural parameters Alexandru V Avram1, Adam S Bernstein2, M. Okan Irfanoglu1, Amber Simmons2, Martin Cota3, Neville Gai4, Neekita Jikaria3, Anita Moses3, Christine L Turtzo3, Lawrence Latour3, Dzung Pham4, John A Butman4, and Peter J Basser5 1NIBIB, National Institutes of Health, Bethesda, MD, United States, 2NICHD, National Institutes of Health, Bethesda, MD, United States, 3NINDS, National Institutes of Health, Bethesda, MD, United States, 4Diagnostic Radiology, National Institutes of Health, Bethesda, MD, United States, 5National Institutes of Health, Bethesda, MD, United States We describe the construction of an anatomical template of 3D probability distributions water molecule displacements in tissues (i.e., diffusion propagators) measured with MAP MRI in a population of healthy volunteers. From the template of 3D diffusion propagators, we compute normative values of MAP MRI microstructural parameters and visualize the orientational characteristics of water net displacement profiles using orientation distribution functions (ODFs). This atlas could provide a reference for protocol development in longitudinal and multi-center studies, and for clinical studies seeking to detect and characterize subtle microstructural changes, such as those occurring in mild traumatic brain injury (mTBI), or metastatic cancer.

 1578 Spatial normalization of individual fractional anisotropy (FA) maps to widely used population templates for analysis can increase variability and create spurious differences in the measured FA values Amritha Nayak1,2, Elisabeth Wilde3, Brian Taylor3, CENC Neuroimaging Core Investigators4, Laura Reyes1,2, and Carlo Pierpaoli1 1Quantitative Medical Imaging Section, NIBIB, NIH, Bethesda, MD, United States, 2The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc, Bethesda, MD, United States, 3Michael E.DeBakey VA Medical Center and Baylor College of Medicine, Houston, TX, United States, 4Chronic Effects of Neurotrauma Consortium, Richmond, VA, United States In this study we evaluate the effects of spatial normalization of individual fractional anisotropy (FA) maps to widely used population templates for analysis and its introduction of variability, creating spurious differences in the measured FA values.

 1579 Clinical assessment of simultaneous diffusion tensor imaging and T2 relaxometry of lumbar nerve roots in patients with low back pain Takayuki Sakai1,2, Masami Yoneyama3, Tosiaki Miyati4, Atsuya Watanabe5,6, Eunju Kim7, and Noriyuki Yanagawa1 1Eastern Chiba Medical Center, Tougane, Japan, 2Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan, 3Philips Japan, Tokyo, Japan, 4Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan, 5Orthopaedic Surgery, Eastern Chiba Medical Center, Tougane, Japan, 6Chiba University Graduate School of Medicine, Chiba, Japan, 7Philips Healthcare Korea, Seoul, Korea, Democratic People's Republic of We developed a single-shot dual-echo EPI-DTI sequence (Diffusion-Relaxation Matrix: DRM) that can simultaneously provide the diffusion tensor parameters and T2 values. The purpose of this study was to investigate the clinical feasibility of DRM for the lumbar nerve roots in patients with low back pain. FA values were negatively correlated with each quantitative value. Prolongation of T2 values were observed in case of abnormally enlarged nerve roots. Therefore,simultaneous acquisition of diffusion tensor imaging and T2 map by using DRM technique might be able to evaluate the extent of nerve disorders more accurately.

 1580 q-Space Deep Learning for Alzheimer’s Disease Diagnosis: Global Prediction and Weakly-Supervised Localization Vladimir Golkov1, Phillip Swazinna1, Marcel M. Schmitt1, Qadeer A. Khan1, Chantal M.W. Tax2, Marat Serahlazau1, Francesco Pasa1,3, Franz Pfeiffer3, Geert Jan Biessels4, Alexander Leemans5, and Daniel Cremers1 1Department of Informatics, Technical University of Munich, Munich, Germany, 2CUBRIC, Cardiff University, Cardiff, United Kingdom, 3Physics Department, Technical University of Munich, Munich, Germany, 4Department of Neurology, University Medical Center Utrecht, Utrecht, Netherlands, 5Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands Most diffusion MRI approaches rely on comparably long scan time and a suboptimal processing pipeline with handcrafted physical/mathematical representations. They can be outperformed by recent handcrafted-representation-free methods. For instance, q-space deep learning (q-DL) allows unprecedentedly short scan times and optimized voxel-wise tissue characterization. We reformulate q-DL such that it estimates global (i.e. scan-wise rather than voxel-wise) information. We use this formulation to distinguish Alzheimer’s disease (AD) patients from healthy controls based solely on raw q-space data without handcrafted representations such as DTI. Classification quality is very promising. Weakly-supervised localization techniques indicate that the neural network attends to AD-relevant brain areas.

 1581 A method to estimate the product of perfusion fraction f and pseudodiffusion coefficient Dp of IVIM without estimating f and Dp Eizou Umezawa1, Masahiro Kawasaki1, Yukiko Sonoda1, Takashi Fukuba2, Kazuhiro Murayama3, Kazuki Takano1, Masayuki Yamada1, Toshiyuki Onodera4, and Masahiro Ida4 1Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan, 2Department of Radiology, Fujita Health University Hospital, Toyoake, Japan, 3School of Medicine, Fujita Health University, Toyoake, Japan, 4Department of Radiology, Tokyo Metropolitan Health and Medical Treatment Corporation Ebara Hospital, Tokyo, Japan IVIM analysis can provide the perfusion fraction f and the pseudodiffusion coefficient D* or Dp in addition to the diffusion parameters. The product of f and D* is known to relate to cerebral blood flow. Recently, a higher diagnostic performance of fD* than f and D* has been reported. We propose a method to estimate fDp without estimating f and Dp using DKI analysis. The DKI based IVIM analysis can be implemented easily and provides fDp values with a high degree of precision.

 1582 Histogram Analysis of Diffusion Weighted Image for Body Tumors Manabu Arai1, Koichi Oshio1, Shigeo Okuda1, and Masahiro Jinzaki1 1Department of Radiology, Keio Univerisity School of Medicine, Tokyo, Japan Weighted diffusion subtraction (WDS) is a new imaging tool  which may be useful for estimating the tissue characteristics within a voxel. In this study, DWI histogram (low b vs. high b) was generated and referred to WDS. On the histogram, the data distribution represents the tissue composition with blurring caused by partial volume. DWI histogram can visualize the relationship between T2WI (low b value DWI) and WDS.

 1583 Regularized nonnegative least-square fitting for intravoxel incoherent motion data processing: a simulation study André Monteiro Paschoal1, Renata Ferranti Leoni1, and Fernando Fernandes Paiva2 1InBrain Lab - FFCLRP, University of Sao Paulo, Ribeirao Preto, Brazil, 2Physics Institute of Sao Carlos, University of Sao Paulo, Sao Carlos, Brazil Fitting model plays a crucial role in the analysis of intravoxel incoherent motion (IVIM) data due to limited number of points and to typical noisy data. Also, injured tissues can change the diffusion coefficient (D) value so that the number of D that contributes to total signal might be unknown. A possible solution for this problem is the nonnegative least-square (NNLS) fitting. This study aimed to evaluate the impact of the parameters used in the fitting and its applicability to simulated IVIM signal data processing.

 1584 New analysis and visualization tools AFNI-FATCAT (and implementing other software) Paul Taylor1, Justin Rajendra1, Amritha Nayak2,3, M. Okan Irfanoglu2, Daniel R Glen1, and Richard C Reynolds1 1NIMH, NIH, Bethesda, MD, United States, 2NIBIB, NIH, Bethesda, MD, United States, 3Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States The typical size of MRI data sets being processed for a study is rapidly increasing, particularly with the growth of publicly available data sets and “big data” strategies for approaching problems. This produces a dual need in analysis: having scriptable and reproducible pipelines for analysis, as well as having a method for visualizing data both during intermediate steps and for final results presentation.  Here, we describe new AFNI-FATCAT tools that provides a succinct set of processing steps for a full DTI analysis pipeline, from DICOM conversion to tractography and statistical anlyses; these tools create QC images and quantitative checks at each step for pipeline evaluation.

 1585 A review of the oscillating-gradient spin-echo signal model: Does a finite gradient duration alter Jeff Kershaw1 and Takayuki Obata1 1Applied MRI Research, National Institute of Radiological Sciences, QST, Chiba, Japan The oscillating gradient spin-echo (OGSE) sequence has emerged as a promising diffusion-weighted imaging (DWI) technique for probing in vivo tissue microstructure. However, due to the finite duration of the diffusion gradients, there are some aspects of the signal model that should be considered in more detail. This work re-examines the derivation of the OGSE method to better understand how the properties of the selected MPG are reflected in the signal equation.

 1586 Group Analysis of Healthy Aging Microstructural Integrity Parameters Maíra Siqueira Pinto1, Antonio Carlos Santos2, and Carlos Ernesto Garrido Salmon1 1InBrain Lab, Department of Physics, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil, 2Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil The aim of this work is to compare FA and AFD as integrity parameter of white matter between groups of different ages to evaluate which areas of the white matter are affected in its fiber composition in the healthy aging process, and to evaluate if it happens in a global or specific manner.  The results show that the largest decreases in FA and AFD occur in the brain of the elderly (over 60 years) due to more advanced axonal degeneration. AFD seems to show complementary information for understanding the white matter integrity alterations throughout the lifespan.

 1587 Diffusion exchange spectroscopic imaging of the spinal cord Dan Benjamini1, Michal E Komlosh1,2, and Peter J Basser1 1Section on Quantitative Imaging and Tissue Sciences, National Institutes of Health, Bethesda, MD, United States, 2Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States Diffusion exchange spectroscopy (DEXSY) is successfully used in conjunction with imaging on the spinal cord, and with excellent prospects for preclinical and clinical applications. DESXY is a model-free approach to measure water migration between and among distinct microenvironments. The time dependency of water migration from the intra- and extracellular microdomains indicates that different regions within gray or white matter exhibit different exchange kinetics, and points to the importance of the spatial scale of this heterogeneity.

 1588 A Novel Strategy For Morphologically Faithful Registration and Template Creation for Diffusion MRI Data M. Okan Irfanoglu1, Neda Sadeghi1, Carlo Pierpaoli1, and Moebius Syndrome Research Consortium2 1QMI/NIBIB, National Institutes of Health, Bethesda, MD, United States, 2National Institutes of Health, Bethesda, MD, United States Spatial alignment of diffusion tensor MRI (DTI) data is of fundamental importance for voxelwise statistical analysis and creation of population specific atlases of diffusion MRI metrics. Most available DTI-based spatial normalization algorithms emphasize alignment of anisotropic structures and disregard the quality of alignment for gray matter and CSF-filled regions. Additionally, standard atlas creation strategies using these registration tools do not generate templates that are morphologically representative of average features of the population. In this work, we propose a new DTI-based registration and atlas creation method that aims to overcome these challenges.

 1589 Reproducibility of Diffusion Tensor Imaging Data between Morning and Evening Scans Domitille Dempuré1,2, Jia Fan2,3, André J.W. van der Kouwe4, Ernesta M. Meintjes2,3,5, and A. A. Alhamud2,3,5 1Higher Institute of Bioscience of Paris (ISBS), Paris, France, 2MRC/UCT Medical Imaging Research Unit, Division of Biomedical Engineering, University of Cape Town, Cape Town, South Africa, 3Department of Human Biology, University of Cape Town, Cape Town, South Africa, 4Massachusetts General Hospital, Boston, MA, United States, 5Cape Universities Body Imaging Centre (CUBIC-UCT), Cape Town, South Africa Diffusion Tensor Imaging (DTI) is widely used to study brain white matter integrity. However, instability of the MRI scanner including heating of the iron plates in the shim trays or physiological changes during the day may influence DTI indices. The aim of this work was to evaluate DTI parameters through scans performed at two different times of the day, early morning and late afternoon, and repeated over six days. The results showed that DTI data acquired at different times of day differed, as mean diffusivity was higher in the morning than the evening.

 1590 IVIM D and f - Optimal estimation technique and their potential for tissue differentiation Oscar Jalnefjord1,2, Mats Andersson3, Mikael Montelius1, Anna-Karin Elf4, Viktor Johanson4, Johanna Svensson5, Göran Starck1,2, and Maria Ljungberg1,2 1Department of Radiation Physics, University of Gothenburg, Gothenburg, Sweden, 2Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden, 3Department of Radiology, University of Gothenburg, Gothenburg, Sweden, 4Department of Surgery, University of Gothenburg, Gothenburg, Sweden, 5Department of Oncology, University of Gothenburg, Gothenburg, Sweden IVIM parameter estimation restricted to D and f (avoiding D*) has gained increased popularity. In this study we show that the commonly used segmented fitting approach is preferable. We also show that differentiation between tumor and healthy liver tissue is substantially enhanced by the combined use of D and f.

 1591 The influence of gradient nonlinearity on spherical deconvolution approaches: to correct or not to correct? Fenghua Guo1, Greg Parker2, Alberto De Luca1, Derek Jones2, Max Viergever1, Alexander Leemans1, and Chantal Tax2 1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2Cardiff University Brain Research Imaging Centre, Cardiff, United Kingdom Gradient non-linearities affects diffusion weighted imaging (DWI) as it can result in geometric distortions and spatially varying b-values and gradient directions. The effect is more severe at high gradient strengths. Spherical deconvolution, in particular, relies on a spherical sampling of q-space, which might be affected due to gradient nonlinearities. In this work, we explored the sensitivity of two widely used spherical deconvolution approaches to the gradient non-linearity effect by investigating FOD peak orientation deviations, and evaluate a modified version of DRL that can take into account spatially varying diffusion gradients and weighting. Monte-Carlo simulations and two datasets from the HCP project were used for evaluation.

 1592 Value of Whole-Tumor Histogram Analysis of Diffusion Tensor Imaging in Differentiating Intrahepatic Mass-forming Cholangiocarcinoma and Solitary Hypovascular Hepatic Metastases Ying Zhao1, Ailian Liu1, Lihua Chen1, Lizhi Xie2, and Ye Li1 1Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, China, 2MR Research, GE Healthcare, Beijing, China Diffusion tensor imaging (DTI) is an imaging modality that detects the microstructural and pathological changes of organisms according to the diffusive characteristics of water molecules in the tissues. MR histogram analysis reflects the tumor heterogeneity. In the current study, histogram analysis of DTI was demonstrated to be capable to differentiate mass-forming cholangiocarcinoma and solitary hypovascular hepatic metastases, which can provide quantitative information for further clinical diagnosis.

 1593 Characterization and Correction of Abnormally Low Mean Kurtosis Values Fan Zhang1, Lipeng Ning1, Lauren J. O'Donnell1, and Ofer Pasternak1 1Harvard Medical School, Boston, MA, United States Diffusion kurtosis imaging (DKI) often yields abnormally low mean kurtosis (MK) values that are physically and/or biologically implausible. We aim to characterize the relationship between abnormally low MK and baseline (b0) values. We show that too low b0 signals explain abnormally low MK values. We propose an automatic and threshold free approach for the identification of low MK voxels, along with a correction strategy based on adaptive smoothing. Our results suggest that modifying the b0 is sufficient to resolve the vast majority of low MK values, and is preferred over two other popular correction methods.

 1594 A novel method for the detection of the number of compartments in diffusion MRI data Emma Metcalfe-Smith1,2,3, Niloufar Zarinabad2,3, Jan Novak2,3, Hamid Dehghani1,4, and Andrew Peet2,3 1Physical Sciences for Health Doctoral Training Centre, University of Birmingham, Birmingham, United Kingdom, 2Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom, 3Department of Oncology, Birmingham Children's Hospital, Birmingham, United Kingdom, 4School of Computer Science, University of Birmingham, Birmingham, United Kingdom There is a need for a method that can detect the number of components within multi b-value diffusion-weighted imaging.  In particular, this would aid in the identification and correction of partial volume effects (PVE) within the brain. A PVE model was simulated to contain varying ratios of cerebrospinal fluid and white matter. Multi-exponential fitting methods were applied and found to be unsuccessful in identifying the number of components within the model. A novel fitting method, the Autoregressive Discrete Acquisition Points Transformation, was applied to simulations. Following manipulation through the discrete Z-domain, the number of components were correctly identified.

 1595 Multicompartment modelling of diffusion-weighted MRI data with no prior assumptions Emma Metcalfe-Smith1,2,3, Niloufar Zarinabad2,3, Jan Novak2,3, Hamid Dehghani1,4, and Andrew Peet2,3 1Physical Sciences for Health Doctoral Training Centre, University of Birmingham, Birmingham, United Kingdom, 2Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom, 3Department of Oncology, Birmingham Children's Hospital, Birmingham, United Kingdom, 4School of Computer Science, Birmingham, United Kingdom Multi-compartment modelling of Diffusion-Weighted MRI data can provide additional diffusion related parameters. However, to ensure meaningful parameters are attained, multi-compartment models have to make several assumptions prior to fitting, including initial parameter values and multi-step fitting procedures.  The novel Autoregressive Discrete Acquisition Points Transformation (ADAPT) method was applied to in vivo data. ADAPT demonstrated that it could infer the number of compartments within the data.  When 1- and 2-compartment ADAPT models were investigated, the ADAPT coefficients were found to correlate with the parameters attained by the Apparent Diffusion Coefficient (ADC) and the Intravoxel Incoherent Motion (IVIM) models.

 1596 An efficient regularization method for diffusion MAP-MRI estimation Hsu Yung-Chin1 and Tseng Isaac Wen-Yih1,2,3,4 1Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 2Molecular Imaging Center, National Taiwan University, Taipei, Taiwan, 3Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, Taipei, Taiwan, 4Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan In the study, we proposed a regularization method for MAP-MRI estimation, called ReMAP. This method includes a regularization term in the cost functional in order to penalize the coefficients. The penalty is a simple diagonal matrix with entries determined only by the order of the Hermite functions, where higher order functions take more penalization, therefore, this method is easy to implement. In addition, ReMAP outperforms MAP-MRI in both estimation efficiency and accuracy, revealing that the regularization term is crucial for a robust estimation. Therefore, ReMAP is an improved version of MAP-MRI and would be beneficial for clinical studies.

 1597 Are Intravoxel Incoherent Motion and Dynamic Contrast-Enhanced Perfusion Parameters Related in Glioblastomas? Nicholas Majtenyi1, Thanh B. Nguyen2,3, Gerd Melkus2, Ryan Gotfrit4, Gregory O. Cron2,3,5, and Ian G. Cameron1,2,3 1Department of Physics, Carleton University, Ottawa, ON, Canada, 2Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada, 3Radiology, University of Ottawa, Ottawa, ON, Canada, 4Department of Undergraduate Medical Education, University of Ottawa, Ottawa, ON, Canada, 5The Ottawa Hospital Research Institute, Ottawa, ON, Canada Intravoxel incoherent motion (IVIM) is an MR-based diffusion-weighted imaging technique that can measure both diffusion and perfusion. Currently, no link has been established between the perfusion parameters obtained from IVIM to those from dynamic contrast-enhanced (DCE)-MRI, particularly in the human brain. This study determined that no correlation exists between these two perfusion measurement techniques in patients with glioblastomas. This indicates that these two imaging techniques measure two separate effects; however, IVIM may be able to provide complementary, additional perfusion information that can potentially aid clinical diagnoses when used in conjunction with DCE-MRI parameters.

 1598 A non-Gaussian bi-exponential diffusion model with CUSP74 sampling for improved myocardial helix angle quantification and segmentation. Cyril Tous1, Alistair Young1, and Beau Pontre1 1Anatomy and Medical Imaging, The University of Auckland, Auckland, New Zealand The non-Gaussianity of diffusion at high b-value, leads to poor estimates of fast diffusion components when using diffusion models that assume Gaussian diffusion distributions. Including the diffusion kurtosis in a bi-exponential model allows better quantification of the partial volume effects when large b-values are used. This study investigates how this improved model can provide a better estimate of the helix angle in fixed heart specimens.

 1599 Where's my water? Untangling the diffusion signal using the phasor representation Michael J van Rijssel1, Martijn Froeling1, and Josien P W Pluim1,2 1Center for Image Sciences, UMC Utrecht, Utrecht, Netherlands, 2Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands The recently proposed phasor representation and associated unmixing method allow separation of multi-exponentially decaying signals. This method has achieved promising results on diffusion MRI data and boasts sub-second analysis of full datasets on regular desktop PCs. This work investigates the noise propagation properties of this method and the influence of misplacing the vertex of a component in phasor space when performing unmixing. Results indicate that the phasor method is feasible and that the influence of component misplacement is systematic, but smaller than the errors due to noise at regular diffusion MR signal-to-noise-ratio levels.

 1600 Intra- and inter-subject variability of diffusivity by DTI and DKI: An small animal study on 7T Hung-Yu Fu1, Wei-Cheng Lee1, Sheng-Min Huang1, Shin-Lei Peng2, Kung-Chu Ho3, and Fu-Nien Wang1 1Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu, Taiwan, 2Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan, 3Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan Diffusivity can be acquired by both DTI and DKI model on the same set of images. To investigate intra- and inter-subject variability of DKI and DTI derived diffusivities, five Sprague- Dawley rats were scanned on a 7T small animal scanner. In intra-subject variability test, lower coefficients of variation are found on DKI derived parameters. In inter-subject analysis, higher values were estimated by DKI in mean diffusivity, axial diffusivity, and radial diffusivity. The CNR between white matter and gray matter of these parameters are also better with DKI. However, the CNR of FA is higher with DTI than with DKI

 1601 Effective potential for MR measurements of restricted diffusion Evren Özarslan1, Cem Yolcu1, Magnus Herberthson2, Carl-Fredrik Westin1,3, and Hans Knutsson1 1Department of Biomedical Engineering, Linköping University, Linköping, Sweden, 2Department of Mathematics, Linköping University, Linköping, Sweden, 3Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States The compartmentalized structure of biological tissues demands a representation of individual compartments and a description of diffusion within them. We identified a quadratic potential energy profile, recently studied in-depth by Yolcu et al. (Phys Rev E, 93, 052602, 2016), as the effective energy landscape for restricted diffusion as far as gradient waveforms featuring long pulses are concerned. Our simulations suggest that the stochastic effective force on the center-of-mass position is approximately linear, thus providing further support for the Hookean effective force model.

 1602 The diagnostic values of DTI and DKI techniques in degeneration of corpus callosum of chronic alcoholism Ke-ning Xu1,2, Guo-shi LYU1, and Lizhi Xie3 1Imaging Center, the 251st Hospital of PLA, Zhangjiakou, China, 2The Graduate School of HeBei North University, Zhangjiakou, China, 3GE Healthcare, China, Beijing, China Chronic alcoholism is a common disease, and many patients are often associated with corpus callosal degeneration. In this study, the values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC), diffusion tensor imaging (DTI) and the mean kurtosis (MK) values in diffusion kurtosis imaging (DKI) were used to analyze chronic alcoholism with corpus callus (MBD) patients, to explore the diagnostic value of these three parameters in MBD patients. Receiver operating characteristic curve（ROC)analysis of the parameters of the diagnosis of the disease. The results showed that FA is better than ADC and MK, and the sensitivity and specificity are better.

 1603 Comparison of intravoxel incoherent motion DWI, diffusion kurtosis imaging, and conventional DWI in predicting the chemotherapeutic response of colorectal liver metastases: preliminary experience Huan Zhang1, Wenhua Li2, Robert Grimm3, Caixia Fu4, Xu Yan5, and Tong Tong1 1Department of Radiology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China, 2Department of Medical Oncology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China, 3MR Application Predevelopment, Siemens Healthcare, Erlangen, Germany, 4APPL, Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 5MR Collaboration NE Asia, Siemens Healthcare, Shanghai, China The aim of this study was to compare the performance of pre-treatment intravoxel incoherent motion DWI (IVIM-DWI), diffusion kurtosis imaging (DKI), and conventional DWI for predicting the chemotherapeutic response in patients with colorectal liver metastases (CRLMs). The results indicates that they are all potentially useful for predicting the chemotherapeutic response of CRLMs, with mean diffusion derived from DKI having the best performance.

 1604 Quantitative Comparison of Multiple High Angular Resolution Diffusion Imaging Techniques for Myocardium Sifangyuan Wang1, Lihui Wang1, Jian Zhang1, Rongpin Wang2, Xinfeng Liu2, and Yuemin Zhu3 1Key Laboratory of Intelligent Medical Image Analysis and Precise Diagnosis of Guizhou Province, School of Compute Science and Technology, Guizhou University, Guiyang, China, 2Department of Radiology, Guizhou Provincial People's Hospital, Guiyang, China, 3Univ.Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69621, Lyon, France We compared quantitatively three commonly used HARDI schemes for describing the myocardium structure in a unified frame-work. One pig heart was firstly scanned with 256 diffusion directions, and then the diffusion ODFs of q-ball imaging (QBI), diffusion spectrum imaging (DSI) and generalized q-space imaging (GQI) were reconstructed respectively, from which the myocardiac fiber orientations and the diffusion metrics were finally extracted and compared. The results show that the cardiac fiber crossing locations, crossing numbers, and the generalized fractional anisotropy detected by three schemes are totally different.

 1605 Diffusion gradient performance optimization for B-tensor encoded q-space trajectory imaging of the human brain Jan Martin1, Andreas Wetscherek2, Lars Müller3,4, Tristan Anselm Kuder3, Michael Uder1, Bernhard Hensel5, and Frederik Bernd Laun1 1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, 3Department Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4CUBRIC, School of Psychology, University of Cardiff, Cardiff, United Kingdom, 5Center for Medical Physics and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany q-Space trajectory imaging is a recently introduced approach for determining microscopic diffusion tensor properties like μFA and orientation coherence. To create the necessary higher order B-tensors special gradient trajectories are needed. The initial implementation of q-space trajectory imaging was based on magic-angle-spinning of the q-vector, and required echo times of 160 ms for b-values of 2000 s/mm2. In the current abstract, numerically optimized gradient trajectories were implemented, which reduced the required echo time to 115 ms. The resulting parameter maps benefited from the increase in signal-to-noise ratio.

