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Electronic Power Pitch Poster
Weekend and Oral

Electronic Posters (no CME credit)

Electronic Power Pitch Poster

### Poster: CV PowerBeat: Part 1

 Power Pitch Theater A - Exhibition Hall Monday 9:15 - 10:15

 1 Plasma 1 Non-invasive pressure estimations by virtual fields – cardiovascular pressure drops from 4D flow MRI David Marlevi 1,2, Bram Ruijsink3, Maximilian Balmus3, Desmond Dillon-Murphy3, Daniel Fovargue3, Kuberan Pushparajah3,4, Pablo Lamata3, C. Alberto Figueroa3,5, Massimiliano Colarieti-Tosti1,6, Matilda Larsson1, Reza Razavi3,4, and David A. Nordsletten3 1Department of Medical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden, 2Clinical Sciences, Karolinska Institutet, Stockholm, Sweden, 3Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, 4Department of Congenital Heart Disease, Evelina Children’s Hospital, London, United Kingdom, 5Departments of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, 6Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden 4D-flow-MRI enables the non-invasive assessment of cardiovascular pressure drops; however, estimation accuracy depends on vascular topology and acquisition noise. Here, we present a method that minimizes the impact of these by using virtual fields to isolate and probe hemodynamic pressure drops. We show that, in-silico, the method accurately assesses pressure drops over multiple segments of a patient-specific co-arcted aorta (average error below 22%), independent of anatomical bifurcations. Additionally, the method compares successfully against catheter measurements, using 4D-flow-MRI in-vivo (average error at peak systole below 15%). With this, the method represents a refined tool for hemodynamic analysis of cardiovascular flow.

 2 Plasma 2 The Effect of Model Compliance and Pulsatile Flow for In-Vitro Simulation of the Aorta Timothy Aaron Ruesink1, Matthew Smith2,3, Katrina Ruedinger4, Christopher J François2,3, and Alejandro Roldán-Alzate1,2,4 1Mechanical Engineering, University of Wisconsin, Madison, WI, United States, 2Radiology, University of Wisconsin, Madison, WI, United States, 3School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States, 4Biomedical Engineering, University of Wisconsin, Madison, WI, United States In-vitro cardiovascular simulation permits quantification of hemodynamics that cannot be assessed in-vivo. However, simulation accuracy depends on anatomical and physiological realism of in-vitro models and flow. To determine the effect of model compliance and pulsatile flow, a rigid model of an aorta was compared with a geometrically identical compliant model. Models were perfused with pulsatile flow using a positive displacement pump. Flow dynamic parameters for simulations, obtained using 4D flow MRI, showed that model compliance plays a significant role in hemodynamics during pulsatile flow. Future development of realistic in-vitro simulation, paired with in-vivo validation, will aid in surgical planning.

 3 Plasma 3 3D Hemodynamics Characterization in Patients with Hypercholesterolemia using 4D Flow data and a Finite Element Method. Julio Sotelo1,2, Animesh Tandon3, Andrew Tran3, Joaquín Mura1, Daniel E Hurtado4,5, Tarique Hussain3, and Sergio Uribe1,4,6 1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 3Department of Radiology and Biomedical Engineering, University of Texas Southwestern, Dallas, TX, United States, 4Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile, 5Department of Structural and Geotechnical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 6Department of Radiology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile Familial hypercholesterolemia (FH) is an autosomal dominant disorder of lipoprotein metabolism, that are associated with premature atherosclerosis, early-onset of cardiovascular disease (CVD) with an elevated mortality. It would be prudent to develop and investigate imaging-based hemodynamics biomarkers that assist in cardiovascular risk assessment of FH patients. In this work, we obtain several hemodynamics parameters in HP patients using a single methodology, which is based on the analysis of 4D flow data using a finite element method. We found distinctive biomarkers as WSS (magnitude, axial, circumferential) and Kinetic Energy those present more significant differences along the entire aorta.

 4 Plasma 4 Caval Blood Flow Distribution in Fontan Circulation: Comparison between ASL-Measured Pulmonary Perfusion and 4D Flow Joshua S. Greer1,2, Jerry Michael3, Barbara Burkhardt3, Animesh Tandon2,3, Gerald F. Greil2,3,4, Tarique Hussain2,3, and Ananth J. Madhuranthakam2,4 1Bioengineering, University of Texas at Dallas, Richardson, TX, United States, 2Radiology, UT Southwestern Medical Center, Dallas, TX, United States, 3Pediatrics, UT Southwestern Medical Center, Dallas, TX, United States, 4Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States Caval flow contribution to each lung is of interest in Fontan circulation due to the increased risk of developing pulmonary arteriovenous malformations when flow is unevenly distributed. Existing methods to assess this risk are invasive and require ionizing radiation, posing additional risks to pediatric patients during longitudinal monitoring. In this study, we demonstrate a non-invasive, non-ionizing assessment of the origin of pulmonary blood flow, as well as quantitative pulmonary perfusion using arterial spin labeled MR, and compare with the previously proposed 4D-flow measurement of caval flow distribution.

 5 Plasma 5 Postoperative changes in volume flow rate in the thoracic aorta and the aortic arch branches in patients with aortic valve stenosis: a prospective serial 4D flow MRI study Hiroki Kamada1, Hideki Ota1, Masanori Nakamura2, Yohsuke Imai3, Wenyu Sun1, Yoshiaki Komori4, Ko Sakatsume5, Ichiro Yoshioka5, Yoshikatsu Saiki6, and Kei Takase1 1Department of Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan, 2Department of Electrical and Mechanical Engineering, Nagoya Institute of technology, Nagoya, Japan, 3School of Engineering, Tohoku University, Sendai, Japan, 4Siemens Japan K.K., Tokyo, Japan, 5Division of Cardiovascular Surgery, Tohoku University Hospital, Sendai, Japan, 6Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan Postoperative hemodynamic changes in the aorta in patients with aortic valve stenosis (AS) remain unclear. Four-dimensional (4D) flow MRI was perfumed in 11 AS patients before and after aortic valve replacement (AVR). We evaluated volume flow rate and the main flow direction, setting 15 planes of the aorta and 3 planes of the arch branches. Volume flow rate significantly increased in the ascending aorta and the arch branches. The main flow direction came to match with the axial direction of the aorta. These results suggest that AVR results in more efficient blood transport to the upper body including the brain.

 6 Plasma 6 4D-Flow-MRI analysis of aortic flow patterns after replacement of the ascending aorta with a physiologically pre-shaped, 90° bent prosthesis Thekla Helene Oechtering1, Jennifer Schlueter1, Malte Maria Sieren1, Michael Scharfschwerdt2, Christian Auer2, Markus Huellebrand3, Hans-Hinrich Sievers2, Joerg Barkhausen1, and Alex Frydrychowicz1 1Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Luebeck, Germany, 2Department of Cardiac and Cardiothoracic Vascular Surgery, University Hospital Schleswig-Holstein, Luebeck, Germany, 3Fraunhofer MEVIS, Bremen, Germany Altered aortic anatomy after prosthesis implantation has been shown to increase secondary flow patterns with potential long-term effects. Therefore, patients after valve-sparing aortic root and ascending aorta replacement with a physiologically pre-shaped prosthesis were examined with 4D-Flow-MRI and compared to patients with straight grafts and age-matched volunteers. A reduced angulation at the distal anastomosis as well as a slightly reduced intensity of secondary flow patterns was confirmed. However, there was no reduction of secondary flow patterns in comparison to straight prostheses potentially attributed to a residual angulation at the proximal anastomosis and a dilatation at the distal anastomosis.

 7 Plasma 7 Impact of field strength (1.5, 3.0 and 7.0 Tesla) and sequence on quantification of aortic flow volumes, peak velocity and wall shear stress using 4D flow MRI Stephanie Funk1,2, Sebastian Schmitter3, Marcel Prothmann1, Carsten Schwenke4, Florian von Knobelsdorff-Brenkenhoff1,5, Andreas Greiser6, Emilie Bollache7, Michael Markl7, and Jeanette Schulz-Menger1,2 1Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany, 2DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany, 3Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany, 4SCO:SSIS Statistical Consulting, Berlin, Germany, 5Clinic Agatharied, Department of Cardiology, Ludwig-Maximilians-University Munich, Hausham, Germany, 6Siemens Healthcare, Erlangen, Germany, 7Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States For implementing 4D flow in clinical routine, standardization is important. We evaluated equivalence of 4D flow parameters in different sequences and at three different field strengths. Ten healthy volunteers were scanned at 1.5T, 3.0T and 7.0T. At 1.5T, three different sequences were applied. Ascending aorta, aortic arch and descending aorta of each scan were evaluated for diagnostic quality. After exclusion of non-diagnostic segments, equivalence testing for flow, wall shear stress and peak velocity was performed. Acceptable equivalence was determined by intra-rater analysis. Comparison of different field strengths as well as different sequences did not reach equivalence. 4D flow sequences are not interchangeable.

 8 Plasma 8 Quantifying the Impact of Velocity Field Distortions on Particle Tracking Techniques Magnus Ziegler1,2, Martin Welander1,3, Marcus Lindenberger1,3, Niclas Bjarnegård1,3, Jonas Lantz1,2, Matts Karlsson1,2, Tino Ebbers1,2, Toste Länne1,3, and Petter Dyverfeldt1,2 1Linköping University, Linköping, Sweden, 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden, 3University Hospital Linköping, Linköping, Sweden Distortions in the velocity fields acquired by 4D Flow MRI affect particle tracking based visualization and quantification methods. Particle residence time was calculated in a subject with aortic aneurysm and was used to assess how particle tracking methods are impacted by noise and offset errors. To do so, a computationally derived ideal velocity field was created and distorted by adding noise and background phase-offsets. We found that particle tracking methods are severely impacted by offset errors, though more robust to random noise. Understanding the limits of these methods is crucial for their appropriate use.

 9 Plasma 9 Quantitative MRI detects acute vascular effects of e-cig aerosol inhalation Michael C Langham1, Alessandra Stella Caporale2, and Felix W Wehrli3 13400 Spruce St, University of Pennsylvania, Philadelphia, PA, United States, 2Radiology, University of Pennsylvania, Philadelphia, PA, United States, 3University of Pennsylvania, Philadelphia, PA, United States The rapid rise in the popularity and use of the electronic cigarettes among adolescents are unsettling trends in spite of the limited science that exists on the health effects of e-cigarettes. The purpose of this project was to introduce a noninvasive method for the study of the systemic acute effects of e-cigarette aerosol inhalation on the cardiovascular system by means of quantitative MRI that targets various vascular territories. Preliminary data show reduced femoral vein SvO2 and impaired flow-mediated dilation in the femoral artery, along with elevated aortic arch pulse-wave velocity after an e-cigarette challenge equivalent to one conventional cigarette.

 10 Plasma 10 Accelerating 4D-Flow Acquisitions by Reducing TE and TR with Optimized RF and Gradient Waveforms Michael Loecher1, Patrick Magrath2, Eric Aliotta3, and Daniel B Ennis1,2,3 1Radiological Sciences, University of California, Los Angeles, CA, United States, 2Bioengineering, University of California, Los Angeles, CA, United States, 3Biomedical Physics, University of California, Los Angeles, CA, United States 4D-Flow MRI is a powerful technique for simultaneously imaging vascular anatomy and hemodynamics.  However, its clinical utility is limited by long (10-20 minute) scan times.  This work aims to shorten scan times by using fast RF pulses and convex optimized gradient waveforms.  The waveforms are optimized with arbitrary shapes, and are designed to go as fast possible without causing peripheral nerve stimulation by including an additional PNS constraint.  The optimized sequence is implemented and tested in flow phantoms and a volunteer.  The data acquired with the optimized waveforms is up to 33% faster, with no significant difference in measured data compared to a reference sequence.

 11 Plasma 11 A Dual Echo, Dual VENC (DEDV) phase contrast method for Simultaneous Measurement of Myocardial and Blood Flow Velocities Afis Ajala1, Jiming Zhang2, Benjamin Cheong2, Pei-Herng Hor1, and Raja Muthupillai2 1Physics and Texas Center for Superconductivity, University of Houston [Main Campus], HOUSTON, TX, United States, 2Baylor St. Luke's Medical Center, Houston, TX, United States Dual VENC Velocity quantification has been previously carried out with the two different VENCs acquired in separate repetition cycles (TRs). We propose a magnetic resonance imaging sequence that acquires the phase matrix for two different VENC values in one TR, and use the developed sequence for slow motions and fast flows.

 12 Plasma 12 30 times accelerated 4D flow MRI in the carotids using a Pseudo Spiral Cartesian acquisition and a Total Variation constrained Compressed Sensing reconstruction Eva S Peper1, Lukas M Gottwald1, Qinwei Zhang1, Bram F Coolen2, Pim van Ooij1, Gustav J Strijkers2, and Aart J Nederveen1 1Radiology and Nuclear Medicine, Academic Medical Center (AMC), Amsterdam, Netherlands, 2Biomedical Engineering and Physics, Academic Medical Center (AMC), Amsterdam, Netherlands 4D flow MRI enables visualization and quantification of complex blood flow, and provides relevant biomarkers, such as wall shear stress. A 4D flow MRI acquisition, however, takes between 15-40 min, which complicates its use in clinical practice. In this work, we developed a technique to reduce scan time by prospectively undersampling k-space in a pseudo-spiral Cartesian fashion. Combined with a Compressed Sensing reconstruction using a total variation sparsifying transform in time, this technique makes 4D flow MRI in the carotid arteries 20-30 times faster, while preserving accuracy in flow and wall shear stress measurements.

 13 Plasma 13 Alterations of Cardiac 4D Hemodynamics and Blood Energetics in Hypertrophic Cardiomyopathy Aakash Gupta1, Michael Markl1,2, Bradley Allen1, Lubna Choudhury3, James Carr1,2,3, Robert Bonow3, and Jeremy Collins1 1Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, 2Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, United States, 3Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States 4D flow MRI supports the development of novel energetic biomarkers in hypertrophic cardiomyopathy (HCM) – a disease marked by dynamic left ventricular outflow tract obstruction with mitral regurgitation (MR). We compared kinetic energy and velocity metrics between obstructive and non-obstructive HCM subtypes to determine where in the left heart high kinetic energy and flows were generated. Left atrium showed significantly higher systolic kinetic energy and velocities throughout ventricular systole due to MR. Including these energetic parameters may be useful to detect significant MR that is underestimated by echo, identify patients at higher risk of atrial fibrillation, and inform treatment options.

 14 Plasma 14 Dynamic flow imaging and quantification using cine FISS arterial spin labeling Robert R Edelman1,2, Ali Serhal2, Amit Pursnani3, Jianing Pang4, and Ioannis Koktzoglou1,5 1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, 3Medicine, NorthShore University HealthSystem, Evanston, IL, United States, 4Siemens Medical Systems, Chicago, IL, United States, 5Radiology, Prtizker School of Medicine, University of Chicago, Chicago, IL, United States We describe a new approach for flow imaging and quantification consisting of a prototype cine arterial spin labeling (ASL) pulse sequence using a highly-accelerated radial fast interrupted steady-state (FISS) readout. The technique was successfully applied in several vascular regions (coronary arteries, pulmonary arteries, renal arteries, circle of Willis).  These preliminary results suggest that cine FISS ASL has the potential to provide an efficient and visually-appealing alternative to phase contrast for the depiction and quantification of blood flow.

 15 Plasma 15 4D Flow Cardiac MRI Using Semi-Automated Retrospective Valve Tracking for Assessment of Severe Mitral Insufficiency Carmen PS Blanken1, Jos JM Westenberg2, Pim van Ooij1, Geertruida P Bijvoet3, Steven AJ Chamuleau3, Jean-Paul Aben4, Stefan M Boekholdt1, Aart J Nederveen1, Tim Leiner3, and R Nils Planken1 1Academic Medical Center Amsterdam, Amsterdam, Netherlands, 2Leiden University Medical Center, Leiden, Netherlands, 3Utrecht University Medical Center, Utrecht, Netherlands, 4Pie Medical Imaging, Maastricht, Netherlands Mitral insufficiency (MI) is difficult to quantify, due to cardiac motion and complex regurgitation patterns. This study evaluated the use of 4D flow MRI with semi-automated retrospective valve tracking for assessment of severe MI. Valve tracking of both the mitral and aortic valve allowed for direct measurement of retrograde flow and indirect measurement based on total left-ventricular inflow and aortic outflow. Conventional 2D MRI-based indirect quantification was used as a reference. Eccentric regurgitation patterns complicated direct quantification, necessitating manual plane angulation for accurate measurement. Indirect quantification corresponded well with 2D MRI and might be a more reproducible alternative.

Electronic Power Pitch Poster

### Poster: Trending Topics: Flexible, Material, Portable, Wireless

 Power Pitch Theater B - Exhibition Hall Monday 9:15 - 10:15

 16 Plasma 16 The iPRES-W AIR Coil: A Flexible RF Coil for Simultaneous MR Image Acquisition, Wireless Communication, and Localized B0 Shimming Jonathan D. Cuthbertson1,2, Dean Darnell1, Julia Bresticker1,2, Robert Stormont3, Fraser Robb3, Allen W. Song1,2, and Trong-Kha Truong1,2 1Brain Imaging Analysis Center, Duke University, Durham, NC, United States, 2Medical Physics Graduate Program, Duke University, Durham, NC, United States, 3GE Healthcare, Aurora, OH, United States The iPRES-W AIR coil is a highly novel RF coil design that can simultaneously perform image acquisition, wireless communication, and wirelessly controlled localized B0 shimming. In addition, the iPRES-W AIR coil benefits from all advantages of the recently unveiled AIR coil technology, which offers a flexible and ultra-lightweight coil for increased patient comfort and freedom in overlap positioning between coil elements without degrading the performance. This technology has enormous potential to improve image quality, spatial fidelity, diagnostic accuracy, and patient comfort in a wide range of MRI applications.

 17 Plasma 17 Towards wearable MR detection: A stretchable wrist array with on-body digitization Andreas Port1, Jonas Reber1, Christian Vogt2, Josip Marjanovic1, Benjamin Sporrer3, Lianbo Wu3, Andreas Mehmann2, David Otto Brunner1, Thomas Burger3, Gerhard Troester2, Qiuting Huang3, and Klaas Paul Pruessmann1 1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Electronics Laboratory, ETH Zurich, Zurich, Switzerland, 3Integrated Systems Laboratory, ETH Zurich, Zurich, Switzerland Today, MRI coils can be made flexible and stretchable. Signals can be sent out of bore by optical or wireless links. Nonetheless, wearable digital coil arrays have not yet found their way into MRI although enhanced patient comfort and workflow can be expected. In this work we explore the feasability of stretchable coil arrays with on-coil digitization and optical transmission, and present a first implementation for wrist imaging.

 18 Plasma 18 High Impedance Detector Arrays for Magnetic Resonance Bei Zhang1,2, Daniel K. Sodickson1,2,3, and Martijn A. Cloos1,2 1Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, NY, United States, 2Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, United States, 3The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States Resonant inductive coupling is commonly seen as an undesired fundamental phenomenon emergent in densely packed resonant structures, such as nuclear magnetic resonance phased array detectors. The need to mitigate coupling imposes rigid constraints on the detector design, impeding performance and limiting the scope of magnetic resonance experiments. Here we introduce a high impedance detector design, which can cloak itself from electrodynamic interactions with neighboring elements. We verify experimentally that the high impedance detectors do not suffer from signal-to-noise degradation mechanisms observed with traditional low impedance elements. Using this new-found robustness, we demonstrate an adaptive wearable detector array for magnetic resonance imaging of the hand. The unique properties of the detector glove reveal new pathways to study the biomechanics of soft tissues, and exemplify the enabling potential of high-impedance detectors for a wide range of demanding applications that are not well suited to traditional coil designs.

 19 Plasma 19 Highly Flexible, Light Weight 24 Channel 3T Bilateral Brachial Plexus Array Worn as a Close Fitting Variable Size Vest Ed Boskamp1, Victor Taracila1, Scott Lindsay2, Robert Stormont2, Reni Biswas3,4, Sheronda Statum3,4, Shane Aldas5, Cesar Barraza5, Fraser Robb1, Christine B Chung3,4, and Won Bae3,4 1G. E. Healthcare Technologies, Aurora, OH, United States, 2G. E. Healthcare Technologies, Waukesha, WI, United States, 3Radiology, University of California, San Diego, La Jolla, CA, United States, 4Radiology, VA San Diego Healthcare System, San Diego, CA, United States, 5Electrical Engineering, University of California, San Diego, La Jolla, CA, United States MR neurography of the Brachial Plexus (BP) is technically challenging, due in part to complex topographical anatomy that is sub-optimally accommodated with existing rigid receiver coil arrays. In this work we propose a wearable garment with integrated flexible loop receiver coils that conforms to the contour of the neck and shoulder, as well as variations in subject size. The loops can flex in multiple dimensions without seriously affecting noise correlation.

 20 Plasma 20 Custom, 3D Sprayed MRI receive coils Alla Zamarayeva1, Michael Liu2, Joseph Corea1, Karthik Gopalan1, Kelvin Pang3, Miki Lustig1, and Ana Claudia Arias1 1EECS, UC Berkeley, Berkeley, CA, United States, 2Georgia Institute of Technology, Atlanta, GA, United States, 3ME, UC Berkeley, Berkeley, CA, United States We developed process for fabricating patient-specific MRI receive coils via scalable and adaptable additive manufacturing approaches. Process relies on spray-depositing solution-processed electronic materials onto 3D printed custom substrates. We conducted careful materials selection, process optimization and fabricated fully functional coils. The coils spray deposited onto spherical substrate demonstrated higher SNR than control coil, when evaluated using phantom of the spherical shape, due to superior conformability to the phantom. Our approach is poised to enhance high quality clinical imaging by ensuring optimum fit of the MRI receive coils to the body parts with complex geometries, enabling reproducible placing on the patient and eliminating motion artifacts.