 1606 Application value of DKI in grading of pancreatic cancer Meiying Yan1, Xiaoqi Wang2, and Rengen Xu1 1Department of Radiology, Jiangxi Cancer Hospital, Nanchang, China, 2Philips Healthcare, Beijing, Beijing, China Tumor cells and the complex micro-environment would lead to restricted the water molecules diffusion, in the form of non-Gaussian distribution at space, and diffusion kurtosis imaging (DKI)(1)  describes the degree of non-Gaussian distribution, and it has shown to reflect more sensitive diffusion information comparing with regular diffusion weighted image(DWI)(2). It was reported that DKI helped to classify tumors like astrocytomas (3). However, there is challenges on the DKI application mostly due to low SNR in pancreas diffusion images and motion artifacts. pancreatic cancer is a malignant pancreatic tumor,and the recent prognosis of patients with pancreatic cancer is determined by the histopathological grade of tumor. Herein, we reported the investigation on applying DKI to differentiate the histological grade of pancreatic cancer.,by assessing DKI parameters.

 1607 Return-to-the-origin probability calculation in single shell acquisitions Santiago Aja-Fernandez1, Antonio Tristan-Vega1, Malwina Molendowska2, Tomasz Pieciak2, and Rodrigo de Luis-Garcia1 1Universidad de Valladolid, Valladolid, Spain, 2AGH University of Science and Technology, Kraków, Poland One of the problems of estimating q-space scalar measures is the need of a high number of samples in the q-space in order to properly reconstruct the diffusion signal without aliasing. In this work we propose an alternative method to estimate the return-to-origin probability (RTOP) from a single shell acquisition using a prior assumption over the diffusion signal. The method provides significant structural information even for single shell acquisitions with moderate b-values.

 1608 Comparison between readout segmented diffusion weighted imaging and single shot echo planar imaging for differential diagnosis of prostate cancer Chuangbo YANG1, Qi YANG1, Nan YU1, Hui TAN1, Wei WEI1, Guangming MA1, Shaoyu WANG1, and Shenglin LI2 1Departments of Diagnostic Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang，China, China, 2Shaanxi University of Chinese Medicine, Xianyang，China, China Readout segmented diffusion weighted imaging (Rs-EPI) with ultra-high b value  ( 1000、2000、3000s/mm2)  have high sensitivity , specificity, PPV and NPV in the differential diagnosis of prostate cancer than single shot echo planar imaging (SS-EPI)  does.

 1609 Comparison of three diffusion models: monoexponential vs. intravoxel incoherent vs. stretched model Jeong Hee Yoon1, Eunju Kim2, and Jeong Min Lee1 1Seoul National University Hospital, Seoul, Republic of Korea, 2Philips Healthcare Korea, Seoul, Republic of Korea A diffusion heterogeneity index (α) derived from a stretched exponential model may serve as a more sensitive parameter for hepatic fibrosis compared with paramters from mono-or bi-exponential diffusion weighted imaging (DWI).

 1610 Multi-platform reproducibility of advanced diffusion weighted MRI parameters in phantoms and healthy volunteers Shah Islam1, Matthew Grech-Sollars2, Matthew Orton3, Lesley Honeyfield4, Eric Aboagye2, and Adam Waldman1,5 1Brain Sciences, Imperial College London, London, United Kingdom, 2Surgery and Cancer, Imperial College London, London, United Kingdom, 3CRUK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, London, United Kingdom, 4Department of Imaging, Imperial Healthcare NHS Trust, London, United Kingdom, 5Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom Quantitative diffusion imaging has an evolving role in tumour characterisation and disease monitoring. Most clinical DWI sequences use ADC derived from two b-values.  Multiple b-value acquisition allows further biologically-relevant diffusion components to be interrogated using bi-, multi- and stretched exponential models; these require validation for application in multicentre trials. This study compared the reproducibility of ADC, IVIM and stretched exponential parameters across MRI platforms in two phantoms and healthy volunteers.  Our initial results suggest highly reproducibility of all measured parameters in phantoms, and of ADC and IVIM in healthy brains. Stretched exponential data appear less reproducible in vivo.

 1611 Diffusion Weighted Signal Variation with Body Phantom Raj Attariwala1, Wayne Picker1, Amy Chambers1, and Mikko Maatta1 1AIM Medical Imaging, Vancouver, BC, Canada DWI body phantom development and signal to noise calculation based on RSNA QIBA protocol guidelines for identically configured MRI machines shows machine variability and resultant ADC calculation error propagation.

 1612 Non-Gaussian diffusion restriction effects in intravoxel incoherent motion imaging acquired at b-values below 1000 $\tt s/mm^{2}$ Hajime Tamura1, Hideki Ota2, Tatsuo Nagasaka2, Naoko Mori2, and Shunji Mugikura2 1Tohoku University School of Medicine, Sendai, Japan, 2Tohoku University Hospital, Sendai, Japan To know how much the intravoxel incoherent motion (IVIM) parameters deduced by a bi-exponential model are affected by neglecting non-Gaussian diffusion restriction effects, we performed Monte-Carlo simulations: fitting the bi-exponential model to simulated data containing the diffusion restriction effects. The results showed that non-Gaussian diffusion restriction effects may considerably affect estimation of IVIM parameters even when data acquired with low b-values (b≤1000 s/mm2) are used. This should be taken into account when interpreting the results of IVIM analyses based on the bi-exponential model.

### Diffusion MRI: Acquisition & Reconstruction

 Exhibition Hall 1613-1655 Tuesday 8:15 - 10:15

 1613 A comparison of multi-ADC and DTI fit metrics of diffusion MRI data acquired with Stejskal-Tanner and asymmetric bipolar gradients at identical echo time. Alberto De Luca1, Alexander Leemans1, and Martijn Froeling2 1Image Sciences Institute, UMC Utrecht and University Utrecht, Utrecht, Netherlands, 2Department of Radiology, UMC Utrecht, Utrecht, Netherlands Asymmetric-Bipolar (AS) gradients have been proposed in diffusion MRI (dMRI) experiments as alternative to Stejskal-Tanner (ST) gradients to achieve flow and motion-compensation. However, it remains unclear whether the gradient shape affects commonly derived metrics. Data at multiple diffusion-weightings was acquired on 4 subjects with ST and flow-compensated gradients, then fit with a multi-ADC model and DTI. Results showed that some metrics, as free water signal fraction and fractional anisotropy were comparable between AS and ST, whereas diffusion coefficients and perfusion fraction were remarkably different. Great care is suggested when comparing studies using different waveforms despite other identical acquisition parameters.

 1614 Motion Compensated, Optimized Diffusion Encoding (MODE) Gradient Waveforms Waqas Majeed1, Prateek Kalra1, and Arunark Kolipaka1 1Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, United States We present a framework to obtain motion compensated diffusion encoding waveforms that are shorter than all diffusion encoding waveforms available to date. These waveforms can be obtained analytically. We successfully demonstrate the use of these waveforms for cardiac DWI.

 1616 Spatio-Temporal dMRI Acquisition Design: Reducing the Number of Samples Patryk Filipiak1, Rutger Fick1, Alexandra Petiet2, Mathieu Santin2, Anne-Charlotte Philippe2, Stephane Lehericy2, Rachid Deriche1, and Demian Wassermann1,3 1Université Côte d’Azur - Inria Sophia Antipolis-Méditerranée, Valbonne, France, 2CENIR - Center for NeuroImaging Research, ICM - Brain and Spine Institute, Paris, France, 3Inria, CEA, Université Paris-Saclay, Paris, France Acquisition time is a major limitation in recovering brain white matter microstructure with diffusion magnetic resonance imaging. Finding a sampling scheme that maximizes signal quality and satisfies given time constraints is NP-hard. Therefore, we propose a heuristic method based on genetic algorithm that finds sub-optimal solutions in reasonable time. Our diffusion model is defined in the $q\tau$-space, so that it captures both spacial and temporal phenomena. The experiments on synthetic data and in-vivo diffusion images of the C57Bl6 wild-type mouse corpus callosum reveal superiority of our approach over random sampling and even distribution in the $q\tau$-space.

 1617 High resolution in vivo diffusion weighted imaging of the human occipital cortex: enabled by 300mT/m gradients and flexible radio-frequency surface coils. Evgeniya Kirilina1,2, Fakhereh Movahedian Attar1, Luke J. Edwards1, Kerrin J. Pine1, and Nikolaus Weiskopf1 1Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Center for Cognitive Neuroscience Berlin, Free University Berlin, Berlin, Germany Information about intracortical fibers and connectivity can potentially be obtained using diffusion weighted imaging (DWI). However, in vivo intracortical DWI requires extraordinarily high spatial resolution. We demonstrate in vivo DWI imaging in the human occipital cortex with an isotropic resolution of 800 μm enabled by a high-performance 300 mT/m gradient system and flexible high-sensitivity RF receive coil optimized for cortical imaging.  Robust detection of intracortical features was achieved in a reasonable scanning time. The described setup opens the exciting possibility to study intracortical connectomics in humans in vivo.

 1618 In-vivo line-scan diffusion MR at 250 micron inline resolution within human cerebral cortex at 7T Mukund Balasubramanian1,2, Robert V. Mulkern1,2, Jeffrey J. Neil1,3, Stephan E. Maier1,4,5, and Jonathan R. Polimeni1,6,7 1Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Boston Children's Hospital, Boston, MA, United States, 3Department of Neurology, Boston Children's Hospital, Boston, MA, United States, 4Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, 5Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden, 6Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 7Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States We used the line-scan technique to measure in-vivo diffusion at 7T within human primary somatosensory cortex (S1) and primary motor cortex (M1), achieving voxel sizes as low as 0.25 mm in the radial direction (i.e., orthogonal to the cortical surface). Our results are consistent with recent reports of predominantly tangential diffusion in S1 and, to a lesser extent, radial diffusion in M1; however, the smaller voxel sizes used in our study alleviate concerns regarding partial-volume effects and, perhaps more importantly, enable the study of fine-scale variations in diffusion structure across cortical layers.

 1619 Evaluation of Monopolar Diffusion-Prepared TSE for Diffusion Imaging Jialu Zhang1,2,3, Xiufeng Li3, Kamil Ugurbil3, Anna Wang Roe1,2, Xiaotong Zhang1,2,4, and Dingxin Wang3 1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, 2College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 3Center for Magnetic Resonance Research, School of Medicine, University of Minnesota, Minneapolis, MN, United States, 4Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China EPI-based diffusion imaging methods are dominantly used, but suffer from susceptibility associated distortion and signal loss, making it challenging to achieve high-quality high-resolution diffusion imaging results. To overcome these challenges, we implemented monopolar diffusion preparation module for TSE sequence (DP-TSE) and evaluated the performance in comparison to readout segmented multi-shot echo planner (RESOLVE) sequence for diffusion weighted imaging (DWI). Our study results suggest that Diffusion-Prepared TSE is a promising alternative for distortion-free, high-resolution diffusion imaging with superior diffusion SNR.

 1620 Comparison of different diffusion MRI acquisition protocols by tracking callosal motor pathways with deterministic and probabilistic fiber tracking algorithms Meizhen Han1 and Jia-Hong Gao1 1Center for MRI Research, Peking University, Beijing, China High angular resolution diffusion MRI (HARDI), the most widely used method in in-vivo brain imaging experiments to delineate white matter pathways, has been found sufficient for resolving 2-way fiber crossings but unstable for detecting 3-way fiber crossings. Therefore, if more sensitive and accurate tractography is wanted, researchers need to use high b-value with multi-shell q-ball models, which can be time-consuming. In this study, we compared 3 diffusion MRI acquisition protocols by tracking callosal connections between motor areas with both probabilistic and deterministic fiber tracking algorithms and provided a new scheme for the future diffusion MRI experiment.

 1621 Optimization of b values and reproducibility of perfusion and diffusion parameters using IntraVoxel Incoherent Motion (IVIM) with peripheral pulse triggering Yu Ueda1, Minoru Hayashida2, Koji Yoshida2, Tomoyuki Okuaki1, Katsuyoshi Ito3, Makoto Obara1, and Marc Van Cauteren4 1Philips Japan, Tokyo, Japan, 2Kawasaki Medical School, Kurashiki, Japan, 3Yamaguchi University Graduate School of Medicine, Ube, Japan, 4Philips HealthTech, Tokyo, Japan To investigate the reproducibility of IVIM-derived parameters with peripheral pulse unit (PPU) triggering and optimized b values combination to decrease scan time, we assessed the reproducibility by calculating coefficient of variation (CV) for each parameter. Moreover, D* and F calculated with some b value patterns were compared to those with all b values using the Pearson correlation. Our results suggest that cardiac gating does not improve reproducibility of perfusion and diffusion parameter. F with only 4 b values (e.g. b=0-200-500-1000) can provide robust information on perfusion noninvasively with significantly shortened scan time.

 1623 Low b-values and limited diffusion directions introduce bias in FA and MD that increases with decreasing voxel volumes. Ofentse Noko1, Stephen Jermy1,2, Ali Alhamud1,2, and Ernesta Meintjes1,2 1Department of Human Biology, University of Cape Town, Cape Town, South Africa, 2Cape Universities Body Imaging Centre (CUBIC), University of Cape Town, Cape Town, South Africa Due to ECG triggering and breath hold techniques required to compensate for motion of the beating heart and respiration, acquisition times for cardiac diffusion tensor imaging (DTI) are limited. As such, lower b-values and fewer diffusion directions are typically used, together with larger slice thicknesses. This study aims to assess the impact of these changes on fractional anisotropy (FA) and mean diffusivity (MD) in a pineapple phantom. Smaller voxels were found to be more sensitive to changes in b-values and number of diffusion directions.

 1624 Progress in the use of SQUASHER for Diffusion weighted imaging Steen Moeller1, Sudhir Ramanna1, Essa Yacoub1, and Mehmet Akcakaya1,2 1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States The applicability of SQUASHER to EPI, along with a kz-dependent reconstruction approach for highly-accelerated 3D segmented EPI in dMRI

 1625 Shorter Acquisition Times for Diffusion-Weighted Imaging of the Human Spinal Cord with Simultaneous Acquisition of Multiple Inner Fields-of-View Caspar Florin1 and Jürgen Finsterbusch1 1Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Inner field-of-view EPI is widely used for diffusion-weighted acquisitions of the human spinal cord. However, due to the high in-plane resolution required acquisition times to achieve a reasonable signal-to-noise ratio are usually rather long. In this study, inner-field-of-view EPI based on 2D-selectove RF excitations is accelerated with multiband excitations. Two different approaches are considered that differ with respect to the orientation of the 2DRF trajectory and whether side excitations must be suppressed or can be used to cover the bands excited and acquired simultaneously. Results obtained in the human brains stem and cervical spinal cord in vivo are presented.

 1626 Anisotropic Diffusion Filter for Simultaneous Combination and Denoising of Multiple Acquisitions in DWI of the Spinal Cord Sevgi Gokce Kafali1,2, Cagri Aydinkarahaliloglu1, Tolga Çukur1,2, and Emine Ulku Saritas1,2 1Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey In diffusion weighted imaging (DWI), multiple acquisitions are acquired and averaged to attain a reasonable SNR level, especially for high spatial resolution or high b-value imaging. However, bulk or involuntary physiological motion during diffusion-sensitizing gradients alters the k-space, creating unpredictable global and/or local phases across multiple acquisitions. Therefore, direct complex averaging of these multiple acquisitions is prohibited. Here, we propose a reconstruction scheme based on modified anisotropic diffusion filtering, which starts with complex-valued acquisitions and corrects the phase issues while improving the SNR. The proposed reconstruction is demonstrated with in vivo DWI of the cervical spinal cord at 1.5T.

 1627 Improvement of diffusion-weighted image quality by iShim toward realization of cervical spinal cord region QSI Yoshifumi Sone1, Zhouchen Lu1, Junichi Hata2, Daisuke Nakashima3, Katsuya Maruyama4, Alto Stemme5, Takeo Nagura 3, Morio Matsumoto3, and Masaya Nakamura3 1Medical Scanning Tokyo, Tokyo, Japan, 2Central Institute for Experimental Animals, Japan, Tokyo, Japan, 3Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan, 4MR Research & Collaboration Dpt., Diagnostic Imaging Business Area, Siemens Healthcare K.K., Tokyo, Japan, 5Siemens Healthcare GmbH, Erlangen, Germany, Erlangen, Germany Herein, we adopted diffusion-weighted imaging (DWI) with a high fat suppression effect and high signal-to-noise ratio (SNR) in the cervical region, where magnetic field inhomogeneity may occur, using integrated slice-by-slice shimming (iShim), which improves static magnetic field (B0) shimming accuracy. We examined spinal cord SNR and standard deviation in healthy volunteers and performed cervical DWI with the conventional B0 shimming method and iShim, respectively. Furthermore, to verify whether short TI inversion recovery (STIR) or water excitation (WE) was appropriate as a fat suppression method, we used DWI with a high SNR at the cervical region by combining iShim with WE.

 1628 DTI-based free-water elimination with T2-weighting using dedicated anisotropic diffusion fibre phantoms Ezequiel Farrher1, Kuan-Hung Cho2, Richard Buschbeck1, Husan-Han Chiang2, Ming-Jye Chen2, Farida Grinberg1,3, N. Jon Shah1,3,4,5,6, Chang-Hoon Choi1, and Li-Wei Kuo2,7 1Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany, 2Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 3Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany, 4JARA – BRAIN – Translational Medicine, RWTH Aachen University, Aachen, Germany, 5Institute of Neuroscience and Medicine 11, Forschungszentrum Jülich, Jülich, Germany, 6Biomedical Imaging, School of Psychological Sciences, Monash University, Melbourne, Australia, 7Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan In this work we demonstrate the use of two dedicated anisotropic diffusion fibre phantoms for the study of free-water elimination DTI. In particular, we make use of the recently proposed approach in which an extra dimension to the diffusion weighting, namely transverse relaxation weighting, is added to the model.

 1629 In vivo DTI-based free-water elimination with T2-weighting Ezequiel Farrher1, Richard Buschbeck1, Chang-Hoon Choi1, Li-Wei Kuo2,3, Seong-Dae Yun1, Farida Grinberg1,4, and N. Jon Shah1,4,5,6,7 1Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich, Jülich, Germany, 2Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 3Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 4Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany, 5JARA – BRAIN – Translational Medicine, RWTH Aachen University, Aachen, Germany, 6Institute of Neuroscience and Medicine 11, Forschungszentrum Jülich, Jülich, Germany, 7Biomedical Imaging, School of Psychological Sciences, Monash University, Melbourne, Australia Free-water elimination allows one to reduce the bias in DTI metrics induced by partial-volume effects. Unfortunately the fitting problem for this model is ill-conditioned. However, it has been recently demonstrated that the introduction of a second dimension determined by the echo-time, leads to a well-conditioned fitting problem. In this work we investigate the experimental design and data analysis pipeline of such experiments in vivo.

 1630 The Role of Bias Field Correction in the Free Water Elimination Problem Drew Parker1, Abdol Aziz Ould Ismail1, Simon Alexander2, and Ragini Verma1 1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Synaptive Medical Inc., Toronto, ON, Canada Free water elimination (FWE) paradigms provide information about underlying pathology-induced tissue changes, based on a multi-compartment fit to the dMRI acquisition. Non-uniform intensity in MR signal, either due to coil or acquisition sequence, produces inhomogeneous tissue intensity profiles. This negatively affects FWE paradigms, producing artifactual multi-compartment fits. In this work, through extensive application on varied datasets, we demonstrate the effect of using bias field correction, an optimized non-uniform intensity normalization, on reducing artifacts in FWE and producing physiologically relevant maps. This suggests that bias correction should be maintained as an essential step in dMRI preprocessing for FWE.

 1631 Navigated Multi-shot Diffusion-Weighted Imaging with Multiplexed Sensitivity Encoding Valentina Taviani1, Ann Shimakawa1, Lloyd Estkowski1, Arnaud Guidon2, Ersin Bayram3, and Robert Peters4 1Global MR Applications and Workflow, GE Healthcare, Menlo Park, CA, United States, 2Global MR Applications and Workflow, GE Healthcare, Boston, MA, United States, 3Global MR Applications and Workflow, GE Healthcare, Houston, TX, United States, 4Global MR Applications and Workflow, GE Healthcare, Waukesha, WI, United States MUltiplexed Sensitivity Encoding (MUSE) has been successfully used to correct for motion-induced phase errors in multi-shot diffusion-weighted imaging. However, this technique relies heavily on parallel imaging (PI) and can result in residual aliasing and excessive noise amplification when the number of shots is similar to the number of receiver coil elements. We propose a navigated multi-shot approach with multiplexed sensitivity encoding to handle cases where the coil geometry would otherwise limit the maximum number of interleaves. We show that both PI and 2D-selective excitation pulses can be used to reduce the scan duration, while maintaining similar levels of distortion.

 1632 Automatic and Spatially Varying Phase Correction for Diffusion Weighted Images Marco Pizzolato1 and Rachid Deriche2 1EPFL, Lausanne, Switzerland, 2Athena, Inria, Sophia Antipolis, France Phase Correction is a post-processing procedure exploiting the phase of magnetic resonance images in order to obtain real-valued images containing tissue contrast with additive Gaussian noise, as opposed to magnitude images which are typically affected by a bias due to the Rician distribution of noise. This bias is particularly relevant in Diffusion Weighted Images where the signal-to-noise ratio is intrinsically low. We propose a method for automatically assessing the optimal amount of required correction based on properties of the noise affecting the images: its variance and positional non-stationarity. We present results for diffusion metrics such as FA, AD, and MD.

 1633 Image-based Multi-Scale Distortion Correction: Application to Diffusion Imaging Lars Bielak1, Hatice Bunea2, Nicole Wiedenmann2, Anca-Ligia Grosu2, and Michael Bock1 1Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany This work presents an algorithm that calculates a distortion field to correct a geometrically distorted image using an anatomically precise reference image. The algorithm employs mutual information based rigid image registration with a pyramidal architecture. Validation was performed on simulated distortion fields and in vivo comparison to a measured B0-fieldmap.

 1634 High Resolution Reconstruction of Diffusion Weighted Imaging Using EPI-Corrected Snapshots Acquired with Rotated K-spaces Hengameh Mirzaalian1, Benoit Scherrer1, Onur Afacan1, Ali Gholipour1, and Simon K. Warfield1 1Harvard Medical School, Boston, MA, United States We propose a non-Cartesian high resolution reconstruction of diffusion-weighted magnetic resonance imaging (DW-MRI) using multi-snapshots acquired with rotated K-spaces. Our technique boosts the signal level by reducing the echo time and by increasing voxel size for each snapshot. The final high resolution image is reconstructed by fusion of the snapshots, which were corrected for  Echo-Planar-Imaging (EPI) distortions. We applied and evaluated different EPI correction methods. Through qualitative and quantitative evaluations based on in-vivo experiments,  we showed that our protocol and image reconstruction technique leads to high spatial resolution and  high signal-to-noise ratio DW-MRI.

 1635 A living phantom study to evaluate the echo planar imaging (EPI) distortion correction effects in reducing inter-site variability Amritha Nayak1,2, Elizabeth Wilde3, Brian Taylor3, CENC Neuroimaging Core Investigators4, Laura Reyes1,2, and Carlo Pierpaoli1 1Quantitative Medical Imaging Section, NIBIB, NIH, Bethesda, MD, United States, 2The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc, Bethesda, MD, United States, 3Baylor College of Medicine, Houston, TX, United States, 4Chronic Effects of Neurotrauma Consortium, Richmond, VA, United States In this study we evaluate the effect of echo planar imaging (EPI) distortion artifact as a contributing factor in inter-site variability. With living phantom data acquired with opposite phase encoding direction protocol (blipup-blipdown), we show the effectiveness of a robust EPI distortion correction method in reducing inter-site variability.

 1636 High-resolution off-resonance maps improve conformity between distortion-corrected EPI acquisitions and distortion-free references Michael J van Rijssel1, Frank Zijlstra1, Peter R Seevinck1, Peter R Luijten1, Dennis W J Klomp1, and Josien P W Pluim1,2 1Center for Image Sciences, UMC Utrecht, Utrecht, Netherlands, 2Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands The majority of diffusion acquisitions is affected by geometrical distortions due to susceptibility induced off-resonance effects in the EPI readout. This hampers the use and effectiveness of these images in multiparametric cancer protocols, especially in lipid-rich environments such as the human breast where tissue interfaces cause large but local discontinuities. Preliminary results show that improvements upon existing correction techniques can be made by using high-resolution off-resonance information in distortion correction algorithms.

 1637 Effects of phase error on image reconstruction for simultaneous multi-slice readout-segmented diffusion MRI SeyyedKazem HashemizadehKolowri1, Rong-Rong Chen1, Edward V. R. DiBella1,2,3, Edward W. Hsu3, Leslie Ying4, and Ganesh Adluru2 1ECE, University of Utah, SALT LAKE CITY, UT, United States, 2Radiology and Imaging Sciences, University of Utah, SALT LAKE CITY, UT, United States, 3Bioengineering, University of Utah, SALT LAKE CITY, UT, United States, 4Biomedical Engineering, The State University of New York (SUNY) at Buffalo, Buffalo, NY, United States In this work, we  study the effect of phase errors on the quality of image reconstructions for simultaneous multi-slice (SMS) readout-segmented echo planar imaging  (RS-EPI) acquisitions. We propose an iterative split slice-GRAPPA (I-SSG) algorithm to train improved kernels using estimated diffusion weighted images (DWIs) rather than baseline images. Results from stroke patients show that the proposed I-SSG algorithm produces consistently better reconstructions  than the SSG algorithm in the presence of baseline phase errors.

 1638 Distortion Correction using Reverse Polarity Gradient Method: Algorithm Optimization for Prostate Imaging using a Hybrid Weighting Metric Maggie M Fung1, Pauline Worters2, Ek Tsoon Tan3, Arnaud Guidon4, and Ersin Bayram5 1Applications & Workflow, GE Healthcare, New York, NY, United States, 2Applications & Workflow, GE Healthcare, Menlo Park, CA, United States, 3Global Research Center, GE, Niskayuna, NY, United States, 4Applications & Workflow, GE Healthcare, Boston, MA, United States, 5Applications & Workflow, GE Healthcare, Houston, TX, United States Prostate Diffusion Weighted Echo Planar imaging (DW-EPI) routinely suffers from nonlinear geometric distortion due to B0 inhomogeneity. Although reverse phase-encoding polarity-based distortion correction method works well in the brain, the same technique causes artifacts in prostate DWI due to the low SNR nature of body DWI scans, and the inconsistency of image content between the reverse and forward polarity images. In this study, we showed that a hybrid weighting metric method could improve the distortion correction performance in prostate DWI.