 21 Plasma 21 First clinical pilot study using screen-printed flexible MRI receive coils for pediatric applications Simone Angela Winkler1, Joseph Corea2, Balthazar Lechene2, Kendall O'Brien3, John Ross Bonanni3, Fraser Robb4, Greig Scott5, John Pauly5, Michael Lustig2, Ana Claudia Arias2, and Shreyas Vasanawala1 1Department of Radiology, Stanford University, Stanford, CA, United States, 2University of California Berkeley, Berkeley, CA, United States, 3Lucile Packard Children's Hospital Stanford, Stanford, CA, United States, 4GE Healthcare, Aurora, OH, United States, 5Department of Electrical Engineering, Stanford University, Stanford, CA, United States Pediatric MRI is often performed suboptimally by the use of heavy, large, and relatively inflexible coil arrays that are designed and built for adult MR imaging. For the child, these arrays can be intimidating and uncomfortable, restricting breathing.  For parents, they contribute to the stress of the exam.  For pediatric caregivers for smaller children, the coils complicate placing medical support equipment. Here, we assess the use of screen printed flexible coil arrays for pediatric applications, focusing on clinical image quality and caregiver acceptance. We conclude that a flexible screen-printed MRI receive coil is likely to yield diagnostic image quality and be preferred to a traditional coil by patients, parents, and caregivers.

 22 Plasma 22 Volumetric resonators based on novel materials for 3 T MRI Anna Mikhailovskaya1, Alena Shchelokova1, Dmitry Dobrykh1, Ivan Sushkov2, Alexey Slobozhanyuk1,3, and Andrew Webb4 1Department of Nanophotonics and Metamaterials, ITMO University, Saint Petersburg, Russian Federation, 2Department of Radiology, Vreden Russian Institute of Traumatology and Orthopedics, Saint Petersburg, Russian Federation, 3Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra, Australia, 4C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands We propose and characterise a novel metamaterial-inspired approach which reduces substantially the required outer diameter of a dielectric resonator thus making possible to design compact structures for 3 T. When used in an inductively-coupled wireless mode, the sensitivity of the “meta-resonator” was measured to be slightly higher than that of a standard dielectric resonator operating in its degenerate circularly-polarized HEM11 modes. This study demonstrates the first application of a metamaterial-based approach to MR volume coil design.

 23 Plasma 23 New ferroelectric ceramics for transmit efficiency enhancement at 1.5 Tesla Irena Zivkovic1, Alexey Slobozhanyuk2, Elizaveta Nenasheva3, and Andrew Webb1 1Radiology Department, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands, 2Department of Nanophotonics and Metamaterials, ITMO University, Saint Petersburg, Russian Federation, 3Giricond Research Institute, Ceramics Co., Saint Petersburg, Russian Federation The presence of medical implants often results in MR scans with low SAR being prescribed, which reduces the diagnostic quality of the images. This work shows that one can achieve an increase in local transmit efficiency and a corresponding decrease in SAR at 1.5 Tesla  using new ferroelectric materials (based on BaTiO3 with ZrO2 and CeO2-additives) with relative permittivities higher than 4500.  Simulations and phantom/in vivo experiments show an increased local transmit efficiency of ~50% from the body transmit coil, with a corresponding increase in SNR for a given value of SAR.

 24 Plasma 24 Comparison of a 16-channel monopole/dipole hybrid array with a combined 8-channel monopole + 8-channel high dielectric constant (HDC) disk dipole array for head imaging at 10.5T Myung Kyun Woo1, Lance DelaBarre1, Jerahmie Radder1, Russell Lagore1, Yigitcan Eryaman1, Kamil Ugurbil1, and Gregor Adriany1 1Center for Magnetic Resonance Research, Minneapolis, MN, United States We evaluate the performance both in simulation and experiment of two 10.5T head transceiver arrays. The first is a 16-channel monopole/dipole hybrid array (called the Mono-Dipole array for brevity). The second is a 16-channel monopole/HDC disk dipole array. (A combination of two 8-channel arrays: a monopole array and a high dielectric constant (HDC) disk dipole array). These novel coil designs were compared against a standard 16-channel stripline array to elucidate their relative benefits and drawbacks.

 25 Plasma 25 Pilot Tone Software Synchronization for Wireless MRI Receivers Greig Scott1, Shreyas Vasanawala2, Fraser Robb3, Pascal Stang4, and John Pauly1 1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Stanford University, Stanford, CA, United States, 3GE Healthcare, Aurora, OH, United States, 4Procyon Engineering, San Jose, CA, United States For wireless MRI to become a reality, methods must be developed to synchronize receivers that have no physical connection to the scanner. Here, we demonstrate that dual pilot tones are needed to correct for both timing skew and frequency offsets. Bench tests were performed with a master and free running slave receiver, in which the images were re-synchronized by frequency estimation methods on pilot tones.

 26 Plasma 26 Demonstration of a new volumetric wireless coil for extremities imaging Alena Shchelokova1, Dmitry Dobrykh1, Stanislav Glybovski1, Mikhail Zubkov1, Ekaterina Brui1, Cornelis A.T. van den Berg2, Irina Melchakova1, and Pavel Belov1 1Department of Nanophotonics and Metamaterials, ITMO University, Saint Petersburg, Russian Federation, 2Centre for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands We demonstrate experimentally a new design of self-resonant tunable volumetric wireless coil based on a periodic array of coupled split-loop resonators. The wireless coil operates via inductive coupling with a birdcage coil enhancing the sensitivity of the latter at 1.5T and can be used for extremities imaging. Phantom and in-vivo wrist imaging with the proposed coil demonstrate 8.6 times higher transmit power efficiency in comparison with the birdcage coil and up to 2 times higher SNR versus standard receive-only coil.

 27 Plasma 27 High Precision Wireless Clock Recovery for On-Coil MRI Receivers Using Round-Trip Carrier Phase Tracking. Arne Reykowski1, Paul Redder1, Rodrigo Calderon Rico1, Tracy Wynn1, Tim Ortiz1, Greg Dowling1, Randy Duensing2, and Scott B King1 1Invivo Corporation, Gainesville, FL, United States, 2Philips Research, Hamburg, Germany Wireless MRI coils require a local frequency reference that is very tightly synchronized with the main MRI system clock. In order to keep phase encoding errors to less than 1 degree of phase at 3T, the local reference clock cannot drift by more than +/-22ps. Unlike RF cables or optical fibers, a wireless communication channel is not constant in phase over time. Patient motion and multi-path fading cause the wireless signal to be modulated in amplitude and phase. When disciplining a local clock with the MRI system clock by wireless means, channel impairments have to be monitored and corrected.

 28 Plasma 28 Antenna Design for Wireless Clock Syncing and Q-spoiling in MRI Jonathan Y Lu1, Thomas Grafendorfer2, Shreyas Vasanawala1, Fraser Robb2,3, John M Pauly1, and Greig C Scott1 1Stanford University, Stanford, CA, United States, 2GE Healthcare Inc., Stanford, CA, United States, 3GE Healthcare Inc., Aurora, OH, United States This work explored the antenna design choices for wireless MRI, specifically for clock synchronization and scanner state detection. Antennas at 1.6GHz for the clock signal, and 3.5GHz for Q-spoil signal were tested for transmit and receive performance. Reflectors were constructed and improvements in antenna path loss were observed. A better understanding of these antennas is necessary to help satisfy link budget requirements.

 29 Plasma 29 3D imaging with a portable MRI scanner using an optimized rotating magnet and 1D gradient coil Patrick McDaniel1, Clarissa Z Cooley2,3, Jason P Stockmann2,3, and Lawrence L Wald2,3 1Massachusetts Institute of Technology, Cambridge, MA, United States, 2Athinoula A Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 3Harvard Medical School, Boston, MA, United States A low-cost portable brain MRI scanner could extend the reach of brain MRI to remote locations and point-of-care situations and extend the use of MRI into monitoring applications. We previously presented 3D imaging in a portable magnet without gradient coils using the natural field variation of a rotating permanent magnet for in-plane encoding and RF phase gradients for encoding the third direction. In this work, we show that an efficient gradient coil can phase-encode the third direction in a single shot CPMG train with minimal current (~2A) allowing low-cost amplifiers and negligible power needs, acoustic noise or heating.

 30 Plasma 30 Portable single-sided MR: multicomponent T2 relaxometry and depth profiling with a Unilateral Linear Halbach sensor Ashvin Bashyam1,2, Chris J Frangieh1,2, Matthew Li2, Jason Stockmann3,4, and Michael J Cima2,5 1Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2David H. Koch Institute For Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States, 3A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 4Harvard Medical School, Boston, MA, United States, 5Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States Widely accessible, fast, and portable MR relaxometry can provide highly valuable diagnostic information in many diseases including fluid overload, dehydration, and muscle degeneration. High cost, large size, and extended acquisition time limit the use of traditional MRI for relaxometry. We introduce a novel portable MR sensor with a large, remote, uniform magnetic field created by a Unilateral Linear Halbach array capable of performing spatially selective, multi-component relaxometry. Strong agreement between simulation and experimental results indicates highly reliable magnet design methods. Spatial selectivity is achieved through variation of either RF pulse length or B1 frequency. Quantitative multi-component T2 relaxometry is demonstrated.

Electronic Power Pitch Poster

### Poster: Molecular & Metabolic Imaging

 Power Pitch Theater A - Exhibition Hall Monday 14:45 - 15:45

 102 Plasma 1 A novel iterative sparse deconvolution method for multicolor 19F-MRI Jasper Schoormans1, Claudia Calcagno2, Mariah Daal1, Christopher Faries2, Brenda L Sanchez-Gaytan2, Aart J Nederveen3, Zahi A Fayad2, Willem J M Mulder2, Bram F Coolen1, and Gustav J Strijkers1,2 1Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, Netherlands, 2Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Radiology, Academic Medical Center, Amsterdam, Netherlands We introduce a new deconvolution approach for multicolor imaging of different 19F compounds with complex spectra. The method exploits the sparse nature of most 19F images by iterative sparse deconvolution, removes the chemical shift artifacts associated with multiple peaks in the 19F spectra, and efficiently separates multiple 19F compounds in the images. We performed numerical simulations and phantom experiments, which showed that the signal from two fluorinated compounds, i.e. PFOB and PFCE, can be separately detected without chemical shift artifacts. Moreover, we demonstrated chemical shift artifact-free multicolor detection of PFOB- and PFCE emulsion in a mouse.

 103 Plasma 2 Multimodal Assessment of Orbital Immune Cell Infiltration and Tissue Remodeling During Development of Graves’ Disease by 1H/19F MRI Ulrich Flögel1, Anke Schlüter2, Christoph Jacoby1, Sebastian Temme1, J Paul Benga2, Anja Eckstein2, Jürgen Schrader1, and Utta Berchner-Pfannschmidt2 1Experimental Cardiovascular Imaging, Heinrich Heine University, Düsseldorf, Germany, 2University of Essen, Essen, Germany The purpose of the present study was to evaluate key molecular and cellular features of Graves’ orbitopathy by simultaneous monitoring of alterations in morphology, inflammatory patterns, and tissue remodeling. Beyond anatomical 1H MRI, we employed T2 mapping for visualization of edema, chemical exchange saturation transfer for detection of hyaluronan, and 19F MRI for tracking of in situ labeled immune cells after intravenous injection of perfluorcarbons. In particular, 19F MRI allowed a sensitive demarcation of inflammatory foci in the orbit, even when other markers indicated only weak or no signs of tissue alterations.

 104 Plasma 3 Hyperpolarized Xe-129 Imaging of Pluripotent Stem Cell-Derived Alveolar-Like Macrophages in the Lungs: Proof-of-Concept Study Using Superparamagnetic Iron-Oxide Nanoparticles Vlora Riberdy1,2, Michael Litvack2, Elaine Stirrat2, Marcus Couch2, Martin Post2, and Giles Santyr1,2 1Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada A promising approach to treatment of chronic lung diseases is the intratracheal delivery of pluripotent stem cell derived alveolar-like macrophages (PSC-ALMs) into the injured lung to facilitate repair of damaged tissue. This treatment is hindered by the inability to assess where in the lung these cells end up. Here, hyperpolarized Xe-129 MRI paired with iron-labeled cells was used to demonstrate a proof-of-concept visualization of cells introduced in the lungs of rats. Signal hypointensities were observed at least one hour after instillation of approximately two million labeled cells in one rat, compared to instillation of control solutions in separate rats.

 105 Plasma 4 In Vivo Molecular Imaging of MUC1-Expressing Colorectal Tumors Using Targeted Hyperpolarized Silicon Particles Nicholas Whiting1,2, Jingzhe Hu1,3, Shivanand Pudakalakatti1, Caitlin McCowan1,3, Daniel Carson3, Jennifer Davis1, Niki Millward1, David Menter1, Pamela Constantinou3, and Pratip Bhattacharya1 1The University of Texas MD Anderson Cancer Center, Houston, TX, United States, 2Rowan University, Glassboro, NJ, United States, 3Rice University, Houston, TX, United States Silicon nano- and microparticles are well-suited for targeted molecular imaging, due to their biocompatibility, easily modifiable surface, and long-lasting 29Si MR signal (which can be enhanced by several orders of magnitude via dynamic nuclear polarization). We demonstrate targeted molecular imaging of human MUC1-expressing colon tumors in orthotopic mouse models using hyperpolarized 29Si MRI. The particles were able to selectively bind to MUC1-expressing tumors compared to controls, and the results were confirmed via histology of the excised tissue. The goal is to develop these targeted particles as a platform technology that will allow non-invasive screening of colorectal cancer using 29Si MRI.

 106 Plasma 5 Imaging glutathione depletion in the rat brain using ascorbate-derived hyperpolarized MR and PET probes Hecong Qin1,2, Valerie Carroll1, Renuka Sriram1, Cornelius von Morze1, Zhen Jane Wang1, Christopher Mutch1, Kayvan R. Keshari3, Robert R. Flavell1, John Kurhanewciz1,2, and David M. Wilson1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and San Francisco, CA, United States, 3Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States We studied brain redox capacity using ascorbate-derived hyperpolarized (HP) 13C MR and 11C PET probes. We first demonstrated the molecular transport and biodistribution features of the ascorbic acid (VitC)-dehydroascorbate (DHA) pair by leveraging both HP MR and PET modalities. We then showed that HP 13C DHA could detect redox modulation of the brain in a pharmacologic glutathione-depletion rat model. In conclusion, HP 13C DHA MR has the potential for non-invasive evaluation of brain redox capacity.

 107 Plasma 6 In-vivo metabolism of co-hyperpolarized [1-13C] pyruvate and [1,3-13C] acetoacetate identifies cytosolic and mitochondrial redox in ischemic perfused hearts Gaurav Sharma1, Craig R. Malloy1,2,3, A. Dean Sherry1,2,4, and Chalermchai Khemtong1,2 1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 3Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States, 4Department of Chemistry, University of Texas at Dallas, Dallas, TX, United States Cellular redox state is intricately linked with cardiac ischemia. Historically, tissue levels of lactate to pyruvate and β-hydroxybutyrate to acetoacetate have been used as indices of cytosolic and mitochondrial redox, respectively. The present study was designed to evaluate the potential of using co-hyperpolarized (HP) [1-13C] pyruvate and [1,3-13C] acetoacetate as reporters of cytosolic and mitochondrial redox, respectively. 13C NMR spectra of perfused rat hearts displayed increased production of both HP-lactate and HP-β-hydroxybutyrate in low flow ischemia, rotenone, and aminooxyacetate (AOA) treated hearts.  The result suggests that HP-lactate and HP-β-hydroxybutyrate are sensitive metabolic markers of tissue redox in heart tissue.

 108 Plasma 7 Probing perturbed hepatic metabolism in bile-duct-ligated rats with hyperpolarized 13C pyruvate and arginine Hikari A. I. Yoshihara1, Dmitri Firsov2, Cristina Cudalbu3, and Rolf Gruetter4 1Laboratory for Functional and Metabolic Imaging, Swiss Federal Institute of Technology, Lausanne (EPFL), Lausanne, Switzerland, 2Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland, 3Centre d'Imagerie Biomedicale (CIBM), Swiss Federal Institute of Technology, Lausanne (EPFL), Lausanne, Switzerland, 4Laboratory for Functional and Metabolic Imaging & Centre d'Imagerie Biomedicale (CIBM), Swiss Federal Institute of Technology, Lausanne (EPFL), Lausanne, Switzerland Detoxification of ammonia by the urea cycle and maintenance of glucose homeostasis by gluconeogenesis are two critical functions of the liver. The bile duct ligation (BDL) model of cirrhosis was used to test the ability of hyperpolarized [6-13C]arginine and [1-13C]pyruvate to detect changes in liver function. The conversion of hyperpolarized L-[6-13C]arginine to 13C-urea was observed in a sham-operated rat but not in BDL rats. Striking differences in pyruvate metabolism between the two groups were also noted, indicating that these probes can sense changes in hepatic mitochondrial and cytoplasmic metabolism associated with biliary cirrhosis.

 109 Plasma 8 Hollow Manganese-Silicate (HMS) Nanoparticles as a Liver Specific MRI contrast agent Moon-Sun Jang1, Jin Goo Kim2, Geun Ho Im1, Jung Hee Lee1,3, Won Jae Lee1, and In Su Lee2 1Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea, 2National Creative Research Initiative Center for Nanospace-confined Chemical Reactions and Department of Chemistry, Pohang University of Science and Technology (POSTECH), Gyeongbuk, Republic of Korea, 3Departments of Health Science and Technology and Medical Device Management and Research, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Republic of Korea In this study, we demonstrate hollow manganese silicate nanoparticle (HMS) as a liver specific magnetic resonance imaging (MRI) contrast agent. HMS releases Mn2+ ions in the acidic physiological condition, which can be utilized for characterizing different tumor types.

 110 Plasma 9 Magnetic Resonance Temperature Imaging for Nanoparticle-Mediated Tumor Photothermal Therapy Fu Guifeng1,2, Guo Jianxin1, Wei Xiaocheng3, Zhang Fan2, and Yang Jian1 1Medical Imaging Department, First Affiliated Hospital of Xi'an Jiaotong University, Xi’an, China, 2Center for Molecular Imaging and Translational Medicine, Xiamen University, Xiamen, China, 3MR Research China, GE Healthcare, Beijing, China Image-guided cancer therapy have the ability to integrate noninvasive imaging and minimally invasive interventions such as photothermal therapy (PTT) together to improve the precision of treatment. In the present study, we investigated magnetic resonance temperature imaging (MRTI) as a tool for non-invasive monitoring of tumor temperature distribution and changes during laser irradiation. To this end, we injected PEGylated graphene oxide (GO-PEG) to 4T1 tumor models and irradiated the tumors to induce PTT. Our studies demonstrate that MRTI, which is a feasible tool for the determination of temperature distribution, can be used to guide nanoparticle-mediated tumor photothermal therapy.

 111 Plasma 10 Amide proton transfer-weighted imaging in meningioma: Prediction of tumor grade, histologic subtype and association with Ki-67 proliferation status Hao Yu1, Xianlong Wang1, Qihong Rui1, Shanshan Jiang2, Jinyuan Zhou2, and Zhibo Wen1 1Department of Radiology, Zhujiang Hospital of Southern Medical University, Guangzhou, China, 2Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States A correct preoperatively predicting grade histologic subtype and tumor proliferation of meningioma is important in clinic treatment. APT imaging are designed to assess brain tumor on the level of cell and molecule. In this study we hoping to explore if this technique was useful in evaluating the meningioma comprehensively.

 112 Plasma 11 Brown Adipose Tissue Mass Measurement by Z-Spectrum Imaging Alessandro M Scotti1,2,3, Rongwen Tain1,3, Weiguo Li1,4,5, Victoria Gil6, Chong Wee Liew6, and Kejia Cai1,3 1Radiology, University of Illinois, Chicago, IL, United States, 2Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 3Center for MR Research, University of Illinois at Chicago, Chicago, IL, United States, 4Research Resource Center, University of Illinois at Chicago, Chicago, IL, United States, 5Radiology, Northwestern University, Chicago, IL, United States, 6Physiology and Biophysics, University of Illinois, Chicago, IL, United States Brown adipose tissue (BAT) has a great relevance in metabolic diseases and has been shown to be reduced in obesity and insulin resistance patients. Currently, Dixon MRI is used to calculate fat-water fraction (FWF) and differentiate BAT from the less hydrated and more lipid-rich white fat. However, it may introduce fat-water swapping artifacts. Here, we showed that Z-Spectrum MRI can effectively measure FWF and BAT mass in vivo free from artifacts, due to the direct saturation of both water and fat protons.

 113 Plasma 12 Carbon Nanodots as Diamagnetic CEST MRI Contrast Agents for Cell Labeling Jia Zhang1, Minling Gao2,3, Yue Yuan1,4, Yuguo Li1, Peter van Zijl1,5, Mingyao Ying2,3, and Guanshu Liu1,5 1Department of Radiology and Radiological Science, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 2Department of Neurology, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 3Kennedy Krieger Institute, Baltimore, MD, United States, 4Institute for Cell Engineering, 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 Carbon nanodots (Cdots), are a relatively new type of eco-friendly nanoparticles that are being utilized extensively as drug carriers with inherent fluorescence imaging. In the present study, we explored their intrinsic chemical exchange saturation transfer (CEST) MRI contrast. We showed that Cdots can be directly detected by CEST MRI due to the abundant exchangeable hydrogen protons on their surfaces, which allows Cdots inherently bimodal contrast agents. Application to cell labeling was demonstrated in vitro. To the best of our knowledge, this is the first demonstration of diamagnetic nanoparticulate CEST MRI contrast agents.

 114 Plasma 13 Correlation of tissue pH via 31P-MRSI with MTRasym derived from APT-CEST-MRI in glioblastoma and normal appearing white matter Jan Rüdiger Schüre1, Stella Breuer1, Manoj Shrestha2, Ralf Deichmann2, Marlies Wagner1, and Ulrich Pilatus1 1Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany, 2Brain Imaging Center, Goethe University Frankfurt, Frankfurt am Main, Germany The pH-value as physiological marker for clinical diagnosis can be measured with special hardware over 31P-MRSI. APT-CEST MRI offers an alternative method for such quantification but is challenging because of magnetization transfer from other tissue compartments. To evaluate the role of pH for APT-CEST, we investigated 12 patients with first diagnosis of glioblastoma and 11 healthy controls, based on asymmetric analysis of magnetization transfer (MTRasym) and calculated pH maps over 31P-MRSI. Our results show a high correlation between both parameters and support the hypothesis that an enhancement of MTRasym at 3.5ppm is associated with increased pH.

 115 Plasma 14 Imaging vascular inflammation as a marker for T-cell infiltration in preclinical tumor models. Johannes Riegler1, Vincent Javinal2, Maj Hedehus1, Jill Schartner2, and Richard A.D. Carano1 1Biomedical Imaging, Genentech, South San Francisco, CA, United States, 2Genentech, South San Francisco, CA, United States Checkpoint inhibitors, adoptive T-cell transfer and tumor vaccination are different cancer immunotherapies which have demonstrated clinical efficacy in certain patients1-3. All of these therapies require sufficient infiltration of cytotoxic T-cells into the tumor and direct contact with cancer cells. However, the reasons why certain tumors present with high T-cell infiltration while others do not are poorly understood. We therefore set out to assess if imaging vascular adhesion molecule 1 (VCAM-1) expression in the tumor vasculature could explain some of the observed differences in T-cell infiltration.

 116 Plasma 15 Translational Radiogenomics of Brain Tumors: From Lab-Invesigation to Clinical Application Dieter Henrik Heiland1, Horst Urbach2, and Irina Mader3 1Department of Neurosurgery, Medical Center Freiburg, Freiburg, Germany, 2Department of Nueroradiology, Medical Center Freibrurg, Freibrurg, Germany, 3Medical Center Freiburg, Freiburg, Germany The interpretation of radiogenomic findings and its biological or clinical meaning is currently discussed and still unknown. Therefrom, a translational approach is aimed for integration of laboratory investigations and radiogenomic findings resulting in meaningful integration of radiogenomic discoveries. The presented study aimed to explore the molecular background of a MR-Spectroscopy imaging. In a stepwise approach findings were validated on tissue samples and finally taken into glioma cell models.

Electronic Power Pitch Poster

### Poster: MRI in Cancer Therapy & Diagnostics

 Power Pitch Theater B - Exhibition Hall Monday 14:45 - 15:45

 117 Plasma 16 MRI-only Treatment Planning using Pseudo CT Generation from Deep Learning Approach Fang Liu1, Poonam Yadav2, Andrew M Baschnagel2, and Alan McMillan1 1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Department of Human Oncology, University of Wisconsin-Madison, Madison, WI, United States A MRI-only treatment planning pipeline, deepMTP, was constructed using a deep learning approach to generate continuously-valued pseudo CT images from MR images. A deep convolutional neural network was designed to identify tissue features in volumetric head MR images training with co-registered kVCT images. A set of 40 retrospective 3D T1-weighted head images was utilized to train the model, and evaluated in 10 clinical cases with brain metastases. Statistical analysis was used to compare dosimetric parameters of plans made with pseudo CT images generated from deepMTP to those made with kVCT based clinical treatment plan, where no significant difference was found.

 118 Plasma 17 Online Super-resolution 4D T2-weighted MRI for MRI-guided Radiotherapy Joshua Nathan Freedman1,2, David John Collins2, Oliver Jacob Gurney-Champion1, Simeon Nill1, Uwe Oelfke1, Martin Osmund Leach2, and Andreas Wetscherek1 1Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, 2CR-UK Cancer Imaging Centre, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom To assist treatment delivery to moving tissues on hybrid MRI-guided radiotherapy systems, high quality midposition (of the respiratory cycle) and 4D-T2w images are desirable. Current approaches to rapidly obtaining 4D-T2w MRI are often limited by thick slices, incomplete motion information and binning artefacts. Midposition and 4D-T2w images were calculated using motion-modelling and a super-resolution reconstruction, and verified by comparison with the initially acquired images. Calculated 4D-T2w images exhibited high spatiotemporal resolution (1.0x1.0x1.0 mm3, 8 respiratory phases), displayed reduced binning artefacts and no missing data. An acquisition time of 5.0-7.5 minutes was found sufficient to obtain representative midposition T2w images.

 119 Plasma 18 Rapid MR Imaging of Ocular Movement using Shared K-Space Data for Radiotherapy Planning Luc van Vught1,2, Kirsten Koolstra2, and Jan-Willem Beenakker1,2 1Ophthalmology, Leiden University Medical Center, Leiden, Netherlands, 2Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands During ocular movement, the shape and location of the intra-orbital structures change. Outlining these changes will improve the accuracy of radiotherapy treatment planning for ocular tumors and the treatment of impaired ocular movement. The resolution of ocular MRI is, however, limited by acquisition time due to eye-motion. Therefore, an acquisition strategy in which outer k-space data is shared between gaze directions was developed and evaluated in 7 healthy and 2 myopic subjects. With this technique, the location of the orbital structures was determined for nine gaze directions in approximately one minute.

 120 Plasma 19 Visual pathway structure and localisation of tumour-induced disturbance in optic pathway glioma: correlations between diffusion-MRI, visual evoked potentials, and optical coherence tomography Patrick W Hales1, Sian Handley2, Alki Liasis2, Darren Hargrave3, and Chris Clark1 1UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 2Opthalmology Department, Great Ormond Street Children’s Hospital, London, United Kingdom, 3Haematology and Oncology Department, Great Ormond Street Children’s Hospital, London, United Kingdom Optic pathway glioma (OPG) is a childhood tumour of the visual pathway. Clinical management of OPG remains challenging, as the extent of tumour infiltration of the visual pathway is not perceptible on conventional MRI. We used diffusion-MRI to delineate the visual pathway in OPG patients. Advanced ophthalmological assessment was also performed using visual evoked potentials (VEP) and optical coherence tomography. We demonstrate that fractional anisotropy (FA) in the optic pathway correlates with retinal nerve-fibre layer thickness and VEP response, and tumour invasion anterior to the optic chiasm can be detected via inter-ocular differences in optic nerve FA.

 121 Plasma 20 Differentiation between vasogenic edema and infiltrative tumor in patients with high grade gliomas using texture patch based analysis Moran Artzi1,2, Gilad Liberman1,3, Deborah T. Blumenthal2,4, Orna Aizenstein1, Felix Bokstein2,4, and Dafna Ben Bashat1,2,5 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, 4Neuro-Oncology Service, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, 5Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel This study proposes a radiomics patch-based analysis, based on conventional MRI, for classification of the non-enhancing lesion area into vasogenic edema and infiltrative tumor in patients with high-grade-gliomas. 179 MRI scans obtained from 102 patients were included: 67 patients with high-grade-gliomas and 35 patients with brain-metastases. A total of 225 histogram and gray-level-co-occurrence-matrix based features were extracted from the non-enhancing lesion. Classification was performed using various machine-learning classifiers. The best results were obtained using Linear support-vector-machine, with accuracy=87%, sensitivity=86%, and specificity=89%. Preliminary results in patients treated with bevacizumab demonstrate the clinical potential of this method to improve therapy response assessment.

 122 Plasma 21 Evaluating intratumoral necrosis in gliomas: a multi-modal study of acidosis, cellularity, and vascularity Maxime Parent1, John J. Walsh2, Lucas C. Adam1, Daniel Coman1, and D.S. Fahmeed Hyder1,2 1Radiology & Biomedical Imaging, Yale University, New Haven, CT, United States, 2Biomedical Engineering, Yale University, New Haven, CT, United States The malignant form of human glioblastoma multiforme (GBM) is linked to intratumoral necrosis. Since novel immunotherapies are being sought to treat these patients, non-invasively characterizing intratumoral necrosis in gliomas is clinically important. Here, we describe a multi-modal MRI study of acidity, cellularity, and vascularity in two glioma models that feature comparable necrosis and proliferation, but differ in vascular markers. The intratumoral necrotic core (INC) and intratumoral surrounding tissue (IST) had distinct slow and fast Gd-enhanced profiles, respectively. Despite immunohistochemical/histopathological differences, these GBM models show similar profiles of INC-IST gradients for acidity and cellularity, but not for vascularity.

 123 Plasma 22 Oxygen enhanced-MRI detects radiotherapy-induced change in hypoxia in xenograft models and lung cancer patients Ahmed Salem1,2, Ross Little3, Adam Featherstone3, Muhammad Babur4, Hitesh Mistry4, Susan Cheung3, Yvonne Watson3, Victoria Tessyman4, Marie-Claude Asselin3, Alan Jackson3, Kaye Williams4, Geoffrey Parker3,5, Corinne Faivre-Finn1,2, and James O'Connor1,6 1Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom, 2Department of Clinical Oncology, The Christie Hospital NHS Trust, Manchester, United Kingdom, 3Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom, 4Division of Pharmacy and Optometry, University of Manchester, Manchester, United Kingdom, 5Bioxydyn Ltd, Manchester, United Kingdom, 6Department of Radiology, The Christie Hospital NHS Trust, Manchester, United Kingdom Oxygen-enhanced MRI (OE-MRI) has shown promise as a technique for quantifying and spatially mapping tumour hypoxia. Here, we report a world first-in-man study showing that OE-MRI signals in perfused tumour can non-invasively track changes in hypoxia induced by radiotherapy. We show that OE-MRI detects (1) reduction in hypoxia in Calu6 xenografts and that this change is due to hypoxia modification; and (2) reduction in hypoxia is also seen in 14 patients with non-small cell lung cancer. These data support first-in-man use of OE-MRI biomarkers in clinical trials of (chemo)-radiotherapy as single agent or in combination with hypoxia-modifying agents.

 124 Plasma 23 Assessment of Distant Tumor Stimulation from Liver Radiofrequency Ablation in a Rat Breast Carcinoma Model using Hyperpolarized 13C-Pyruvate MRI Joseph Scott Goodwin1, David Mwin1, Patricia Coutinho de Souza1, Svayam Dialani1, John T Moon1, Aaron K Grant1, Muneeb Ahmed1, and Leo L Tsai1 1Radiology, Beth Israel Deaconess Medical Center, Boston, MA, United States Radiofrequency ablation (RFA) is commonly used to treat tumors such as hepatocellular carcinomas. However, there is evidence that liver RFA can stimulate growth in tumors at other sites, a process attributed to the HFG/c-Met pathway. Hyperpolarized 13C-pyruvate MRI showed increased intratumoral lactate production in subcutaneously-implanted R3230 tumors following RFA of normal liver in a rat model. This effect is suppressed when liver RFA is combined with a c-Met inhibitor. 13C MRI could potentially be used to identify tumors at risk for this off-target effect.

 125 Plasma 24 Late gadolinium enhancement of colorectal liver metastases post-chemotherapy is associated with tumour fibrosis and overall survival post-hepatectomy Helen Cheung1, Paul J Karanicolas2, Eugene Hsieh3, Natalie Coburn2, Tishan Maraj1, Jin J Kim1, Howaida Elhakim3, Masoom A Haider1, Calvin Law2, and Laurent Milot1 1Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada, 2Department of Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada, 3Department of Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada Preoperative MRI is routinely used for diagnosis, staging, and operative planning of colorectal liver metastases (CRCLM), but still relatively unexplored for preoperative prognosis.  Tumour fibrosis in post-hepatectomy CRCLM  specimens is associated with long-term survival and late gadolinium enhancement is associated with tumour fibrosis in other disease processes (eg. cholangiocarcinoma).  We performed a retrospective cohort study (n=121) in patients who received a clinical gadolinium-enhanced MRI prior to hepatectomy for CRCLM.  We determined that strong enhancement on delayed phase MRI was associated with tumour fibrosis post-hepatectomy and overall survival.

 126 Plasma 25 Human Hyperpolarized 13C MR of Liver and Bone Metastases using both EPSI and EPI Acquisitions Zihan Zhu1,2, Jeremy W Gordon1, Hsin-Yu Chen1, Eugene Milshteyn1,2, Daniele Mammoli1, Lucas Carvajal1, Peter J Shin1, Rahul Aggarwal3, Robert Bok1, John Kurhanewicz1, Pamela Munster3, and Daniel B Vigneron1 1Department of Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States, 2UC Berkeley - UCSF Graduate Program in Bioengineering, UCSF, San Francisco, CA, United States, 3Department of Medicine, UCSF, San Francisco, CA, United States Hyperpolarized 13C metabolic imaging is a powerful technique with proven safety and efficacy for human studies. The goal of this project was to investigate pyruvate metabolism in patients with prostate and breast cancer metastases with both echo-planar spectroscopic imaging (EPSI) and the echo-planar imaging (EPI) acquisitions in the same exam. The results revealed similarly valuable information of up-regulated LDH-catalyzed conversion of pyruvate to lactate with some advantages and differences between the two acquisition methods.

 127 Plasma 26 Two Dimensional COSY on Biopsy Distinguishes Indolent From Aggressive Kidney Masses Aaron Urquhart1, Sharon Del Vecchio2, Lutz Krause3, Robert Ellis2, Keng Lim Ng4, Hema Samaratunga5, Sonja Gustafson6, Graham Galloway1,3, Glenda Gobe2, Peter Malycha1, Simon Wood4, and Carolyn Mountford1 1Translational Research Institute, Brisbane, Australia, 2Faculty of Medicine, The University of Queensland, Brisbane, Australia, 3The University of Queensland, Brisbane, Australia, 4Department of Urology, Princess Alexandra Hospital, Brisbane, Australia, 5Aquesta Uropathology, Brisbane, Australia, 6Department of Radiology, Princess Alexandra Hospital, Brisbane, Australia Kidney tumour metabolism may have chemical signatures that distinguish indolent from aggressive small renal masses (SRM). Indolent or benign SRM could be managed conservatively. Here we have used two dimensional (2D) COrrelation SpectroscopY (COSY) on nephrectomy samples to assign and measure metabolite and lipid resonances. High level bioinformatics analysis was then applied. We report metabolic chemical signatures that can be used to distinguish histologically-diagnosed kidney tumour subtypes.

 128 Plasma 27 In vivo cancer detection and dynamics with magnetic particle imaging Elaine Yu1, Mindy Bishop1, Bo Zheng1, R Matthew Ferguson2, Amit P Khandhar2, Scott J Kemp2, Kannan M Krishnan2,3, Patrick Goodwill1,4, and Steven Conolly1,5 1Department of Bioengineering, University of California, Berkeley, CA, United States, 2Lodespin Labs, Seattle, WA, United States, 3Department of Material Science and Engineering, University of Washington, Seattle, WA, United States, 4Magnetic Insight, Inc., Alameda, CA, United States, 5Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, United States Magnetic Particle Imaging (MPI) is a novel, high-contrast, and quantitative imaging modality that directly detects superparamagnetic iron oxide nanoparticle (SPIO) tracers.  These SPIOs have been previously used as a MRI contrast agent. However, with MRI SPIOs are limited by poor specificity and difficulty associated with quantifying the negative signal.  MPI enables the direct detection of these SPIOs with both high sensitivity and positive contrast. MPI is  well poised to support MRI in developing a clinically translatable cancer detection platform with SPIO. Here we demonstrate in vivo cancer detection and dynamic perfusion imaging with MPI.

 129 Plasma 28 Ferumoxytol-enhanced MRI: Early Results in Solid Organ Masses. Puja Shahrouki1,2, Woo Kyoung Jeong1,3, Steven S. Raman1, Ely R. Felker1, David S. Lu1, and J. Paul Finn1,2 1Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 2Diagnostic Cardiovascular Imaging Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 3Department of Radiology and Imaging Sciences, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea Whereas experience is growing rapidly with the use of ferumoxytol as an alternative to gadolinium based contrast agents (GBCA) for cardiovascular imaging, little has been reported about its potential for imaging of solid organs.  The pharmacokinetics and relaxometry of ferumoxytol are very different to all of the available GBCA, and data are lacking about its behavior in extracranial solid organ lesions.  We report early results of FE-MR imaging in a variety of solid organ mass lesions with focus on enhancement characteristics and clinical impact.

 130 Plasma 29 Whole-Body MRI for Metastatic Cancer Detection using T2-Weighted Imaging with Fat and Fluid Suppression Xinzeng Wang1, Ali Pirasteh1, James Brugarolas2,3, Neil M. Rofsky1,4, Robert E. Lenkinski1,4, Ivan Pedrosa1,3,4, and Ananth J. Madhuranthakam1,4 1Radiology, UT Southwestern Medical Center, Dallas, TX, United States, 2Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States, 3Kidney Cancer Program, Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, United States, 4Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States Whole-body diffusion with background suppression (DWIBS) has increased sensitivity and specificity for metastatic cancer detection. However, DWIBS using echo-planar readout suffers from geometric distortions due to large B0 inhomogeneities associated with large FOV, used in whole-body MRI. Additionally, DWIBS suffers from low spatial resolution and long scan times due to low signal to noise ratio. In this work, we developed an alternative WB-MRI technique at 3T using fast, high-resolution and high-SNR T2-weighted imaging with simultaneous fat and fluid suppression, called DETECT. Patient studies show that, DETECT is time-efficient, robust, and generates distortion-free images with good lesion conspicuity, compared to DWIBS.

 131 Plasma 30 Whole body functional and anatomical MRI: Accuracy in staging and interim response monitoring of Childhood and Adolescent Hodgkin’s Lymphoma compared to multimodality conventional imaging Arash Latifoltojar1, Shonit Punwani1, Andre Lopes2, Paul D Humphries1, Deena Neriman3, Leon Menezes3, Stephen Daw4, Ananth Shankar4, Bilyana Popova2, K M Mak2, Heather Fitzke1, Paul Smith2, Laura Clifton-Hadley2, and Stuart Andrew Taylor1 1Centre for Medical Imaging, University College London, London, United Kingdom, 2Cancer Research UK and UCL Cancer Trial Centre, University College London, London, United Kingdom, 3Institute of Nuclear Medicine, University College London Hospital, London, United Kingdom, 4Department of Paediatric Haemato-oncology, University College London Hospital, London, United Kingdom Whole-body MRI (WB-MRI) offers an alternative non-ionising radiation technique to current gold-standard imaging,  18F-FDG PET-CT, for assessment of paediatric and adolescent Hodgkin's lymphoma (HL). In this work we prospectively evaluated WB-MRI, including diffusion-weighted-imaging (DWI), for initial staging and early interim response monitoring in 50 paediatric HL patients. WB-MRI with DWI has reasonable intrinsic diagnostic accuracy for nodal and extra-nodal staging of paediatric HL but it fails to achieve full concordance with standard imaging for all disease sites in minority of patients. WB-MRI has reasonable accuracy for interim response classification but tends to underestimate disease response, particularly in extra-nodal disease sites.

Electronic Power Pitch Poster

### Poster: Pulse Sequence Highlights

 Power Pitch Theater A - Exhibition Hall Monday 17:15 - 18:15

 207 Plasma 1 Maxwell-compensated waveform design for asymmetric diffusion encoding Filip Szczepankiewicz1,2 and Markus Nilsson1 1Clinical Sciences, Lund, Lund University, Lund, Sweden, 2Random Walk Imaging AB, Lund, Sweden Asymmetric gradient waveforms enable efficient diffusion encoding but suffer from signal bias and image artifacts due to Maxwell terms (concomitant fields). We propose a novel method for generating "Maxwell-compensated" waveforms, and we demonstrate that such waveforms retain superior efficiency and exhibit negligible effects due to concomitant fields.

 208 Plasma 2 Spin And Field Echo (SAFE) dynamic field correction in 3T fetal EPI Lucilio Cordero-Grande1, Anthony Price1, Giulio Ferrazzi2, Jana Hutter1, Daan Christiaens1, Emer Hughes1, and Jo Hajnal1 1King's College London, London, United Kingdom, 2Physikalisch-Technische Bundesanstalt, Braunschweigh and Berlin, Germany A method for echo planar imaging dynamic B0 field correction based on phase unwrapping is presented. For gradient-echo functional studies, the phase of the natively acquired images is used to estimate the accumulated B0-induced dephasing. For spin-echo diffusion, a matched echo planar imaging field echo navigator is acquired after the spin-echo readout so that motion-induced phase components can be subtracted before unwrapping. Application to both functional and diffusion in-vivo 3T fetal brain imaging is illustrated.

 209 Plasma 3 Self-Gated and Real-time Simultaneous Multi-Slice Cardiac MRI from the Same Acquisition Sebastian Rosenzweig1, Hans Christian Martin Holme1,2, Nick Scholand1, Robin Niklas Wilke1,2, and Martin Uecker1,2 1Intistut für Diagnostische und Interventionelle Radiologie, University Medical Center Göttingen, Göttingen, Germany, 2Partner Site Göttingen, German Centre for Cardiovascular Research (DZHK), Göttingen, Germany Cardiac MRI requires fast and robust acquisition and reconstruction strategies to generate clinically reliable results. Using a combination of non-aligned radial Simultaneous Multi-slice (SMS) acquisitions and Regularized Nonlinear Inverse reconstruction, time-consistent movies of multiple slices can be generated. Here, we develop a self-gating technique for real-time radial SMS measurements which allows for the reconstruction of high-quality self-gated cine loops in addition to real-time movies from the same measurement.

 210 Plasma 4 Phase Encoded xSPEN: A High-Definition Approach to Volumetric MRI with Unusually High Acceleration Factors Zhiyong Zhang1, Michael Lustig2, and Lucio Frydman1 1Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel, 2Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, United States xSPEN is a single-shot MRI approach whose timing and pre-acquisition hyperbolic phase, endow it with exceptional resilience to offsets. We recently introduced multi-scan, phase-encoded (PE) 3D xSPEN MRI which preserves this while increasing resolution along the PE (y) and slab-selection (z) dimensions. It is here shown that parallel receivers endow this 3D approach with unprecedented PE downsampling performances. This reflects xSPEN’s unusual kernel, whose hyperbolic phase couples the directly-sampled kz information with the y coil sensors. This mitigates the artifacts associated with a highly undersampled ky axis, as demonstrated by highly accelerated in vitro and human scans.

 211 Plasma 5 Accelerated T2-Weighted Imaging of the Abdomen with Self-Calibrating Wave-Encoded 3D Fast Spin Echo Sequences Feiyu Chen1, Valentina Taviani2, Joseph Y. Cheng3, John M. Pauly1, and Shreyas S. Vasanawala3 1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Global MR Applications and Workflow, GE Healthcare, Menlo Park, CA, United States, 3Radiology, Stanford University, Stanford, CA, United States In this work, a self-calibrating wave-encoded 3D FSE technique was proposed with self-refocusing gradient waveforms and autocalibrated estimation of wave-encoding point-spread-function and coil sensitivity maps. Compared to conventional Cartesian approach at the same acceleration factor, the proposed method achieves reduced artifacts and better anatomical delineation for highly undersampled abdominal imaging. It enables 10-fold acceleration for 3D FSE scans of the abdomen, allowing 3D FSE sequences to be less sensitive to subject motion.