 1639 An integrated model-based framework for the correction of signal pile-up and translational offsets in prostate diffusion MRI Muhammad Usman1, Lebina Kakkar2, Karin Shmueli3, Simon Arridge1, and David Atkinson2 1Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom, 2Centre for Medical Imaging, Division of Medicine, University College London, London, United Kingdom, London, United Kingdom, 3Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, London, United Kingdom Prostate diffusion EPI scans suffer from geometric distortions, signal pile-up and signal drop-out due to differences in susceptibility values at interface between prostate and rectal-air. In this work,  an integrated model based framework is proposed that can correct for signal pile-up in regions of severe distortions and can compensate for any translational offsets that may exist between different scans. In-vivo validation of the proposed method is done in patients.

 1640 Spatially Varying Signal-Drift Correction in Diffusion MRI Khoi Minh Huynh1,2, Geng Chen2,3, Wei-Tang Chang2,3, Weili Lin2,3, Dinggang Shen1,2,3, and Pew-Thian Yap2,3 1Department of Biomedical Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Biomedical Research Imaging Center (BRIC), The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 3Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States The magnetic field in a MR scanner varies slightly in strength over time and causes the signal to drift. This drift can vary from voxel to voxel both in extent and direction. In this abstract, we show using diffusion MRI data that signal drift can be corrected more accurately when done locally than globally over the whole image volume1. For this purpose, we employ a non-parametric correction method using non-diffusion-weighted scans interspersed in the diffusion-weighted image series.

 1642 2D Single-Shot Radial Diffusion-Weighted Imaging free of geometric distortion and optimization of SNR using Variable Flip-Angle and Random View-Ordering Kyle Jeong1,2 and Eun-Kee Jeong1,3 1Utah Center for Advanced Imaging and Research, University of Utah, Salt Lake City, UT, United States, 2Department of Bioengineering, University of Utah, Salt Lake City, UT, United States, 3Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States The 2D ss-DWEPI is routinely used for in-vivo DW imaging, because of its immunity to motion-induced artifact, but prone to susceptibility-induced geometric distortion. We present a novel DWI technique using single-shot radial imaging, which produces DW images with minimal geometric distortion, no motion artifact, and with optimized SNR and reduced effect of undersampling radial streak artifact. Variable-flip angle (VFA) and random-view ordering (RVO) were implemented to improve the SNR and reduce the geometric distortion, respectively.

 1643 Single-scan Mapping of Mean Diffusivity Using the Incomplete Initial Nutation Diffusion Imaging (INDI) framework Andrada Ianus1,2 and Noam Shemesh1 1Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal, 2Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom Diffusion MRI techniques require at least two different acquisitions separated by a repetition time in order to map mean diffusivity. Thus, dynamic imaging techniques, such as diffusion functional MRI, which aim to measure rapid diffusivity changes, might provide results confounded by T2 changes over the repetition time. This study introduces and validates the INDI (incomplete initial nutation diffusion imaging) framework, which can be used to accelerate diffusion acquisition so that the reference and diffusion weighted images are acquired within a few tens of milliseconds of each other.

 1644 Removal or correction of volumes affected by bulk motion: impact on DTI and NODDI metrics Kerstin Pannek1, John Welsh2, Jurgen Fripp1, Joanne George3, Paul Colditz3, Roslyn Boyd3, and Stephen Rose1 1CSIRO, Brisbane, Australia, 2University of Newcastle, Newcastle, Australia, 3The University of Queensland, Brisbane, Australia In difficult patient populations, the interleaved acquisition of diffusion weighted volumes often leads to images that are not self-consistent due to movement. Here, we investigated the effect of removing or correcting volumes with movement artefacts on the DTI measures FA and MD, as well as on NODDI measures. While removal of affected volumes is typically used, we found that a simple correction strategy leads to markedly lower bias and variability in all diffusion measures. Data that may need to be rejected entirely if volume removal is used, may be salvaged if correction is used.

 1646 Intravoxel Incoherent Motion (IVIM) Fingerprinting Qiuting Wen1, Li Feng2, Kun Zhou3, and Yu-Chien Wu1 1Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University, School of Medicine, Indianapolis, IN, United States, 2Center for Advanced Imaging Innovation and Research (CAI2R), New York University, School of Medicine, New York, NY, United States, 3Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China Intravoxel incoherent motion (IVIM) imaging employs a bi-exponential diffusion model to estimate capillary contributions to the diffusion-weighted signal. Major challenges of IVIM are long acquisition time, long processing time, and image distortion associated with EPI acquisition. In this work, we proposed a novel framework for rapid and distortion-free IVIM imaging called IVIM-Fingerprinting. It employs a single-shot acquisition scheme and an advanced image reconstruction scheme in combination with the recently proposed concept of MR Fingerprinting. Its performance was demonstrated both for simulation and for in-vivo studies.

 1647 Investigating the effect of gradient nonlinearities on Diffusional Kurtosis Imaging parameters: Results from the Human Connectome Project Hamed Y. Mesri1, Szabolcs David1, Max A. Viergever1, and Alexander A. Leemans1 1Image Sciences Institute, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands Gradient field nonlinearities in diffusion-weighted MRI may lead to systematic errors in the diffusion metrics. Despite previous works highlighting the adverse impact of gradient field nonuniformities on diffusion-weighted MRI, these effects are usually neglected and left uncorrected. In this work we use simulations and real data from the Human Connectome Project to investigate the effect of gradient field nonlinearities on the measures from Diffusional Kurtosis Imaging. Our results demonstrated that in general, the effect for the diffusion tensor metrics is larger than the effect for diffusional kurtosis metrics. However, the effect of the gradient nonlinearities on the kurtosis metrics should not be neglected.

 1648 Error estimation and evaluation of spatial smoothing processing for diffusion kurtosis imaging Suguru Yokosawa1, Yoshitaka Bito2, and Hisaaki Ochi1 1Research & Development Group, Hitachi, Ltd., Tokyo, Japan, 2Healthcare Business Unit, Hitachi, Ltd., Tokyo, Japan DKI often suffers from error estimation such as unphysical negative kurtosis values which result in black voxels on mean kurtosis (MK) map. In this study, causes of the estimation error are investigated by using simulation. In addition, effect of smoothing processing is quantitatively evaluated in terms of reduction in estimation error and image sharpness. Our findings will be useful for clinical diagnosis using DKI.

 1649 Improved diffusion propagator reconstruction using Hermite functions and compressed sensing Gabriel Varela-Mattatall1,2, Carlos Castillo-Passi1,2, Joaquin Mura1, and Pablo Irarrazaval1,2,3 1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 3Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile Mean apparent propagator (MAP) reconstructs the diffusion pdf using a dictionary based on Hermite functions. The first element corresponds to a tensor approximation; and the following elements add non-gaussian components. To improve non-gaussian accuracy, one needs to increase the size of the dictionary, but it also increases the number of q-space samples for a robust optimisation. We propose the use of compressed sensing to efficiently increase the number of atoms in the dictionary by exploiting its sparsity for a better reconstruction.

 1650 The Determination of Voxel Anisotropic Properties From Data of Low Agular Resolution Using Machine Learning Method and Compressed Sensing Reconstruction Xuesong Li1, Zhendong Niu1, Zhangxuan Hu2, Sen Song3, and Hua Guo2 1School of Computer Science and Technology, Beijing Institute of Technology, Beijing, China, 2Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China, 3Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China The estimation of voxel anisotropic properties from diffusion tensor imaging is critical for fiber tracking. Here machine learning was used to estimate the voxel anisotropic properties from undersampled data that were reconstructed by dictionary learning.

 1651 Deep learning with synthetic data for free water elimination in diffusion MRI Miguel Molina-Romero1,2, Pedro A. Gómez1,2, Shadi Albarqouni1, Jonathan I. Sperl2, Marion I. Menzel2, and Bjoern H. Menze1 1Technical University of Munich, Munich, Germany, 2GE Global Research Europe, Munich, Germany Diffusion metrics are typically biased by Cerebrospinal fluid (CSF) contamination. In this work, we present a deep learning based solution to remove the CSF contribution. First, we train an artificial neural network (ANN) with synthetic data to estimate the tissue volume fraction. Second, we use the resulting network to predict estimates of the tissue volume fraction for real data, and use them to correct for CSF contamination. Results show corrected CSF contribution which, in turn, indicates that the tissue volume fraction can be estimated using this joint data generation and deep learning approach.

 1652 A supervised learning approach for diffusion MRI quality control with minimal training data Mark S Graham1, Ivana Drobnjak1, and Hui Zhang1 1Centre for Medical Image Computing & Department of Computer Science, University College London, London, United Kingdom Quality control (QC) in diffusion-weighted MRI (DW-MRI) involves identifying problematic volumes in datasets. The current gold standard involves time-consuming manual inspection of data, and even supervised learning techniques that aim to replace the gold standard require manually labelled datasets for training. In this work we show the need for manual labelling can be greatly reduced by training a supervised classifier on realistic simulated data, and using a small amount of labelled data for a final calibration step.  Such an approach may have applications in other image analysis tasks where labelled datasets are expensive or difficult to acquire.

 1653 Efficient Reconstruction of Diffusion Kurtosis Imaging Based on a Hierarchical Convolutional Neural Network Ting Gong1, Hongjian He1, Zhiwei Li2, Zhichao Lin2, Qiqi Tong1, Chen Li1, Yi Sun3, Feng Yu2, and Jianhui Zhong1,4 1Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University, Hangzhou, China, 2Department of Instrument Science & Technology, Zhejiang University, Hangzhou, China, 3MR Collaboration NE Asia, Siemens Healthcare, Shanghai, China, 4Department of Imaging Sciences, University of Rochester, Rochester, NY, United States Diffusion kurtosis imaging (DKI) captures more complex microstructural properties than the widely used diffusion tensor imaging (DTI) but requires a longer acquisition time. To accelerate its acquisition, and thus facilitate its practical clinical use, a hierarchical convolution neural network (H_CNN) reconstruction method was proposed. The results showed that the H_CNN method provides efficient reconstruction of all eight DTI and DKI measures using as few as nine DWIs, with improved robustness against noise and the retention of fine structures, compared to artificial neural network-based methods. The H_CNN method potentially enables DKI clinical applications with an acquisition time of one minute.

 1654 Principal component analysis for model-free denoising of multi b-value diffusion-weighted images Oliver J Gurney-Champion1, David J Collins2, Mihaela Rata2, Andreas Wetscherek1, Uwe Oelfke1, Kevin J Harrington3, and Matthew R Orton2 1Joint department of physics, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, 2CRUK Cancer Imaging Centre, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, 3Division of Radiotherapy & Imaging, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom We introduce principal component analyses (PCA) as a denoising technique for diffusion-weighted MRI (DWI) that is independent of the diffusion attenuation model. PCA denoises DWI data using only informative components while removing noisy ones. We show that it outperforms model-based denoising in simulations as well as in vivo. In simulations, PCA-denoising resulted in smaller systematic errors, while random errors were similar. In vivo, PCA-denoising rendered less noisy images and when motion was present, PCA recovered certain structures that were obscured by motion in model-based denoising. In conclusion, PCA-denoising is a powerful model-free tool for denoising DWI data.

 1655 PCA denoising using random matrix theory provides an optimal compromise between noise suppression and preservation of non-Gaussian diffusion. Rafael Neto Henriques1,2 and Marta Morgado Correia2 1Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal, 2Cognition and Brain Sciences Unit, MRC, Cambridge, United Kingdom Recent studies showed that PCA denoising algorithms using random matrix theory provide an optimal compromise between noise suppression and loss of anatomical information for standard diffusion measures and tractography approaches. In this study, we show that this algorithm seems also to optimally preserve the non-Gaussian diffusion properties. Several factors that influence the performance of the PCA denoising algorithm are also assessed, such as the spatial heterogeneity of diffusion parameters across neighbour voxels and different scanning protocols. Moreover, the compatibility of PCA denoising with Gibbs artefact suppression and noise bias correction is evaluated.

### Diffusion MRI: Applications

 Exhibition Hall 1656-1675 Tuesday 8:15 - 10:15

 1656 Diffusion MRI as a descriptive imaging marker of the pathogenesis of treatment-resistant depression. Julie Coloigner1, Jean-Marie Batail1,2,3, Isabelle Corouge1, Jean-Christophe Ferré1,4, Dominique Drapier2,3, and Christian Barillot1 1Univ Rennes, INRIA, CNRS, Inserm, IRISA UMR 6074, VISAGES ERL U-1228, F-35000, Rennes, France, 2Academic Psychiatry Department, Centre Hospitalier Guillaume Régnier, Rennes, France, 3EA 4712 Behavior and Basal Ganglia, CHU Rennes, University of Rennes 1, Rennes, France, 4Department of Neuroradiology, University Hospital of Rennes, Rennes, France Despite the extensive therapy options available for depression, treatment-resistant depression (TRD) occurs in 20-30% of depressed patients. . Consequently, identification of neural changes in TRD could support to better understand the mechanism of resistance and to improve the treatment of individual depressed patients. We aimed to investigate the white-matter microstructure in a sample of depressed patients in which response to treatment was subsequently evaluated 6 months after. Our findings suggest the abnormalities of the white-matter integrity in multiple white matter tracts, such as anterior limb of internal capsule and genu of corpus may play a role in the pathogenesis of treatment-resistant depression.

 1657 Diffusion tensor MR imaging of optic radiation in advanced bilateral glaucoma patients in comparison to normal control subjects Chanon Ngamsombat1, Thanakorn Chareankarunyuta1, Prapaporn Pornwuthi1, Panida Charnchaowanish1, Yudthaphon Vichianin2, Ngamkae Ruangvaravate3, Shuo Zhang4, and Orasa Chawalparit1 1Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, 2Department of Radiological Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand, 3Department of Ophthalmology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, 4Philips Healthcare, Singapore, Singapore Glaucoma is a worldwide leading cause of irreversible vision loss characterized by degeneration of retinal ganglion cells. The damage can be found in visual pathway beyond retina and optic disc to visual cortex. Diffusion tensor MR imaging (DTI) is widely used for evaluation of early microstructural change in the brain parenchyma. Here we reported abnormal change of the optic radiation in advanced bilateral glaucoma patients using DTI as compared to the age-matched normal control subjects. The obtained DTI parameters may serve as potential quantitative imaging biomarkers to provide complementary indication of the disease condition in glaucoma.

 1658 Altered white matter tracts in schizophrenia with persistent negative symptoms Jing-Ying Huang1,2, Chih-Min Liu3,4, Tzung-Jeng Hwang3,4, Yung-Chin Hsu1, Hai-Gwo Hwu3,4, and Wen-Yih Isaac Tseng1,4,5,6 1Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 2Department of Radiology, Wei Gong Memorial Hospital, Miaoli, Taiwan, 3Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan, 4Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, Taipei, Taiwan, 5Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan, 6Molecular Imaging Center, National Taiwan University, Taipei, Taiwan This article aimed to investigate the alteration of white matter tracts in schizophrenia with persistent negative symptoms (PNS) in an attempt to identify white matter tracts that are characteristic of PNS. We performed diffusion spectrum imaging (DSI) and whole brain tract-based automatic analysis (TBAA) to compare the tract integrity among healthy controls, PNS and non-PNS groups. Our results showed that the right uncinate fasciculus and bilateral thalamic radiations of the ventral lateral prefrontal cortex are tract correlates of PNS.

 1659 Functional organisation of the hyperdirect pathway by in vivo structural connectivity imaging in healthy humans at 3T Gizem Temiz1,2, Chantal François1, Carine Karachi1,3, Sonia Pujol4, Eric Bardinet1,2, and Sophie Bernadette Sébille1,2 1Brain and Spine Institute, CNRS UMR 7225 - INSERM U 1127 - UPMC-P6 UMR S 1127, Paris, France, 2Center of NeuroImaging Research - CENIR, Paris, France, 3AP-HP, Hôpital de la Pitié-Salpêtrière, Department of Neurosurgery, Paris, France, 4Surgical Planning Laboratory, Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States The goal of this study is to investigate the anatomo-functional organization of the hyperdirect pathway between the subthalamic nucleus (STN) and the cortex in humans. We identified motor, limbic and associative areas of the whole cortex. We used DWI from 30 healthy subjects and probabilistic tractography between the STN and 39 cortical areas. The motor part of the hyperdirect pathway was found predominant compare to the limbic and above all the associative parts.

 1660 Utility of Advanced Diffusion Models in Assessing Abscess Structure Robert Wujek1, Mona Al-Gizawiy1, Kathleen Schmainda1, and Rodney Willoughby2 1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States MR imaging is commonly used in the diagnosis and monitoring of cerebral abscess, especially diffusion weighted imaging. However, the use of advanced diffusion models has yet to be seen with respect to this type of brain mass. The stretched-exponential, intra-voxel incoherent, and kurtosis diffusion models not only generate diffusivity coefficients, but also other parameters that may prove valuable in properly understanding the structure and progression of such lesions.

 1661 Optic radiation tractography in pediatric brain tumor and epilepsy surgery: a test-retest reliability assessment of the tractography method Joseph Yuan-Mou Yang1,2,3, Richard Beare1,4, Michelle Hao Wu5, Sarah M. Barton1,6,7, Charles B. Malpas1,8, Vicki Anderson6,8,9,10, Wirginia J Maixner2,3, and Marc L Seal1,6 1Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia, 2Neuroscience Research, Murdoch Children's Research Institute, Melbourne, Australia, 3Neurosurgery, The Royal Children's Hospital, Melbourne, Australia, 4Medicine, Monash University, Melbourne, Australia, 5Medical Imaging, The Royal Children's Hospital, Melbourne, Australia, 6Paediatrics, University of Melbourne, Melbourne, Australia, 7Neurology, the Royal Children's Hospital, Melbourne, Australia, 8Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Australia, 9Clinical Sciences, Murdoch Children's Research Institute, Melbourne, Australia, 10Psychology, the Royal Children's Hospital, Melbourne, Australia Existing optic radiation (OR) tractography methods lack pediatric and surgical focus. We proposed a clinically feasible tractography framework and examined its test-retest reliability using both the preoperative and intraoperative MRI from eight pediatric epilepsy and brain tumor patients. Good to excellent intra- and inter-rater reproducibility was demonstrated in the assessments of all diffusion and morphological track metrics. The reconstructions closely resembled classic anatomy. All OR images were used to assist surgical planning and resection. Postoperatively, no patient had new visual field deficits. Our tractography method generates reproducible OR images that can be safely implemented in routine, non-emergency pediatric neurosurgical settings.

 1662 Impaired executive and visual network integrity in patients with Parkinson’s disease and psychosis: A structural connectome based study Abhishek Lenka1, Apurva Shah2, Jitender Saini3, Pramod Kumar Pal1, and Madhura Ingalhalikar2 1Neurology, NIMHANS, Bengaluru, India, 2Department of Electronics, Symbiosis Institute of Technology, Symbiosis International University, Pune, India, 3Radiology, NIMHANS, Bengaluru, India Psychosis manifested as formed visual hallucinations is one of the debilitating non-motor symptoms of Parkinson’s disease (PD), the patho-physiology of which remains unclear. To gain insights into the neural correlates of psychosis in PD this study analyzed the structural connectomic sub-networks of visual, executive and memory circuits between patients with PD and psychosis (PD-P), PD without psychosis (PD-NP) and controls (HC). When PD-P and HCs were compared, a global connectivity deficit was observed in the visual and executive circuits and multiple connections within the visual network demonstrated significantly lower connectivity in PD-P. Such changes were not observed in PD-NP vs. HCs.

 1663 A comparison of different brain connectivity markers for classifying Gulf-war illness Bang-Bon Koo1 and Kimberly Sullivan2 1Anatomy and Neurobiology, Boston University, Boston, MA, United States, 2Boston University School of Public Health, Boston, MA, United States Gulf War Illness (GWI) represents a cluster of multi-system chronic symptoms experienced by a third of veterans who served in the Gulf War.  The exact cause of GWI remains unknown and efforts directed towards developing treatments have been hampered by the lack of meaningful objective biomarkers of the illness.  Combining machine learning technology to brain connectivity imaging may allow for better understanding of the complex pathobiology of GWI. Choosing optimal imaging index should be a first step to maximize its classification performance.

 1664 DWI assessment of the optic nerve and chiasma of acute optic neuritis:  Advantages in field-of-view optimized and constrained undistorted single shot (FOCUS) method Yuan Tian1, Lin Ma1, Gang Liu1, Mengyu Liu1, and Mingge Li1 1radiology department, General Hospital of the People’s Liberation Army, Beijing, China In the current study, we evaluated the performance of the field-of-view optimized and constrained undistorted single shot (FOCUS) DWI in assessing the optic nerve and chiasma abnormalities of acute optic neuritis. Visual assessment was obtained for the FOCUS-DWI and the conventional-DWI (c-DWI). We found that FOCUS-DWI provided better visual assessments of the optic nerve and chiasma abnormalities in acute optic neuritis (AON), with much reduced blurring effects and geometric deformations. It might indicated that the FOCUS-DWI would improve the diagnostic accuracy and prognosis evaluation in AON.

 1665 A Method to Quantitatively Assess and Compare Diffusion MRI Protocols between MR Systems Samuel Anthony Hurley1,2 and Alan B McMillan1 1Radiology, University of Wisconsin, Madison, WI, United States, 2Neuroscience, University of Wisconsin, Madison, WI, United States MRI systems and protocols capable of achieving diffusion measurements with comparable imaging parameters and equal or better performance to the Human Connect Project (NCP) acquisitions will enable studies in additional populations or patient groups to leverage existing HCP data as control data, decreasing costs and increasing statistical power of findings. To evaluate new MRI systems and potential protocols, we present an automated and quantitative method for evaluation of diffusion imaging performance from in-vivo data, use this method to evaluate the performance of a dMRI protocol acquired in a prototype wide bore 3T MRI system.

 1666 Tractography based parcellation of the frontal lobe: reproducibility & functional significance. Michel Thiebaut de Schotten1, Marika Urbanski1, Leonardo Cerliani1, and Emmanuelle Volle1 1BCBlab, Institut du Cerveau et de la Moelle, Paris, France Dividing the brain based on structural connectivity is a challenge that we circumvented using the principal component analysis framework. By doing so, we reliably divided the frontal lobe into 12 areas across datasets and participants. Additionally, these areas showed neat functional specificity as defined by functional magnetic resonance imaging.

 1667 Application of DTI on hyroid-associated ophthalmopathy (TAO) with Dysthyroid Optic Neuropathy (DON) or diplopia patient after intravenous methylprednisolone strategy. ping liu1 and jing zhang1 1department of radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, wu han, China The pathogenesis of DON and diplopia is totally different. This study use the MRI-DTI on DON and diplopia patients with good therapeutic efficacy, the multiple DTI parameters of optic nerve were calculated and assessed. The final results furtherly confirmed this difference. And the statistical difference of DTI parameter changes in DON patients validate the DTI can exactly, objectively and reliably detect the microstructure and functional repair of optic nerve after iv MP therapy.

 1668 Automated fibre quantification predicts early Wallerian degeneration of the CST after acute ischemic stroke Min TANG1, Wei DI2, Xin ZHANG1, Jie GAO1, Xiaoling ZHANG1, Zhizheng ZHUO3, Xia ZHE1, Dongsheng ZHANG1, and Xuejiao YAN1 1Shaanxi provincial peoples hospital, Xi’an, China, 2Department of neurology, Shaanxi provincial peoples hospital, Xi’an, China, 3Philips Healthcare, Beijing, China This study aimed to observe the microstructural alterations in corticospinal tract (CST) after motor pathway infarction and predict early Wallerian degeneration based on automated fiber quantification (AFQ). 53 patients with first-onset stroke in motor pathway and 29 health age-matched controls were enrolled. FA, MD, AD and RD values were significantly reduced on lesions of the affected side, while DKI values (MK, AK and RK) exhibited significant increase. AFQ was performed to identify differences on the whole CST pathway in the affected side between control and patient group. AD and MD values in CST of the affect side were significantly higher than them in healthy control. The findings of AD and MD have the same pathological changes on the affected CST pathway no matter the primary stroke lesions located in any regions (brainstem, posterior limb of internal capsule or above centrum semiovale). Our findings suggest that AFQ has the potential to detect the early Wallerian degeneration in the central nervous system in vivo after the first 24 hours in stroke.

 1669 Diffusion tensor imaging (DTI) in patients with cystic fibrosis Petr Bednarik1, Alena Svatkova2, Silvia Mangia1, Christophe Lenglet1, Antoinette Moran2, and Amir Moheet3 1Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States, 3Department of Medicine, University of Minnesota, Minneapolis, MN, United States Cystic fibrosis (CF) is the most common fatal autosomal recessive disorder in Caucasians. As the effects of CF on the brain structure remain unexplored, we piloted initial MRI investigations of brain structure by diffusion weighted imaging in CF and cystic fibrosis related diabetes (CFRD), a common complication in CF patients. Diffusion metrics were obtained in selected white and gray matter regions of 5 healthy controls (HC) and 5 CF patients with CFRD. Diffusion metrics of deep gray matter structures appeared to differ between patients with CF and HC, possibly related to increased iron deposition, warranting more comprehensive MRI investigations in larger cohorts of patients.

 1670 DW-MRI in assessment of 3D Cell Culture Jui-Heng Lin1, Hao-Chun Peng1, Shao-Chieh Lin2, Yi-Jui Liu2, Ruey-Hwang Chou3, Ke-Sin Yan3, Tan-Wei Liao3, Chia-Wei Lin4, Chao-Chun Lin4, Wei-Ching Lin 4, and Wu-Chung Shen4 1Master's Program of Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, 2Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, 3Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, 4Department of Radiology, China Medical University Hospital, Taichung, Taiwan In extracellular and intracellular space, the Brownian motion of water is restricted by organelles, cellmembranes, and extracellular fibers. DWI is sensitivity to microscopic motion, which is due to Brownian motion of water molecules. In this study, 3D cell culture with hydrogels ECM was used to investigate whether DWI may provide information on these microenvironmental parameters and the microenvironment-associated metastatic propensity of tumors. Our results demonstrated DW-MRI may provide the potential biomarkers on the change of microenvironment in the application of 3D cell culture experiment.