 212 Plasma 6 Tilted-CAIPI for Highly Accelerated Distortion-Free EPI with Point Spread Function (PSF) Encoding Zijing Dong1, Fuyixue Wang2,3, Timothy G. Reese2, Mary Kate Manhard2, Berkin Bilgic2, Lawrence L. Wald2,3, Hua Guo1, and Kawin Setsompop2,3 1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, 2A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 3Harvard-MIT Health Sciences and Technology, MIT, Cambridge, MA, United States The main challenge in high-resolution EPI is the significant B0-distortion and T2*-blurring artifacts. PSF-encoded EPI has been proposed to achieve distortion- and blurring- free imaging at a cost of extremely long acquisition time, not practical for most applications. In this work, we introduce the “tilted-CAIPI” method, which can provide >20x acceleration for PSF-EPI by utilizing the concept of B0-inhomogeneity encoding and optimized sampling. With the proposed method, PSF-encoded EPI at a 1mm resolution range can be obtained using just 4-8 EPI-shots. PSF-EPI with tilted-CAIPI was demonstrated for efficient acquisition of distortion- and blurring- free T2-weighted, T2*-weighted, and diffusion-weighted images.

 213 Plasma 7 Silent MRF : Quantitative scan with reduced noise using the Magnetic Resonance Fingerprinting (MRF) framework Dan Ma1, Bhairav B Mehta1, and Mark A Griswold1 1Radiology, Case Western Reserve University, Cleveland, OH, United States Because MRF provides a flexible framework without any requirement for constant repetition times or gradient amplitudes, we propose to use arbitrary gradient waveforms and randomized TR times to reduce the acoustic noise, while still providing quantitative 3D T1 and T2 values.

 214 Plasma 8 Focused, High-Resolution, Distortion-Free Diffusion Imaging Myung-Ho In1, Yi Sui1, Joshua D Trzasko1, Yunhong Shu1, Shengzhen Tao1, Erin M Gray1, John Huston1, and Matt A Bernstein1 1Department of Radiology, Mayo Clinic, Rochester, MN, United States This study reports focused, high-resolution, distortion-free diffusion imaging using a combination of DIADEM (Distortion-free Imaging: A Double Encoding Method) and reduced field-of-view (rFOV) imaging. DIADEM is a hybrid, multi-shot approach inspired by the point-spread-function mapping technique for distortion-free imaging. The multiple-shots effectively signal average and compensate for the reduced image SNR resulting from the rFOV. The rFOV reduces the number of phase-encoding steps, which shortens the scan time, making it more clinically feasible. The results demonstrate focused distortion-free diffusion images with a high in-plane resolution (0.86 mm2), which could provide improved anatomic depiction of local brain tissue structures.

 215 Plasma 9 DP-TSE MRF: Rapid and Accurate T2 and ADC Quantification Using Diffusion-Prepared Turbo Spin-echo Magnetic Resonance Fingerprinting Zhixing Wang1,2, Xiaozhi Cao2, Congyu Liao2, Huihui Ye2,3, Hongjian He2, and Jianhui Zhong2 1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China, 3State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, China This study proposes a rapid and accurate MR fingerprinting (MRF) framework based on a diffusion-prepared, turbo spin-echo (DP-TSE) sequence. Compared to both conventional parametric mapping and recent FISP-based MRF methods, the proposed framework provides accurate T2 maps and three main apparent diffusion coefficients (ADCs) for 15 slices within 7 minutes. This new MRF strategy can achieve accurate, inherently co-registered, high resolution T2 and ADC maps simultaneously.

 216 Plasma 10 Shuttered EPI Brain Imaging at 7 Tesla Saikat Sengupta1, Kawin Setsompop2, and William A Grissom3 1Department of Radiology, Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 2Department of Radiology, A.A. Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, MA, United States, 3Department of Biomedical Engineering, Vanderbilt University Institute of Imaging Science, Vanderbilt Univserity, Nashville, TN, United States Achieving robust sub-millimeter resolution EPI at 7 Tesla is a challenge since conventional single shot images suffer from long echo times and severe image distortions, while multishot EPI suffers from motion- and respiration-induced shot-to-shot phase errors. Recently, Taviani et al described an ‘in-plane multiband’ or ‘shuttered EPI’ method for 3T breast diffusion imaging, in which data are acquired in each shot after exciting a set of shutters across the imaged slice and combined using a phase- and motion-insensitive reconstruction. Here we present an implementation of this approach for high-resolution 7T brain imaging, which required a new RF pulse construction.

 217 Plasma 11 Echo Planar Time-resolved Imaging (EPTI) Fuyixue Wang1,2, Zijing Dong3, Timothy G. Reese1, Berkin Bilgic1, Mary Kate Manhard1, Lawrence L. Wald1,2, and Kawin Setsompop1,2 1A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard-MIT Health Sciences and Technology, MIT, Cambridge, MA, United States, 3Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China A new technique, termed Echo Planar Time-resolved Imaging (EPTI), was developed to address EPI’s geometric distortion and blurring, and to provide new temporal signal evolution information across the EPI readout window. Using only a few shots, a time-series of multi-contrast images can be created free of distortion and blurring (up to 100 T2- and T2*-weighted images with time interval of an EPI echo spacing). This should make EPTI useful for numerous applications where undistorted images across multiple-contrasts are desired. We demonstrated EPTI in brain to simultaneously map T2, T2*, and tissue phase, as well as to provide SWI.

 218 Plasma 12 TOPPE: A framework for rapid prototyping of MR pulse sequences Jon-Fredrik Nielsen1 and Douglas C Noll1 1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States We present a simple MR pulse programming framework for rapid prototyping of complex, custom MR pulse sequences. We define a file format that contains all low-level details of an MR imaging experiment, along with a driver (or interpreter) that loads the file(s) and executes the experiment on a General Electric scanner. We demonstrate that a wide range of sequences can be implemented with this setup, subject to limitations such as non-overlapping waveforms. Our framework is conceptually similar to Pulseq, a recently-introduced file format specification for which drivers for other vendor platforms exist (at present, Siemens and Bruker).

 219 Plasma 13 Time-optimal control based RF pulse design under gradient imperfections Christoph Stefan Aigner1, Armin Rund2, Samy Abo Seada3, Shaihan Malik3, Joseph V Hajnal3, Karl Kunisch2,4, and Rudolf Stollberger1 1Institute of Medical Engineering, Graz University of Technology, Graz, Austria, 2Institute for Mathematics and Scientific Computing, University of Graz, Graz, Austria, 3Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, 4Johann Radon Institute for Computational and Applied Mathematics (RICAM), Austrian Academy of Sciences, Linz, Austria We demonstrate the joint design of minimum duration RF and slice selective gradient shapes with included gradient impulse response function (GIRF) to correct for non-ideal slice selective gradients in the pulse design. The proposed time-optimal control method designs slice selective gradient shapes with matched RF shapes for the distorted slice selective gradient. Phantom experiments on a 3T scanner validate the optimized results and demonstrate the successful correction of gradient imperfections with the proposed approach.

 220 Plasma 14 Fast multi-component T1 and T2 correlation measurements using steady-state free precession Julian Pfister1, Felix A. Breuer1, Peter M. Jakob2, and Martin Blaimer1 1Magnetic Resonance and X-ray Imaging Department, Fraunhofer Development Center X-ray Technology (EZRT), Würzburg, Germany, 2Experimental Physics 5, University of Würzburg, Würzburg, Germany An inversion recovery bSSFP measurement allows to generate a spectrum of the apparent relaxation time T1* and hence to identify multiple components in a voxel. However, it is not possible to extract unambiguous T1 and T2 information for each individual component. Here, we demonstrate that this limitation can be overcome by an additional bSSFP measurement without inversion pulse. Additive and subtractive combinations of the measured signal courses provide enough information for assigning unambiguous T1, T2 and proton density values to each component. In that way, 2D T1-T2 correlation spectra can be generated voxel-wise in a very time-efficient manner.

 221 Plasma 15 MEG-Navigators for Motion Detection and Quality Assurance in MR Elastography Christian Guenthner1 and Sebastian Kozerke1 1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland We propose to use the motion encoding gradients (MEGs) of a conventional 3D GRE-MRE sequence as efficient 1D projection navigators with only minor changes to the sequence timing. We show that MEG-NAVs can be used to detect breathing motion, flexing of the thigh muscle, as well as changes in magnitude and phase of the MRE transducer. The additional MEG-NAV data can be used to check breath-hold compliance in conventional GRE-MRE liver exams as well as to ensure optimal transducer operation.

Electronic Power Pitch Poster

 Power Pitch Theater B - Exhibition Hall Monday 17:15 - 18:15

 222 Plasma 16 Iron-related gene expression associated with magnetic susceptibility reductions: Application to the pathophysiology of a movement disorder population Ahmad Seif Kanaan1,2, Alfred Anwander1, Riccardo Metere1, Andreas Schäfer3, Torsten Schlumm1, Jamie Near4, Berkin Bilgic5, Kirsten Müller-Vahl2, and Harald Möller1 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Department of Psychiatry, Hannover Medical School, Hannover, Germany, 3Siemens Healthcare, Erlangen, Germany, 4Douglas Mental Health Institute, McGill University, Montreal, QC, Canada, 5Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States We employ a genetic-imaging approach to examine the underlying genetic basis of magnetic susceptibility reductions at a major locus of pathophysiology in Gilles de la Tourette syndrome (GTS). Voxel-wise statistical differences of motor-striatal susceptibility exhibited significant associations with the expression profile of iron-related gene-sets extracted from the Allen Human Brain Atlas, thus suggesting that the expression of iron-related genes coincides with patterns of susceptibility reductions in GTS. This work supports previous studies relating magnetic susceptibility to brain iron and provides an example of an analytic strategy in which valuable insights can be gleaned by exploring associations between gene-expression and image-derived phenotypes.

 223 Plasma 17 Multimodal ASL/PET/mRNA-expression analysis reveals CBF changes after single dose of antipsychotics depend on dopamine D2 receptor density profiles. Pierluigi Selvaggi1, Mattia Veronese1, Peter C. T. Hawkins1, Ottavia Dipasquale1, Gaia Rizzo2,3, Juergen Dukart4, Fabio Sambataro5, Alessandro Bertolino6, Steven C.R. Williams1, Federico E Turkheimer1, and Mitul A. Mehta1 1Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom, 2Imanova Ltd., Centre for Imaging Sciences, Hammersmith Hospital, London, United Kingdom, 3Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK, London, United Kingdom, 4Translational Medicine Neuroscience and Biomarkers, F. Hoffmann-La Roche Ltd, Basel, Switzerland, 5Department of Experimental and Clinical Medical Sciences, University of Udine, Udine, Italy, 6Department of Basic Medical Science, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy In this study, we tested whether CBF changes after acute administration of antipsychotics in healthy volunteers are associated with receptor distribution profiles of one of their main targets, namely the dopamine D2 receptor.  Receptor distribution profiles were extracted from an in-house [18F]Fallypride template and from the Human Allen Brain Atlas. Results show that changes in CBF measures are directly proportional to dopamine D2 receptor levels as indexed by PET maps and mRNA expression levels. Overall the present study shows evidence that CBF is ultimately a functional marker which can be adopted in drug challenges to inform the drug development process.

 224 Plasma 18 Impaired modulation of hippocampal glutamate during memory consolidation in schizophrenia: Evidence from ¹H fMRS Jeffrey A. Stanley1, Patricia Thomas1, Dalal Khatib1, Asadur Chowdury1, Usha Rajan1, Luay Haddad1, Amirsadri Alireza1, and Vaibhav A. Diwadkar1 1Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States Schizophrenia is one of the most debilitating, life-long mental illnesses where treatment has a limited impact in restoring real-life functions such as deficits in learning and memory.  The hippocampus is particularly rich in glutamatergic neurons and altered neuroplasticity related to glutamate has been proposed as a critical mechanism mediating learning and memory in schizophrenia. Understanding glutamate-related dysfunction in schizophrenia may therefore, elucidate mechanisms underlying the illness as well as help tailor intervention strategies. Here we provide the first ever evidence of a dysfunctional modulation of hippocampal glutamate during memory encoding in schizophrenia using ¹H fMRS.

 225 Plasma 19 N-acetyl-cysteine supplementation improves functional connectivity in the cingulate cortex in early psychosis Emeline Mullier1, Timo Roine1, Alessandra Griffa2, Philipp Baumann3, Philippe Conus4, Kim Q. Do4, and Patric Hagmann1 1Radiology, Lausanne University Hospital (CHUV), Lausanne, Switzerland, 2Dutch connectome lab, University Medical Center (UMC), Utrecht, Netherlands, 3Service of General Psychiatry and Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland, 4Department of psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland Schizophrenia implies different alterations in prefrontal cortex and in particular, a disrupted connectivity in this brain area and a redox dysregulation. In a previous analysis, glutathione levels (main antioxidant and redox regulator) correlated with functional connectivity within the cingulate cortex. In this study, we investigate the effect of N-acetyl-cysteine (NAC) (precursor of glutathione) supplementation on functional connectivity in early psychosis patients. The results show an increased functional connectivity strength and betweenness centrality in these regions, suggesting that cingulate cortex functional connectivity could be a biomarker for NAC treatment efficacy

 226 Plasma 20 Altered Brain Development in Infants and Young Children with at Risk Genetics for Psychiatric Dysfunction Justin Remer1,2, Douglas C. Dean III3, Muriel Bruchhage2,4, and Sean C.L. Deoni2 1Brown University Warren Alpert School of Medicine, Providence, RI, United States, 2Memorial Hospital, Brown University, Providence, RI, United States, 3Waisman Center, University of Wisconsin, Madison, WI, United States, 4Center for Neuroimaging, King's College, London, United Kingdom Catechol-O-methyltransferase (COMT) polymorphisms have been implicated as an important contributor to psychosis and cognitive differences. Such cognitive alterations may have a neurodevelopmental basis, however, the effect of COMT polymorphisms on early brain development are unclear. Here, we perform the first longitudinal study of differential cortical maturation in infants and young children ages 1 to 6 based on COMT genotype. We demonstrate altered rates of cortical development in the cingulate, frontal and temporal lobes in children with the rs46480 (Val/Met) genotype, suggesting the COMT genotype has an important impact on brain maturation.

 227 Plasma 21 7T MRS in First Episode Psychosis: Neurotransmitter Deficits and Neuronal Impairment Anna Min Wang1,2, Subechhya Pradhan1,2, Akira Sawa3, and Peter B. Barker1,2 1Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Kennedy Krieger Institute, Baltimore, MD, United States, 3Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, United States The results of a 7T MRS study of a large cohort of patients with a first episode of psychosis (FEP) and healthy control subjects (HC) are reported. In patients with FEP, significant reductions in the neurotransmitters glutamate and GABA were found in selected gray matter regions, and the neuromodulator NAAG was reduced in white matter. Other metabolic abnormalities were reduced NAA (suggesting neuroaxonal damage) and glutathione. Metabolite differences were also found to depend on diagnosis. This study suggests that 7T MRS is a useful modality for understanding the molecular pathophysiology of psychosis.

 228 Plasma 22 A DTI connectome and machine learning approach to predict symptom improvement in depressed adolescents with cognitive-behavioral therapy (CBT) Olga Tymofiyeva1, Justin Yuan1, Colm G Connolly2, Eva Henje Blom3, Duan Xu1, and Tony Yang1 1University of California, San Francisco, San Francisco, CA, United States, 2Florida State University, Tallahassee, FL, United States, 3Umea University, Umea, Sweden We applied machine learning to DTI-based structural connectome data in order to predict improvement of symptoms in 30 depressed adolescents with cognitive-behavioral therapy (CBT). The J48 pruned tree classifier was applied with a 10-fold cross-validation, resulting in an 83% accuracy. The resulting tree highlights the role of the thalamus, a region known to be directly involved in anticipatory anhedonia and generation of goal-directed behavior, the lack of which can make subsequent CBT ineffective. The gained knowledge can significantly improve treatment planning in cases of adolescent depression and help optimize and develop new preventive and therapeutic interventions for this devastating disorder.

 229 Plasma 23 Neural network classification of ADHD based on white matter connectograms derived from diffusion spectrum imaging Chang-Le Chen1,2, Yung-Chin Hsu1, Susan Shur-Fen Gau2,3, and Wen-Yih Isaac Tseng1,2,4 1Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 2Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, Taipei, Taiwan, 3Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan, 4Molecular Imaging Center, National Taiwan University, Taipei, Taiwan The diagnosis of ADHD relies on psychiatrists’ knowledge and subjective experience. Many studies aimed to develop an objective method to assist diagnosis, but the performance of classification between ADHD and controls was not acceptable for clinical use. Here, we proposed a neural network model based on white matter information to classify ADHD and typically developing controls. Diffusion spectrum imaging and tract-based automatic analysis were used to measure properties of white matter. The neural network classification model was developed with high accuracy in the training and test data. It might be helpful to provide an objective way for diagnosis of ADHD.

 230 Plasma 24 Hippocampal-subfield Specific Connectivity Alterations in Major Depressive Disorder Patients at 7 Tesla John W Rutland1, Prantik Kundu 1, Patrick R Hof2, James W Murrough3, and Priti Balchandani1 1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States This study quantifies connectomic changes that occur within hippocampal subfields in patients with major depressive disorder (MDD). Using ultra-high field MRI (7 Tesla), we performed subfield-specific tractography in 6 MDD patients and 9 healthy controls. The degree of the hippocampal fissure was bilaterally increased in MDD patients compared to controls. Edgewise analyses revealed that CA3-vPFC, CA3-dlPFC, and CA1-vPFC edges were significantly increased in MDD patients compared to controls within the right hemisphere. These in vivo findings indicate that MDD patients display increased connectivity within certain hippocampal subfields, and between subfields the prefrontal cortex (PFC).

 231 Plasma 25 Reduced Local Segregation in Single-Subject Grey Matter Networks in Adult PTSD Running Niu1, Du Lei2, and Qiyong Gong3 1HMRRC, West China Hospital, Chengdu, China, China, 2Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom, London, United Kingdom, 3uaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan, Chengdu, China The present study investigated graph properties of single-subject grey matter networks in PTSD using a new method proposed by Tijms and colleagues to statistically describe gray matter networks in individual subjects using T1-weighted MRI scans. Compared with trauma exposed controls, global topology of single-subject grey matter networks of PTSD was characterized by decreased clustering coefficient and local efficiency. The reduced segregation in grey matter network and its negative relation with increased segregation in the functional network may be important for understanding the nature of the brain network disorganization associated with PTSD and facilitate clinical diagnosis in patients with suspected PTSD

 232 Plasma 26 Sertraline treatment modulates salience connectivity in major depressive disorder Li-Ming Hsu1, Changwei W. Wu1, Chien-Yuan Lin2, Chi-Yun Liu1, Timothy Lane1, Ching-Po Lin3, Chi-Bin Yeh4, and Hung-Wen Kao4 1Brain and Consciousness Research Center, Taipei Medical University, Taipei, Taiwan, 2GE Healthcare, Taipei, Taiwan, 3National Yang-Ming University, Taipei, Taiwan, 4Department of Radiology, National Defense Medical Center, Taipei, Taiwan How sertraline alleviates depressive syndrome by modulating the intrinsic connectivity networks (ICNs) remains elusive. Herein, we take a network-based investigation on SN to rationalize the functional and behavior effect of the sertraline treatment using resting-state functional connectivity (rsFC). Our study demonstrated that the sertraline treatment exhibited beneficial modulations on the DNMTL–SN–thalamus pathway for alleviating depressive syndromes in MDD patients.

 234 Plasma 28 Abnormal Perfusion and Perfusion fluctuation in Bipolar Disorder measured by ASL Weiying Dai1, Mingzhao Chen1, Li Zhao2, Nicolas Bolo3, David C. Alsop2, and Keshavan Matcheri3 1State University of New York at Binghamton, BINGHAMTON, NY, United States, 2Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 3Department of Psychiatry, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States We aim to investigate whether dynamic perfusion image time series instead of static perfusion image can offer extra insight to bipolar disorder (BD). Average perfusion and perfusion fluctuation maps were compared between patients with BD and controls using customized Statistical non-Parametric Mapping (SnPM). Perfusion decrease in the posterior lateral regions of the default mode network and increase of perfusion fluctuations in the parahippocampus and amygdala regions were observed. The abnormal perfusion fluctuations may be supported by perturbed functional connectivity at the same regions. These results indicate that dynamic perfusion image series may serve as potential novel neuroimaging biomarkers for BD.

 235 Plasma 29 Elevated brain iron in cocaine addiction as indexed by magnetic field correlation imaging Vitria Adisetiyo1, Corinne E. McGill1, William DeVries2, Jens H. Jensen1,3, Colleen A. Hanlon2, and Joseph A. Helpern1 1Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, United States, 3Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States Brain iron is critical for neural processes implicated in addiction. Recently, disrupted iron regulation was detected in individuals with cocaine use disorder (CUD) using quantitative susceptibility mapping. Our goal was to replicate these findings using an alternative iron imaging method called magnetic field correlation imaging. Consistent with the only study of brain iron in CUD, we detected elevated brain iron levels in globus pallidus regions and loss of age-related iron accumulation in CUD. Our replication of aberrant brain iron findings in CUD using a different MRI modality lends support for further investigation of iron homeostasis in CUD.

 236 Plasma 30 Deletion of CRTC1 is associated with strong neuroenergetic dysfunctions in a mouse model of mood disorders. Antoine Cherix1, Guillaume Donati1, Blanca Lizarbe1, Hongxia Lei2, Carole Poitry-Yamate2, Jean-René Cardinaux3, and Rolf Gruetter1,4,5 1Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne., Lausanne, Switzerland, 3Center for Psychiatric Neuroscience (CNP), Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland, 4Department of Radiology, University of Geneva, Geneva, Switzerland, 5Department of Radiology, University of Lausanne, Lausanne, Switzerland This project pursues a previous study presented at ISMRM1 which established an age- and brain region dependent neurochemical metabolic profile in a Crtc1-/- based mouse model of mood disorders. Here, we show that a decline in cerrebral lactate levels is a consistent and reliable endophenotype2 of Crtc1 deletion, and an indicator of neuroenergetic dysfunction in the dorsal hippocampus. The decline in brain lactate levels appears to arise from a measured reduction of glucose entering the brain.

Electronic Power Pitch Poster

### Poster: Neuro Acquisition: Seeing the CNS Better

 Power Pitch Theater A - Exhibition Hall Tuesday 9:15 - 10:15

 312 Plasma 1 Imaging of the Thoracic Spinal Cord using Radially Sampled Averaged Magnetization Inversion Recovery Acquisitions (rAMIRA) Matthias Weigel1,2, Tanja Haas1,3, and Oliver Bieri1,2 1Division of Radiological Physics, Dept. of Radiology, University Hospital Basel, Basel, Switzerland, 2Dept. of Biomedical Engineering, University of Basel, Basel, Switzerland, 3Dept. of Radiology, University Hospital Basel, Basel, Switzerland Particularly for improved imaging of the thoracic spinal cord, a radial sampling variant of the averaged magnetization inversion recovery acquisitions approach was developed (radial AMIRA). The radial AMIRA approach is less prone to fold over artifacts and it is demonstrated that simple pulse triggering removes potential streak artifacts that may occur near big vessels or near the heart. Just as for the conventional Cartesian AMIRA approach, a series of images with remarkable different tissue contrasts is acquired and some of these images can be combined to enhance and fine-tune the desired tissue contrast.