 1671 Structural and functional brain connectivity highlights in neurosensorial profound deafness Pedro Henrique Rodrigues da Silva1, Antonio Carlos Santos Senra Filho2, Karol Dell Ducas Senra3, Renata Ferranti Leoni1, Luiz Otavio Murta Junior2, and Antonio Carlos dos Santos3 1Department of Physics, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil, 2Department of Computing and Mathematics, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil, 3Department of Medical Clinics, FMRP, University of São Paulo, Ribeirão Preto, Brazil The absence of auditory stimuli for a long period leads to modifications in brain structural and functional connectivity. However, the relationship between the brain changes and neurosensorial hearing loss is not fully clarified. In this study we considered a group of subjects with pre-lingual congenital deafness and analyzed their structural and functional connectivity. Our results suggest that auditory input deprivation not only alters the activity of sensory areas but also reshape the structural and functional organization of cognitive-related networks. These findings can be instructive to clinical practice.

 1672 Novel Multi-band accelerated, Reference-less, Multifaceted Icosahedral and Multishell Diffusion MRI Protocol for human whole brain clinical applications Khader M Hasan1, Refaat E Gabr1, John A Lincoln2, and Ponnada A Narayana1 1Diagnostic and Interventional Radiology, UThealth, Houston, TX, United States, 2Neurology, UThealth, Houston, TX, United States We describe a comprehensive multishell and multifaceted icosahedral diffusion MRI protocol that enables whole brain coverage in less than 10 minutes using multiband (MB)  technology at 3 T. We show the protocol utility in providing estimates of blood fraction, extent of CSF-contamination, diffusion tensor and kurtosis derived measures including fractional, axonal water fraction and extracellular tortuosity. The diffusion gradient encoding is based the Icosa6 and Icosa15 sets forming the Icosa21 for additional quality assurance. In this report we describe the protocol, show feasibility and utility for mapping a host of useful quantitative measures in the same session without repeated scans.

 1673 Role of intravoxel incoherent motion diffusion-weighted imaging in the assessment of invasiveness for bladder cancer Fang Wang1, Guangyu Wu1, and Weibo Chen2 1Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, 2Philips Healthcare, Shanghai, China The degree of bladder wall invasion by bladder cancer determines the clinical management, for muscle invasive bladder cancer (MIBC, Stage T2 or more) recommended neoadjuvant chemotherapy before radical cystectomy and non-muscle invasive bladder cancer (NMIBC, Stage T1 or lower) treated with transurethral resection (TUR). Thus, differentiating NMIBC from MIBC using preoperative imaging plays a crucial role in clinical practice.

 1674 Relationship between peripheral Interleukin 10 and white matter integrity in stable medicated schizophrenia Gui Fu1, Dongsheng Wu1, Wenjing Zhang1, Jieke Liu1, Yuan Xiao1, Li Yao1, Jiaxin Zeng1, John A Sweeney1,2, and Su Lui1 1West China Hospital, Sichuan University, Chengdu, China, 2Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, United States To our knowledge, this is the first time to study the association between plasm IL10 level and WM disruption in stable medicated schizophrenia using diffusion tensor imaging (DTI). The present study provided empirical evidence that dysregulation of inflammation contributes to anatomical dysconnectivity in schizophrenia.

 1675 Prediction of histological grade of hepatocellular carcinoma using quantitative diffusion-weighted magnetic resonance imaging: a retrospective multi-vendor study Yoshio Kitazume1, Yusuke Ogihara1,2, and Ukihide Tateishi1 1Tokyo Medical and Dental University, Tokyo, Japan, 2JA Toride Medical Center, Ibaraki, Japan Eighty-three patients with 100 histologically diagnosed hepatocellular carcinomas (HCCs) who preoperatively underwent diffusion-weighted (DW) imaging at any of 6 institutes were retrospectively studied. Receiver-operating characteristic analysis revealed that quantitative measurements such as the relative contrast ratio (RCR) and the contrast-to-noise ratio (CNR) between lesion and liver parenchyma on DW images were superior to the apparent diffusion coefficient (ADC) in predicting poorly differentiated HCCs, and intraclass correlation coefficients for the RCR tended to be greater than for the CNR and the ADC.

### Diffusion MRI: Microstructure

 Exhibition Hall 1676-1688 Tuesday 8:15 - 10:15

 1676 Diffusion Weighted Imaging with uniform fat suppression using a Modified Dixon based Single Shot Turbo Spin Echo Xinzeng Wang1, Holger Eggers2, Marco C. Pinho1,3, Ivan Pedrosa1,3,4, Robert E. Lenkinski1,3, and Ananth J. Madhuranthakam1,3 1Radiology, UT Southwestern Medical Center, Dallas, TX, United States, 2Philips Research, Hamburg, Germany, 3Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, 4Kidney Cancer Program, Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, United States Diffusion weighted imaging using single-shot turbo spin echo (DW-SShTSE) with Dixon showed uniform fat suppression without geometric distortions, compared to DW-EPI and DW-SShTSE with spectrally selective fat suppression (SPIR). However, the phase insensitive preparation used in DW-SShTSE reduces the SNR by half, impeding the robustness of Dixon reconstruction. In this work, we developed a hybrid DW-SShTSE, where the b=0 s/mm2 image was acquired without the phase insensitive preparation for improved SNR. This combined with modified acquisition order improved the robustness of fat/water separation and generated diffusion-weighted images of the cervical spine with improved spatial resolution.

 1677 Diagnostic value of diffusion tensor imaging and positron emission tomography in early stages of frontotemporal dementia Julia Krämer1, Gero Lueg2, Jan-Gerd Tenberge1, Patrick Schiffler1, Alexis Vrachimis3, Matthias Weckesser3, Christian Wenning3, Andreas Johnen1, Matthias Pawlowski1, Sven G. Meuth1, and Thomas Duning1 1Department of Neurology, Westfälische Wilhelms University, Münster, Germany, 2Department of geriatric medicine and early rehabilitation, Marien Hospital Herne, Herne, Germany, 3Department of Nuclear Medicine, Westfälische Wilhelms University, Münster, Germany The study intended to investigate the sensitivity of DTI and FDG-PET in 30 patients with early behavioral variant frontotemporal dementia (bvFTD) despite inconspicuous conventional MRI. Based on individual FDG-PET data analysis, 20 patients were rated as bvFTD “typical” with bifrontal/ bitemporal hypometabolism (bvFTD/PET+) and 10 patients as “not typical/normal” (bvFTD/PET-). DTI voxel-based group analyses revealed bifrontal/ bitemporal microstructural degeneration in all patients. However, individual DTI data analysis revealed alterations in only 14%. Neuropsychological symptoms were associated to DTI and FDG-PET identifiable cerebral changes. Summarising improvement of individual DTI analysis tools is necessary to make this technique applicable for clinical routine.

 1678 Monte Carlo simulations of diffusion in myelin spirals: Impact on diffusional water exchange Lorenza Brusini1, Gloria Menegaz1, and Markus Nilsson2 1University of Verona, Verona, Italy, 2Lund University, Lund, Sweden How does the myelin structure impact water diffusion? The answer is still not clarified but is important for interpreting diffusion MRI in conditions with altered myelin structure such as neurological disorders or developing brain. Myelin is sometimes modelled as permeable to explain exchange between compartments. This work investigates the impact of the spiralling nature of myelin on water exchange, until now only indirectly explored in one case. Findings emphasized that small axons and low number of myelin wraps lead to exchange times shorter than a second, which can be assessed at clinical scanners.

 1679 Measuring water exchange using cumulant expansions Lipeng Ning1,2, Markus Nilsson3, Carl-Fredrik Westin1,2, and Yogesh Rathi1,2 1Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital, Boston, MA, United States, 3Lund University, Lund, Sweden Diffusion MRI (dMRI) can provide important information about water exchange between different tissue compartments. In this abstract, we introduce a generalized model to measure the exchange rate using arbitrary gradient sequences. We present a unified theory that incorporates water diffusion and exchange as a stochastic diffusion-exchange process. Our work for the first time allows to compare different diffusion sequences and allows to determine the optimal experimental configurations to measure the exchange rate. In the most common situation with single- or double-diffusion encoding (SDE, DDE) sequences, our theory shows that DDE is more sensitive to water exchange at short time scale. We validate our theory using Monte-Carlo simulations.

 1680 Using GPUs to accelerate computational diffusion MRI: From microstructure estimation to tractography and connectomes Moises Hernandez-Fernandez1,2, Istvan Reguly3,4, Saad Jbabdi1, Mike Giles3, Stephen Smith1, and Stamatios N. Sotiropoulos1,5 1Oxford Centre for Functional MRI of the Brain (FMRIB), University of Oxford, Oxford, United Kingdom, 2Section for Biomedical Image Analysis (SBIA), University of Pennsylvania, Philadelphia, PA, United States, 3Oxford e-Research Centre, University of Oxford, Oxford, United Kingdom, 4Faculty of Information Technology and Bionics, Pazmany Peter Catholic University, Budapest, Hungary, 5Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, United Kingdom The great potential of computational diffusion MRI (dMRI) relies on indirect inference of tissue microstructure and brain connections, as modelling and tractography frameworks map diffusion measurements to neuroanatomical features. This mapping however can be computationally expensive, particularly given the trend of increasing dataset sizes and/or the increased complexity in biophysical modelling. We present here a number of frameworks for accelerating dMRI computations using Graphics Processing Units (GPUs), for both microstructure estimation and tractography/connectome generation. We show that despite differences in challenges for parallelising these problems, GPU-based designs can offer accelerations of more than two orders of magnitude.

 1681 On the estimation of the apparent bundle-wise diffusivity profiles for axon damage detection Ricardo Coronado-Leija1, Alonso Ramirez-Manzanares1, Jose Luis Marroquin1, Luis Concha2, Gilberto Rojas-Vite2, and Ramsés Noguez-Imm2 1Computer Science, Centro de Investigacion en Matematicas, Guanajuato, Mexico, 2Institute of Neurobiology, Universidad Nacional Autonoma de Mexico, Queretaro, Mexico To estimate the physical features of intra-voxel axon bundles in the detection of axon damage it is important to compute bundle-wise apparent diffusivities. There is a first family of methods that factors-out the effects of the orientation-dispersion under a convolution model (e.g. Spherical Mean), and a second family that associates the diffusivity properties with specific orientations (e.g. Gaussian-Mixture-Models). Here we demonstrate that only the second family provides bundle-wise apparent diffusivities, and thus it provides the useful information for clinical applications. This is demonstrated on a broad synthetic validation as well as on ad-hoc rat ex-vivo phantom with a damaged bundle.

 1682 Diffusion-Weighted MR Imaging of the Parotid glands in healthy volunteers before and after a gustatory stimulation to quantify relative function Matthew George Birkbeck 1, Fiona Elizabeth Smith1, and Andrew Matthew Blamire1 1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom Diffusion Weighted MR Imaging has been used to quantify the function of parotid glands. Clinically gland function is measured using Scintigraphy, but MR offers a non-invasive, non-ionising alternative to this method. A DWI sequence for investigating parotid gland function is presented and tested in five healthy volunteers scanned on two occasions. We used four parameters to represent gland function: perfusion fraction (fv), apparent perfusion coefficient (ADCperfusion), diffusion fraction (fd) and apparent diffusion coefficient (ADCdiffusion). Statistically significant changes were observed in fv, fd  and ADCdiffusion in volunteers. Results indicate a normal range for these parameters.

 1683 DWI virtual MR elastography of the upper abdominal organs in healthy volunteers Min Wang1, Yu Shi1, Xiaoqi Wang2, Yanqing Liu1, Ruoyun Ji1, Lizhuo Cang1, and Qiyong Guo1 1Shengjing Hospital of China Medical University, Shen Yang, China, 2Philips Healthcare, Beijing, China Le et al1recently found that apparent diffusion coefficient (ADC) calculated from 2 key b values (“shifted ADC”, or sADC) can be directly and quantitatively represent healthy liver stiffness and be compared with results obtained by standard MR elastography (MRE). In this study, we found that there is a strong linear relationship between sADC and stiffness in both liver and pancreas, and a weak relationship in spleen, but no coherence in kidney in healthy volunteers.

 1684 Investigation of diffusion, susceptibility, and vessel morphology effects on R2 in characterizing normal and tumorous vasculature using simulations Mohammed Salman Shazeeb1,2, Jayashree Kalpathy-Cramer2, and Bashar Issa1 1UAE University, Al-Ain, Abu Dhabi, United Arab Emirates, 2Radiology, MGH & Harvard Medical School, Boston, MA, United States Brain vasculature is conventionally represented as straight cylinders when simulating BOLD contrast effects in fMRI. In reality, the vasculature is more complicated with branching and coiling especially in tumors. We applied a cylinder fork model to reflect the bifurcation, rotations, and size of vessels and performed simulations to study the effect of the rotation angle (ϕ) on R2 at different bifurcation angles, vessel diameters, diffusion rates, and susceptibility values. This model clearly showed an R2 dependence on ϕ, which could potentially be used, in addition to R2*, as a tool to differentiate between normal and tumor vessels.

 1685 Obtaining the barrier distribution in the micro-structure from diffusion spectra Carlos Castillo-Passi1,2, Gabriel Varela-Mattatall1,2, Claudia Prieto1,2,3, Carlos Sing-Long2,4,5, and Pablo Irarrazaval1,2,5 1Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 3Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom, 4Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, United States, 5Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile Inspired in the solution of the diffusion equation in the restricted case, we propose to express the diffusion $q$-space information in a restricted basis. This representation allows to obtain the distribution of barriers separations, thus providing useful information about the micro-structure. Previous methods used multiple Diffusion Spectrum Imaging (DSI) images with different diffusion times, which is impractical to characterize barriers in multiple directions. Our method proposes to obtain the barrier distribution with only a single DSI image. Furthermore, the model does not use a strong assumption for the geometry of the barriers (or axons) nor for the probability distribution of the barrier separation.

 1686 Increasing Mixing Time in STEAM-DTI Enhances Inter-Muscle Heterogeneity Patterns in the Lower Leg of Healthy Subjects Celine Baligand1, Thom TJ Veeger1, Jedrek Burakiewicz1, Melissa T Hooijmans1, Jan JGM Verschuuren2, Erik H Niks2, and Hermien E Kan1 1Radiology, Leiden University Medical Center, C.J. Gorter Center for High-field MRI, Leiden, Netherlands, 2Neurology, Leiden University Medical Center, Leiden, Netherlands Hereditary muscular disorders are characterized by progressive skeletal muscle wasting and weakness. Although these diseases are caused by ubiquitous genetic mutations, the symptoms appear at different rates in different muscles. We investigated the differences in microstructural properties of different muscles of the lower leg in healthy subject using STEAM-DTI with varying diffusion times at 3T. We identified a characteristic pattern of differences in fractional anisotropy and diffusivity in healthy muscles than can serve as a knowledge base for future studies on disease progression in muscular disorders.

 1688 Fitting MAP-MRI in 2 shell DWI Datasets using Model-based Extrapolation maryam afzali1, Sharlene Newman1, Eleftherios Garyfallidis2, and Hu Cheng1 1Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States, 2Department of Intelligent Systems Engineering, Indiana University, Bloomington, IN, United States We showed that three shells are sufficient to result in good approximations of MAP-MRI indices from numerical simulation. We used multiple compartment microstructure models to fit the two shell data and extrapolate the third shell with a higher b-value. We compared the performance of two models, NODDI and NODDI with fiber crossing (NODDIx), on the Human Connectome Project (HCP) DWI data. NODDIx showed improvement in the white matter with extrapolation but NODDI did not. Both NODDI and NODDIx failed to improve the results in the gray matter. Our approach also provides a new mechanism in validating or comparing microstructure models.

### RF Coils & Electronics

 Exhibition Hall 1689-1736 Tuesday 13:45 - 15:45

 1689 Construction of an open PXIe based scalable MRI console Andrew Ang1, Sergei Obruchkov2, and Robin Dykstra1 1School of Engineering and Computer Science, Victoria University of Wellington, Wellington, New Zealand, 2Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand We have developed an open source PXIe platform tailored for MRI console development.  The example design has a multichannel RF transceiver, and signal generation for gradient drive.

 1690 Software defined radio-based platform for parallel transmission MRI research Fred Tam1, Benson Yang1, and Simon J Graham1,2 1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada Parallel transmission (PTx) research platforms are challenging to implement and to integrate with commercial MRI systems. A prototype PTx research platform was demonstrated that leverages off-the-shelf software-defined radio (SDR) for flexibility and scalability, with easy integration and moderate cost. The SDR system was evaluated on the bench and connected to a commercial 3-T MRI system for an initial RF shimming demonstration. Substantial latency was found, likely due to the preliminary software implementation, but overall measurements and images were promising. Scaling to 32 transmit channels and applications other than RF shimming are expected to be practical.

 1691 A Gate Modulated Digitally Controlled Modified Class-E Amplifier for On-Coil Applications in 1.5 T MRI Bismillah Nasir Ashfaq1,2, Fatima Tu Zahra1,2, Berk Silemek2, Uğur Yılmaz2, and Ergin Atalar1,2 1Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey A novel technique of modulating both the amplitude and frequency of the desired MR Radiofrequency pulse in a class-E amplifier topology, without utilizing supply-modulation, is presented. Amplifier’s MATLAB model is developed and the carrier frequency bitstream is intelligently controlled to achieve both the amplitude and phase modulation of the output waveform. Benchtop experiments are performed showing accurate translation of software predictions on hardware, however requiring some additional optimization steps. MR experiments are performed to demonstrate the slice-selective capability of the generated RF pulse. Images are acquired at input powers of up to 80 W with 89% peak drain efficiency.

 1692 Accurate Noise Figure Measurements for Highly Mismatched Preamplifiers Daniel Højrup Johansen1, Juan D. Sanchez-Heredia1, Vitaliy Zhurbenko1, and Jan H. Ardenkjær-Larsen1,2 1Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark, 2GE Healthcare, Brøndby, Denmark A method reducing the uncertainty of noise figure measurements of highly mismatched preamplifiers is presented. In many cases when measuring the noise figure of preamplifiers for MRI receive arrays the uncertainty is approximately ±0.4 dB. Since the noise figure of the preamplifier is also in this range, a more accurate method is needed. Here we show an increase of 59 % in noise figure accuracy by adding an attenuator between the noise source and preamplifier.

 1693 A Tx/Rx Coil Concept Using the Same Receiver Array Coils Xiaoyu Yang1, Haoqin Zhu1, Tsinghua Zheng1, and Yong Wu1 1Quality Electrodynamics, LLC, Mayfield Village, OH, United States Typical Tx/Rx coils require a separate local transmitter and complicated T/R switches to make a local transmitter. They are expensive and may degrade receiver coil performance. We propose a novel Tx/Rx coil concept using the same receiver array coils. All receiver coils are allowed to inductively couple to the WBC in Tx mode. The combined induced amplified Tx field from the array coils is uniform and can be used as local Tx B1 field. This new concept simplifies Tx/Rx coil design and enables highly parallel array coil design with local Tx capability.

 1694 A Low Cost Prototype Pre-Gate Amplifier to Study Radiofrequency Power Amplification for Parallel Transmission MRI at 3 T Benson Yang1 and Simon J Graham1,2 1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada There is a growing interest to increase the channel count on parallel transmit systems. With system cost always a major consideration, substantial savings may be possible as the channel count becomes high (ie. ≥32). Typically, radiofrequency power amplifier (RFPA) designs involve multiple amplification stages to achieve a target output power. Three stages are identified in the design approach of the present work: (1) a low noise pre-amplifier; (2) a driver amplifier; and (3) a power gain amplifier. The present goal is introduce and characterize system architecture for a prototype “pre-gate” amplifier (stage 1 and 2) to explore power amplification technology for stage 3 of the RFPA.

 1695 A Prototype Four-Channel Parallel Transmission System to Investigate MRI Safety at 3 T Benson Yang1, Fred Tam1, Pei-Shan Wei1, Clare E McElcheran2, and Simon J Graham1,3 1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, 2Baylis Medical, Missisauga, ON, Canada, 3Medical Biophysics, University of Toronto, Toronto, ON, Canada Interest in parallel transmission (pTx) continues to grow with many research groups investigating methods to increase channel count and applications on commercial MRI systems. It can be challenging, however, to integrate pTx hardware onto existing systems without disrupting normal operation. The present work successfully interposes a four-channel pTx system on an existing 3 T Siemens Prisma system and performs validation to demonstrate: (1) four-channel radiofrequency (RF) shimming; and (2) reduced RF heating in an electrically conductive implant.

 1696 A meander slot element with microstrip line match and tune Dheyaa Alkandari1, Chung-Huan Huang1, and Steven M Wright1 1Texas A&M University, College station, TX, United States lot antennas have been widely used in communications because of their obvious low-profile nature. In MRI applications, the ability to ‘hide’ ancillary electronic components behind a shield containing a slot antenna could lead to interesting and very “clean” transmit antenna designs. Using the meander slot as elements for multi-channel coils allows for more compact multi-channel transmit coil designs with a shielded “clean” imaging area. This shielded imaging area provides a desirable environment for placing a receiver coil. More importantly, using meander slot coil elements can potentially allow for the design of multi-channel coils without the need of using matching and tuning networks or decoupling circuits. We believe this may  significantly simplify the design of multi-channel transmit coils.

 1697 A 32-Channel Array Coil for Bilateral Breast Imaging and Spectroscopy at 7T Romina Del Bosque1, Matthew Wilcox1, Jiaming Cui2, Sergey Cheshkov3,4, Ivan Dimitrov4,5, Craig Malloy3,4,6, Steve Wright1,2, and Mary McDougall1,2 1Biomedical Engineering, Texas A&M University, College Station, TX, United States, 2Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States, 3Radiology, UT Southwestern Medical Center, Dallas, TX, United States, 4Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, 5Philips Medical Systems, Cleveland, OH, United States, 6Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States This work describes the design, construction, and performance of a 32-channel array coil for bilateral breast imaging at 7T. Imaging indicated an increase in average SNR over a T/R volume coil of 5.5 times, with a three times increase in the center and up to 20 times along the periphery. Channel noise correlations indicated well decoupled elements and highly unilaterally isolated sets of 16 elements. In combination with high field strength benefits, this array will enable high resolution accelerated breast imaging.

 1698 A Neck Adapted 4-Ch Saddle-Shaped pTx Transceive Coil for Carotid Imaging at 7T Fabian J. Kratzer1, Reiner Umathum1, Sebastian Flassbeck1, Thomas M. Fiedler1, Andreas K. Bitz1,2, Mark E. Ladd1,3, Gregor Adriany4, and Sebastian Schmitter1,5 1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Electrical Engineering and Information Technology, FH Aachen - University of Applied Sciences, Aachen, Germany, 3Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany, 4Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, MN, United States, 5Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany Stroke is one of the most common causes of death, often caused by accumulation of plaques in the carotid arteries. This motivates investigating the anatomy and blood hemodynamics in the carotid bifurcation with high resolution. For early diagnostics, this work presents a new, saddle-shaped neck-adapted 4-channel parallel transceive coil for imaging at 7T. Coil design and optimization were performed using numerical simulations, and a safety assessment was performed with an anatomical body model. A head-shoulder phantom was built and used to validate measurements. High-resolution anatomical images and flow measurements were acquired in the common carotid artery.

 1699 A Fast MOSFET RF Switch for TRASE MRI at Low Magnetic Field Pierre-Jean Nacher1, Sashika Kumaragamage2, Geneviève Tastevin1, and Christopher P Bidinosti3 1Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC-Sorbonne Université, Collège de France, Paris, France, 2Rady Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, MB, Canada, 3Department of Physics, University of Winnipeg, Winnipeg, MB, Canada TRansmit Array Spatial Encoding (TRASE) MRI uses trains of B1 pulses alternatively produced by distinct transmit coils. Commonly used coil switching involving PIN diodes is too slow for low-field MRI and would introduce wait times between pulses typically as long as each individual pulse (hence, significant diffusion-induced resolution loss in TRASE MRI of gas samples). A MOSFET-based RF switch is described and characterised. Up to 200 kHz, it allows for sub-µs switching of RF currents from a single amplifier to several coils with sufficient isolation ratio and no delay between pulses.

 1700 A 22-Channel RF coil array for fetus MR imaging at 3T Chao Luo1,2, Guoxi Xie3, Jo Lee1,2, Xing Yang4, Xiaoliang Zhang5,6, Xin Liu1,2, and Ye Li1,2 1Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Shenzhen Key Laboratory for MRI, Shenzhen, China, 3School of Basic Science, Guangzhou Medical University, Guangzhou, China, 4High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, Chengdu, China, 5Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 6UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States Due to lack of dedicated fetal imaging RF coils, the system body coil is often used to acquire fetal images. This setup is not optimized and offers limited sensitivity and image quality. In this work, we designed and manufactured a 22-channel flexible coil array for fetal examinations. Compared with Siemens 6-channel body coil, the proposed fetal coil array achieves significant improvements in imaging coverage, image SNR and parallel acceleration capability.

 1701 Magnetically coupled RF coil for optimizing noise correlation Yosuke Otake1, Kohjiro Iwasawa1, Hisaaki Ochi1, Masayoshi Dohata2, and Yoshihisa Soutome1 1Research & Development Group, Hitachi, Ltd., Tokyo, Japan, 2Healthcare Business Unit, Hitachi, Ltd., Tokyo, Japan A magnetically coupled radiofrequency (RF) coil (MC coil) for optimizing noise correlation has been developed. The electric fields of each RF coil, which determine noise correlation, were controlled by a small magnetic coupling between a pair of RF coils. The MC coil was implemented as a two-channel loop coil in 1.5 T magnetic resonance imaging (MRI). The experimental results show that noise correlation can be controlled by using a small magnetic coupling without signal-to-noise ratio (SNR) loss. MC coils that can optimize noise correlation give a new degree of freedom to coil design.

 1702 Small self-decoupled RF coils Xinqiang Yan1,2, John C. Gore1,2,3, and William A. Grissom1,2,3 1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States, 3Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States The self-decoupled coil that is intrinsically decoupled proves to be a simple way to solve coupling issues in RF arrays. Small mode capacitances are needed to balance the dipole- and loop-mode coupling in self-decoupled coils, which then requires the addition of inductors to maintain the resonant frequency. But inductors may lead to loss and thus decrease transmit efficiency. In this work, we investigated the performance of small self-decoupled coils at 7T and compared it to ideal conventional coils. It was found that the coil performance of self-decoupled array could be well preserved so long as the sample loss is dominated. Based on these simulation and experimental results, the self-decoupled coil is a good candidate for dense coil arrays at ultrahigh fields.

 1703 Strip transmission line RF coil combined with RF shielded PET detector for existing MRI systems Md Shahadat Hossain Akram1, Takayuki Obata1, and Taiga Yamaya1 1National Institute of Radiological Sciences, Japan, Chiba, Japan PET insert for the existing MRI systems can be a potential affordable alternative of body PET/MRI system. To avoid mutual interference between PET front-end electronics and the MRI system, PET front-end (F/E) electronics are enclosed in RF shielded Faraday cage that is connected to the RF ground for shielding purpose. On the other hand, strip transmission line RF coil requires a grounded plane in parallel with a strip conductor as coil that are connected by shunt capacitors. In this study, we proposed a strip transmission line coil that replaced the ground one layer conductor with the shielded PET detector module. The combined system shows promise for a compact PET/RF coil modality as insert for simultaneous PET/MR imaging with existing MRI systems, suitable even at ultrahigh field MRI.

 1704 Fixed-phase prostate imaging with a 8-channel transmit/receive dipole antenna array on a conventional 3T system Aidin Ali Haghnejad1, Mark Gosselink1, Ingmar Voogt1, Dennis Klomp1, Peter Luijten1, and Alexander Raaijmakers1,2 1Radiology, UMC Utrecht, Netherlands, Utrecht, Netherlands, 2Eindhoven University of Technology, Biomedical Image Analysis, Eindhoven, Netherlands Local multi-transmit arrays at 3T provide reduced power requirements and reduced local SAR. However, it requires 3T scanners with multi-transmit functionality which are rare. This work presents add-on hardware that enables the use of local transmit/receive arrays. An exploration on prostate imaging with fixed phase settings using a 8-channel dipole array has been performed on four subjects. B1+ levels range from 5 to 8.5 uT for 8 x 215-300 W input power. T2w images have been acquired successfully for each subject. The modest inter-subject variation in B1+ demonstrates the feasibility of this approach.

 1705 Large FOV 16-channel receive array with a volume transmit coil for human forearm/wrist/hand imaging at 7 T Özlem Ipek1, Jérémie Clément2, and Maria Isabel Vargas3 1CIBM-AIT, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 2LIFMET, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 3Neuroradiology division, Geneva University Hospitals, Geneva, Switzerland A large-field-of-view 16-channel circular loop receive array with a volume transmit coil for the human forearm, wrist and hand imaging at 7 Tesla was constructed. While the volume transmit coil yields homogeneous transmit field distribution along the 350-mm in length , the 16-channel receiver array enables two times faster imaging with a similar MR image quality. In conclusion, the use of this large field-of-view RF coil configuration for a total MR protocol of 15 minutes is feasible, and it enables visualization of different anatomical structures on the human forearm and hand at 7 Tesla.

 1706 A Flexible Transceiver Array for Cardiac MRI at 7 T: Performance Evaluation on a Torso Phantom Sajad Hosseinnezhadian1,2, Roberta Frass-Kriegl2, Sigrun Goluch2, Michael Pichler2, Jürgen Sieg2, Marie Poirier-Quinot1, Luc Darrasse1, Ewald Moser2, Jean-Christophe Ginefri1, and Elmar Laistler2 1IR4M (Imagerie par Résonance Magnétique Médicale et Multi-Modalités), Univ. Paris-Sud, CNRS, Université Paris-Saclay, Orsay, France, 2Division MR Physics - Center for Medical Physics and Biomedical Engineering, Vienna, Austria A flexible 12-channel transceiver transmission line resonator (TLR) array for 7 T cardiac 1H MRI compatible with parallel transmission systems was developed. The size of the array is 38  cm x 28.5 cm with individual TLRs of 84 mm diameter. A decoupling ring-based inter-element decoupling technique was used where the basic TLR geometry is surrounded by a conducting ring. Its efficiency was demonstrated with the array bent on a torso phantom and a human torso (Sij < -16 dB). Acceleration factors up to 3 in bent configuration can be employed without significant SNR degradation (g-factor < 1.6).

 1707 Sensitivity Improvement of Quadrature Surface Coil using Isotropic Metamaterial Flat Lens Tejkiran A. Patil1, A. Sidhique1, Pulkit Sharma1, Rajesh Harsh1, and P. H. Rao2 1Indigenous Magnetic Resonance Imaging Laboratory, SAMEER, Mumbai, India, 2SAMEER-CEM, Chennai, India Metamaterial lens has previously been used to improve the sensitivity of phased array coils and the improvement is specifically seen at the epicenters of the loops and a sharper notch is formed at the critical overlapping region because of  high resolving capability of the lens and it is not desirable for larger field of view (FOV). This work proposed a novel concept of nearly constant improvement in receiver sensitivity over the FOV using a combination of both metamaterial flat lens and quadrature surface coil.

 1708 A 12-Channel Degenerate Birdcage Body Transmit Array Coil for 1.5T MRI Scanners Ehsan Kazemivalipour1,2, Alireza Sadeghi Tarakameh1,2, Ugur Yilmaz2, Volkan Acikel3, Bulent Sen3, and Ergin Atalar1,2 1Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey, 3Aselsan, REHIS Power Amplifier Technologies, Ankara, Turkey In this work, we designed and manufacture a 12-channel body birdcage degenerate transmit array coil. After determining the size of the coil, the trace thickness for each of the conductors and the location of the capacitors, an EM solver is used to find the equivalent circuit model of the coil. The capacitor values are tuned by solving the circuit model and recalculating the EM model iteratively. After reaching the minimum total reflection of 14%, we constructed the 12-channel body degenerate birdcage transmit array coil. The strongest coupling was observed between adjacent channels measuring as -15.7 dB.

 1709 A double resonant (1H/23Na) whole-body RF system for MRI at 3T Matthias Malzacher1, Nadia Paschke1, Jorge Chacon-Caldera1, and Lothar R. Schad1 1Computer Assisted Clinical Medicine,Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany 23Na MRI keeps increasingly demonstrating diagnostic value in a multitude of studies and clinical applications due to its capability to provide information on tissue viability. In order to co-register 23Na and 1H MR images, a double resonant 23Na/1H RF system is the optimal solution. In this work we present a clinical double-resonant RF system consisting of a shielded 23Na BC coil, a 16 channel 23Na Rx array and a local 1H Helmholtz coil inside the shielded 23Na BC coil. The complete system is demonstrated in EM simulations and initial feasibility measurements are performed.

 1710 300 W Modified Class-E RF Amplifiers for 64 MHz Transmit Array System Fatima tu Zahra1,2, Bismillah Nasir Ashfaq1,2, Berk Silemek2, Ugur Yilmaz,2, Redi Poni3, and Ergin Atalar1,2 1Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey, 3ValoTec,Engineering Consultant, Paris, France In this work, highly efficient 300 W digitally controlled supply-modulated Class-E amplifiers for two-channel RF transmit array are presented. Load pull analysis is performed for load optimization purposes. Coupling between the transmit coils is measured to be 8% when 12 cm diameter coils are placed with a distance of 7 cm. The performance of amplifiers while working simultaneously at same frequency and at different frequencies is evaluated.  MR experiments are conducted and it is observed that MR images show no artifact in the presence of amplifier near transmit coil inside the scanner.

 1711 Ideal Coil Decoupling in Receive Arrays using Negative Resistance Preamplifiers Daniel Højrup Johansen1, Juan D. Sanchez-Heredia1, Vitaliy Zhurbenko1, and Jan H. Ardenkjær-Larsen1,2 1Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark, 2GE Healthcare, Brøndby, Denmark This work presents the method of achieving ideal decoupling between elements in a receive coil array. Generally, preamplifier decoupling is limited by nonidealities of the implemented components. It is shown analytically and numerically, that for the ideal (lossless) matching circuits the input resistance of the preamplifier should be zero, while for the realistic lossy case a small negative resistance can be used to achieve ideal decoupling. Here we use a negative input resistance preamplifier (NIRP) to compensate for the loss of the circuit. The analysis is verified experimentally showing a decoupling of -62 dB when a NIRP with an input resistance of -0.023 Ω is used.

 1712 Using Noise Waves for Simulation and Measurement of Array SNR Penalty due to Passive Impedance Match Arne Reykowski1, Christian Findeklee2, Paul Redder1, Tracy Wynn1, Tim Ortiz1, Randy Duensing2, and Scott B King1 1Invivo Corporation, Gainesville, FL, United States, 2Philips Research, Hamburg, Germany Active impedance matching versus passive impedance matching of array coils is a concept well understood when designing transmit arrays. Lesser known however is that this concept also applies to receive arrays. Even though it appears that preamplifiers are noise matched to the passive port impedance (usually 50 Ohms), preamplifier noise coupling creates active noise match impedances which are mode dependent. In this context, a mode is defined by a signal vector and the corresponding weighting factors for optimum combined SNR.  We use coupled noise waves to explain by simple concepts how the weighted and combined coupled noise changes the active noise match impedance.

 1713 Micro-strip Surface Coils Using Fractal Geometry for 129Xe Lung Imaging Applications Olga M. Dona Lemus1, Norman B. Konyer2, and Michael D. Noseworthy2,3 1McMaster University, Hamilton, ON, Canada, 2Imaging Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada, 3Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada We compared a fractal patterned micro-strip surface coil with a simple circular micro-strip surface coil for hyperpolarized 129Xe lung imaging applications. Both patterns were simulated using a finite element solver and electric and magnetic fields were calculated in the surface coil and adjacent air volume. The fractal-patterned coil showed relatively higher magnetic field compared to the circular coil in both the micro-strip surface and the air volume. Although, further simulations are required, fractal-patterned designs of MRI coils could offer specific improvement in signal penetration and magnetic field homogeneity.

 1714 A Dual-Tuned 70 cm Whole-Body Resonator for 13C and Proton MRI/MRS at 3T Ed Boskamp1, Zhentian Xie2, Victor Taracila1, Amy Stephen2, Mike Edwards2, Tim Skloss2, Ralph Hurd3, Fraser Robb1, and Joe Murphy-Boesch4 1G. E. Healthcare Technologies, Aurora, OH, United States, 2G. E. Healthcare Technologies, Waukesha, WI, United States, 3Radiological sciences lab, Stanford University, Palo Alto, CA, United States, 4NINDS-NIH, Bethesda, MD, United States Hyperpolarized 13C enhances the SNR of signals from 13C metabolites.  Separate transmit and receive coils are inserted into the magnet bore to image 13C, limiting patient space.  Here, a dual tuned 13C /1H body coil is developed that is capable of imaging both proton and 13C in one exam. The coil has the same 70 cm inner diameter as the standard body coil and can be used stand-alone as the Tx/Rx coil, or as the transmit coil for proton and 13C receive arrays. The efficiency for proton excitation is comparable to that of the standard proton only body coil.

 1715 High precision MR-TEM cell for in-situ calibration of RF field probes in clinical MR systems Frank Seifert1 and Bernd Ittermann1 1Physikalisch-Technische Bundesanstalt (PTB), Braunschweig und Berlin, Germany An MR-TEM cell is a transverse electromagnetic (TEM) cell operated as a Tx/Rx coil directly inside an MR scanner. From a precise flip angle measurement in a tiny sphere of water the RF electric field inside the cell can be determined using the TEM condition |E|=2c0|B1+|. Thus, an MR-TEM cell can be utilized for the calibration of RF E- and H-field probes as well as for the determination of the RF voltages and RF currents at its ports which is important e.g. for experimental validation of simulation results in RF safety research. We report here on the high precision flip angle calibration of an MR-TEM cell with 0.1% uncertainty.

 1716 Dual-resonant helmet coil for 1H/31P at 3T MRI Suk-Min Hong1, Chang-Hoon Choi1, Jörg Felder1, and N. Jon Shah1,2 1Institute of Neuroscience and Medicine – 4, Forschungszentrum Jülich, Jülich, Germany, 2Department of Neurology, Faculty of Medicine, RWTH Aachen University, JARA, Aachen, Germany The partial volume helmet coil is the intermediate coil type between surface coil and volume coil in terms of SNR and B1 uniformity. The helmet coil was introduced to increase the filling factor leading to increasing SNR. In this study, we modified the helmet coil geometry by inserting additional ring to achieve a dual resonance, which is tuned for 1H/31P. The feasibility of dual-tuned helmet coil was evaluated by simulation and MR measurement, and the results were compared with those acquired by commercial single- and dual-tuned birdcage coils.

 1717 A genuine design for a dual-tuned $^{1}H/^{31}P$ coil with no lumped elements operating at 4.7T Anna Hurshkainen1, Anton Nikulin1, Stanislav Glybovski1, Christophe Vilmen2, Marc Dubois3, Djamel Berrahou3, Stefan Enoch3, Irina Melchakova1, Pavel Belov1, Redha Abdeddaim3, and David Bendahan2 1Department of Nanophotonics and Metamaterials, ITMO University, Saint-Petersburg, Russian Federation, 2CNRS/CRMBM, Aix-Marseille University, Marseille, France, 3CNRS/Institute Fresnel, Aix-Marseille University, Marseille, France For a wide range of MRI and MRS applications dual-tuned MR coils are used capable of multi-nuclear studies. Conventional ultra-high-field preclinical dual-tuned coils are either surface loops having high SNR over a limited FOV or volumetric coils with ultimate coverage compromised by low SNR while used in Tx and Rx regimes. In this contribution we propose an alternative design of the dual-tuned 1H/31P coil based on an open self-resonant periodic structure, which doesn’t require variable lumped capacitors for tuning and matching. It has been shown that the proposed coil is suitable for studying energetics in human forearm muscles at 4.7T.

 1718 Decoupling strategies for Double Tuned Radio Frequency coils at 7T F. Maggiorelli1, E. B. Boskamp2, A. Retico1, G. Tiberi3, J. D. Kaggie4, F. Robb5, and M. Tosetti3 1Pisa Division, National Institute of Nuclear Physics, Pisa, Italy, 2GE Healthcare, San Diego, CA, United States, 3IRCCS Stella Maris, Imago7 Foundation, Calambrone,Pisa, Italy, 4University of Cambridge, Cambridge, United Kingdom, 5GE Healthcare, Aurora, OH, United States Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) with nuclei different from protons, often require the acquisition of proton signal for shimming and co-registration procedures. For this purpose Double Tuned Radio Frequency (DT-RF) coils are needed. The drawback of DT-RF coils is basically the coupling between the two resonant structures, which reduces SNR and increases focal heating. The aim of this study is to compare active and passive decoupling strategies in terms of Q factor and S21 parameter. Workbench measurements show that PIN Diode active decoupling is an interesting alternative for DT-RF coils.

 1719 Optimization study of a double-tuned nested birdcage RF coil for 1H/23Na MRI Angelo Galante1,2,3, Marco Fantasia1,2,3, and Marcello Alecci1,2,3 1Life, Health and Environmental Science, L'Aquila University, L'Aquila, Italy, 2Laboratori Nazionali del Gran Sasso, Istituto Nazionale di Fisica Nucleare, L'Aquila, Italy, 3Istituto SPIN-CNR, CNR, L'Aquila, Italy The nested birdcage design is useful to develop dual tuned volume transceiver RF coils. Despite its apparently simple design, coupling among coils affects the resonance frequencies, making its practical realization cumbersome. FEM simulations were first validated by workbench measurements for a specific nested double-birdcage suitable for 1H/23Na MRI at 2.35T. Then were used to study the isolation and RF efficiency for a set of different geometrical parameters. We demonstrate that an optimized nested design is obtained if the disposition of the birdcages rugs, lengths and shield diameter are carefully taken into account.

 1720 The Design of A Short Solenoid with Homogeneous B1 for A Low-field Portable MRI Scanner Using Genetic Algorithm Zhi Hua Ren1 and Shao Ying Huang1 1Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore A short solenoid that provides field homogeneity with relatively low inductance and low length-to-radius ratio was successfully designed and validated to work in a Halbach array based portable MRI scanner. The optimization is done by applying genetic algorithm and by using Bio-Savart Law as a forward calculation model. The optimized design shows advantages of much higher homogeneity with a practically small length-to-radius ratio compared with a constant-pitch solenoid.

 1721 Remote tuning and matching of a non-resonant wire loop J. Rock Hadley1, Laura Slusser1, Robb Merrill1, and Dennis L. Parker1 1Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States There are several situations, such as some interventional applications or intracavitary placement, where it would be desirable to remotely tune and match a local RF coil. Although remote lumped element placement will result in decreased SNR, it is likely that net loss in SNR may be a function of the designs used. This study investigated the SNR trade-off of different methods of remote tuning by comparing the SNR that could be achieved with the placement of lumped elements at the coil. A large variation in SNR based on method was observed.

 1722 Endoluminal coil-sensitivity degradation with the coil-orientation effect with respect to B0 field: preliminary results HAMZA RAKI1,2, SIMON A. LAMBERT1, KEVIN TSE VE KOON1, HENRI SOUCHAY2, FRASER ROBB3, ISABELLE SANIOUR1, and OLIVIER BEUF1 1Univ. Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69000, LYON, France, 2General Electric Healthcare, Buc, France, 3General Electric Healthcare, Aurora, OH, United States Single-loop endoluminal RF-coils are a possible solution for the SNR limitations of external coils. However, they suffer from signal variations due to the coil sensitivity dependence with the coil orientations with respect to the B0 field. We simulated (electromagnetic simulations with Feko) an RF-coil along the Ox axis (0°) taken to be that of the B0 field and for specific coil orientations (30, 45, 60 and 90°) around and in oblique position with respect to the Ox axis (B0). We then evaluated the signal distribution (H-field 2D map) variation with the coil orientations to can propose an adequate architecture.

 1723 Tunable Phase Shifters and Ratio-adjustable Power Splitters for Array-compressed Parallel Transmission and MR Fingerprinting Charlotte R Sappo1,2, Xinqiang Yan2,3, and William A Grissom1,2,3,4 1Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University of Imaging Science, Vanderbilt University, Nashville, TN, United States, 3Department of Radiology, Vanderbilt University, Nashville, TN, United States, 4Department of Electrical Engineering, Vanderbilt University, Nashville, TN, United States Array-compressed parallel transmission was recently proposed as a way to reduce the number of RF power amplifiers required for many-coil parallel transmission [1]. This is achieved by connecting a large number of coils to a small number of amplifiers via an array compression network that implements optimized coil-to-channel combinations using ratio-adjustable power splitter (RAPS) circuits [2,3] and phase shifters. Currently, the RAPS circuit ratios are determined by tuning coaxial cable lengths within the RAPS circuit (Figure 2), but this prevents dynamic switching of the compression weights via remote tuning. Remotely tunable RAPS circuits and phase shifters would also be useful for dynamic mode switching in MR fingerprinting [4,5]. To achieve this, here we describe the design and validation of a quad hybrid-based phase shifter that can be tuned by varying terminating capacitors, and integrate it into a RAPS circuit. Bench tests and 7T imaging and B1+ mapping experiments were performed to validate the phase shifters and new RAPS circuit design.