 313 Plasma 2 FLAWS imaging improves depiction of the thalamic subregions for DBS planning in epileptic patients Elise Bannier1,2, Giulio Gambarota3,4, Jean-Christophe Ferré1,2, Tobias Kober5,6,7, Anca Nica8, Stephan Chabardes9, and Claire Haegelen3,4,10 1Radiology, University Hospital of Rennes, Rennes, France, 2VISAGES ERL U-1228, Univ Rennes, Inria, CNRS, Inserm, IRISA UMR 6074, Rennes, France, 3LTSI, Université de Rennes 1, Rennes, France, 4U1099, INSERM, Rennes, France, 5Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, 6Radiology, University Hospital Lausanne (CHUV), Lausanne, Switzerland, 7Signal Processing Laboratory, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 8Neurology, University Hospital of Rennes, Rennes, France, 9Neurosurgery, University Hospital of Grenoble, Grenoble, France, 10Neurosurgery, University Hospital of Rennes, Rennes, France Accurate localization of the thalamic subregions is of paramount importance for Deep Brain Stimulation (DBS) planning. Current MRI protocols use T2 and Gadolinium-enhanced T1 images, to visualize both the basal ganglia and the vessels, in order to define the electrode trajectory and target. This study shows the usefulness of Fluid and White Matter Suppression, i.e. FLAWS imaging, in eleven drug-resistant epileptic patients for preoperative Deep Brain Stimulation planning and anterior thalamic nucleus targeting.

 314 Plasma 3 Silent T2* Encoding using ZTE Combined with Gradient-Echo Burst (BURZTE) Rolf F Schulte1, Guido Buonincontri2, Mauro Costagli2, Anne Menini3, Florian Wiesinger1, and Ana Beatriz Solana1 1GE Healthcare, Munich, Germany, 2IMAGO7 Foundation, Pisa, Italy, 3GE Healthcare, Menlo Park, CA, United States ZTE image encoding was combined with burst imaging by reversing segments of 3D radial spokes both in time and amplitude. This recalls gradient echoes for the individual spokes. Multiple burst echoes can be acquired by repeating the trajectories. This “burzte” pulse sequence encodes T2* in a silent manner.

 315 Plasma 4 Using 3D high-resolution MR Fingerprinting (MRF) to assist detection and characterization of epileptic lesions Dan Ma1, Irene Wang2, Imad Najm2, Anagha Deshmane3, Debra McGivney1, Ken Sakaie4, Mark Lowe4, Vikas Gulani1, Mark Griswold1, and Stephen Jones4,5 1Radiology, Case Western Reserve University, Cleveland, OH, United States, 2Epilepsy Center, Cleveland Clinic, Cleveland, OH, United States, 3Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 4Imaging Institute, Cleveland Clinic, Cleveland, OH, United States, 5Neuroradiology, Cleveland Clinic, Cleveland, OH, United States The goal of this study is to develop 3D high resolution MRF scans and partial volume analysis methods to assist detection and characterization of epileptogenic foci in patients with drug refractory epilepsy undergoing presurgical evaluation. In addition to providing quantitative T1/T2 values for tissue characterization, we hypothesize that quantitative maps also provide better sensitivity in detecting subtle epileptic lesions. To this end, high resolution T1 and T2 maps, as well as gray matter, white matter fractions maps and tissue cluster maps, were used to detect and characterize epileptic lesions that were difficult to identify from the weighted images and from conventional voxel-based post-processing analysis based on T1-weighted images.

 316 Plasma 5 An Optimized Single-shot Sequence for Fast T2w Imaging of the Brain Mahesh Bharath Keerthivasan1,2, Blair Winegar2, Unni Udayasankar2, Ali Bilgin1,3, Maria Altbach2, and Manojkumar Saranathan2 1Electrical and Computer Engineering, University of Arizona, Tucson, AZ, United States, 2Medical Imaging, University of Arizona, Tucson, AZ, United States, 3Biomedical Engineering, University of Arizona, Tucson, AZ, United States T2-weighted imaging of the brain using single shot sequences such as HASTE suffer from reduced spatial resolution, blurring artifacts and decreased conspicuity of small lesions. We present an analytic framework to design the refocusing flip angles for the HASTE sequence tailored for brain imaging.  The flip angles are optimized to minimize SAR and blurring, and maximize SNR. The utility of this sequence is demonstrated by incorporating it in a brain tumor protocol and comparing its performance to conventional T2w Turbo Spin Echo in 21 patients.

 317 Plasma 6 The UK7T Network – optimized design of a multi-site, multi-vendor travelling heads study. William T Clarke1, Olivier Mougin2, Ian D Driver3, Catarina Rua4, Andrew T Morgan5, Stuart Clare1, Susan Francis2, Richard Wise3, Adrian Carpenter4, Keith Muir5, and Richard Bowtell2 1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 3Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom, 4Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, 5Institute of Neuroscience & Psychology, University of Glasgow, Glasgow, United Kingdom Research sites in the “UK7T Network”, a consortium of 7 tesla capable sites in the UK, have conducted a pilot multi-site, multi-vendor neuroimaging study. The Network aims to create a harmonized set of imaging protocols relevant for clinical research. This study evaluates the differences seen in a set of structural and functional sequences run on three different scanner models, manufactured by two different vendors, at four different sites. In this abstract we identify key differences found between systems and a provide a synopsis of the main findings. The results will inform a future ten subject “travelling heads” study.

 318 Plasma 7 Evaluation of a wave-MPRAGE sequence for brain morphometery Ross W. Mair1,2, Jared A. Nielsen1,3,4, and Randy L. Buckner1,2,3,4 1Center for Brain Science, Harvard University, Cambridge, MA, United States, 2AA Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 3Department of Psychology, Harvard University, Cambridge, MA, United States, 4Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, United States A new readout method for 3D scans, wave-CAIPI, with low g-factor characteristics that enable high degrees of acceleration, can reduce the scan time for a 1.0 mm MPRAGE to under 90 seconds. We have validated the morphometrics from this rapid wave-MPRAGE with those from conventional MPRAGE scans. The wave-MPRAGE sequence produces a lower-SNR image of the brain, but surfaces created from the wave images match those from the conventional scans well. In morphometric data, a bias is seen toward the conventional MPRAGE scans in average cortical thickness and estimated total intra-cranial volume, however values for total brain volume are similar.

 319 Plasma 8 Methods to accelerate STAGE: Toward 8 min for Twelve 3D images on 1.5T Aiqi Sun1, Feng Huang1, Yu Wang1,2, Wei Xu1, Yiran Wang1, Hongyu Guo1, Yongsheng Chen3,4,5, and Ewart Mark Haccke2,3,5 1Neusoft Medical System, Shanghai, China, 2Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, 3The MRI Institute for Biomedical Research, Detroit, MI, United States, 4Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China, 5Department of Radiology, School of Medicine, Wayne State University, Detroit, MI, United States A technique named Strategically Acquired Gradient Echo (STAGE) was recently published, which can acquire 10 images with sufficient resolution, good SNR, and co-registration in one 5-min scan on 3T. With an additional 4-min scan, MRAV and MRA can also be produced. However, to acquire a full set of 12 images on 1.5T takes over 20 minutes, which is still longer than clinical expectation. Novel acquisition and reconstruction schemes are developed in this work to further reduce acquisition time. Feasibility experiments demonstrate it is achievable to acquire 12 high quality clinically meaningful images with 0.67×1.33×2.7 mm3 in 8 minutes on 1.5T.

 320 Plasma 9 Accelerated quantitative susceptibility and R2* mapping with flexible k-t-segmented 3D-EPI Rüdiger Stirnberg1, Andreas Deistung2,3,4, Jürgen Reichenbach2, and Tony Stöcker1,5 1MR Physics, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, 2Medical Physics Group, Institute of Diagnostic and Interventional Radiology, University Hospital Jena, Jena, Germany, 3Department of Neurology, Essen University Hospital, Essen, Germany, 4Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 5Department of Physics and Astronomy, University of Bonn, Bonn, Germany We introduce and demonstrate a novel “k-t-segmented” gradient echo 3D-EPI variant for motion-robust, rapid quantitative susceptibility and R2* mapping at 3T. The combination of a versatile 2D-CAIPIRINHA EPI sampling (“k-segmentation”) and two complementing multi-echo options (“t-segmentation”) provides maximum time- and SNR-efficiency by acquiring exactly as many k-space lines per echo time as fit to the required R2* sampling without compromising spatial resolution. Offline averaging of multiple, rapid measurements (here: 6 averages, 6 echo times from 6.5-31.5ms, 52s/average) following optional, retrospective correction for motion and B0 drift, yields excellent quantitative whole-brain maps at 0.8mm isotropic resolution acquired in approximately 5 minutes.

 321 Plasma 10 Myelin Lipid 1H Density Measurements by IR-UTE are Consistent Before and After D2O Exchange Alan C Seifert1,2, Michael J Wilhelm3, Suzanne L Wehrli4, and Felix W Wehrli1 1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Chemistry, Temple University, Philadelphia, PA, United States, 4SAIF Core Facility, Children's Hospital of Philadelphia, Philadelphia, PA, United States In this work, the efficacy of long-T2 tissue water suppression by adiabatic inversion-recovery preparation is examined by IR-UTE imaging of an ovine spinal cord specimen in native hydration and deuterium oxide (D2O)-exchanged states.  Myelin density in three white matter regions of interest (ROIs) was found to be 18.1% to 23.5% in the non-exchanged cord, and 19.9% to 22.5% in the D2O-exchanged cord, with the highest density in the dorsal columns.  The agreement of myelin density measurements between non-exchanged and D2O-exchanged cords supports the efficacy of tissue water suppression in white matter by adiabatic inversion-recovery with an appropriately-chosen TI.

 322 Plasma 11 Formalin Tissue Fixation Biases Myelin Density Measurement by Quantitative Magnetization Transfer and Myelin Water Imaging Alan C Seifert1,2,3, Melissa Umphlett4, Mary Fowkes4, and Junqian Xu1,2,3,5 1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 5Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States Quantitative magnetization transfer (qMT) and multi-exponential T2-based myelin water imaging (MWI) are commonly-used MRI methods to quantify myelin content.  Ex vivo MRI remains an essential step for validating these quantitative in vivo MRI biomarkers.  However, ex vivo tissue is often preserved using formalin, which cross-links proteins and directly impacts these methods. We performed qMT and MWI on human spinal cord tissue before and after formalin fixation to quantify the effect of fixation on these biomarkers.  QMT bound pool fraction (F) increased by 37.5% and MWI myelin water fraction (MWF) increased by 35.5-38.6%, but myelin-related image contrast was preserved.

 323 Plasma 12 High Resolution Diffusion Tensor Imaging of the Hippocampus in Temporal Lobe Epilepsy Sarah Treit1, Trevor Steve2, Tom Nowacki2, Graham Little1, Christian Beaulieu1, and Donald W Gross2 1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada, 2Neurology, University of Alberta, Edmonton, AB, Canada Diffusion tensor imaging of the hippocampus in temporal lobe epilepsy (TLE) has previously relied on very low spatial resolution acquisitions, limiting localization of hippocampal substructure and leading to partial volume effects in diffusion parameter quantification. This study uses a high resolution (1x1x1 mm3) single-shot diffusion protocol to yield excellent quality mean diffusion weighted images (DWIs) that allow for visualization of hippocampal substructure (e.g. presence/absence of the stratum lacunosum moleculare). Improved delineation of structure allows for segmentation of the hippocampus in native space (without co-registration to anatomical images), revealing elevated MD and loss of internal architecture in TLE subgroups.

 324 Plasma 13 Repeatability of measuring pulsatile brain tissue motion and volumetric strain with retrospectively-gated DENSE at 7T Ayodeji L. Adams1, Jacob-Jan Sloots1, Peter R. Luijten1, and Jaco J. M. Zwanenburg1 1Radiology, University Medical Center Utrecht, Utrecht, Netherlands Cardiac-induced brain tissue volumetric strain (an important metric reflecting microvascular blood volume pulsation) exhibits large inter-subject variability. We measured the intra-subject repeatability of brain tissue volumetric strain over the cardiac cycle in healthy subjects at 7T using a high resolution retrospectively-gated DENSE and found that the strain curve shape and peak value were very consistent between measurements. Furthermore, we validated the peak brain tissue volume change against measured spinal CSF stroke volume at C2-C3, and observed a strong correlation. The consistent findings strengthens the potential of volumetric strain as biomarker for microvascular function in the ageing brain.

 325 Plasma 14 Isotropic 3D quantification of R1 and R2 relaxation and proton density in 6 minutes scan time Marcel Warntjes1,2, Peter Johansson1, Anders Tisell3,4, and Peter Lundberg3 1SyntheticMR, Linköping, Sweden, 2Center for Medical Imaging Science and Visualization (CMIV), Linköping, Sweden, 3Radiation Physics, Linköping, Sweden, 4Center for Medical Imaging Science and Visualization (CMIV), Linkoping, Sweden Absolute quantification of R1 and R2 relaxation and proton density PD has been gaining considerable attention in the recent years. As yet, simultaneous quantification of R1, R2 and PD has been restricted to 2D methods, with high resolution in-plane but using relatively thick slices. A previously published method on cardiac quantification, QALAS, has been applied to the brain, providing a full quantification of R1, R2 and PD at 1.2 mm isotropic resolution in 3D using only 6 minutes scan time.

 326 Plasma 15 Zero Time of Echo imaging with an Adiabatic Fat Suppression Pulse at 7T Mark Symms1, Mauro Costagli2,3, Guido Buonincontri2,3, Florian Wiesinger4, Doug Kelley5, Martin A Janich4, Giacomo Aringhieri2,6, Massimo Marletta2,6, Gareth Barker7, Virna Zampa2,6, Mirco Cosottini2,6, and Michela Tosetti2,3 1GE Healthcare, Pisa, Italy, 2Imago7, Pisa, Italy, 3IRCCS Stella Maris, Pisa, Italy, 4GE Healthcare, Munich, Germany, 5GE Healthcare, Waukesha, WI, United States, 6University of Pisa, Pisa, Italy, 7King's College London, London, United Kingdom We present results using a Zero Time of Echo sequence ("Silent") with an Adiabatic Fat Suppression Pulse (ASPIR). As well as providing fat suppression that is relatively robust to field inhomogeneities at 7T, ASPIR-Silent also generates images with an additional off-resonant contrast. We show this contrast derives primarily from Magnetisation Transfer effects, and give an in vivo example.

Electronic Power Pitch Poster

 Power Pitch Theater B - Exhibition Hall Tuesday 9:15 - 10:15

 327 Plasma 16 Intramuscular variability and sex difference in diffusion properties and 3D architecture of human lower leg muscles assessed with ultra-high-field diffusion tensor imaging and tractography Alexandre Fouré1, Augustin C Ogier1, Christophe Vilmen1, Arnaud Le Troter1, Thorsten Feiweier2, Maxime Guye1,3, Julien Gondin4, Pierre Besson1, and David Bendahan1 1Aix-Marseille Univ, CNRS, CRMBM, Marseille, France, 2Siemens Healthcare, Erlangen, Germany, 3APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France, 4Institut NeuroMyoGène, Université Claude Bernard Lyon 1, INSERM, CNRS, Villeurbanne, France Skeletal muscle function impairment can be associated to changes in both muscle volume and structural arrangement of fascicles/fibers within the muscle thereby leading to the reduction of muscle force production. Diffusion properties and 3D structural organization of muscle fibers were quantified from high-resolution diffusion tensor images recorded at ultra-high-field MRI (UHF-7T). These parameters were assessed regarding their intramuscular variability and sensitivity to sex difference. This application of UHF-7T might be of high interest for the assessment of muscular injuries in both athletes and patients with muscular disorders.

 328 Plasma 17 Time-dependent diffusion and the random permeable barrier model predict muscles fiber dimensions in Duchenne muscular dystrophy mice Bauke Kogelman1, Kevin Adamzek2, Ernst Suidgeest1, Gregory Lemberskiy3, Dmitry S. Novikov3, Els Fieremans3, Maaike van Putten2, and Louise van der Weerd1,2 1Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Human Genetics, Leiden University Medical Center, Leiden, Netherlands, 3Radiology, New York University School of Medicine, New York, NY, United States We used time-dependent diffusion, with diffusion times up to 500ms to assess the muscle tissue microstructure in two different mouse models of Duchenne muscular dystrophy (DMD). We found significant differences in diffusivities between DMD models and the genetic background matched wild types in diffusion times up to 100ms. We modeled diffusion time-dependence with the random permeable barrier model (RPBM), which yielded surface-to-volume ratios indicative of fiber size and compared these values to gold-standard histology of the same muscles. The RPBM predicted relative differences in fiber dimensions between mdx and wild type within each genetic background.

 329 Plasma 18 Relationship of paraspinal muscle DTI metrics to isometric strength measurements Elisabeth Klupp1, Barbara Cervantes2, Sarah Schlaeger2, Stephanie Inhuber3, Florian Kreuzpointer3, Michael Dieckmeyer2, Friedemann Freitag2, Ernst J. Rummeny2, Claus Zimmer1, Jan S. Kirschke1, Dimitrios C. Karampinos2, and Thomas Baum1 1Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technische Universität München, München, Germany, 2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technische Universität München, München, Germany, 3Department of Sport and Health Sciences, Technische Universität München, München, Germany Diffusion Tensor Imaging (DTI) enables the microstructural examination of muscle tissue as well as its pathological and stress-dependent changes. Little is known about the associations between muscular DTI parameters and corresponding muscle strength measurements. The present study investigated the correlations of DTI parameters of paraspinal muscles with isometric strength measurements in healthy subjects. The results indicate that DTI may potentially track slight changes of back muscle tissue microstructure that relate to muscle strength and may be useful in the early diagnosis of back muscle diseases and back pain.

 330 Plasma 19 Imaging human motor unit activity using MRI. Paola Porcari1, Ian Schofield2, Roger Whittaker3, and Andrew M Blamire4 1Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom, 2Newcastle University, Newcastle upon Tyne, United Kingdom, 3Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom, 4Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom Neuromuscular diseases can lead to characteristic changes in the anatomy of motor units (MU).  In this study we developed an MR approach to image motor unit activity.  In-scanner electrical stimulation of MU was synchronized to a pulsed-gradient spin-echo imaging sequence sensitive to microscopic contraction of muscle fibers.  Experimental data was compared to a simple theoretical model and scan parameters evaluated.  The spatial pattern of muscle fibers forming different MU was imaged for the first time in healthy controls.

 331 Plasma 20 Clinical Feasibility of Isotropic MAVRIC SL Imaging of Total Joint Arthroplasties Matthew F. Koff1, Suryanarayanan Kaushik2, Parina H. Shah1, Erin G. Argentieri1, and Hollis G. Potter1 1Hospital for Special Surgery, New York, NY, United States, 2General Electric Healthcare, Waukesha, WI, United States Multi-spectral MRI reduces susceptibility when imaging near total joint arthroplasty (TJA). MAVRIC SL acquires 24 bins of off-resonance data to generate images, but most implants require fewer bins. This study uses a calibration scan, to determine an adequate number of bins, coupled with long echo trains and variable flip angles to permit an isotropic MAVRIC SL acquisition in clinically feasible scan times. The isotropic MAVRIC SL acquisition showed an improved detection of the implant-bone interface surrounding TJA, while retaining image contrast and overall SNR. An isotropic acquisition may improve the diagnostic capability of MAVRIC SL images.

 332 Plasma 21 Solid-State MRI as a noninvasive alternative to computed tomography for craniofacial imaging Hyunyeol Lee1, Xia Zhao1, Hee Kwon Song1, Rosaline Zhang2, Scott P Bartlett2, and Felix W Wehrli1 1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Plastic Surgery, University of Pennsylvania, Philadelphia, PA, United States Computed tomography (CT) imaging is the imaging modality of choice for 3D visualization of bone. However, there is growing concern about repeated exposure to ionizing radiation, in particular during infancy, for instance, in patients with craniosynostosis pre- and post-surgery. Here, we developed a dual-RF, dual-echo, 3D UTE sequence using view-sharing to minimize scan time. Images are reconstructed by combining long- and short-RF, first and second echoes, yielding soft-tissue suppressed skull images at 1.1 mm isotropic resolution in 6 minutes scan time in a human skull ex vivo and test subjects in vivo. 3D renderings display the relevant craniofacial skeleton similar to CT.

 333 Plasma 22 Subregional bone marrow adipose tissue composition in the proximal femur: Comparison of 3T Chemical Shift Encoded-MRI and Magnetic Resonance Spectroscopy Dimitri MARTEL1, Benjamin LEPORQ2, Mary BRUNO1, Stephen HONIG3, Amit SAXENA4, H.Michael BELMONT4, Gabrielle TURYAN1, Ravinder R. REGATTE1, and Gregory CHANG1 1Radiology, NYU Langone Health, New York, NY, United States, 2Université de Lyon; CREATIS CNRS UMR 5220, Inserm U1206, INSA-Lyon, UCBL Lyon 1, Villeurbanne, France, 3Osteoporosis Center, Hospital for Joint Diseases, NYU Langone Health, New York, NY, United States, 4Department of Rheumatology, NYU Langone Health, New York, NY, United States Studies of bone marrow adipose tissue (bMAT) composition in osteoporosis has revealed increased [a1] in fat content and decreased unsaturated fatty acid in the proximal femur in osteoporosis (OP) patients compared to controls. Advancements in MR image-based methods for fat assessment have allowed quantification of fat content though chemical-shift encoded MRI (CSE-MRI). CSE-MRI methods have not been compared to MRS for bMAT composition assessment. The aim of this study was to quantify, within subregions of the proximal femur, bone marrow PDFF as well as saturated and unsaturated fat using both CSE-MRI and MRS.