 1724 A low cost Internet of Things solution for real time magnetic field measurement for MRI polarization coils using a computer numeric control machine Priyanka Harish1, Likith P S1, Mamatha M R1, Meghana S1, Vikas Vasisht A1, and Sairam Geethanath1,2 1Medical Imaging Research Center, Dayananda Sagar Institutions, Bengaluru, India, 2Department of Radiology, Columbia University Medical Center, New York, NY, United States An Internet of Things solution for real time Magnetic Field Measurement of polarization coils using Computer Numeric Control (CNC) machine was developed in order to automatically map the static magnetic field at a low cost ($722). The results were transformed into a visualization report of the magnetic field and uploaded on the cloud server. This report can be accessed by any authorized user with an internet connection from any device, to conduct further analysis. The magnetic field measuring CNC is a multipurpose 3-axis robotic system which can be equipped with other field probes to serve as a multi-parametric measurement device.  1725 Optoelectronical-based multiplexed transmission of analog signals in a magnetic environment. Christophe Vilmen1, Louis Bortoli1,2, Evan Gallouin1,3, Maxime Guye1,4, Monique Bernard1, David Bendahan1, and Alexandre Fouré1 1Aix-Marseille Univ, CNRS, CRMBM, Marseille, France, 2Aix-Marseille Univ, Polytech° Marseille, Ecole d'ingénieurs, Marseille, France, 3ESTIA Ecole supérieure des technologies industrielles avancées, Bidart, France, 4APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France This study describes the methodological developments to both convert and transmit several mechanical signals in a magnetic environment (3T Verio Siemens) as optical signals. Multiple sensors were connected to a MR-compatible ergometer used to assess dynamic knee extensions kinetics. The corresponding signals were analog to digital converted and transmitted as optical signals through a single optical fiber. The quality of mechanical and 31P MR spectroscopy (31P-MRS) signals remained high and disclosed no adverse interference from the transducers ensuring both conversion and transmission. The multiplexed signals transmission allowed an accurate assessment of human movement kinetics in a magnetic environment.  1726 Pulseq-GPI Compatible console for 9.5mT MRI system Syed Saad Siddiq1, Sneha Potdar1, and Sairam Geethanath1,2 1MIRC, Dayananda Sagar Institutions, Bangalore, India, 2Department of Radiology, Columbia University Medical Center, New York, NY, United States A cost effective console, compatible with Pulseq-GPI has been designed for 9.5mT using general purpose microcontroller boards. Data from Pulseq-GPI was extracted in a text file and uploaded on the microcontroller to play the gradient waveforms (Gx, Gy) and radio frequency (RF) pulses, with a dwell time of 5us. Current work involves integration of Analog to Digital Convertor (ADC) for Gradient Recalled Echo (GRE) sequence and reducing the time required to upload the waveforms for the entire sequence. Future work involves interfacing the console with coil driver apparatus to integrate with 9.5mT lab MRI systems.  1727 10µm isotropic voxels acquired with a CMOS-based planar microcoil at 14.1T: Preliminary results Marlon Arturo Pérez Rodas1,2, Jonas Handwerker3,4, Hellmut Merkle1, Rolf Pohmann1, Jens Anders3,4, and Klaus Scheffler1,5 1High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Graduate Training Centre of Neuroscience, IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany, 3Institute of Microelectronics, University of Ulm, Ulm, Germany, 4Institute of Theory of Electrical Engineering, University of Stuttgart, Stuttgart, Germany, 5Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany The quest for high resolution MR have push the technology to miniaturization. Thus, microcoils have been used for imaging with very high resolution. Here, we have designed and constructed a fully integrated CMOS NMR transceiver containing an on-chip microcoil, integrated amplifiers and demodulator for the high-frequency MR signal. In the present work, the initial microimaging results of this fully-integrated NMR transceiver in a 14.1 T animal scanner are presented. The on-chip microcoil allows imaging with a spatial resolution down to 10 µm with an SNR of 64 and with an improvement in SNR/volume ratio of 150 compared to a 10 mm surface coil.  1728 High Definition Sodium (23Na) In Vivo MRI of the Human Eye at 7.0 Tesla: Need for Substantially Enhanced Spatial Resolution than Commonly Used in Brain MRI Daniel Wenz1, Andre Kuehne2, Till Huelnhagen1, Armin M. Nagel3,4, Helmar Waiczies2, Oliver Stachs5, Erdmann Seeliger6, Bert Flemming6, and Thoralf Niendorf1,2 1Berlin Ultrahigh Field Facility, Max Delbrueck Centrum, Berlin, Germany, 2MRI.TOOLS GmbH, Berlin, Germany, 3Institute of Radiology, Unviersity Hospital Erlangen, Erlangen, Germany, 4Division of Medical Physics in Radiology, German Research Centre (DKFZ), Heidelberg, Germany, 5Department of Ophthalmology, University of Rostock, Rostock, Germany, 6Institute of Physiology, Charite University Medicine, Berlin, Germany Sodium ions are crucial in the physiology of human eye and its compartments like vitreous humor, aqueous humor, lens and retina. In this work we used a six-channel transceiver array dedicated for ocular 23Na MRI and obtained in vivo images of the eye of exceptional quality with enhanced spatial resolution like (1.0x1.0x1.0) mm3 and demonstrated why spatial resolutions currently used for sodium MRI of the human brain are not sufficient in the context of 23Na in vivo MRI of the human eye. Enhancing spatial resolution is essential to investigate changes of sodium concentration in subtle eye compartments (aqueous humor, lens).  1729 A 3D printed lung phantom for exploration of the limits of 19F-C3F8 ventilation imaging resolution and SNR Adam Maunder1, Fraser Robb1,2, Madhwesha Rao1, and Jim Wild1 1POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom, 2GE Healthcare Inc., Aurora, OH, United States Fluorinated gas imaging is a complementary method to hyperpolarized gas ventilation imaging, but suffers from lower SNR by virtue of low spin density and thermal polarisation. We present a 3D printed lung phantom based on a gold standard lung ventilation scan acquired from 3He MRI used to explore the limits of fluorinated gas MR in terms of spatial resolution and SNR. Images acquired with unrealistically long imaging times for in-vivo exams were compared to lower resolution images. The results demonstrate that resolutions obtainable with in-vivo fluorinated gas imaging miss potentially important spatial variation information.  1730 Clinical Improvement of 19F Image Sensitivity using the Inductive Coupling at 7.0T Animal MRI Bu S Park1, Sunder S Rajan2, and Brenton McCright1 11Division of Cellular and Gene Therapies, FDA/CBER/ Office of Tissues and Advanced Therapies, Silver Spring, MD, United States, 2Biomedical Physics, FDA/CDRH/Office of Science and Engineering Laboratories, Silver Spring, MD, United States We present numerical simulations and experimental validation data testing the feasibility to improve 19F image sensitivity of perfluorocarbon labeled cells using the secondary resonator tuned at 287 MHz to make an enhancing induced RF magnetic field (B1) at 7.0T 19F/1H MRI. The numerical simulation results of |B1+| and corresponding experimental 19F images without and with the secondary resonator tuned at 287 MHz show the improvement of |B1+| and 19F image uniformity. To model a potential clinical application, we used inductive coupling MR to image 19F perfluorocarbon labeled cells encapsulated in polyethylene glycol (PEG) after their transplantation into mice.  1731 A Tool For Rapid Power Analysis for Arbitrary Circular Surface Coil Near Arbitrary Spherical Sample at Any Frequency Giuseppe Carluccio1,2, Karthik Lakshmanan1,2, and Christopher Michael Collins1,2 1Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York, NY, United States, 2Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York, NY, United States We present a tool to quickly estimate the noise induced by the resistance of a surface coil and the noise induced by the coil in a sphere. The tool relies on two analytical solutions, and results depend on many parameters. We show plots of the dissipated power in the sample and the coil as function of some of these parameters such as the diameter of the coil, the distance of the coil from the sphere and the wire diameter of the coil. The tool can be useful in the design process of coils, especially dense receive arrays.  1732 Nested Birdcage Receive Array for Simultaneous Multislice EPI Kenneth M Bradshaw1, Daniel Sheltraw2, Greyson Tarbox3, and Ben Inglis4 1ECEn Department, Brigham Young University, Provo, UT, United States, 2University of California - Berkeley, Berkeley, CA, United States, 3ECEn, Brigham Young University, Provo, UT, United States, 4UC BerkeleyUniversity of California - Berkeley, Berkeley, CA, United States We present a novel RF coil design that is capable of simultaneous multi-slice (SMS) echo planar imaging (EPI) for functional MRI along the z axis at 3 T, while maintaining high in-plane (x-y) homogeneity to minimize the effects of receive field contrast on subject motion and motion correction. The coil is symmetric and is open front and rear, making it compatible with fMRI stimulus devices including transcranial magnetic stimulation (TMS) coils.  1733 A new dual-mode RF-coil array element for 7T MRI based on dipole antennas Georgiy Solomakha1, Stanislav Glybovski2, Alexander J.E. Raaijmakers3, Constantin Simovski 4, Alexander Popugaev5, Irina Melchakova2, Pavel Belov2, and Redha Abdeddaim6 1Depatment of Nanophotonics and metamaterials, ITMO University, Saint-Petersburg, Russian Federation, 2Nanophotonics and metamaterials, ITMO University, Saint-Petersburg, Russian Federation, 3Department of Radiology, UMC Utrecht, Utrecht, Netherlands, 4Electronics and Nanoengineering, Aalto University, School of Electrical Engineering, Helsinki, Finland, 5RF and SatCom Systems, Fraunhofer Institute for Integrated Circuits IIS, Erlangen, Germany, 6CNRS, Institut Fresnel, Aix-Marseille Universite, Marsel, France In this work, we demonstrate a new RF-coil for 7 Tesla ultrahigh ﬁeld MRI with two orthogonal channels to achieve better SAR and SNR of images. The ﬁrst phase of the work involves numerical study of diﬀerent multimode structures consisting of coupled electrical dipoles to form a radiofrequency coil that may operate both as a surface loop [1] or a single radiative electrical dipole [2] depending on the driven channel.  1734 Design of an electromagnetic actuator for magnetic resonance elastography Yuan Feng1, Xuefeng Zhao1, Suhao Qiu1, Mo Zhu2, Ping Shen2, Shengyuan Ma1, Chun-hong Hu2, and Liang Guo2 1Soochow University, Suzhou, China, 2the First Affiliated Hospital of Soochow University, Suzhou, China We introduced a novel design of electromagnetic actuator for magnetic resonance elastography. The actuator consists of a vibration control module and an actuation module. The actuation frequency and magnitude were manually tuned in a control panel of the control module. The actuation module could be easily converted to imaging phantom, organs of the abdomen region and the brain. Results showed a steady elastic wave propagation at gel phantom, liver, and brain tissues.  1735 MR-Compatible, Organic Light-Emitting Diode (OLED) display for functional MRI YunKyoung Ko1, Seond Dae Yun1, Jörg Felder1, Chang-Hoon Choi1, and N.Jon Shah1 1Institute of Neuroscience and Medicine - 4, Juelich, Germany Functional MRI (fMRI) frequently relies on visual stimulation. In this study, we designed and implemented a MR compatible display unit based on organic light-emitting diodes (OLED) and evaluated its performance on a 3T clinical MRI scanner by carrying out a visual block-paradigm fMRI experiment using the OLED display. The OLED display was successfully operated during the MR measurements. And an fMRI examination was successfully demonstrated with a visual functional study using the OLED display.  1736 Ultra-low power transmitter for encoding non-MR signals in Magnetic Resonance (MR) recordings Jan Raagaard Petersen1, Jan Ole Pedersen1,2, Vitaliy Zhurbenko1, Jan Henrik Ardenkjær-Larsen1, and Lars G. Hanson1,2 1Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark, 2Research Centre for Magnetic Resonance, Dept 714 Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark Advancing Magnetic Resonance Imaging (MRI) technology requires integration of the MRI scanners with sensors and systems for monitoring various non-MRI signals. In this paper, we present design and integration of a low power AM radio transmitter into a 3T MRI scanner, which can be used for efficient collection of data from non-MRI sensors. The transmitter consumes only 1.3mW while transmitting 2.7µW at 120MHz with high frequency stability. The presented design is useful in low power applications requiring high frequency stability and is intended for wireless transmission of non-MR signal recordings during MRI scanning. Traditional Poster ### PET & Hybrid Systems  Exhibition Hall 1737-1743 Tuesday 13:45 - 15:45  1737 Development of a radiolucent 64-channel on-body receive array to enhance image quality of the MR-linac Stefan E. Zijlema1, Luca van Dijk1, Sara L. Hackett1, Jan J.W. Lagendijk1, Rob H.N. Tijssen1, and Cornelis A.T. van den Berg1 1Radiotherapy, UMC Utrecht, Utrecht, Netherlands To improve the spatiotemporal resolution of 3D imaging on the MR-linac, we are developing a new radiolucent 64-channel receive array, which can be placed directly onto the patient during treatments. Coil prototypes caused no significant dosimetric changes. Measurements with 4-channel prototypes showed that overlapping coil loops lead to the highest potential imaging performance. Imaging comparisons with the current MR-linac array showed that the signal-to-noise ratio is improved.  1738 Concentric PET shields and wide-bore 1.5 T MR birdcage for optimal MR and PET signal Deb Rivera1,2, Erik R Huijing3, Cezar Alborahal2,4, Flavio Meliado3,5, Bart Steensma3, Thomas Dey6, Volkmar Schulz7, Björn Weißler7, E Versteeg3, Hugo de Jong3, Martino Borgo8, Michel Italiaander2, and Dennis Klomp2,3 1Academic Medical Center, Amsterdam (AMC), Amsterdam, Netherlands, 2MR Coils BV, Zaltbommel, Netherlands, 3University Medical Center Utrecht (UMCU), Utrecht, Netherlands, 4MR Focus BV, Zaltbommel, Netherlands, 5MR Code BV, Zaltbommel, Netherlands, 6Rheinisch-Westfaelische Technische Hochschule Aachen, Aachen, Netherlands, 7Rheinisch-Westfaelische Technische Hochschule Aachen, Aachen, Germany, 8Furtura, Heerhugowaard, Netherlands Prioritizing signal fidelity for PET and MR, we simulated, built, and tested a wide-bore 1.5T body coil with a concentric ring of novel PET shields. With such an approach, the inherent reduced transmit efficiency can be compensated for by applying more power. Through B1+ measurements in phantoms and in the head, we validate that dual RF power amplifiers meet the power requirements.  1739 Design and evaluation of RF coils for hybrid MR-PET imaging of the prostate Chang-Hoon Choi1, Karl Ziemons2, Tim Felder1,2, Hans-Peter Wegener2, and N. Jon Shah1,3 1Forschungszentrum Juelich, Juelich, Germany, 2Faculty of Medical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Juelich, Germany, 3Faculty of Medicine, Department of Neurology, RWTH Aachen University, JARA, Aachen, Germany Prostate cancer is one of the most common diseases in men, and using multimodality, hybrid systems, such as MR-PET provides valuable data for early diagnosis. A human prostate is quite flexible and can move into different positions under external conditions so it is important to localise the critical region-of-interest using both MRI and PET under the same circumstances. In this study, we focused on various MRI RF coil designs suitable for use in MR-PET prostate imaging, and investigated their performance by evaluating SNRs and penetration depths as a function of coil tilting angle against B0.  1740 A comprehensive study on electrically floating PET insert for efficient RF penetrability at 3 T MRI system Md Shahadat Hossain Akram1, Craig S. Levin2, Takayuki Obata1, Genki Hirumi1, and Taiga Yamaya1 1National Institute of Radiological Sciences, Japan, Chiba, Japan, 2Stanford University, Stanford, CA, United States A comprehensive experimental study has been conducted on the geometrical aspects of electrically floating radio frequency (RF) penetrable PET inserts to improve the RF penetration efficiency for acceptable MR imaging performance. Several one ring and two ring PET insert prototypes were used to do experiments in a 700-mm bore diameter 3 T clinical MRI system with a homogeneous cylindrical phantom. Study results provide guidance for optimized PET ring design for efficient RF field penetration inside the shielded ring.  1741 MR Compatibility of MADPET4: A Small Animal PET Insert for a 7T MRI System Geoffrey Topping1, Negar Omidvari1, Jorge Cabello1, Stephan Paul2, Markus Schwaiger1, and Sibylle Ziegler1,3 1Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany, 2Physics, Technical University of Munich, Garching, Germany, 3Nuclear Medicine, University Hospital of LMU Munich, Munich, Germany The impacts of operating a small animal PET insert in a 7T MRI system were studied. The MRI's performance was compared with and without the insert by measuring the static field, flip angle distribution, RF noise, and several imaging sequences with two RF volume coils. With the insert inside a large 1H volume coil, the MR was limited to T1-weighted anatomical imaging, and required a surface receive coil for adequate SNR. With the insert enclosing a small 1H/13C volume coil, the primary impact on MRI was up to 38% reduced SNR, and all tested MRI sequences were functional.  1742 Low cost Earth Field NMR Spectrometer with improved Shimming (LESS) Chennagiri Rajarao Padma1, ThejasVishnu Ramesh1, Syed Saad Siddiq1, Darshan Shivaramu Keelara1, and Sairam Geethanath1,2 1MIRC, Dayananda Sagar Institutions, Bengaluru, India, 2Department of Radiology, Columbia University Medical Centre, New York, NY, United States A simple, portable and low cost Earth’s Field NMR (EFNMR) spectrometer with improved shimming has been demonstrated. Basic NMR principles such as signal transmission, signal detection, and the pulse sequence for MR signal formation have also been demonstrated. The EFNMR spectrometer has been benchmarked with the commercially available Terranova system. The spectrometer was designed with inexpensive and readily available electronic components, costing less than$130. The current work focuses on improving the signal-to-noise ratio of the system using conventional shimming methods, which is a challenge in ultra-low field systems. Future work involves incorporation of gradients and time-shared pulse sequence design.

 1743 A New Yokeless Permanent Magnet Array with High Field Strength and High Field Homogeneity for Low-field Portable MRI System Zhi Hua Ren1, Wen Chuan Mu1, and Shao Ying Huang1 1Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore Permanent magnet array is a good candidate for providing the main magnetic field for a low-field portable MRI system. In this abstract, we present the design of a new yokeless permanent magnet array that generates a longitudinal magnetic field with a significant increase in field strength and in homogeneity compared to a traditional two-ring structure. It is compatible with existing RF coils thus the advancement in coil designs can be applied. The optimization was done based on genetic algorithm and a current model which shows much higher calculation efficiency than finite element method. The effectiveness of the optimization is validated by realistic simulations using COMSOL.

### Pre-Clinical

 Exhibition Hall 1744-1749 Tuesday 13:45 - 15:45

 1744 3-Fold SNR Enhancement of Small Animal ${^1}{^3}$C MRI using a Cryogenically Cooled (88 K) RF Coil Juan Diego Sánchez-Heredia1, Daniel Højrup Johansen1, Rafael A. Baron1, Matthias Schneider2, Gabriele Spörl2, Jarek Wosik3, Vitaliy Zhurbenko1, and Jan H. Ardenkjær-Larsen1 1Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark, 2Institut für Luft- und Kältetechnik gemeinnützige GmbH, Dresden, Germany, 3Electrical and Computer Engineering Department, University of Houston, Houston, TX, United States SNR in hyperpolarized 13C MRI is often limited by the low sensitivity of the receive RF chain at the low Larmor frequency of 13C. In this study we present an RF transparent (non-metallic) cryostat designed for small animal imaging, which allows a coil temperature of 88 K, with a coil-to-sample distance below 3 mm. Performance of the cryostat equipped with a 30 x 40 mm2 13C surface coil (3 T, 32 MHz) was tested and 3-fold SNR gain over room temperature coil was achieved.

 1745 A coil-noise-dominated flexible array inside a whole-head coil to improve temporal SNR in non-human primate imaging Kyle M Gilbert1, Peter Zeman1, Jorn Diedrichsen2, Julio C Martinez-Trujilloc3, J Andrew Pruszynski3, and Ravi S Menon1 1Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, ON, Canada, 2Department of Computer Science, The University of Western Ontario, London, ON, Canada, 3Department of Physiology and Pharmacology, The University of Western Ontario, London, ON, Canada Typically, coil elements or arrays are dispersed on a two-dimensional surface to ensure their sensitivity profiles do not overlap, since correlated noise mitigates an SNR improvement when overlapping coils are operating in the sample-noise-dominated regime. In this study, we show that a small flexible array, operating in the coil-noise-dominated regime, can locally improve temporal SNR when placed inside a whole-head array. The two concentric arrays are inductively decoupled using preamplifier decoupling, and the contribution of coil noise to the overall noise reduces the noise correlation. Up to a two-fold increase in temporal SNR is achieved in the motor cortex.

 1746 Feasibility test of magnetron surface coil for preclinical MRI at 11.7 T Sergio E Solis-Najera1, Fabian Vazquez1, Rodrigo Martin1, Oscar Marrufo2, and Alfredo Odon Rodriguez3 1Department of Physics, Faculty of Sciences, UNAM, Mexico City, Mexico, 2Department of Neuroimage, INNN MVS, Mexico City, Mexico, 3Electrical Engineering Department, UAM Iztapalapa, Mexico City, Mexico A magnetron surface coil was developed for rodent MRI at 11.7 T. The prototype performance was Ql6.5=Qu, and, the noise figure was 1.6. Phantom images were acquired with the magnetron coil to prove its feasibility. A circular coil was also used to acquire phantom images for comparison purposes. A SNR roll-off comparison was computed and showed an improvement of the magnetron coil over the circular one. Image SNR values were also calculated showing a 28.14% improvement of our coil over the circular coil. These results demonstrate the versatility and feasibility of the magnetron design to be used at UHF MRI.

 1747 An 8 Channel Dipole Transmit Array and 8 Channel Loop Receive Array for Head Imaging of Non-Human Primates at 10.5T Russell Luke Lagore1, Lance DelaBarre1, Jerahmie Radder1, Noam Harel1, Essa Yacoub1, Edward J Auerbach1, Kamil Ugurbil1, and Gregor Adriany1 1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States Described herein is the design, construction, and testing of a head coil for imaging non-human primates at 10.5T. The coil is composed of an 8-channel decoupled dipole array for transmit and an 8-channel loop array for receive. We present preliminary transmit efficiency, SNR, noise correlation, and g-factor results for a phantom with immediate plans to acquire in vivo images. This coil is a proof of concept for higher channel count receive arrays of 16 or 24 loops for head imaging of non-human primates at 10.5T.

 1749 Development of an integrated RF coil and restraint system for awake rat scanning at 7T Dan Madularu1, Chathura Kumaragamage1, Axel Mathieu1, Sricharana Rajagopal1, and Jamie Near1 1McGill University/Douglas Hospital, Montreal, QC, Canada Research utilizing awake rodents has been conducted for the past 10-15 years, however limitations still exist surrounding this technique. Our goal is to build a restraining/RF coil system that circumvents some of the shortcomings present in existing systems, while allowing for the delivery of various stimuli during preclinical neuroimaging. The proposed design (i.e. TriCoil) has integrated access ports for binocular visual stimulation, gustatory and olfactory stimuli presentation, as well as intranasal delivery. SNR obtained with the TriCoil was superior to a volumetric RF coil for awake rat imaging, while a CO2 challenge yielded significant brain-wide BOLD changes.

### Gradients & Other Effects on B0

 Exhibition Hall 1750-1764 Tuesday 13:45 - 15:45

 1750 An actively-shielded planar gradient coil design scheme in limited coil-layer-placing space Yaohui Wang1, Xuegang Xin1, Lei Guo2, Zhifeng Chen1, and Feng Liu2 1South China University of Technology, Guangzhou, China, 2The University of Queensland, Brisbane, Australia A novel gradient coil design scheme was proposed for use in planar MRI systems. Unlike conventional scheme in a limited magnet pole-pole space which usually applies unshielded design, the novel strategy integrated a set of actively-shielded gradient coils in only four layers in the pole-pole space with the utilization of the system peripheral sections. The design largely improved the shielding effect of the gradient coils and meanwhile left adequate space for the patients and installation of cooling device. The design scheme did not significantly increase the system manufacturing complexity either.

 1751 High-performance of Multi-axes DWI sequences using Advanced Charge of Gradient power supply Sho Kawajiri1, Yuki Takai1, Motohiro Miura1, and Masashi Hori1 1MRI Systems Development Department, Toshiba Medical Systems Corporation, Tochigi, Japan Optimizing the energy distribution to the 3 axes output sections of the gradient power supply allows attaining high-performance Multi-axes DWI sequences. In this study, we propose an ‘Advanced Charge’ method for preferential energy supply with one axis emitting the largest fraction of output energy of all 3 axes. To realize it, the energy consumption simulation model for gradient power supply and gradient coil was updated accounting for the energy distribution to each individual axis. The new simulation model was implemented in the Advanced Charge control and the feasibility of high-performance of Multi-axes DWI sequences was then confirmed.

 1752 Calibration of Siemens MAGNETOM(TM) Terra 7T Shim System and Analysis of Static 3rd-order B0-Shimming of the Heart Using B0DETOX Michael Hock1, Maxim Terekhov1, David Lohr1, Maria Roxana Stefanescu1, Anja Schröder2, Heike Walles2, Christoph Juchem3, and Laura Maria Schreiber1 1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital, Wuerzburg, Germany, 2Translational Center Regenerative Therapies (TLC-RT), Fraunhofer Institute for Silicate Research (ISC), Wuerzburg, Germany, 3Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY, United States Susceptibility-induced field inhomogeneities in both space and time make B0-shimming a prerequisite for cardiac MRI at ultra-high field. All individual terms of the static 3rd-order spherical harmonics shim system were calibrated. Field mapping and calculation of shim currents are performed in customized B0DETOX software. Analysis of B0-inhomogeneities is later tested both in measurement of an ex-vivo pig heart and in-vivo in humans. The adjustment of the shim volume to the three measured slices in a healthy volunteer reduced the standard deviation of the field map by 4%, 19% and 18% compared to shimming of the global heart.

 1753 Interferences of local B0-shim coils and RF coils on a 3T MRI scanner Qiaoyan Chen1,2, Jo Lee1,2, Jianghong Wen1,2, Chao Zou1,2, Xiaoliang Zhang3,4, Xin Liu1,2, and Ye Li1,2 1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Shenzhen Key Laboratory for MRI, Shenzhen, China, 3Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 4UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States In this work, we quantitatively studied the impact of the local shim coil to RF coil in a combined B0 shim coil and RF coil system in terms of SNR, transmit B1+ and receive B1. By using the results as a design guideline, a 5-channel shim coil was constructed, of which interferences on RF coils were minimized with the appropriate shim coil diameters, number of turns and distances between the shim coil and the sample.

 1754 Comparison of patient bore tube supporting structures for a high-performance gradient whole-body MRI system to reduce acoustic noise Hiromitsu Takamori1, Kaoru Ikeda1, Shoji Ishizaki1, Kazuya Okamoto1, Hitoshi Kanazawa1, and Kazuto Nakabayashi1 1Yokohama Development Center, Toshiba Medical Systems, Yokohama, Japan A whole-body MRI scanner with high-performance gradient system produces loud acoustic noise during scan. In the present study we have evaluated the acoustic noise performance for a new gantry structure aimed at noise reduction with a vacuum chamber insert between the gradient coil cylinder and the patient bore tube cylinder. Two different supporting structures for the bore tube were compared. The method supporting the bore tube by means of a beam structure mounted on the feet of magnet scored better performance than the alternative method supporting it by short brackets mounted at the edges of magnet bore opening.

 1755 A feasibility study of ultra-high-strength gradient system on 3T: demonstration using DTI on anisotropic diffusion fibre phantoms Ming-Jye Chen1, Kuan-Hung Cho1, Chang-Hoon Choi2, Ezequiel Farrher2, Richard Buschbeck2, Hsuan-Han Chiang1, N. Jon Shah2,3, Hsu Chang1, and Li-Wei Kuo1 1Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 2Institute of Neuroscience and Medicine – 4, Forschungszentrum Juelich, Juelich, Germany, Juelich, Germany, 3Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany In this study, we aimed to integrate an ultra-high-strength gradient system (15 gauss/cm) on a 3T scanner and to demonstrate its feasibility by employing diffusion tensor imaging (DTI) on dedicated anisotropic diffusion fibre phantoms. Two DTI experiments were performed to explore the feasibility of this gradient system, i.e. comparisons of gradient strengths and number of averages. Our results demonstrate reasonable SNR and diffusion contrast acquired on this system using pulsed gradient spin echo diffusion weighted scans could provide useful information. Consistently, it also suggests higher gradient strength could be beneficial to improve the quality of diffusion MRI experiments and its ability to resolve fibre orientations, especially when higher b-values are used.

 1756 Driving Mutually Coupled Coils in Gradient Array Systems in Magnetic Resonance Imaging Koray Ertan1,2, Soheil Taraghinia1,2, and Ergin Atalar1,2 1National Magnetic Resonance Resarch Center (UMRAM), Bilkent University, ANKARA, Turkey, 2Department of Electrical and Electronics Engineering, Bilkent University, ANKARA, Turkey Gradient array systems recently have gained attention due to their various flexibilities and capabilities in different applications. Reducing the mutual-coupling between the coil elements is one of the constraints during the process of the coil design. However, by determining any existing coupling value between the array elements, required decoupling can be achieved. For a typical trapezoidal gradient current waveform, desired voltage values during rise/fall times, are recalculated considering all mutual-couplings between the array elements. This method is evaluated experimentally for different trapezoidal current combinations and can be used in any gradient array system with mutually coupled elements.

 1757 Design of breast gradient coil with the control of field nonlinearity Feng Jia1, Sebastian Littin1, stefan kroboth1, Huijun Yu1, Theresa Palm2, Frederik B. Laun2, Mark E. Ladd3, and Maxim Zaitsev1 1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 3Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany High performance gradient coils are required to assess the tissue microstructure in human breast in vivo with diffusion-weighted imaging. A deisgn methodology of nonlinear breast gradient coil  is proposed to increase resultant gradient strength with the control of field nonlinearity. The method is tested by designing a unilateral breast gradient coil for diffusion weighting. The results are analysis to reveal new insights of coil designs.

 1758 A Bo Tapestry: MRI Magnet Technology, 1977-2017 Gregory Hurst1, Ewald Moser2, Martyn Paley3, and Franz Schmitt4 1Upstate Medical University, Syracuse, NY, United States, 2Medical University of Vienna, Vienna, Austria, 3University of Sheffield, Sheffield, United Kingdom, 4Lakeside Imaging-e, Erlangen, Germany This is a preliminary report from a project to gather and organize an objective historical record of human MRI scanner technology.  This report spans magnet technology from 1977 to present (2017), covering about 100 magnets and scanners, and invites additional information.

 1759 Magnetic gradient mapping of a 3T MRI scanner using a modular array of novel three-axis Hall sensors Joris Pascal1, Nicolas Weber2,3, Jacques Felblinger2,3, and Julien Oster2,3 1FHNW, University of Applied Sciences and Arts Northwestern Switzerland, Muttenz, Switzerland, 2U947, Inserm, Nancy, France, 3IADI, Université de Lorraine, Nancy, France This paper presents a multi-point and modular magnetic field sensor system compatible with a 3T-MRI environment. The system features a three-axis magnetometer on a chip. This monolithic sensor is to our knowledge the only integrated sensor commercially available that provides full field vector information as well as sufficient dynamic range and acquisition rate for MRI-applications. We have validated experimentally our demonstrator through the measurement of static magnetic field and magnetic field gradients simultaneously acquired at nine locations within a MRI bore (Prisma, Siemens, Erlangen, Germany).

 1760 Switched Gradient Impulse Response Measurement with Uniform Excitation of Eigenmodes Magdoom Kulam1, Malisa Sarntinoranont1, William W Brey2, and Mareci H Thomas1 1University of Florida, Gainesville, FL, United States, 2National High Magnetic Field Laboratory, Tallahassee, FL, United States For pulsed field gradient experiments, it is important to characterize gradient switching to correct for errors in measured diffusivity and velocity resulting from imbalances in the gradient time integrals. Accurate characterization of the system requires the time derivative of the test gradient pulse mimic that of an impulse function which excite all the gradient eigenmodes uniformly. We introduce a new test pulse, called the Fresnel pulse whose derivative is a chirp function, which has a uniform spectrum like the impulse function. We also introduce a MR imaging based method to measure the spatiotemporal magnetic fields generated after the test pulse.

 1762 Optimization of a traversable wire path of a gradient coil for a magnetic resonance microscope Takahiro Nishigaki1, Shin-ichi Urayama2, Naozo Sugimoto1, and Tomohiro Ueno1 1Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan, 2Center for the Promotion of Interdisciplinary Education and Resarch, Kyoto University, Kyoto, Japan We designed 1 T/m gradient coils for a 14.1 T magnetic resonance microscope. The calculated contour wire pattern, however, should be transformed to a traversable wire path for actual construction. In this study, we optimized a connecting method by comparing three loop connecting patterns with the inside and outside return paths as a function of the transition size. We found that larger transition size in smooth parts of the loop reduced more the root mean square of deviations from the center gradient value. This optimization is applicable to gradient coils of larger size.