 334 Plasma 23 Temporal Changes of a Canine Model of Patellar Tendinopathy Using UTE MRI T2* Assessment: A Pilot Study Sarah G. Pownder1, Kei Hayashi2, Brian G. Caserto3, Bin Lin1, Hollis G. Potter1, and Matthew F. Koff1 1Department of Radiology and Imaging - MRI, Hospital for Special Surgery, New York, NY, United States, 2Cornell University, Ithaca, NY, United States, 3VetPath Services, Stone Ridge, NY, United States Tendon damage has been traditionally evaluated invasively with biopsy. This pilot study evaluated the effects of an induced mechanical strain of the patellar tendon on UTE-MRI metrics and corresponding histology. The induced strain had a greater effect on the quantitative MRI metrics over time, by percentage change, than by the level of induced strain. A corresponding histologic analysis had similar findings. The results indicate the capability of utilizing MRI to evaluate differences in the quantitative T2* metrics of the patellar tendon. Time dependent changes in quantitative UTE-MRI metrics may be detected using a model of induced subclinical tendon damage.

 335 Plasma 24 Knee Cartilage UTE T2* Quantification with Water-Fat Decomposition Misung Han1, Peng Cao1, Michael Carl2, Thomas M Link 1, Peder EZ Larson1,3, and Roland Krug1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Global MR Applications and Workflow, General Electric, San Diego, CA, United States, 3Joint Graduate Program in Bioengineering, University of California, San Francisco/Berkeley, San Francsico, CA, United States Recently, there has been a growing interest in assessing lesions in the deep layers of knee cartilage as a pathogenesis of osteoarthritis. Ultrashort echo-time (UTE) T2* mapping in the deep layers has demonstrated great potential to detect early degenerative changes. Fat suppression is normally accompanied to reduce off-resonance artifacts from adjacent fatty tissues; however, it can also suppress significant amount of short T2 tissues and affect quantification. In this work, we quantified cartilage T2* by decomposing fat and water components using no fat-suppressed 3D multi-echo UTE images and demonstrated shorter T2* compared to that from fat-suppressed 3D UTE images.

 336 Plasma 25 Strategies for Obtaining Relaxation Rates due to Chemical Exchange from Parameter Free Atomistic Simulations Henning Henschel1, Matti Hanni1,2, and Miika T. Nieminen1,2 1University of Oulu, Oulu, Finland, 2Oulu University Hospital, Oulu, Finland Chemical exchange has likely a significant impact on the dispersion of T1ρ in cartilaginous tissue. In order to quantify this effect, we are developing atomistic simulation strategies for direct modelling of proton transfer reactions between biomacromolecules – first and foremost chondroitin sulfate – and water. Here we present benchmarking results from a number of semi-empirical quantum mechanics methods for several key system properties. Results suggest feasibility of the chosen approach.

 337 Plasma 26 Automatic Segmentation of Hip Cartilage with Deep Convolutional Neural Nets for the evaluation of Acetabulum and Femoral T1ρ and T2 relaxation times. Michael Girard1, Valentina Pedoia2, Berk Norman2, Jasmine Rossi-Devries2, and Sharmila Majumdar2 1Center for Digital Health Innovation, University of California, San Francisco, San Francisco, CA, United States, 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States In this study we utilize a deep learning approach to automatically segment the femoral and acetabular cartilages in the hip. From these segmentations we also calculate T1ρ and T2 relaxation times then compare to manual segmentations and their T1ρ and T2 values. We show the T1ρ and T2 relaxation times, calculated using manual and automatic segmentations, are very correlated, R values above .94, and comparable.

 338 Plasma 27 Assessment of the clinical feasibility of routine T2 mapping of the intervertebral disc using highly undersampled k-space data Marcus Raudner1, Markus Schreiner1,2, Tom Hilbert3,4,5, Tobias Kober3,4,5, Vladimir Juras6, Claudia Kronnerwetter6, David Stelzeneder2, and Siegfried Trattnig1 1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Department of Orthopaedics, Medical University of Vienna, Vienna, Austria, 3Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, 4Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland, 5LTS5, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 6High Field MR Centre of Excellence, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria Even though the measurement of T2 relaxation time is one of the most widespread available assets of quantitative MRI in clinical routine, it is left with untapped potential as the required scan time is too long. GRAPPATINI is a model-based iterative algorithm reconstructing T2 maps and T2-weighted images from highly-undersampled k-space data. The aim of this study was to compare the quantitative results of an established standard method with this novel technique in the intervertebral disc with the additional benefit of GRAPPATINI to simulate T2w contrasts at arbitrarily chosen echo times.

 339 Plasma 28 Voxel-wise ratios of amide proton transfer (APT) signals and standardized uptake values (SUVs) of fluorodeoxyglucose (FDG) in the differentiation of myxoid-rich soft-tissue tumors with FDG-PET/MR imaging Koji Sagiyama1, Yuji Watanabe2, Keisuke Ishimatsu1, Takeshi Kamitani1, Yuzo Yamasaki2, Takuya Hino1, Sungtak Hong3, Jochen Keupp4, Yoshihiro Matsumoto5, and Hiroshi Honda1 1Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan, 2Department of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan, 3Healthcare, Philips Electronics Japan, Tokyo, Japan, 4Philips Research, Hamburg, Germany, 5Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan It is often difficult to differentiate myxoid-rich soft-tissue tumors on conventional imaging. In this study, we performed a direct voxel-wise comparison of amide proton transfer (APT) signals and standardized uptake values (SUVs) obtained on FDG-PET/MR imaging. Among myxoid-rich tumors including myxoid liposarcomas, myxofibrosarcomas, myxoid chondrosarcomas, and schwannomas, the mean APT/SUV was significantly higher in liposarcomas than in the other myxoid-rich tumors while a single parameter such as APT, SUV or apparent diffusion coefficient (ADC) did not show any significant differences between the two groups. The APT/SUV could be a reliable bio-imaging marker for differentiating soft-tissue tumors.

 340 Plasma 29 Assessment of early treatment response by multiparametric whole-body MRI as a 1-step approach to prediction of overall response rate in patients with multiple myeloma Miyuki Takasu1, Takayuki Tamura1, Yuji Akiyama1, Yoko Kaichi1, Shota Kondo1, Chihiro Tani1, and Kazuo Awai1 1Department of Diagnostic Radiology, Hiroshima University Hospital, Hiroshima, Japan We compared remission status at completion of chemotherapy with changes in MRI biomarkers obtained by advanced MRI techniques, including total tumor volume calculated from whole-body diffusion-weighted imaging and fat fraction by mDIXON soon after induction of chemotherapy for patients with multiple myeloma. The early change in fat fraction of lumbar bone marrow and serum monoclonal protein after 2 cycles of chemotherapy contributed significantly to the prediction of CR/VGPR status. Results of this study may indicate that prediction of remission status can be achieved by assessing bone marrow on lumbar spinal MRI with mDIXON.

 341 Plasma 30 Simultaneous Bilateral Knee MR Imaging Feliks Kogan1, Evan Gregory Levine1, Akshay Chaudhari1, Uchechukwuka D. Monu1, Kevin Epperson1, Edwin Oei2, Garry Gold1, and Brian Hargreaves1 1Radiology, Stanford University, Stanford, CA, United States, 2Radiology, Erasmus MC, Rotterdam, Netherlands Osteoarthritis (OA) is commonly a bilateral disease. While long scan time and costs have precluded separate scanning of both knees in clinical MRI, there is evidence that bilateral examinations are beneficial for evaluation of OA changes, especially for longitudinal studies. In this study, we demonstrate that a bilateral coil-array setup can image both knees simultaneously in similar scan times as conventional unilateral knee scans with comparable image quality and quantitative accuracy. This has the potential to improve the value of MRI knee evaluations.

Electronic Power Pitch Poster

### Poster: Machine Learning Unleashed

 Power Pitch Theater A - Exhibition Hall Tuesday 14:45 - 15:45

 428 Plasma 1 Deep Learning Method for Non-Cartesian Off-resonance Artifact Correction David Y Zeng1, Jamil Shaikh2, Dwight G Nishimura1, Shreyas S Vasanawala2, and Joseph Y Cheng2 1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States 3D cones trajectories have the flexibility to be more scan-time efficient than 3D Cartesian trajectories, especially with long readouts. However, long readouts are subject to blurring from off-resonance, limiting the efficiency. We propose a convolutional residual network to correct for off-resonance artifacts to allow for reduced scan time. Fifteen exams were acquired with both conservative readout durations and readouts 2.4x as long. Long-readout images were corrected with the proposed method. The corrected long-readout images had non-inferior (p<0.01) reader scores in all features examined compared to conservative readout images.

 429 Plasma 2 Gibbs-Ringing Artifact Reduction in MRI via Machine Learning Using Convolutional Neural Network Qianqian Zhang1, Guohui Ruan1, Wei Yang1, Kaixuan Zhao1, Ed X. Wu2,3, and Yanqiu Feng1 1Guangdong Provincial Key Laboratory of Medical Image Processing, School of Biomedical Engineering, Southern Medical University, Guangzhou, China, 2Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 3Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China The Gibbs-ringing artifact is caused by the insufficient sampling of the high frequency data. Existing methods generally exploit smooth constraints to reduce intensity oscillations near high-contrast boundaries but at the cost of blurring details. This work presents a convolutional neural network (CNN) method that maps ringing images to their ringing-free counterparts for Gibbs-ringing artifact removal in MRI. The experimental results demonstrate that the proposed method can effectively remove Gibbs-ringing without introducing noticeable blurring.

 430 Plasma 3 Simultaneous detection and identification of MR artifact types in whole-body imaging Thomas Kuestner1,2, Ke Liu2, Annika Liebgott2,3, Lukas Mauch2, Petros Martirosian1, Fabian Bamberg3, Konstantin Nikolaou3, Bin Yang2, Fritz Schick1, and Sergios Gatidis3 1Section on Experimental Radiology, University Hospital of Tuebingen, Tuebingen, Germany, 2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, 3Department of Radiology, University Hospital of Tuebingen, Tuebingen, Germany Varying acquisition and reconstruction conditions as well as long examination times make MRI susceptible to various kinds of artifacts. If suitable correction techniques are not available/applicable, if human experts who judge the achieved quality are not present or for epidemiological cohort studies in which a manual quality analysis of the large database is impracticable, an automated detection and identification of these artifacts is of interest. Convolutional neural networks with residual and inception layers localize and identify occurring artifacts. Artifacts (motion and field inhomogeneity) can be precisely identified with an accuracy of 92% in a whole-body setting with varying contrasts.

 431 Plasma 4 Automatic Assessment of MR Image Quality with Deep Learning Jifan Li1, Shuo Chen1, Qiang Zhang1, Huiyu Qiao1, Xihai Zhao1, Chun Yuan1,2, and Rui Li1 1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, 2Vascular Imaging Laboratory, Department of Radiology, University of Washington, Seattle, WA, United States In this study, we aimed to develop a convolutional neural network (CNN) to assess the quality of multi-contrast carotid plaque MR images automatically. The network was trained on large amount of plaque images combined with image quality scores labeled by experienced radiologists. Transfer learning was utilized to take the advantage of state-of-the-art CNN pre-trained on ImageNet dataset. The accuracy of image quality estimation achieved 86.0% with preprocessing and fine-tuning of the network.

 432 Plasma 5 Automatic detection of cerebral microbleeds using Susceptibility-Weighted Imaging and a 3D deep residual network Yicheng Chen1, Melanie Morrison2, Javier Villanueva-Meyer2, and Janine M Lupo1,2 1The UC 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 Francisco, San Francisco, CA, United States In this abstract, a deep residual neural network based approach that improves the automatic detection and labeling of cerebral microbleeds by significantly reducing the number of false positives compared to previously published algorithms is proposed. This combined method removed 89% of false positives in the test patients with brain tumors who had radiation-induce CMBs while losing only 3% of the true microbleeds and has the potential to fully automate CMB detection.

 433 Plasma 6 Deep learning diffusion fingerprinting to detect brain tumour response to chemotherapy Thomas A Roberts1, Ben Hipwell1, Giulia Agliardi1, Valerie Taylor1, Mark F Lythgoe1, and Simon Walker-Samuel1 1Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom Convolutional neural networks (CNNs) often require very large datasets for robust training and evaluation. As an alternative approach, we introduce deep learning diffusion fingerprinting (DLDF), which treats every voxel as an independent data point, rather than using whole images or patches. We use DLDF to classify diffusion-weighted imaging voxels in a mouse model of glioblastoma, both prior to and in response to Temozolomide chemotherapy. We show that, even with limited training, DLDF can automatically segment brain tumours from normal brain, can distinguish between young and older tumours and that DLDF can detect if a tumour has been treated with chemotherapy.

 434 Plasma 7 Machine learning based estimation of axonal permeability: validation on cuprizone treated in-vivo mouse model of axonal demyelination Marco Palombo1, Ioana Hill1, Mathieu David Santin2,3, Francesca Branzoli2,3, Anne-Charlotte Philippe2,3, Demian Wassermann4,5, Marie-Stephane Aigrot2, Bruno Stankoff2,6, Hui Zhang1, Stephane Lehericy2,7,8, Alexandra Petiet2,7, Daniel C. Alexander1, and Ivana Drobnjak1 1Computer Science Department and Centre for Medical Imaging Computing, University College London, London, United Kingdom, 2CENIR, ICM, Paris, France, 3Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France, 4INRIA, Université Côte d'Azur, Sophia-Antipolis, France, 5Parietal, CEA, INRIA, Saclay, France, 6AP-HP, Hôpital Saint-Antoine, Paris, France, 7Hôpital de la Pitié Salpêtrière, Sorbonne Universités, UPMC Paris 06 UMR S 1127, Inserm UMR S 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière, Paris, France, 8AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France Estimating axonal permeability reliably is extremely important, however not yet achieved because mathematical models that express its relationship to the MR signal accurately are intractable. Recently introduced machine learning based computational model showed to outperforms previous approximate mathematical models. Here we apply and validate this novel method experimentally on a highly controlled in-vivo mouse model of axonal demyelination, and demonstrate for the first time in practice the power of machine learning as a mechanism to construct complex biophysical models for quantitative MRI.

 435 Plasma 8 Direct and Fast Learning of Fiber Orientation Distribution Function for Tractography Ting Gong1, Hongjian He1, Zhichao Lin2, Zhiwei Li2, Qiqi Tong1, 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 Multi-shell, multi-tissue, constrained spherical deconvolution is an appealing method for the reconstruction of fiber orientation distribution function (fODF), which is of great importance for solving complex fiber configurations to achieve reliable tractography. However, many diffusion measurements and multiple reconstruction steps are required. In this study, the deep neural network were employed to form a multi-output regression problem for establishing a fast and direct estimation of fODF. The proposed method offers a new streamlined reconstruction procedure which exhibits great potential for accelerating the reconstruction of fODF with whole-brain coverage, with satisfactory accuracy in two minutes.

 436 Plasma 9 Predict the slow oscillation of the single-vessel resting-state fMRI signal of rats and humans with echo state networks Filip Sobczak1, Yi He1, and Xin Yu1 1MPI for Biological Cybernetics, Tübingen, Germany Single-vessel fMRI has enabled the detection of slow fluctuations (<0.1Hz) of the hemodynamic fMRI signal from individual vessels in both rat and human brains. The Echo State Network (ESN) has been used to encode the slowly changing temporal dynamics of individual vessels by training the network to predict the oscillatory signals from individual vessels 10 seconds ahead in time. Distinct network reservoirs are optimized for human and animal vascular signals, showing high correlation for the ESN-predictive signal with the original fresh data. This work establishes ESN-based signal prediction for the slow-oscillatory brain fMRI signal in real-time.

 437 Plasma 10 Dynamic Causal Modelling with neuron firing model in Generalized Recurrent Neural Network framework Yuan Wang1, Yao Wang1, and Yvonne W Lui2 1Department of Electrical and Computer Engineering, New York University, Brooklyn, NY, United States, 2Department of Radiology, New York University, New York, NY, United States DCM-RNN is a Generalized Recurrent Neural Network accommodating the Dynamic Causal Modelling (DCM), which links the biophysical interpretability of DCM and the power of neural networks. It significantly extends the flexibility of DCM, provides unique parameter estimation methods, and offers neural network compatibility. In this abstract, we show how to incorporate neuron firing model into DCM-RNN with ease. An effective connectivity estimation experiment with simulated fMRI data shows that the influence of the firing model is substantial. Ignoring it, as the classical DCM does, can lead to degraded results.

 438 Plasma 11 AUTOmated pulse SEQuence generation (AUTOSEQ) using Bayesian reinforcement learning in an MRI physics simulation environment Bo Zhu1,2,3, Jeremiah Liu4, Neha Koonjoo1,2,3, Bruce R Rosen1,2, and Matthew S Rosen1,2,3 1Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Physics, Harvard University, Cambridge, MA, United States, 4Department of Biostatistics, Harvard University, Cambridge, MA, United States Although the macroscopic equations of motion for nuclear magnetic resonance have been described and modeled for decades by the Bloch equations, limited human intuition of their nonlinear dynamics is an obstacle to fully exploiting the vast parameter space of MR pulse sequences. Here we recast the general problem of pulse sequence development as a game of perfect information, and propose an approach to optimize game play with a Bayesian derivative of reinforcement learning within a MRI physics simulation environment. We demonstrate an AI agent learning a canonical pulse sequence (gradient echo) and generating non-intuitive pulse sequences approximating Fourier spatial encoding.

 439 Plasma 12 Towards a fully Automated Time-context Sensitive Convolutional Neural Network for Common Carotid Artery Lumen Segmentation on Dynamic MRI Roberto Souza1, Mariana Bento1, Lívia Rodrigues2, Letícia Rittner2, Roberto Lotufo2, and Richard Frayne1 1Seaman Family Magnetic Resonance Research Centre, Calgary, AB, Canada, 2Medical Image Computing Lab, Campinas, Brazil Carotid artery atherosclerosis is one of the main causes of stroke and there is a pressing need for a non-invasive method to quantify, monitor and assess carotid artery stenosis, composition and distensiblity. Here we focus on developing a fully automated convolutional neural network (CNN) with time-context for segmenting the common carotid artery lumen from dynamic magnetic resonance images.  The challenge in developing a fully automated carotid segmentation algorithm is that there are other vessels with size and spatial location comparable to the carotid artery. Our preliminary results indicate that a CNN with time-context is capable of distinguishing and segmenting the carotid artery from other vessels.

 440 Plasma 13 Artificial neural networks for stiffness estimation in magnetic resonance elastography Matthew C Murphy1, Armando C Manduca1, Joshua C Trzasko1, Kevin C Glaser1, John C Huston1, and Richard C Ehman1 1Mayo Clinic, ROCHESTER, MN, United States Artificial neural networks (ANNs) were trained using simulated displacement fields to perform stiffness estimation from MRE data. These neural network-based inversions (NNIs) are evaluated in simulation and in vivo. In a test set of simulated data, NNI is shown to provide a more accurate estimate of stiffness compared to a standard direct inversion (DI) approach. In vivo, NNI-based stiffness strongly correlated with DI-based stiffness across a range of fibrosis stages in the liver and ages in the brain, indicating that NNI can detect relevant biology. Finally, test-retest error in the brain is reduced using NNI compared to DI.

 441 Plasma 14 MLS: Self-learned joint manifold geometry and sparsity aware framework for highly accelerated cardiac cine imaging Ukash Nakarmi1, Konstantinos Slavakis1, Hongyu Li1, Chaoyi Zhang1, Peizhou Huang1, Sunil Gaire1, and Leslie Ying1,2 1Electrical Engineering, University at Buffalo, Buffalo, NY, United States, 2Biomedical Engineering, University at Buffalo, Buffalo, NY, United States In this work, we propose a novel joint manifold learning and sparsity aware framework for highly accelerated cardiac cine imaging. The proposed method efficiently captures the intrinsic low dimensional nonlinear manifold geometry and inherent periodicity of cardiac data, and outperforms the current state-of-the-art accelerated MRI methods.

 442 Plasma 15 MoDL: Model Based Deep Learning Architecture for Image Recovery with Prior Information. Hemant Kumar Aggarwal1, Merry Mani1, and Mathews Jacob1 1University of Iowa, Iowa City, IA, United States The primary focus of this work is to introduce a novel deep learning framework, which synergistically combines the benefits of model-based image recovery with the power of deep learning. This work enables the easy exploitation of prior information available from calibration scans, in addition to significantly reducing the number of network parameters, amount of training data required, and computational complexity. More importantly, the insensitivity of the learned model to the acquisition parameters also facilitates its easy reuse with a range of acquisition settings.

Electronic Power Pitch Poster

### Poster: Hot Topics in MRS

 Power Pitch Theater B - Exhibition Hall Tuesday 14:45 - 15:45

 443 Plasma 16 Structural Determination Using 129Xe NMR Line-shape in Chemical Shift Imaging Stephen Kadlecek1, Mehrdad Pourfathi1, Luis Loza1, Ian Duncan1, Kai Ruppert1, Hooman Hamedani1, Sarmad Siddiqui1, Yi Xin1, Faraz Amzajerdian1, Harrilla Profka1, Ryan Baron1, Mary Spencer1, Tahmina Achekzai1, Shampa Chatterjee2, Maurizio Cereda3, and Rahim R. Rizi1 1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Physiology, University of Pennsylvania, Philadelphia, PA, United States, 3Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States We present a method to discriminate dissolved 129Xe spectra by tissue type and location based on local variations in T2*.  Mixed contributions of parenchyma and vasculature can be separated almost completely. The method is particularly useful to high field imaging in species lacking distinct dissolved phase spectral components.

 444 Plasma 17 Standardisation and quantification of 23Na-MRI: repeatability and reproducibility of sodium imaging Damien J McHugh1,2, Frank Riemer2,3, Daniel Lewis1, Fulvio Zaccagna2,3, Ferdia A Gallagher2,3, and Geoffrey J. M. Parker1,2,4 1Informatics, Imaging and Data Sciences, The University of Manchester, Manchester, United Kingdom, 2CRUK and EPSRC Cancer Imaging Centre in Cambridge and Manchester, United Kingdom, 3Department of Radiology, University of Cambridge, Cambridge, United Kingdom, 4Bioxydyn Ltd., Manchester, United Kingdom Based on its sensitivity to cell viability and tissue microstructure, sodium MRI has the potential to provide quantitative biomarkers of tumor grade and response to therapy. For biomarkers such as total sodium concentration (TSC) to have clinical utility, they require technical and biological validation. This work focuses on the technical validation of TSC, specifically assessing the repeatability and reproducibility of measurements in healthy volunteers. The results presented here show consistent TSC measurements across repeated scans at different sites, and good repeatability and reproducibility (coefficients of variation, CoVs < 10%).

 445 Plasma 18 Improved Quantification of Hepatic Fatty Acid Metabolism in Nonalcoholic Steatohepatitis: Serum Biochemistry and In vivo Proton MRS Study with Spin-Spin Relaxation Time Correction at 9.4 T Kyu-Ho Song1, Min-Young Lee1, Song-I Lim1, Chi-Hyeon Yoo1, and Bo-Young Choe1 1Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea Changes in saturated and unsaturated fatty acids with hepatic triglycerides following the formation of abnormal metabolites, which play an important pathogenic role, can be measured by magnetic resonance (MR) spectroscopy. High-field-strength MR imaging scanners, which have an improved signal-to-noise ratio and high resolution for multiple lipid resonance components, are used to detect each component of lipid resonance. The aims of this study were to quantify hepatic lipid content and triglyceride composition in a preclinical nonalcoholic steatohepatitis model during the progression of steatohepatitis by assessing potential biomarkers, including spin-spin relaxation time, and applying in vivo proton MR spectroscopy with serum biochemistry.

 446 Plasma 19 Assessing metabolism and function of normothermically perfused ex vivo livers by multi-nuclear MR imaging and spectroscopy Liam AJ Young1, Carlo DL Ceresa2, Jack Miller3, Ladislav Valkovic1,4, Daniel Voyce5, Elizabeth M Tunnicliffe1, Jane Ellis1, Damian J Tyler3, Peter J Friend2, Constantin C Coussios6, and Christopher T Rodgers1,7 1Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Oxford, United Kingdom, 2Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom, 3Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 4Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia, 5OrganOx Ltd, Oxford, United Kingdom, 6Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom, 7Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom Liver transplantation is the only cure for end-stage liver disease. Unfortunately, 20% of patients die waiting for a donor. New techniques for preserving transplant livers, such as normothermic machine perfusion (NMP), provide an opportunity to utilise ‘marginal’ (currently discarded) donated livers if their viability can be assessed accurately. We present initial results from a CE-marked NMP system that we adapted for use in an MRI scanner. We demonstrate the power of NMP-MRI to assess structure and metabolism in a freshly donated pig liver, dynamically over a 10-hour period. Our protocol includes 1H imaging, 31P spectroscopy, and hyperpolarised 13C spectroscopy.

 447 Plasma 20 Effects of Deuteration on Pyruvate Metabolism in the Isolated Heart Alexander Max Funk1, Nesmine Maptue1, Chalermchai Khemtong1, Dean Sherry1,2, and Craig Malloy1,3 1UT Southwestern Medical Center, Dallas, TX, United States, 2University of Texas at Dallas, Richardson, TX, United States, 3Veterans Affairs North Texas Healthcare System, Dallas, TX, United States Deuteration of metabolites is increasingly popular in hyperpolarization experiments as it prolongs the T1 of the 13C resonances. However, the effect of deuteration on metabolism needs to be investigate to validate the hyperpolarization experiments. Kinetic isotope effects of deuteration of pyruvate were analyzed in isolated rat hearts. No kinetic isotope effect were observed in the pyruvate pool (lactate/alanine) or the TCA cycle (glutamate C5), but a 2H-1H displacement was observed in alanine transaminase and an increase of the contribution of unlabeled sources.

 448 Plasma 21 Oxidative stress measured by in-vivo, longitudinal 1H MRS and ex-vivo ESR spectroscopy in a rat model of chronic Hepatic Encephalopathy Katarzyna Pierzchala1, Veronika Rackayova1, Olivier Braissant2, Dario Sessa3, Stefanita Mitrea1, Andrzej Sienkiewicz4, Valérie A. McLin3, Rolf Gruetter1, and Cristina Cudalbu1 1Center for Biomedical Imaging, EPFL, Lausanne, Switzerland, 2Service of Biomedicine, CHUV, Lausanne, Switzerland, 3Swiss Center for Liver Disease in Children, Department of Pediatrics, HUG, Geneva, Switzerland, 4Laboratory of Physics of Complex Matter, EPFL, Lausanne, Switzerland Oxidative stress is believed to play a role in the pathogenesis of chronic hepatic encephalopathy (CHE), however no in-vivo studies to assess the course of cerebral oxidative stress in CHE were performed. We investigated the oxidative stress in the hippocampus of a rat model of chronic HE using in-vivo and longitudinal 1H-MRS combined with ex-vivo ESR spectroscopy. Early changes in brain antioxidants (Asc, 4weeks post-BDL), concomitant with Gln and NH4+ changes were detected for the first time in-vivo. These results were confirmed by ESR spectroscopy suggesting that central oxidative stress is an early event in CHE.

 449 Plasma 22 NMR spectroscopy based blood test to diagnose brain cancer at early stages Shivanand Pudakalakatti1, Alessandra Audia2, Anirudh Mukhopadhyay3, Krishna Bhat2, and Pratip Bhattacharya1 1Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, United States, 2Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, Houston, TX, United States, 3Biochemistry and Cell Biology | Chemistry, Rice University, Houston, TX, United States Early detection of brain cancer will help saving lives. The currently available diagnostic techniques are not robust and expensive. Therefore, it is necessary to develop cost effective, minimally invasive, and highly sensitive analytical tools to identify brain tumors at an early stage. In this study we are investigating metabolism based biomarkers in platelets derived from low grade glioma II, glioblastoma, and healthy patients identified by nuclear magnetic resonance (NMR) spectroscopy. The platelet metabolites - glucose, citrate, and succinate are determined to be promising candidates for identifying and differentiating different stages of brain tumors with implication of employing simple blood based NMR metabolomics for early detection of brain cancer.

 450 Plasma 23 Human Glioblastoma Cell Lines Co-oxidize [2,4-13C]betahydroxy-butyrate and [U-13C]-glucose: A 13C NMR Spectroscopic Study Omkar B. Ijare1, Athena Hoppe1, Cole Holan1, Martyn A Sharpe1, David S Baskin1, and Kumar Pichumani1 1Kenneth R. Peak Center, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, United States Ketogenic diet has been proposed for the adjuvant therapy in the treatment of brain tumors. The rationale behind using ketogenic diet in the cancer treatment is the inability of tumor mitochondria to oxidize KBs. Recent studies on ketone body metabolism using 9L and RG2 cell lines and glioma models suggest that brain tumor mitochondria are capable of oxidizing ketone bodies. The current study was undertaken to determine relative utilization of betahydroxy-butyrate (BHB) and glucose in patient-derived glioblastoma cells. Our findings clearly indicate that human brain tumor cells are fully capable of oxidizing ketone bodies even under normoglycemic conditions.

 451 Plasma 24 Patch-based super-resolution of 7 T MRSI of Glioma: Initial results Gilbert Hangel1,2, Saurabh Jain3,4, Eva Hečková1,2, Bernhard Strasser5, Michal Povazan6,7, Stephan Gruber1,2, Elisabeth Springer1,2, Georg Widhalm8, Matthias Preusser9, Siegfried Trattnig1,2, Diana Sima3,10, Dirk Smeets3,11, and Wolfgang Bogner1,2 1High Feld MR Centre, Medical University of Vienna, Vienna, Austria, 2Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 3icometrix, R&D, Leuven, Belgium, 4Diagnostic Image Analysis Group, Radboud University Medical Center, Nijmegen, Netherlands, 5Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 6Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 7F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 8Department of Neurosurgery, Medical University of Vienna, Vienna, Austria, 9Department of Medicine 1, Division of Oncology, Medical University of Vienna, Vienna, Austria, 10Department of Electrical Engineering-ESAT, STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, KU Leuven, Leuven, Belgium, 11BioImaging Lab, Universiteit Antwerpen, Antwerp, Belgium The application of high-resolution MRSI at 7T to the measurement of brain tumours was recently shown with preliminary data. In order to better resolve the glioma structure and metabolism for clinical use, a further increase in resolution over the currently achievable would be necessary. This can be achieved by the application of modern image up-sampling techniques. Therefore, we demonstrate the successful application and benefits of one such technique, patch-based superresolution, to 7T MRSI maps in glioma patients. Our results show the resolution of metabolic hotspots with unprecedented detail.

 452 Plasma 25 IMPORTANCE OF THE LACTATE SHUTTLE FOR BRAIN ACTIVATION: AN IN VIVO LOCALIZED 1H-MRS AND FUNCTIONAL MRI STUDY DURING WHISKER STIMULATION Jordy Blanc1, Charlotte Jollé2, Hélène Roumes1, Nicole Déglon3, Luc Pellerin2, and Anne-Karine Bouzier-Sore1 1CNRS/Université Bordeaux, Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, Bordeaux, France, Metropolitan, 2CH Lausanne, Switzerland, Département de Physiologie, Lausanne, Switzerland, 3Lausanne University Hospital, Department of Clinical Neurosciences, Laboratory of Cellular and Molecular Neurotherapies (LCMN), Lausanne, Switzerland Although several in vitro and ex vivo evidence support the existence of lactate exchange between astrocytes and neurons, a direct demonstration in vivo is still lacking. The aim of this study was to determine if the neuronal lactate transporter MCT2 is required for proper substrate use by neurons during brain activation. We therefore quantified the brain lactate content by 1H-NMR spectroscopy shRNA-control injected rats (called UNIV rats), MCT4 knockdown rats (called MCT4 rats) and MCT2 knockdown rats (called MCT2 rats), at rest or during whisker stimulation. Moreover, we examined the BOLD fMRI response of the somatosensory cortex associated with whisker stimulation.

 453 Plasma 26 Real time observation of shifts in cerebral metabolism caused by cocaine administration via MRS, DNP, and NMR Joanna Long1, Daniel Downes2, James Collins2, Marcelo Febo2, and Bimala Lama3 1Box 100245, University of Florida, Gainesville, FL, United States, 2University of Florida, Gainesville, FL, United States, 3University of Colorado, Boulder, CO, United States The high energy requirements of the brain are sustained by a unique metabolic relationship between astrocytes and neurons. Here, we show how cocaine administration shifts neurometabolism at a fundamental level. Using a novel approach combining dynamic nuclear polarization-enabled metabolic flux measurements with steady state magnetic resonance measures of metabolite pools, we reveal acute cocaine administration disrupts the balance of oxidative and non-oxidative metabolic pathways. These results demonstrate significant metabolic shifts in response to cocaine administration, providing insight into the observed short-term effects of cocaine use.

 454 Plasma 27 Evidence for Two T2 Components of N-Acetyl-Aspartate (NAA) In Healthy White Matter Erin L. MacMillan1,2,3, Carina Graf4,5, Cornelia Laule4,5,6,7, and Alex L. MacKay2,4,7 1MR Clinical Science, Philips Healthcare Canada, Markham, ON, Canada, 2UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada, 3ImageTech Lab, Simon Fraser University, Surrey, BC, Canada, 4Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada, 5International Collaboration on Repair Discoveries, Vancouver, BC, Canada, 6Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada, 7Radiology, University of British Columbia, Vancouver, BC, Canada N-acetyl-aspartate (NAA) is commonly referred to as an ‘axonal marker’ but recent electron microscopy evidence demonstrates higher levels of NAA in myelin than in neurons. Given the multi-exponential T2 nature of water in white matter (WM), we sought to determine if there are similarly two pools of NAA in WM. We performed multi-echo magnetic resonance spectroscopy in the WM of 5 healthy volunteers at 3T with TE from 10-800ms and observed a short T2 component between 13-40ms arising from 16-20% of the total signal. These preliminary results encourage further research into the bi-exponential nature of NAA in WM.

 455 Plasma 28 Elevated brain NAA occurs without loss of neuronal integrity and correlates with increasing Sickle Cell Disease related stress. Min-Hui Cui1, Seetharama A Acharya2,3, Sandra Suzuka2, Henny H Billett2,4,5, and Craig A Branch1,3 1Radiology, Albert Einstein College of Medicine, Bronx, NY, United States, 2Hematology, Albert Einstein College of Medicine, Bronx, NY, United States, 3Physiology & Biophysics, Albert Einstein College of Medicine, Bronx, NY, United States, 4Pathology, Albert Einstein College of Medicine, Bronx, NY, United States, 5Medicine, Albert Einstein College of Medicine, Bronx, NY, United States Brain NAA is known to be elevated in Canavan’s disease but is usually decreased in association with loss of neuronal integrity.  Elevated NAA is herein reported in murine models of sickle cell disease (SCD) and is associated with anemia, hypoxic and oxidative stress and may reflect  increased glutathione turnover and / or increase demand for mitochondrial energy.  These findings provide insight into why elevated NAA has been observed in children but not adults with SCD, and suggests a mechanism for increased susceptibility to stroke, and alternative roles for NAA in the brain.

 456 Plasma 29 Cerebral Metabolite Changes and Sleep Correlates in Obstructive Sleep Apnea Manoj K Sarma1, Paul M Macey2, Andres Saucedo1, Maithili Gopalakrishnan1, Zahra Meghjani1, Zohaib Iqbal1, Rajakumar Nagarajan3, Ravi Aysola4, Ronald M. Harper5, and M. Albert Thomas1 1Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 2School of Nursing, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 3Radiological Sciences, UCLA School of Medicine, Los angeles, Los Angeles, CA, United States, 4Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, 5Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States Obstructive sleep apnea (OSA) is a chronic, multisystem sleep disorder that has been linked with dementia, stroke and increased risks of cardiovascular disease. Continuous positive airway pressure (CPAP) is the most common treatment method for OSA patients, but its effect on different organ systems and to reverse the rate of cognitive decline is still unclear. In this study, we evaluated neurochemical changes of untreated and CPAP treated OSA patients versus healthy controls in twelve brain regions using a semi-laser based accelerated five-dimensional (5D) echo-planar J-resolved spectroscopic imaging (EP-JRESI) sequence. We also explored the relationship between brain metabolite ratios and apnea hypopnea index (AHI), a measure indicative of the severity of sleep apnea. We observed significant differences of several metabolites in many brain regions. We also found that, among other metabolites, AHI correlated positively with lactate in right parietal insular cortex. This may be the result of hypoxemia and tissue hypoxia during sleep caused by OSA. To validate our findings, further longitudinal studies using a large cohort of OSA subjects before and after CPAP are required.

 457 Plasma 30 Cortical GABA levels correlate with visual search performance in children with autism spectrum disorder David A Edmondson1,2, Pingyu Xia1, Debra A Patterson1,2, Brandon Keehn3, and Ulrike Dydak1,2,3 1School of Health Sciences, Purdue University, West Lafayette, IN, United States, 2Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States, 3Department of Speech, Language, & Hearing Sciences, Purdue University, West Lafayette, IN, United States Although diagnosed based on sociocommunicative deficits, autism spectrum disorder (ASD) is characterized by superior performance on selective attention tasks, particularly visual search. In neurotypical individuals, region-specific concentrations of GABA are associated with differences in attention and perception. While it has been hypothesized that ASD may be associated with an excitatory-inhibitory imbalance, it remains unclear how this may contribute to autistic search advantage. To test this, 10 children with ASD participated in a magnetic resonance spectroscopy (MRS) study using MEGA-semi-LASER to detect GABA concentrations in target regions, including the frontal eye fields, temporal parietal junction, and visual cortex.

Electronic Power Pitch Poster

### Poster: Conductivity, Relaxation, Water-Fat & Beyond

 Power Pitch Theater A - Exhibition Hall Tuesday 17:15 - 18:15

 533 Plasma 1 On the Sensitivity of Bone Marrow Magnetic Susceptibility and R2* on Trabecular Bone Microstructure Maximilian N. Diefenbach1, Anh Van2, Jakob Meineke3, Jan S. Kirschke4, Benedikt Schwaiger1, Thomas Baum4, Alexandra Gersing1, and Dimitrios C. Karampinos1 1Diagnostic and Interventional Radiology, Technical Univeristy of Munich, Munich, Germany, 2Institute of Medical Engineering, Technical University of Munich, Munich, Germany, 3Philips Research Laboratory, Hamburg, Germany, 4Department of Diagnostic and Interventional Neuroradiology, Technical University of Munich, Munich, Germany In numerical simulations and initial in vivo results of multi-parametric mapping in the calcaneus, the feasibility of measuring trabecular bone microstructure is explored. The combination of R2* for measuring intra-voxel dephasing and quantitative magnetic susceptibilty to detect trabecular bone density is investigated and indicates feasibility to differentiate trabecular bone networks with isotropic and anisotropic microstructure.

 534 Plasma 2 Pushing the limits of short-T2 MRI: 200 mT/m gradient strength and 2 MHz bandwidth Romain Froidevaux1, Markus Weiger1, Manuela Barbara Rösler1, David Otto Brunner1, Bertram Wilm1, Benjamin Dietrich1, Jonas Reber1, and Klaas Paul Pruessmann1 1Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland MRI of tissues with short transverse relaxation times below 1 millisecond such as bone or myelin raises both scientific and clinical interest. However, achieving high spatial resolution for short-T2 signals is challenging as large gradient strengths are required. Furthermore, large G implies high signal bandwidth, thus increasing the demands for short-T2 imaging techniques. Therefore, currently, short-T2 imaging faces significant restrictions with respect to spatial resolution and accessible T2s. In this work, all these challenges are tackled to expand the limits of short-T2 MRI using large G up to 200 mT/m and high BW up to 2 MHz.

 535 Plasma 3 New post-processing methods for simultaneous measurement of R2, R2', R2*, QSM, positive and negative susceptibility maps using mGESFIDE acquisition Dongmyung Shin1, Se-Hong Oh2, Doohee Lee1, Jingu Lee1, 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, Gyeonggi-do, Republic of Korea In this work, we demonstrated that a modified gradient-echo sampling of FID and echo (mGESFIDE) sequence was able to produce multiple contrast images (R2, R2', R2*, local field map, QSM, positive and negative susceptibility maps) in 5 minutes of scan time. We developed a new algorithm for improved R2 and R2' maps by considering RF slice profiles in the excitation and refocusing RF pulses. Additionally, we developed a new method that generated a high-quality local field map by utilizing all echoes of mGESFIDE.

 536 Plasma 4 Repeatability and Reproducibility of a New Method for Quantifying Triglyceride Saturation Using Bipolar Multi-Echo MRI Manuel Schneider1, Felix Lugauer1, Gemini Janas2,3, Dominik Nickel4, Brian M Dale5, Berthold Kiefer4, Andreas Maier1, and Mustafa R Bashir2,3 1Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, 2Radiology, Duke University Medical Center, Durham, NC, United States, 3Center for Advanced Magnetic Resonance Development, Duke University Medical Center, Durham, NC, United States, 4MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany, 5MR R&D Collaborations, Siemens Healthineers, Cary, NC, United States Our purpose was to develop a robust method for joint quantification of water and fat fractions as well as fatty acid maps from bipolar multi-echo MR data. Its accuracy and reproducibility across field strengths and sequences was demonstrated using an oil phantom. Repeated in-vivo breath-hold acquisitions in n = 11 patients yielded median absolute differences of 4.8%, 1.0% and 8.2% for the saturated, mono-unsaturated and poly-unsaturated fat components in the liver, spleen and subcutaneous, perirenal and mesenteric fat depots.

 537 Plasma 5 Calibrating variable flip angle (VFA)-based T1 maps: when and why a simple scaling factor is justified Sofia Chavez1 1CAMH, Toronto, ON, Canada Variable Flip Angle (VFA)-based T1 maps are known to be prone to errors deriving from B1 errors (inaccurate knowledge of flip angles) and poor signal spoiling. In general, in vivo T1VFA values tend to overestimate T1 values obtained using a gold standard inversion recovery method :T1IR. Calibrating T1VFA with T1IR has been proposed but it requires knowledge of the exact relationship between these. This work models the contribution of B1 errors and poor spoiling to T1VFA errors and via simulations, the conditions for T1VFA/T1IR= constant (i.e. simple scaling) are derived. Experiments on phantoms and in vivo are used for validation.

 538 Plasma 6 “In vivo” Field-Cycling relaxometry of tumours. Evidence for the role of the intracellular water lifetime as tumour biomarker. Simonetta Geninatti Crich1, Simona Baroni2, Maria Rosaria Ruggiero1, Stefania Pezzana1, Gianni Ferrante3, and Silvio Aime1 1University of Torino, Torino, Italy, 2University of torino, Torino, Italy, 3Stelar srl, Mede (PV), Italy This work aims at developing an innovative diagnostic strategy, based on the "in vivo" measurements of longitudinal relaxation times at low and ultra-low magnetic fields with Fast Field Cycling FFC-NMR to obtain quantitative information on tumour metastatic potential, due to different water content and mobility, that is invisible to standard MRI. Preliminary results show that the endogenous contrast between normal and diseased tissue, due to differences in T1, is much greater at low field and the shape of the relaxation dispersion profiles may be used as a reporter of the molecular dynamical processes, biomarkers of the disease grade.

 539 Plasma 7 In-vivo Vagus Nerve to Central Nervous System Tracing using Manganese Enhanced Magnetic Resonance Imaging Steven Oleson1, Kun-Han Lu2, Jiayue Cao1, and Zhongming Liu1 1Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 2Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States Tracing neuronal connections of the peripheral and central nervous system has relied on invasive techniques that make it difficult to reconstruct information. We demonstrate the feasibility of utilizing manganese enhanced magnetic resonance imaging (MEMRI) and vagus nerve stimulation (VNS) to trace the vagus nerve to central nervous system (CNS) connections. This experimental approach shows the non-invasive visualization and quantified increased enhancement of manganese transport from the nodose ganglion to the left nucleus tractus solitaries (NTS).

 540 Plasma 8 Fat Quantification Using A High-Resolution Bipolar Gradient Water-Fat Sequence Alireza Akbari1,2, Lanette J Friesen-Waldner1, Timothy RH Regnault3,4, and Charles A McKenzie1,2 1Medical Biophysics, Western University, London, ON, Canada, 2Robarts Research Institute, Western University, London, ON, Canada, 3Obstetrics and Gynaecology, Western University, London, ON, Canada, 4Physiology and Pharmacology, Western University, London, ON, Canada In this work we demonstrate high-resolution bipolar water-fat imaging sequence produces same fat quantification as compared to conventional unipolar water-fat imaging sequence under the same scan time. Images of resolved boundaries in bipolar Proton Density Fat Fraction (PDFF) maps are presented. Fat quantifications of the same regions of interest drawn on bipolar and unipolar PDFF were compared and statistical analysis was performed to evaluate the similarity of the two methods.