 1763 Biplanar PCB based Micro-Gradient-System-Insert for a Small Animal MRI Thomas Hüfken1 1Ulm University, Ulm, Germany MR microscopy demands dedicated gradient systems for providing sufficient spatial resolution, which can normally not be met on conventional small animal or whole-body systems. In this contribution a dedicated gradient insert based on a rather simple biplanar design realized with PCB technique is presented. The gradient shows excellent linearity and provides 1.2 T/m amplitude in continuous mode.

 1764 Gradient system characterization of a 1.5T MRI-Linac with application to UTE imaging Tom Bruijnen1, Bjorn Stemkens1, Jan J W Lagendijk1, Cornelis A T van den Berg1, and Rob H N Tijssen1 1Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands We characterize the gradient system of a hybrid 1.5T MRI-Linac, which has been developed as the ideal platform for MRI-guided radiotherapy. The system is equipped with a split gradient coil that potentially complicates reconstruction of non-Cartesian sequences such as ultra short echo time (UTE) imaging, which is a promising sequence for pseudo-CT generation and lung imaging. Here, we determine the zeroth and first spatial order gradient impulse responses. These are used to show that UTE imaging is feasible and image quality can be increased significantly using the gradient impulse response.

### Neonatal & Pediatric Neuroimaging

 Exhibition Hall 1765-1802 Tuesday 16:15 - 18:15

 1765 Towards a high-resolution MRI Atlas of the Human Foetus: a Post-Mortem Pilot Study of ex-vivo preserved Foetal specimens at 7 Tesla. Sean Lester Moen1, Anthony J Weinhaus2, Joseph M Metzger2, Michael Garwood3, Bharathi Jagadeesan3, and Pierre-François Van de Moortele3 1Neurosurgery, University of Minnesota, Minneapolis, MN, United States, 2Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States, 3Radiology, University of Minnesota, Minneapolis, MN, United States In an effort to expand the existing MRI reference material available to Medical professionals, including developmental anatomists, foetal specimens of gestational ages ranging from 7-26 weeks were scanned using ultra high field MRI systems ( 7 Tesla) and high resolution, multiplanar images of the whole body were obtained in each of these specimens. A unique set of processes, materials and equipment facilitated the execution of these MRI scans including custom built specimen holders, transmit and receive coils, protocol optimization and image reconstruction techniques.  Using these techniques, a total of 21 preserved ex-vivo fetal specimens were successfully scanned.

 1766 High-Resolution Radial Diffusivity Images Provide Insights of Fetal Brain Development Akiko Uematsu1,2,3, Keigo Hikishima4, Junichi Hata1,3, and Hideyuki Okano2,3 1Central Institute for Experimental Animals, Kanagawa, Japan, 2RIKEN Brain Science Institute, Saitama, Japan, 3Keio University School of Medicine, Tokyo, Japan, 4Okinawa Institute of Science and Technology, Okinawa, Japan Investigating prenatal neural development provide depth knowledge of brain ontogeny. DTI-derived radial diffusivity (RD) imaging has advantage to provide information of microstructural tissue organization information without damaging the tissues. In this study, we investigate the changes of the radial diffusivity (RD) values during fetal development in non-human primate. The RD image contrast was enough to clearly depict the emergence of each brain regions as well as major white matter bundles during prenatal period. In addition, its whole brain intensity distribution histogram provided the information of critical period for the growth of myelination.

 1767 Preeclampsia related to delayed development of white matter and cortical infolding. Ting Liu1, Miaomiao Wang1, Chao Jin1, Xianjun Li1, and Jian Yang1 1Department of Diagnostic Radiology, the first Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China Offspring born from preeclampsia exhibit deficits in cognitive impairment. But the pathogenesis is not clear. We assessed brain maturation and white matter development in neonatal period using total maturation score and tract-based spatial statistics. TMS showed the scores of TMS, B and C scores were lower in preeclampsia group. TBSS results displayed FA values decreased, while AD and RD values increased on anterior & posterior limb of internal capsule, external capsule, splenium of corpus callosum, optic radiation and centrum semiovale in preeclampsia group. The results indicated preeclampsia is associated with delayed development of white matter and cortical infolding.

 1768 Is cortical microstructure related to folding during development? A longitudinal MRI study in preterms Alexandra Hertz1, Antonietta Pepe2, Julien Lefevre2, Marie Zomeno1, Francois Leroy1, Jessica Lebenberg1,3, Linda de Vries4, Floris Groenendaal4, David Germanaud5, Manon Benders4, and Jessica Dubois1 1INSERM, Gif-sur-Yvette, France, 2Aix-Marseille University, CNRS, Marseille, France, 3CEA, Gif-sur-Yvette, France, 4Wilhelmina Children's Hospital, University Medical Center, Utrecht, Netherlands, 5APHP, INSERM, Paris, France The human brain cortex develops dramatically during the preterm period, in terms of both morphology, intra-cortical maturation and dendritic arborization. Here we aimed to investigate whether different stages of microstructural maturation are observed in cortical regions that fold successively. We studied preterm infants longitudinally at around 30 and 40 weeks of post-menstrual age, and combined measures from diffusion tensor imaging (DTI) and spectral analysis of gyrification (SPANGY). We highlighted that proxies of primary folds have an advanced microstructural maturation early on, and that the progression until term age is more intense in proxies of secundary folds than in gyri.

 1769 Changes in neonatal regional brain volume associated with preterm birth and perinatal factors Bonnie Alexander1, Claire E Kelly1, Chris Adamson1, Richard Beare1,2, Diana Zannino1, Jian Chen1,2, Andrea Murray1, Wai Yen Loh1,3,4, Lillian G Matthews5, Simon K Warfield6, Peter J Anderson1,7,8, Lex W Doyle1,8,9,10, Marc Seal1,8, Alicia Spittle1,9,11, Jeanie Cheong1,9,10, and Deanne K Thompson1,3,8 1Murdoch Children's Research Institute, Melbourne, Australia, 2Dept of Medicine, Monash University, Melbourne, Australia, 3Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 4The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia, 5Dept of Newborn Medicine, Harvard Medical School, Boston, MA, United States, 6Dept of Radiology, Harvard Medical School, Boston, MA, United States, 7Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia, 8Dept of Paediatrics, The University of Melbourne, Melbourne, Australia, 9Neonatal services, Royal Women's Hospital, Melbourne, Australia, 10Dept of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia, 11Dept of Physiotherapy, The University of Melbourne, Melbourne, Australia In a cohort of 285 preterm and term infants at term equivalent age, associations were investigated between gestational age (GA) at birth, perinatal factors, and volumes of 100 regions of the M-CRIB neonatal brain atlas. Volumes increased with increasing GA in some regions, and decreased with increasing GA in other regions including primary visual, motor and somatosensory cortices. Robust increases in many regional volumes were found for birthweight standard deviation score, and male sex. These results provide increased insight into the complex array of correlates of preterm birth.

 1770 T2 relaxometry MRI predicts cerebral palsy in preterm infants Yi-Shan Tsai1, Li-Wen Chen2, and Feng-Mao Chiu3 1Department of Diagnostic Radiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan, 2Departments of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan, 3Clinical MR application, Philips Healthcare, Taipei, Taiwan T2 relaxometry brain MRI could be of prognostic value in preterm infants. The maturation patterns of periventricular white matter differed according to neurodevelopmental outcomes. T2 relaxation values over mid-body periventricular white matter at > 1 month old of corrected age could predict CP. T2 relaxometry brain MRI provides neuroimaging-outcome correlation among preterm infants, especially when interpreted with age-specific and area-selective considerations.

 1771 Automatic Brain Segmentation in a Neonatal Population Using a Multi-Delay Multi-Echo Sequence Maarten Naeyaert1, Tim Vanderhasselt1, Marcel Warntjes2, and Hubert Raeymaekers1 1Department of Radiology, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium, 2SyntheticMR AB, Linköping, Sweden Synthetic MRI using a multi-delay multi-echo sequence was applied to a pre-term neonatal and full term neonatal population. The brain was segmented into different tissue types using the relaxometric data and using an improved algorithm which suppresses CSF partial volume fractions in grey matter. The volumes and volume fractions were calculated. The relation between volumetric quantities and either gestational age (preterm patients only), or corrected age (whole population) was investigated. The Brain Parenchymal and grey matter fraction were found to be dependent on gestational age at birth, while grey matter, CSF, intracranial and brain parenchymal volume are dependent on age.

 1772 Longitudinal Mapping of Local Relationship of Surface Area, Cortical Thickness and Cortical Folding in Infants Dingna Duan1,2, Shunren Xia2, Zhengwang Wu1, Fan Wang1, Weili Lin1, John H Gilmore3, Dinggang Shen1, and Gang Li1 1Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China, 3Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States A simple physical law on the global relationship of surface area, cortical thickness, and cortical folding is found across a full range of mammalian species’ brains, including adult human brains1,2. However, little is known about the local relationship of these cortical properties, especially in infant brains with rapid development in the first two years of life. To fill this knowledge gap, we explored the local relationship of surface area, cortical thickness and cortical folding on 73 normal infants, each of which was longitudinally scanned at 0, 1, and 2 years of age. We reveal that the relationship of these three cortical properties is age-specific and region-specific.

 1773 Evaluation of cortical thickness estimation methods in neonates. Martina Lucignani1, Andrea Pittella2, Maria Camilla Rossi Espagnet3, Daniela Longo3, Giulia Lucignani3, Maurizio Schmid2, and Antonio Napolitano1 1Medical Physics Department, IRCCS Bambino Gesù Children’s Hospital, Rome, Italy, 2Enginerring Department, Roma Tre University, Rome, Italy, 3Imaging Department, IRCCS Bambino Gesù Children’s Hospital, Rome, Italy Cortical thickness (CT) is a sensitive indicator of normal brain structural and functional development, aging, as well as a variety of neuropsychiatric disorders. The state of the art for cortical thickness estimation in children in not as good as the one for adults. We then compared two different algorithms and assess the agreement between these methods and their local variability.

 1774 Asynchrony of the cortical maturation in the infant brain studied with MRI Jessica Lebenberg1,2, Jean-François Mangin1,3, Cyril Poupon4, Lucie Hertz-Pannier5, François Leroy2, Parvaneh Adibpour2, Claire Kabdebon2, Ghislaine Dehaene-Lambertz2, and Jessica Dubois2 1UNATI, CEA DRF/Institut Joliot, Université Paris-Sud, Université Paris-Saclay, NeuroSpin center, Gif-sur-Yvette, France, 2Cognitive Neuroimaging Unit U992, INSERM, CEA DRF/Institut Joliot, Université Paris-Sud, Université Paris-Saclay, NeuroSpin center, Gif-sur-Yvette, France, 3Multicenter Neuroimaging Platform, CATI, cati-neuroimaging.com, France, 4UNIRS, CEA DRF/Institut Joliot, Université Paris-Sud, Université Paris-Saclay, NeuroSpin center, Gif-sur-Yvette, France, 5UNIACT, CEA DRF/Institut Joliot, INSERM U1129, Université Paris-Sud, Université Paris-Saclay, Université Paris-Descartes, NeuroSpin center, Gif-sur-Yvette, France Intense changes in cortical microstructure occur during early infancy. Here, we aimed to study cortical maturation over this largely unexplored developmental period using quantitative MRI in 17 infants from 1 to 5 post-natal months. By taking benefit of robust intra- and inter-individual registrations of anatomical images and parametric maps, we measured T1, T2 relaxation times, and DTI longitudinal diffusivity over cortical surfaces and regions of interest. Results showed that each parameter relevantly but differently reflects the progressive maturation. This suggests that multi-parametric approaches might provide interpretable measures of the developing microstructure by accounting for the parameters complementarity.

 1775 High resolution neonatal brain relaxometry in 10 minutes – A preliminary proof of concept Rui Pedro A. G. Teixeira1, Tomoki Arichi1, Johannes Steinweg1, Katy Vecchiato1, Sophie Arulkumaran1, Shaihan J. Malik1, Mary A. Rutherford1, Joseph V. Hajnal1, and Serena J. Counsell1 1Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom Quantitative MRI promises to allow objective and reproducible tissue metrics which are of special interest in newborn brain maturation characterization. However, such methods require acquisition times above 20 minutes which hinders their clinical applicability. With an increasing trend towards examination without sedation during natural sleep, subject motion is an important issue for neonatal applications. With this in mind, this work builds on the previously described Joint System Relaxometry framework and presents a neonatal specific protocol which allows 1.25mm isotropic 3D maps of Proton Density, T1 and T2 relaxation times in a total of 10minutes examination time.

 1776 Anatomo-functional correlates of auditory development in infancy Parvaneh Adibpour1, Jessica Lebenberg1,2, Claire Kabdebon 1, Francois Leroy1, Ghislaine Dehaene-Lambertz1, and Jessica Dubois1 1Cognitive Neuroimaging Unit, INSERM, UMR992; CEA, NeuroSpin Center, Gif-sur-Yvette, France, 2UNATI, CEA DRF Institut Joliot, Gif-sur-Yvette, France Early infancy is a period of intense behavioral acquisitions and brain development. Nevertheless, how functional and structural maturations are inter-related has been little explored so far. Following studies of visual domain, we aimed to address this question for the auditory modality in 1 to 5-month-old infants, by combining EEG and quantitative MRI measures supposed to reflect fiber myelination and intra-cortical development of dendritic arborization. We investigated the relationships between the functional maturation of auditory-evoked responses in terms of latency and speed, and the maturation of microstructural properties for both white matter tracts and cortical regions of the auditory network.

 1777 Optimization of phase-contrast MRI for cerebral blood flow quantification in neonates Peiying Liu1, Charlamaine Parkinson1, Dengrong Jiang1, Jill B De Vis1, Li Pan2, Himanshu Bhat2, Andrea Poretti1, Frances Northington1, Aylin Tekes1, Thierry Huisman1, and W Christopher Golden1 1Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Siemens Healthineers, Baltimore, MD, United States Knowledge of CBF in neonates may provide valuable information in many pathological conditions. When applied to very young children, CBF mapping using arterial-spin-labeling (ASL) MRI suffers from low signal-to-noise ratio and poor quantification, whereas phase-contrast (PC) MRI may provide reliable estimation of global CBF. This study aimed to optimize the PC-MRI protocol for future applications in neonates. By comparing the cardiac-gated and non-gated implementations, we found non-gated PC-MRI could provide accurate CBF measurement with shorter scan time. We also found lower imaging resolution would over-estimate CBF, and therefore recommend the use of 0.3mm resolution with 6 averages in neonates.

 1778 Clinical application of 4D ASL-MRA in neonatal Vein of Galen malformation Magdalena Sokolska1, Subhabrata Mitra2, Yuriko Suzuki3, Matthias van Osch3, H Rolf Jäger4, Adam Rennie4,5, Fergus Robertson5, Giles Kendall2, and Alan Bainbridge1 1Medical Physics and Biomedical Engineering, University College Hospital, London, United Kingdom, 2University College Hospital, London, United Kingdom, 3Leiden University Medical Center, Leiden, Netherlands, 4UCL National Hospital for Neurology & Neurosurgery, London, United Kingdom, 5Great Ormond Street Hospital for Children, London, United Kingdom This work investigates the feasibility of using time-resolved magnetic resonance angiography, based on arterial–spin-labelling (ASL), to investigate neonatal vein of Galen malformation for the purpose of aiding diagnosis and surgical treatment planning.

 1779 Intraoperative Volatile Anesthetic Exposure Predicts Reduced Frontal Lobe Connectivity Compared to Dexmedetomidine in Infants with Congenital Heart Disease Vincent Kyu Lee1, Phillip Adams2, Benjamin Meyers1, Lauren Dennis3, Nancy Beluk1, Tracy Baust4, Lucas Saenz4, Yulia Domnina4,5, Joan Sanchez de Toledo4,5, Vincent J Schmithorst1, and Ashok Panigrahy1,6 1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 2Anesthesiology, Children's Hospital of Pittsburgh UPMC, Pittsburgh, PA, United States, 3Science Technology and Mathematics, Regent University, Pittsburgh, PA, United States, 4Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States, 5Critical Care Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States, 6Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States Anesthetic neurotoxicity in infants with repetitive exposure is a risk factors for adverse neurodevelopmental outcomes. Dexmedetomidine exposure is thought to have neuroprotective effects. We tested the hypothesis that intraoperative volatile anesthetic exposure is predictive of aberrant brain connectivity in the post-operative period in CHD infants, relative to dexmedetomidine exposure using DTI and BOLD imaging.  Using both hypothesis driven and data driven approaches, as well as graph analysis we showed that Increased volatile anesthetic exposure in the intraoperative period is associated with reduced post-operative frontal brain connectivity in CHD infants, while DEX exposure was associated with metrics of improved brain connectivity.

 1780 Application of Probabilistic Modeling to Motion Correction of Neonatal Brain Resting-State BOLD Data Jenna M Schabdach1, Rafael Ceschin1,2, Vince Lee2, Vincent Schmithorst2, and Ashok Panigrahy1,2 1Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, PA, United States, 2Department of Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States Functional connectivity studies commonly use resting-state BOLD MR images to study the neurodevelopment of healthy and at-risk neonates. BOLD images are highly sensitive to motion; post-acquisition motion correction techniques can be applied to BOLD data to compensate for motion. We compare the corrective performance of two motion correction techniques on a cohort of 17 healthy neonates: the traditional correction to the first volume technique and a novel, HMM-based motion correction technique. We evaluate the corrected images in terms of the Power et al. thresholds and show the HMM-based technique can be used to recover neonatal BOLD data corrupted by motion.

 1781 Anisotropic similarity, a constrained affine transformation: application to brain development analysis Antoine Legouhy1, Olivier Commowick1, François Rousseau2, and Christian Barillot1 1Univ Rennes, INRIA, CNRS, INSERM, IRISA UMR 6074, VISAGES ERL U-1228, F-35000, Rennes, France, 2IMT Atlantique, LaTIM U1101 INSERM, UBL, Brest, France The study of brain development provides insights in the normal trend of brain evolution and enables early detection of abnormalities. We propose a method to quantify brain growth in three arbitrary orthogonal directions of the brain through linear registration. We introduce a 9 degrees of freedom transformation that gives the opportunity to extract scaling factors describing brain growth along those directions by registering a database of subjects in a common basis. We apply this framework to create a longitudinal curve of scaling ratios along fixed orthogonal directions from 0 to 16 years highlighting anisotropic brain development.

 1782 New microstructural asymmetries in the brain Junyu Guo1, Yuanyuan Han2, Yimei Li2, and Wilburn E. Reddick1 1Diagnostic Imaging, St Jude Children's Research Hospital, Memphis, TN, United States, 2Biostatistics, St Jude Children's Research Hospital, Memphis, TN, United States Brain microstructural asymmetry can provide more direct causal explanations of functional lateralization than can macrostructural asymmetry. In this study, we discovered two new types of microstructural asymmetry that help to bridge the gap between macrostructural asymmetry and functional lateralization. Myelin-related asymmetry was prominent in the back brain, and axon-related asymmetry occurred in both the front brain and the back brain. These asymmetries early in development indicate that white matter is more mature and more myelinated in the left back brain, providing an explanation for the leftward lateralization of language and visual functions. The asymmetries continue to increase throughout childhood and adolescence.

 1783 Comparison of Thalamus Segmentation Using Publicly Available Segmentation Methods in a Pediatric Population Salem Hannoun1, Rayyan Tutunji2, Maria El Homsi2, and Roula Hourany2 1Nehme and Therese Tohme Multiple Sclerosis Center, American University of Beirut Medical Center, Beirut, Lebanon, 2Radiology Department, American University of Beirut Medical Center, Beirut, Lebanon 107 subjects were recruited between the ages of one month and 18 years. The study aimed to investigate the differences in the accuracy of five publicly available segmentation techniques on T1-enhanced and non-enhanced images compared to manual segmentation of the thalamus in a pediatric population. volBrain had the best outcomes in enhanced and non-enhanced images. Image segmentation using volBrain is the ideal methodology for thalamus segmentation. Gadolinium-enhancement negatively affects the outcomes of all the tested automated segmentation.

 1784 Magnetization transfer ratio in cortical gray matter: a longitudinal study. Yash P. Patel1,2, Jean Shin2,3, Penny A. Gowland4, and Tomas Paus2,5,6,7 1Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada, 2Rotman Research Institute, University of Toronto, Toronto, ON, Canada, 3The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada, 4Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 5Center for Developing Brain, Child Mind Institute, New York, NY, United States, 6Department of Psychiatry, University of Toronto, Toronto, ON, Canada, 7Department of Psychology, University of Toronto, Toronto, ON, Canada To assess the change in magnetization transfer ratio (MTR) in the human cerebral cortex during adolescence(14 to 19 years of age). We observe an age-related increase in average MTR in both sexes. Inter-regional profiles of MTR measured at a single time-point correlate with gene-expression profiles of CA1 pyramidal cells (membranes of dendritic arbor) but not of oligodendrocytes (myelin). On the other hand, profiles of the MTR change (from 14 to 19 years) correlate with gene-expression profiles of oligodendrocytes, suggesting that the change may be sensitive to intra-cortical myelination.

 1785 Paediatric brain tissue properties measured with magnetic resonance elastography Jade Yeung1, Lauriane Jugé 1,2, and Lynne E. Bilston1,3 1Neuroscience Research Australia, Randwick, NSW, Australia, 2University of New South Wales, School of Medical Sciences, Kensington, NSW, Australia, 3University of New South Wales, Prince of Wales Clinical School, Kensington, NSW, Australia Magnetic resonance (MR) elastography is a technique to noninvasively measure the mechanical properties of soft tissues. While adult brain data obtained with MR elastography is readily available, there is little data for healthy paediatric brains throughout development. MR elastography was performed on 25 healthy paediatric subjects aged between 7-18 years at three frequencies, and the shear moduli of white and grey matter were calculated and compared to data obtained from 10 healthy adults. The shear modulus of paediatric brains was not found to be age dependent, with no significant differences between adult and paediatric brains.

 1786 Clinical Equivalence Assessment of T2 Synthetic Pediatric Brain MRI Basile Kerleroux1, Tobias Kober2, Tom Hilbert2, Mohamed El Ouali3, Dominique Sirinelli3, and Baptiste Morel4 1Pediatric Radiology, CHRU de Tours, Tours, France, 2Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, 3Pediatric Radiology, CHRU de Tours, Tours, Switzerland, 4Pediatric Radiology, CHRU Tours, Tours, France In a prospective randomized study, we compared the image quality of a synthetized T2 with conventional turbo spin echo T2 during pediatric brain MRI. According to several assessment criteria, synthetic T2 seemed to be an overall equivalent to standard TSE T2, with the advantage of new available T2 quantitative data with a similar acquisition time.

 1787 Motor connectivity of the midbrain in healthy children defined using connectivity based parcellation Sonja Soskic1, Hannah Cooper2, Alexandra Bonthrone3, and Chris A. Clark1 1Developmental Imaging and Biophysics Section, UCL GOS Institute of Child Health, University College London, London, United Kingdom, 2UCL Ear Institute, University College London, London, United Kingdom, 3Cognitive Neuroscience and Neuropsychiatry Section, UCL GOS Institute of Child Health, University College London, London, United Kingdom Delineation of midbrain regions connected with the motor cortex may be useful in evaluating disruptions of motor pathways in paediatric patients. We used the established winner-takes-it-all method to parcellate the midbrain according to cortical connectivity in healthy children aged 6-12 years. The percentage of ipsilateral midbrain occupied by motor parcels was negatively associated with age on the right side only, producing an association between age and interhemispheric asymmetry. Our findings indicate that age and interhemispheric differences need to be taken into account if this method is to be utilised for quantitative comparisons of midbrain-motor connectivity in children.

 1788 Assessing white matter development in peri-pubertal children using longitudinal fixel-based analysis Sila Genc1,2, Robert E Smith3, Charles B Malpas2, Vicki A Anderson4,5, Jan M Nicholson6, Daryl Efron5, Timothy J Silk1,2, and Marc L Seal1,2 1Department of Paediatrics, The University of Melbourne, Parkville, Australia, 2Developmental Imaging, Murdoch Childrens Research Institute, Parkville, Australia, 3The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia, 4Clinical Sciences, Murdoch Childrens Research Institute, Parkville, Australia, 5The Royal Children's Hospital, Parkville, Australia, 6Judith Lumley Centre, La Trobe University, Melbourne, Australia Recent evidence suggests that the pubertal period corresponds with changes to white matter microstructure above and beyond age-related development. This study uses a longitudinal fixel-based analysis to investigate which regions of the brain correspond to changes in white matter fibre density and cross-section during pubertal development. We show that, over a 16-month follow-up period, increases in fibre density and cross-section are predominantly in the posterior white matter. These results add to evidence that white matter develops in a posterior-anterior fashion, and signifies the dynamic nature of brain development during puberty.

 1789 Longitudinal myelin development in children born very preterm compared with typically developing peers Deanne Thompson1,2,3,4, Joseph Yang2,5,6, Jian Chen2, Claire Kelly1,2, Bonnie Alexander1,2, Lillian Matthews7, Katherine Lee1,3,8, Rod Hunt1,3,9, Jeanie Cheong1,10,11, Megan Spencer-Smith1,12, Marc Seal2,3, Jeffrey Neil7, Terrie Inder1,7, Lex Doyle1,3,10,11, and Peter Anderson1,3,12 1Victorian Infant Brain Studies (VIBeS), Murdoch Children's Research Institute, Melbourne, Australia, 2Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia, 3Department of Paediatrics, The University of Melbourne, Melbourne, Australia, 4Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 5Neuroscience Research, Murdoch Children's Research Institute, Melbourne, Australia, 6Department of Neurosurgery, The Royal Children's Hospital, Melbourne, Australia, 7Department of Pediatric Newborn Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States, 8Clinical Epidemiology & Biostatistics Unit, Murdoch Children's Research Institute, Melbourne, Australia, 9Neonatal Medicine, The Royal Children's Hospital, Melbourne, Australia, 10Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Australia, 11The Royal Women's Hospital, Melbourne, Australia, 12Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia Myelin development over time in preterm children remains unclear. This study compared T1/T2 myelin maps for 81 very preterm (VP) and 29 full-term children between 7 and 13 years of age. On average, VP children had higher T1/T2 ratios than full-term children in most white matter tracts and deep gray matter structures at both time points. This may reflect compensation or developmental catch-up. T1/T2 ratios increased from childhood to adolescence in both VP and full-term children, shedding light on typical and atypical myelin maturation.

 1790 Regional Brain Myelin Changes in Patients with Single Ventricle Heart Disease Sadhana Singh1, Bhaswati Roy2, Xiaopeng Song1, Nancy Halnon3, Alan Lewis4, Mary Woo2, Nancy Pike2, and Rajesh Kumar1,5,6,7 1Department of Anesthesiology, University of California Los Angeles, Los Angeles, CA, United States, 2UCLA School of Nursing, University of California Los Angeles, Los Angeles, CA, United States, 3Division of Pediatric Cardiology, University of California Los Angeles, Los Angeles, CA, United States, 4Division of Pediatric Cardiology, Children’s Hospital Los Angeles, Los Angeles, CA, United States, 5Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 6Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, United States, 7Brain Research Institute, University of California Los Angeles, Los Angeles, CA, United States Single ventricle heart disease (SVHD) subjects show brain injury in multiple gray and white matter based on MRI procedures. However, the extent of regional myelin integrity in SVHD is unclear. We examined the regional brain myelin integrity in SVHD adolescents using the ratio of T1-weighted and T2-weighted MRI signal intensity, and found decreased values in critical autonomic, mood, and cognitive control sites, functions that are deficient in the condition, likely resulting from hypoxic/ischemic processes.

 1791 Regional CBF differences underlie neurocognitive outcomes in older children with congenital heart disease: a voxelwise mediation analysis Vincent Jerome Schmithorst1 and Ashok Panigrahy2 1Radiology, Children's Hospital of Pittsburgh, Pittsburgh, PA, United States, 2Children's Hospital of Pittsburgh, Pittsburgh, PA, United States We investigate in more detail the relationship between congenital heart disease (CHD), CBF, and neurocognitive outcome in older children by employing a novel voxelwise mediation analysis with CHD status the independent variable, NIH Toolbox scores the dependent variable, and voxelwise CBF the mediating variable.  CHD patients display reduced CBF in the salience network (insula, medial prefrontal, caudate) which mediates lower performance on tests of memory and language function.  However, the reduced CBF in the salience network mediates improved performance of executive function (flanker inhibitory control) likely due to less filtering out of presumed irrelevant but actually relevant information.

 1792 Relationships between brain structure and behavior in children with specific learning disabilities revealed by diffusion spectrum imaging Yi-Chun Liu1, Hsiao-Lan Sharon Wang2, Shan-Chih Lee1, and Jun-Cheng Weng3,4 1Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, 2Department of Special Education, National Taiwan Normal University, Taipei, Taiwan, 3Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, Taiwan, 4Department of Psychiatry, Chang Gung Memorial Hospital, Chiayi, Taiwan We used diffusion spectrum imaging (DSI) to investigate the relationships between brain structure and behavior in children with specific learning disabilities (SLD). The correlation between reading comprehension scores and the DSI indices was found in corpus callosum. The correlation between Chinese character recognition and the DSI indices was found in cingulate and corpus callosum. The correlation between tone awareness scores and the DSI indices was found in cingulate, superior frontal gyrus and corpus callosum. In summary, SLD not only had difficulty reading and spelling individual words but also more likely to have poorer phonological awareness.

 1793 Altered regional brain activities and functional connectivities in children with nonsyndromic cleft and/or lip palate: a resting-state functional MRI study. Hua CHENG1, BO RAO2, YANG FAN3, YingZi Gao1, WenJing Zhang4, and Yun Peng1 1Imaging Center, Beijing Children's Hospital affiliated to Capital Medical University, Beijing, China, 2Capital Medical University, Beijing, China, 3GE Healthcare, MR Research China, Beijing, China, 4Beijing Stomatological Hospital, Capital Medical University, Beijing, China Rs-fMRI has been widely used as an effective method to evaluate the brain functional changes in physiological and pathological process. Altered both regional brain activities and functional connectivities, especially in verbal and cognitive areas, were found in children with nonsyndromic CL/P using resting-state fMRI. It helps to understand the abnormality of functional architecture of CL/P which implies different structures and cognitive patterns in CL/P compared with normal development children.

 1794 Alterations in brain connectivity during olfaction in impulsive children Benito de Celis Alonso1, Silvia Sandra Hidalgo Tobón2,3, Eduardo Barragán Pérez4, and Pilar Dies Suarez2 1Faculty of Mathematical and Physical Sciences, BUAP, Puebla, Mexico, 2Imaging Department, Hospital Infantil de México, Federico Gómez, Mexico City, Mexico, 3UAM Iztapalapa, Mexico City, Mexico, 4Neurology Department, Hospital Infantil de México, Federico Gómez, Mexico City, Mexico Impulsivity is a multi-dimensional construct of behaviors. Here we compared two cohorts of impulsive and control children. Both groups underwent a functional magnetic resonance imaging experiment which food related odor cues. Activations were larger for the impulsive group in: temporal lobe, cerebellum, supplementary motor area, frontal cortex, medial cingulate cortex, insula, precuneus, precentral, para-hippocampal & clacarine. Connectivity results showed that emotional reward based on the smell and processed in temporal lobes was the main cue driving impulsive children. This was followed by a focused attention and sensations of comfort and happiness modulated by precuneus and cingulum.

 1795 Investigation of sickle cell related changes in the basal ganglia of pediatric subjects using QSM and R2*. Richard A Jones1, Binjian Sun1, Deqiang Qiu2, Susan Palasis1, Thomas G Burns1, and Clark Brown3 1Radiology, CHOA, Atlanta, GA, United States, 2Radiology, Emory University, Atlanta, GA, United States, 3Pediatrics, Emory University, Atlanta, GA, United States In previous work on susceptibility differences between controls and subjects with sickle cell disease (SCD) receiving chronic transfusions we found no significant differences in the basal ganglia (BG). In this abstract we added a group of non-transfused SCD subjects and included an analysis of the R2* in order to better understand the nature of any observed changes. Significant differences between the groups were observed in the BG for both susceptibility and R2*, but the pattern of the changes was inconsistent, probably due to the multifactorial nature of R2* in tissues where iron is not the dominant contrast mechanism.

 1796 Quantitative subcortical morphometry in mTOR/AKT/PI3K pathway disorders: A novel clinical biomarker Matthew J Barkovich1, Ryan M Nillo1, Chin Hong Tan1, Leo Sugrue1, Anthony James Barkovich1, and Rahul S Desikan1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States Subcortical volumes were quantitatively evaluated on clinical MRI exams of neurofibromatosis type 1 (NF1) and tuberous sclerosis complex (TSC) patients. Robustly larger volumes of several subcortical structures, including the thalamus, hippocampus and ventral diencephalon, were found in NF1; characteristic NF1 imaging abnormalities are found in these areas.  In TSC, we found smaller cerebellar volumes; findings that have been associated with autistic phenotypes. Cluster analysis reveals three distinct clustering patterns, each corresponding to a patient class. These results show the feasibility of obtaining automatic quantitative measurements of anatomic structures from clinical MRI exams.

 1797 ROTATING FRAME MRI CONTRASTS FOR ASSESSMENT OF WHITE MATTER ALTERATION IN MUCOPOLYSACCHARIDOSIS TYPE I Alena Svatkova1, Bryon A. Mueller2, Petr Bednařík3, Carol Nguyen1, Lubomír Vojtíšek4, Silvia Mangia3, Mikko Nissi5, Shalom Michaeli3, and Igor Nestrasil1 1Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States, 2Department of Psychiatry, University of Minnesota, Minneapolis, MN, United States, 3Radiology, CMRR, University of Minnesota, Minneapolis, MN, United States, 4Central European Institute of Technology, Masaryk University, Brno, Czech Republic, 5Department of Applied Physics, University of Eastern Finland, Kuopio, Finland Mucopolysaccharidosis type I (MPSI) is an inherited metabolic disease with severe and attenuated disease subtypes. While both MPSI subtypes manifest pronounced morphological brain changes, little has been discovered about alterations of white matter (WM) microstructure. Here, we utilized rotating frame MRI contrasts along with DTI to detect WM alterations between in 11 severe and 9 attenuated MPSI patients at 3T. T1ρ and RAFF4 detected WM differences between MPS subtypes that were not depicted by DTI. Outcomes demonstrate an exceptional sensitivity of rotating frame methods to probe WM microstructure in MPSI.

 1798 REDUCED INTRACRANIAL VOLUME IN FABRY DISEASE: A VOLUMETRIC MRI STUDY Giuseppe Pontillo1, Sirio Cocozza1, Arturo Brunetti1, Vincenzo Brescia Morra2, Eleonora Riccio2, Camilla Russo1, Francesco Saccà2, Enrico Tedeschi1, Antonio Pisani2, and Mario Quarantelli3 1Department of Advanced Medical Sciences, University of Naples Federico II, Naples, Italy, 2University of Naples Federico II, Naples, Italy, 3Institute of Biostructure and Bioimaging, National Research Council, Naples, Italy To investigate the possibility that in Fabry Disease (FD), similarly to other LSD, an abnormal brain development could occur, we performed a volumetric MRI analysis on 42 FD patients and 38 healthy controls (HC). MRI data were processed using SPM12 to obtain ICV values, as well as brain parenchymal (BPF) and gray matter (GMF) fractions. Mean ICV of FD patients was 8.1% smaller compared to HC (p < 5·10-5), without significant differences in terms of BPF or GMF, thus suggesting a harmonious volumetric reduction of intracranial structures, as a reflection of a possible abnormal brain development in this condition.

 1799 Quantification of Diffusion Tensor Imaging (DTI) in the Pediatric Spinal Cord: Application to Clinical Evaluation Aashim Bhatia1, Bryson Reynolds2, Samantha By2, Bhavesh Ramkorun2, Quinn Weinberg2, Mark Adams3, John Clifton Wellons III4, and Seth Smith2 1Radiology, Vanderbilt Childrens’s Hospital, Nashville, TN, United States, 2Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 3Urology, Vanderbilt Childrens’s Hospital, Nashville, TN, United States, 4Neurosurgery, Vanderbilt Childrens’s Hospital, Nashville, TN, United States The goal of the study was to apply optimized Diffusion Tensor Imaging (DTI) in the pediatric spinal cord and quantified to determine normative DTI-derived indices based on age. DTI was acquired in 35 patients, 22 being normal and AD, FA, MD, and RD were calculated.   DTI of the spinal cord in the pediatric population can be performed in the clinical setting to produce reliable DTI values. AD and MD demonstrated statistically significant changes based on age in both normal patients and the complete patient population.

 1800 Tag-Based CSF Imaging Performance in Pediatric Patients and Adult Volunteers Jieun Kwak1,2, Tai-Wei Wu1, Skorn Ponrartana3,4,5, Benita Tamrazi3,5, Wende Gibbs5, Thomas Chavez1, William Bradley6, Marvin D Nelson3,5, J. Gordon McComb7,8, Stefan Blüml3,4, and Matthew Borzage1,3,4 1Center for Fetal and Neonatal Medicine, Division of Neonatology | Children's Hospital Los Angeles, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, Los Angeles, CA, United States, 2USC/LAC+USC Neonatal-Perinatal Medicine Fellowship Program, Division of Neonatology LAC+USC Medical Center & Children’s Hospital Los Angeles, Keck School of Medicine of USC, Los Angeles, CA, Los Angeles, CA, United States, 3Department of Radiology, Children’s Hospital Los Angeles, Los Angeles, CA, Los Angeles, CA, United States, 4Rudi Schulte Research Institute, Santa Barbara, CA, Santa Barbara, CA, United States, 5Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, Los Angeles, CA, United States, 6Department of Radiology, University of California San Diego, La Jolla, CA, La Jolla, CA, United States, 7Division of Neurosurgery, Children’s Hospital Los Angeles, Los Angeles, CA, Los Angeles, CA, United States, 8Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles CA, Los Angeles, CA, United States We compared tag-based CSF imaging techniques (TimeSLIP and TimeSTAMP) in 10 healthy adults and 19 pediatric patients with cerebrospinal fluid (CSF) abnormalities. In adults, TimeSLIP and TimeSTAMP contrasts were quantitatively compared. TimeSTAMP sequences showed higher contrasts with decreased contrast variability versus TimeSLIP sequences. In pediatric patients, TimeSTAMP sequences were acquired to observe clinical utility and had similar contrast to the healthy adults. TimeSTAMP may be a superior imaging technique with clinical implications in adults and pediatric patients.

 1801 Factor analysis to determine white matter injury patterns following pediatric traumatic brain injury. Brenda Bartnik Olson1, Nirmalya Ghosh2, Udo Oyoyo1, Barbara Holshouser1, Joy Nichols2, Jamie Pivonka-Jones2, Karen Tong1, and Stephen Ashwal2 1Radiology, Loma Linda University Medical Center, Loma Linda, CA, United States, 2Pediatrics, Loma Linda University Medical Center, Loma Linda, CA, United States Several studies have shown regional disruptions in white matter integrity following TBI although conventional methods don't account for the relationship between regions. In this study we used factor analysis, a data reduction technique, to identify patterns of WM injury that are associated with neurocognitive outcome in pediatric TBI patients. Our findings identified 3 dominant patterns of WM injury in pediatric TBI patients, describing regional changes in: 1) subcortical + cortical diffusivity, 2) subcortical diffusivity, and 3) subcortical + cortical anisotropy. Factor analysis provides a unique statistical approach to analyze DTI data and potentially could be used to combine different data streams (DTI, MR spectroscopy, SWI) representing different elements of injury.

 1802 Structural MRI derived connectivity in Paediatric Mild Traumatic Brain Injury: Acute Neuroimaging and its relationship with executive function outcomes Daniel J King1, Stefano Seri1, Vicki Anderson2, Cathy Catroppa2, Miriam H Beauchamp3, and Amanda G Wood1,4 1Aston Brain Center & School of Life and Health Sciences, Aston University, Birmingham, United Kingdom, 2Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Australia, 3Department of Psychology, University of Montreal, Montreal, QC, Canada, 4Murdoch Childrens Research Institute, Melbourne, Australia The aim of the current study was to identify acute differences in the topology of the structural covariance network of children after a mild traumatic brain injury (TBI). This was to assess the potential utility of this connectivity analysis applied to T1-weighted MR images, novel in the TBI literature. The main findings of this study were i) both patients and controls exhibited typical frequency distribution of few, highly connected nodes, ii) at a group level, patients exhibited connections between nodes a greater distance apart, iii) these differences were not associated with differences in executive function outcome. Future work will have to move to individual-level SCNS to allow for more complex analyses and to enable investigation of more subtle individual differences in structural covariance.

 Exhibition Hall 1803-1845 Tuesday 16:15 - 18:15

 1803 Morphological interrelationships in mid-line white-matter structures are altered in individuals carrying rare neuropsychiatric copy number variants. Mark Drakesmith1,2, Greg D Parker1, Jacqueline Smith 2, Elliot Rees2, Michael Owen2, Derek K Jones1,2, and David E Linden2 1CUBRIC, Cardiff University, Cardiff, United Kingdom, 2Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom Neuropsychiatric copy number variants (CNVs) provide unique insights into the genetic basis of neuropsychiatric disorders. This study utilised a novel approach for characterising morphology of white-matter fibres and combines them with more traditional volumetric and microstructural indices of white-matter to study their relation to penetrance for psychopathology in a CNV cohort. Results show cingulum morphology is significantly affected by the presence of CNVs with high-penetrance for schizophrenia and developmental disorders. Additionally, volumetric interrelationships across several white-matter structures are also altered. In particular, the ratios of tract volumes across segments of the corpus callosum are altered. It is likely that both these effects stem from a single neurodevelopmental trajectory characteristic of neuropsychiatric CNVs.

 1804 Quantitative magnetization transfer imaging in schizophrenia: a closer look at myelin dysfunction Yu Sui1, Pippa Storey1, Hilary Bertisch2, Matthew Lustberg1, Taylor Coats1, Donald Goff3, Alexey Samsonov4, and Mariana Lazar1 1Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, 2Department of Rehabilitation Medicine, New York University School of Medicine, New York, NY, United States, 3Department of Psychiatry, New York University School of Medicine, New York, NY, United States, 4Department of Radiology, University of Wisconsin at Madison, Madison, WI, United States Myelin dysfunction has frequently been identified as one of the neural abnormalities in schizophrenia, yet systematic in vivo examination of myelin content in patients is lacking. The current study compared the degree of myelination in schizophrenia patients and comparison healthy controls. Myelin content was estimated by constructing quantitative whole-brain maps of macromolecular proton fraction, which is believed to be one of the biomarkers for myelination in neural tissues. Statistical analysis revealed that SZ patients were associated with a significant reduction in myelin content throughout white matter, as well as in several grey matter regions including cingulate cortex and hippocampus.

 1805 Acutely treated antipsychotics haloperidol enhances BOLD responses to the somatosensory stimulation in anesthetized rats. Yunbok Kim1, Jeong Pyo Son1, SoHyun Han1, and Seong-Gi Kim1,2 1Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea, 2Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea The use of BOLD fMRI is rapidly increasing for probing the effects of antipsychotics in schizophrenia. Since fMRI BOLD is an indirect measurement of neural activities, it is critical to examine the effect of antipsychotics on neurovascular coupling to prevent misinterpretation of MR data. Acutely treated haloperidol (0.2mg/kg, i.v.) increased BOLD fMRI to the somatosensory stimulation in the 1.5% isoflurane-anesthetized rats (n=5). In parallel with the BOLD results, evoked CBF and LFP by somatosensory stimuli were increased after haloperidol administration (n=8). Our results indicate that acutely treated haloperidol could influence somatosensory responses and the increased BOLD signal is coupled with enhanced neural activities.

 1806 Convolutional Neural Networks on Functional Connectivity Derived From r-fMRI: Explore the Effects of Thresholds Xingjuan Li1, Yu Li1, and Xue Li1 1School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia In this study, we propose a novel CNN to predict autism from functional brain networks. Experimental results demonstrate that the predictive ability of CNN outperforms a logistic regression method by 8% and a five-layer fully-connected network (FCN) by approximately 7%. Network thresholding is often used to control false connections arising in the process of constructing functional brain networks. We also compare the influence of different thresholds on the performance of proposed CNN. Experimental results show that CNN is robust to false connections. Our study will contribute to predict reliable clinical outcomes in autism using deep learning on brain networks.

 1807 Hippocampus and parietal lobe glutamate changes as a function of age in schizophrenia Frank E. Gaston1, S. Andrea Wijtenburg1, Stephanie A. Korenic1, Hongji Chen1, and Laura M. Rowland1 1Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States MRS was used to examine the aging effects of glutamate in participants with schizophrenia versus healthy controls. The parietal lobe and hippocampus, regions associated with general aging and the pathophysiology of schizophrenia, were assessed. Results revealed that hippocampal glutamate was lower in older adults with schizophrenia versus older controls. In contrast, parietal glutamate was lower in schizophrenia versus controls, irrespective of age group. These results suggest that the hippocampus may be particularly vulnerable to aging in schizophrenia. Interventions that halt hippocampal glutamate decline may be beneficial for patients with schizophrenia.

 1808 Amygdala dysfunction during negative emotional situation in Obsessive-Compulsive Disorder Hyunsil Cha1, Sang Won Lee2, Kyung Eun Jang1, Hyejeong Choi1, Eunji Kim1, Moojin Yang1, Jiung Yang1, Moon Jung Hwang3, Huijin Song4, Seung Jae Lee2, and Yongmin Chang1,5 1Department of Medical & Biological Engineering, Kyungpook national university, Daegu, Republic of Korea, 2Department of Psychiatry, Kyungpook national university hospital, Daegu, Republic of Korea, 3GE Healthcare, Seoul, Republic of Korea, 4Biomedical Engineering Research, Kyungpook national university, Daegu, Republic of Korea, 5Department of Radiology and Molecular Medicine, Kyungpook national university, Daegu, Republic of Korea We investigated brain activation in obsessive-compulsive disorder (OCD) patient using thought-action fusion (TAF) task to assess the influence of OCD symptom on amygdala response to the task. Within and between group analysis of close and neutral condition showed decreased amygdala activation in patients with OCD compared to healthy control.

 1809 Assessment of brain volume and shape abnormalities in the major depressive disorders with and without suicidal ideation Hui-Ming Tseng1, Vincent Chin-Hung Chen2,3, Yuan-Hsiung Tsai4, and Jun-Cheng Weng3,5 1Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, 2School of Medicine, Chang Gung University, Taoyuan, Taiwan, 3Department of Psychiatry/ Health Information and Epidemiology Laboratory, Chang Gung Memorial Hospital, Chiayi, Taiwan, 4Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Chiayi, Taiwan, 5Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, Taiwan There is very strong connection between patients with major depressive disorders (MDD) and suicide. We used voxel-based morphometry (VBM) and vertex-wise shape analyses to observe the difference between the MDD patients with and without suicidal ideation in their brain volume of gray and white matter as well as shape. We found the negative correlation between the brain volume of limbic system in MDD patients. We also found the significant difference in brain volume and shape of limbic system between suicidal ideation and non-suicidal ideation.

 1810 Atypical associations between language comprehension network and attention pathways in autism spectrum disorders Yu-Chun Lo1,2, Susan Shur-Fen Gau3, Yu-Jen Chen1, Yung-Chin Hsu1, and Wen-Yih Isaac Tseng1 1Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 2The Ph.D. Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, Taiwan, 3Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan Impaired language comprehension has been consistently found in autism spectrum disorder (ASD). Development of language comprehension highly corresponds to joint attention and impulsivity. We used diffusion spectrum imaging to measure white matter integrity of the language comprehension network and the attention pathways in 60 ASD and 55 typically developing (TD) boys. ASD showed partially reduced white matter integrity in the targeted tracts as compared to TD. The tract covariance between the language comprehension network and the attention pathways showed different patterns in both groups which may shed light in the relationships of language and attention in ASD.

 1811 Connectome analysis of brain functional network alterations in depressed patients with and without self-harm Yu-Syuan Chou1, Vincent Chin-Hung Chen2,3, Yuan-Hsiung Tsai4, Shan-Chih Lee1, and Jun-Cheng Weng3,5 1Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, 2School of Medicine, Chang Gung University, Taoyuan, Taiwan, 3Department of Psychiatry/ Health Information and Epidemiology Laboratory, Chang Gung Memorial Hospital, Chiayi, Taiwan, 4Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Chiayi, Taiwan, 5Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, Taiwan We aimed to use resting-state fMRI (rs-fMRI) to investigate the functional connectivity difference between depressed patients with and without self-harm history as well as healthy participants. The graph theoretical analysis (GTA) and network-based statistic (NBS) analysis were also used to find the network difference between each group. In GTA and NBS analyses revealed different topological organization and poor global integration of the brain network in depressed participants compared with healthy participants. We suggested that depressed patients with or without self-harm history may affect their brain functional connectivity.

 1812 Measurements of rat hippocampus Glu, Gln and GABA using NMR, MRS and HPLC in animal models of autism Pawel Senator1, Elzbieta Zieminska2, Wojciech Hilgier2, Jaroslaw Orzel2, and Beata Toczylowska1,3 1Nalecz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland, 2Mossakowski Medical Research Center Polish Academy of Sciences, Warsaw, Poland, 3Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland The goal of our studies was to compare different measuring methods of glutamine, glutamate and GABA of rat hippocampus used for study of pathogenesis of autism. The methods under consideration were: in vivo MRS and two in vitro ones, NMR and HPLC. Univariate statistical analysis of ratios of tested amino acids with respect to glutamate concentration was performed using General Linear Model. This demonstrated statistically significant differences between the results from three methods  for both, glutamine and GABA ratios. OPLS-DA analysis allowed build models for differentiation of two animal models of disease and control group in NMR and HPLC.

 1813 Resting-state brain functional alteration in dorsal attention network associated with post-chemotherapy breast cancer Chao-Yu Shen1,2,3, Vincent Chin-Hung Chen4,5, Xuan-Ru Zhang2, Meng-Syuan Lin2, Dah-Cherng Yeh6, Yeu-Sheng Tyan2,3, Ming-Chih Chou1,7, and Jun-Cheng Weng5,8 1Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, 2Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, 3Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan, 4School of Medicine, Chang Gung University, Taoyuan, Taiwan, 5Department of Psychiatry/ Health Information and Epidemiology Laboratory, Chang Gung Memorial Hospital, Chiayi, Taiwan, 6Breast Center, Taichung Tzu Chi Hospital, Taichung, Taiwan, 7Division of Thoracic Surgery, Department of Surgery, Chung Shan Medical University Hospital, Taichung, Taiwan, 8Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, Taiwan The current study was to investigate post-chemotherapy breast cancer with rs-fMRI using mfALFF analysis and correlated with clinical cognitive testing. The results showed altered brain activity in the dorsal attention network in breast cancer patients compared to healthy controls and the affected areas were associated with MMSE, CAMS-R and IES-R scores.

 1814 Principal Component Analysis of Schizophrenia Reveals Link Between Auditory Hallucination Severity and Fractional Anisotropy in the Corpus Callosum Meighen M Roes1, Alexander Mark Weber2, and Todd S Woodward1 1Psychiatry, University of British Columbia, Vancouver, BC, Canada, 2Pediatrics, University of British Columbia, Vancouver, BC, Canada A PCA analysis of fractional anistropy (FA) was conducted from a sample of schizophrenia patients (n=42) and healthy controls (n=40) resulted in three major components: “corpus callosum”, “internal capsule/temporal/brainstem”, and “corona radiata”. Average component scores did not differ as a function of group, but a correlation of PSYRATS scores and principal components revealed the frequency, amount of distress associated with voices, and disruption associated with voices correlated significantly with the corpus callosum component. Our findings suggest that reduced interhemispheric connectivity of the prefrontal cortex is related to hallucination severity in schizophrenia, perhaps mediated through top-down processes such as source monitoring.

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