 541 Plasma 9 Robust Fat-water Separation using Binary Decision Tree Algorithm Hao Peng1,2, Chao Zou2, Wenzhong Liu1, Chuanli Cheng2,3, Yangzi Qiao2, Qian Wan2,3, Changjun Tie2, Xin Liu2, and Hairong Zheng2 1Huazhong University of Science and Technology, Wuhan, China, 2Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences, Shen Zhen, China, 3University of Chinese Academy of Sciences, Beijing, China Purpose: To propose an robust fat water separation method using binary decision tree algorithm. Methods: In this paper, a novel fat-water separation algorithm using binary decision tree is proposed. Pixels are firstly clustered into sub-regions. Different from existing region growing algorithms, the proposed method solves the phasor ambiguity problem region by region. The method was tested on data sets from ISMRM 2012 Challenge. Results:Fat-water separation were successfully achieved by the proposed method in the datasets. Conclusion: A novel method using binary decision tree algorithm is proposed for robust and accurate water-fat separation.

 542 Plasma 10 Human In-vivo Brain MR Current Density Imaging (MRCDI) based on Steady-state Free Precession Free Induction Decay (SSFP-FID) Cihan Göksu1,2, Lars G. Hanson1,2, Hartwig R. Siebner2,3, Philipp Ehses4,5, Klaus Scheffler4,6, and Axel Thielscher1,2 1Center for Magnetic Resonance, DTU Elektro, Technical University of Denmark, Kgs. Lyngby, Denmark, 2Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark, 3Department of Neurology, Copenhagen University Hospital, Bispebjerg, Denmark, 4High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany, 5German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, 6Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany MRCDI is a novel technique for non-invasive measurement of weak currents in the human head, which is important in several neuroscience applications. Here, we present reliable in-vivo MRCDI measurements in the human brain based on SSFP-FID, yielding an unprecedented accuracy. We demonstrate the destructive influences of stray magnetic fields caused by the current passing through feeding cables, and propose a correction method. Also, we show inter-individual differences in MRCDI measurements for two different current profiles, and compare the measurements with simulations based on individualized head models. The simulations of the current-induced magnetic fields show good agreement with in-vivo brain measurements.

 543 Plasma 11 Multi-receiver coil combination for breast phase-based Electrical Property Tomography Using B1- estimation Jun-Hyeong Kim1, Jaewook Shin1, Soo-Yeon Kim2, and Dong-Hyun Kim1 1electrical electronic engineering, Yonsei University, seoul, Republic of Korea, 2Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea Phase-based EPT assumes the spatial homogeneity of both B1+ and B1- magnitude. However, when it comes to multi-receivers is used for improved SNR, the assumption becomes invalid especially for B1-. To overcome this problem, a subject-specific multi-Rx combination method was suggested [2]. However, this method can give a solution that is biased by the transmit field (B1+) when it is inhomogeneous.  In this study, an alternative multi-Rx combination method is proposed. B1- is estimated from multi-receiver images by solving an inverse problem. Afterwards, optimal coil-coefficients for combination are calculated using the estimated B1- field. The method is applied to in-vivo breast conductivity imaging.

 544 Plasma 12 Electrical permittivity imaging at 3T: a precision and accuracy study of three $\it{B_1^+}$ mapping techniques Soraya Gavazzi1, Cornelis AT van den Berg1,2, Alessandro Sbrizzi2, Mick Bennis3, Lukas JA Stalpers3, Jan JW Lagendijk1, Hans Crezee3, and Astrid LHMW van Lier1 1Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, 2Center for Image Sciences, University Medical Center Utrecht, Utrecht, Netherlands, 3Department of Radiation Oncology, Academic Medical Center Amsterdam, Amsterdam, Netherlands The feasibility of permittivity imaging relies on high precision of the underlying $\it{B_1^+}$ amplitude maps. We tested AFI, Bloch-Siegert and DREAM $\it{B_1^+}$ mapping techniques on a pelvic-sized phantom at 3T, comparing their SNR in $\it{B_1^+}$ maps and (resulting) permittivity precision. Our results indicated that the DREAM-based permittivity map was the most sensitive to sequence-related systematic errors. The commonly-used AFI technique, instead, was the least precise method. We also found that Bloch-Siegert is generally best suited for permittivity mapping compared to the other two methods, due to its higher  $\it{B_1^+}$ precision and accuracy.

 545 Plasma 13 Multi-frequency MREIT Demonstrated using Semipermeable Membrane Models Munish Chauhan1, Andrew Xi2, Neeta Ashok Kumar1, Fanrui Fu1, and Rosalind J Sadleir1 1SBHSE, Arizona State University, Tempe, AZ, United States, 2ECEE, Arizona State University, Tempe, AZ, United States Magnetic Resonance Electrical Impedance Tomography (MREIT) has been used to measure low frequency (ca. 10 Hz) electrical conductivity properties. Here, finite element simulations are used to show that it should be possible to measure electrical properties at frequencies in the range 10- ~5000 Hz using current waveform modulation. We also show imaging results that demonstrate differential signals can be measured in phantoms containing dialysis membranes with different thicknesses and permittivity characteristics.

 546 Plasma 14 The impact of CSF pulsation on reconstructed brain conductivity Ulrich Katscher1, Christian Stehning1, and Khin Khin Tha2 1Philips Research Europe, Hamburg, Germany, 2Hokkaido University Hospital, Sapporo, Japan It has recently been shown that the WHO grade of a glioma is correlated with its electric conductivity, which can be determined via post-processing the acquired MR transceive phase. However, the transceive phase and thus the derived conductivity might be corrupted by motion induced phase, particularly from cardiac pulsation transferred to the cerebrospinal fluid (CSF). In this study, the impact of CSF pulsation on the reconstructed conductivity was investigated by synchronizing the transceive phase acquisition to the cardiac cycle. It turned out that the pulsation significantly affects reconstructed conductivity of the CSF, but not of gray and white matter.

 547 Plasma 15 In Vivo Conductivity Imaging of Tissue Response after Radiation Therapy In Ok Ko1, Bup Kyung Choi2, Nitish Katoch2, Ji Ae Park1, Jin Woong Kim3, Hyung Joong Kim2, Oh In Kwon4, and Eung Je Woo2 1Division of RI Convergence Research, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea, 2Biomedical Engineering, Kyung Hee University, Seoul, Republic of Korea, 3Radiology, Chonnam National University Medical School, Gwangju, Republic of Korea, 4Konkuk University, Seoul, Republic of Korea Radiation therapy (RT) has been widely used as a powerful treatment to remove cancerous tissues because of its ability to control cell growth. Ionizing radiation works by damaging the DNA of cancerous tissue leading to cellular death. Medical imaging has limitations on credibility for evaluation of tissue response and prediction of therapeutic effect due to lacks of contrast information on gradual and minute tissue changes after RT. Conductivity mapping after RT may provide direct and high sensitive information on tissue response because its contrast mechanism originated from the concentration and mobility of ions in the extra- and intracellular environment.

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### Poster: Advances in Contrast: MT, CEST & Perfusion

 Power Pitch Theater B - Exhibition Hall Tuesday 17:15 - 18:15

 548 Plasma 16 Rethinking vascular artifacts: testing the sensitivity of ASL vascular signal as a biomarker of disease Zachary Mulhollan1, Henk-Jan Mutsaerts1, Jan Petr1,2, Ronald S Lazar3, Randolph S Marshall4, and Iris Asllani1 1Rochester Institute of Technology, Rochester, NY, United States, 2Helmholtz-Zentrum Dresden-Rossendorf Institut für Radiopharmazeutische Krebsforschung PET-Zentrum, Dresden, Germany, 3The University of Alabama at Birmingham, Birmingham, AL, United States, 4Columbia University Medical Center, New York, NY, United States Collateral perfusion has a major effect on clinical outcome in carotid steno-occlusive disease. Arterial spin labeling (ASL) may provide a biomarker of collateral perfusion by measuring arterial transit time (ATT) in addition to cerebral blood flow (CBF). However, the concomitant measurement of ATT and CBF is not feasible for clinical applications. As an alternative, ATT can be estimated from single post-labeling delay ASL image using the spatial coefficient of variance (CoV). In this study, we investigate whether the spatial CoV lateralization through collateral perfusion can predict the side of carotid occlusion as a proof-of-principle. In addition to spatial CoV, we also investigated whether temporal variance (tVAR) of the ASL signal could be used as a predictor of occlusion versus stenosis.

 549 Plasma 17 Exploiting small fluctuations in labeling efficiency in pseudo-continuous arterial spin labeling for combined flow-territory determination and CBF-mapping Thijs W. van Harten1 and Matthias J.P. van Osch1 1Department of Radiology, Leiden University Medical Center, Leiden, Netherlands Since the labeling efficiency in pCASL is dependent on velocity and off-resonance effects, one could imagine that small natural occurring fluctuations at the labeling plane would lead to similar fluctuations in the ASL-signal. Such fluctuations at the brain level would be similar for voxels belonging to the same flow territory and might enable detection of flow territories, e.g. by an ICA-type of resting-state ASL analysis that is normally used for identification of neuronal networks. By deliberately manipulating the labeling efficiency, we can report that with small fluctuations in labeling efficiency flow territories can be determined, which diminish in robustness for smaller fluctuations.

 550 Plasma 18 The Influence of the cardiac cycle on velocity-selective and acceleration-selective Arterial Spin Labeling Suzanne L. Franklin1,2, Sophie Schmid1, Clemens Bos2, and Matthias J.P. van Osch1 1C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands, 2Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands In this study we investigated whether velocity-selective arterial spin labeling (VS-ASL) and acceleration-selective spin labeling (Acc-ASL) can be used to measure pulsatility in the microvascular system of the brain, since the amount of generated label will depend on the velocity or acceleration of the spins at the moment the VS-ASL (Acc-ASL) module is applied. Results showed no significant variation in the amount of label when applying these modules at different cardiac phases. However, the generated label did show a pattern which coincides with the flow territories, suggesting a underlying physiological cause.

 551 Plasma 19 Improving Arterial Spin Labeling using Deep Learning Ki Hwan Kim1, Seung Hong Choi2, and Sung-Hong Park1 1Department of Bio and Brain Engineering, Korea Advanced Institute of Science & Technology (KAIST), Daejeon, Republic of Korea, 2Department of Radiology, Seoul National University College of Medicine, Seoul, Korea, Democratic People's Republic of We proposed a new convolutional neural network (CNN) framework to quantify cerebral blood flow (CBF) in Hadamard-encoded pseudo-continuous arterial spin labeling (HE-pCASL). Improving sensitivity and robustness in ASL signals allows CNNs to quantify CBF accurately with a smaller number of data acquisitions. The proposed methods outperformed the conventional averaging method in both normal and pathologic regions. Therefore, CNNs can be a good alternative to quantify CBF in ASL imaging.

 552 Plasma 20 Contrast Enhancement for Early Tumor Detection by Active-Feedback Field Locking and Refocusing Fang-Chu Lin1, Chao-Hsiung Hsu1, and Yung-Ya Lin1 1Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States Early detection of high-grade malignancy using novel contrast mechanisms and detection methods significantly increases the treatment options and the patients’ survival rate. For this purpose, the local magnetic-field-gradient variations due to irregular water contents and deoxyhemoglobin concentration in early glioblastoma multiforme (GBM) is sensitively detected by active-feedback electronic devices and nonlinear spin dynamics. The active-feedback phases and strength were tuned to manipulate the underlying spin dynamics and thus optimize the feedback-induced avalanching spin amplification effect. In vivo results from GBM mouse models show that up to 12 times of improved tumor-to-normal-tissue contrasts can be achieved to highlight early GBM.

 553 Plasma 21 Measurement of artifact-free arterial input functions for T1-weighted dynamic contrast-enhanced MRI: Inter- and intra-patient variability Leonidas Georgiou1,2, Daniel J Wilson3, Nisha Sharma4, and David L Buckley1 1Department of Biomedical Imaging Science, University of Leeds, Leeds, United Kingdom, 2Department of Medical Physics, German Oncology Centre, Limassol, Cyprus, 3Department of Medical Physics & Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom, 4Department of Radiology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom In 2006, Parker et al published a population-average AIF that has subsequently been used by numerous investigators for both simulation and data analysis. Despite its utility, the published AIF suffers from a number of limitations. In this study we tried to address many of these limitations and made measurements in a population of patients with advanced breast cancer, resulting in a total of 74 individual AIFs. We fitted each AIF with a physiological model and assessed inter- and intra-patient variability.

 554 Plasma 22 Estimation of Pharmacokinetic Parameters in Dynamic Contrast Enhanced MRI via Random Forest Regression Cagdas Ulas1, Michael J. Thrippleton2, Ian Marshall3, Mike Davies4, Paul A. Armitage5, Stephen D. Makin2, Joanna M. Wardlaw2, and Bjoern H. Menze1 1Computer Science, Technical University of Munich, Munich, Germany, 2Neuroimaging Sciences, University of Edinburgh, Edinburgh, United Kingdom, 3Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom, 4Institute for Digital Communication, University of Edinburgh, Edinburgh, United Kingdom, 5Cardiovascular Science, University of Sheffield, Sheffield, United Kingdom We propose a novel alternative approach to estimate pharmacokinetic (PK) parameters of dynamic contrast enhanced (DCE)-MRI. Our approach leverages machine learning field and mainly targets to automatically learn temporal patterns of the voxel-wise concentration-time curves (CTCs) from a large amount of training samples in order to make accurate parameter estimations. We consider the estimation of parameters as a regression problem and specifically use Random Forest (RF) regression. We demonstrate its potential and utility to improve the conventional model-fitting based quantitative analysis of DCE-MRI especially in various noise conditions, and validate our method on clinical brain stroke datasets.

 555 Plasma 23 Influence of whole-brain DCE-MRI (k,t) sampling strategies on variance of pharmaco-kinetic parameter estimates Yannick Bliesener1, Sajan G. Lingala1, Justin P. Haldar1, and Krishna S. Nayak1 1Electrical Engineering Department, University of Southern California, Los Angeles, CA, United States We investigate the influence of 2D $(k_y,k_z,t)$ sampling strategies on the minimum achievable variance without bias for pharmaco-kinetic parameter estimation in 3D whole-brain DCE-MRI (equivalent to the best possible precision without bias). Cramér-Rao analysis is combined with a pathologically- and anatomically-realistic digital reference object to objectively compare measurement procedures independent of any estimator. This study did not identify any significant difference between lattice and random undersampling, or between their uniform and variable density variants.

 556 Plasma 24 Characterization of Breast Lesion using T1-perfusion MRI: Semi- Quantitative Vs Quantitative Analysis Snekha Thakran1, Anup Singh1,2, Pradeep Kumar Gupta3, Vedant Kabra3, and Rakesh Kumar Gupta3 1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Department of Biomedical Engineering, AIIMS Delhi, New Delhi, India, 3Department of Radiology and Imaging, Fortis Memorial Research Institute, Gurgaon, New Delhi, India In this study role of hemodynamic parameters (breast-blood-volume and breast blood-flow), obtained using T1-perfusion MRI data of breast, in the differentiation of benign from malignant breast lesions and classification of malignant lesions into different grades is evaluated. Hemodynamic parameters were also compared with the tracer kinetic parameters and semi-quantitative T1-perfusion analysis in term of grading. The high sensitivity and specificity of breast-blood-volume in differentiating between benign and malignant as well as in the grading of breast lesions (grade-I, grade-II and grade-III) were observed.

 557 Plasma 25 Manganese-enhanced MRI: comparison of agents in the rat pancreas Lucy Elizabeth Kershaw1, David Lilburn1, Maurits Jansen1, Pilar Jimenez-Royo2, Antonella Napolitano Rosen2, Philip Murphy2, Alexandra Morgan2, Rob Janiczek2, Shareen Forbes3,4, and Scott Semple1,4 1Edinburgh Imaging, The University of Edinburgh, Edinburgh, United Kingdom, 2Experimental Medicine Imaging, GlaxoSmithKline, London, United Kingdom, 3Endocrinology Unit, The University of Edinburgh, Edinburgh, United Kingdom, 4BHF/University of Edinburgh Centre for Cardiovascular Sciences, The University of Edinburgh, Edinburgh, United Kingdom Type 1 diabetes mellitus results in autoiummune destruction of β-cells in the pancreas, which are responsible for insulin production.  Paramagnetic Mn2+ ions are taken up by β-cells as a calcium analogue and could be used as an MR contrast agent to monitor β-cell function and therefore treatment or disease progression in these patients.  Three manganese-based contrast agents (MnCl2, mangafodipir and Mn gluconate) were used to measure pancreas enhancement after saline and glucose challenge in healthy rats.  All agents showed greater enhancement after glucose challenge, with no marked difference between the two agents that have been used clinically.

 558 Plasma 26 Novel contrasts at +2.7 ppm, +1.2 ppm, and -1.7 ppm investigated in vivo with high spectral resolution CEST MRI in the human brain at 9.4T Mark Schuppert1, Kai Herz1, Anagha Deshmane1, and Moritz Zaiss1 1High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany Using volumetric snapshot-GRE CEST MRI at 9.4T with high frequency sampling, we were able to separate novel CEST peaks at +2.7 ppm, +1.2 ppm and -1.7 ppm reliably in the CEST-spectrum and showed creation of maps of these CEST MRI contrasts in the healthy human brain to be feasible in vivo.

 559 Plasma 27 A Novel MR Fingerprinting Approach for Fast Quantitative Chemical Exchange Saturation Transfer MRI Analysis by Subgrouping Proton Exchange Models (CEST-SPEM) Hye-Young Heo1,2, Shanshan Jiang1, Peter C.M. van Zijl1,2, and Jinyuan Zhou1,2 1Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States Most current amide proton transfer (APT) imaging protocols, a variant of CEST-MRI, are essentially not quantitative and acquire qualitative APT-weighted images, limiting pH or concentration specificity. Herein, we propose a novel dictionary-free MRF concept to allow APT quantification by subgrouping proton exchange models (CEST-SPEM). The results of numerical phantom studies demonstrate that CEST-SPEM can enable absolute quantification of the APT exchange rate and concentration on 3T clinical scanners. The same model used for in vivo allows fast quantification of exchange rates and apparent concentrations for the combined solute components at the CEST frequency studied.

 560 Plasma 28 Evaluating Feasibility of Creatine-weighted CEST MRI in Human Brain at 7T using Z-spectral Fitting Approach Anup Singh1,2, Mohammad Haris3, Ayan Debnath1, Kejia Cai4, Hari Hariharan5, Puneet Bagga5, and Ravinder Reddy5 1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Biomedical Engineering, AIIMS Delhi, New Delhi, India, 3Sidra Medical and Research Center, DOHA, Qatar, 4Radiology, University of Illinois at Chicago, Chicago, IL, United States, 5Radiology, University of Pennsylvania, Philadelphia, PA, United States Creatine(Cr)-weighted chemical-exchange-saturation-transfer(CEST) MRI is being developed to detect alteration in Cr concentration during modulation as well as Cr-associated disorders. Cr-weighted CEST contrast show dependence on saturation parameters and overlap from other effects in brain. The conventional asymmetry approach results in a mixed contrast, which is less specific to Cr. By using appropriate saturation parameters, contamination from some of the metabolites/molecules can be reduced; however, it is difficult to suppress the contamination completely as shown by simulation studies. Proposed protocol and improved z-spectral fitting approach can be used for computing Cr-weighted CEST contrast with reduced contamination in human brain at 7T.

 561 Plasma 29 CO2 induced pHi changes in the brain of polar fish: a TauCEST application Felizitas Charlotte Wermter1,2, Bastian Maus2, Hans-Otto Pörtner2, Wolfgang Dreher1, and Christian Bock2 1University of Bremen, Bremen, Germany, 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany Chemical exchange saturation transfer from taurine to water (TauCEST) is primarily detectable in the low temperature range. Since, TauCEST asymmetry is bijective in the physiological pH-range (6.8-7.5), TauCEST is a potential candidate for in vivo studies on brain of polar fish. The specificity of TauCEST MRI on the brain of polar cod at 1.5°C shows a taurine contribution of 65%. TauCEST in brain of polar cod significantly increased under elevated CO2 concentrations by about 1.34%-3.17% in comparison to control, reflecting pHi changes since localized 1H NMR spectra show no significant changes in metabolite concentration for the different treatments.

 562 Plasma 30 Characterizing the sensitivity of ihMT for various dipolar relaxation times (T1D) at high RF power using frequency-alternated and cosine-modulated RF pulses for dual frequency-offset saturation Guillaume Duhamel1,2, Samira Mchinda1,2, Valentin H. Prevost1,2, Victor Carvalho1,2, Gopal Varma3, David Alsop3, and Olivier M. Girard1,2 1Aix-Marseille Univ, CNRS, CRMBM, Marseille, France, 2APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France, 3Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical Schooll, Boston, MA, United States In the present study, we used both numerical simulations and experiments performed in a preclinical setup to characterize the mechanisms of the ihMT boost effect (signal enhancement achieved using concentrated bursts of high-power RF for saturation). We demonstrated that the ihMT boost effect depends on T1D and is more intense in short-T1D components. This feature allowed, using various strategies for dual frequency-offset RF saturation, different ihMT contrasts to be produced and revealed strong ihMT signal outside the brain.

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### Poster: Interventional & RF: Safety & Solutions

 Power Pitch Theater A - Exhibition Hall Wednesday 9:15 - 10:15

 638 Plasma 1 Reducing Radiofrequency-induced Heating in Realistic Deep Brain Stimulation Lead Trajectories using Parallel Transmission Pei-Shan Wei1, Benson Yang1, Clare E. McElcheran2, Laleh Golestanirad3, and Simon J. Graham1,4 1Physical Sciences, Sunnybrook Research Institue, Toronto, ON, Canada, 2Baylis Medical, Mississauga, ON, Canada, 3Massachusetts General Hospital, Boston, MA, United States, 4Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada Patients with deep brain stimulation devices have a safety concern for localized heating that can arise during MRI. Clinically, the lead trajectory for the surgical stimulation procedure varies among patient population. We have shown in previous numerical simulations that the lead trajectory would affect the performance of heating suppression in patient-specific pTx optimization. The present work experimentally validated that RF-induced heating can be suppressed for a high-risk patient-specific lead trajectory, using optimal pTx input parameters.

 639 Plasma 2 Electrical lengthening to improve electromagnetic simulations and SAR calculations of meandered body dipole elements at 7T Stephen Bawden1,2, Richard Bowtell1, Penny Gowland1, and Paul Glover1 1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 2National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham, United Kingdom This study investigated the use of electrical-lengthening as an alternative method of simulating meandered dipole arrays. Dipoles were compared with (a) differing inductor positions, (b) rotating dipole along main axis and (c) for multiple dipole transmission. Results showed a simple single wire dipole model with electrical-lengthening produced comparable SAR solutions, were less effected by rotations and cut simulation times by up to 10 times.

 640 Plasma 3 SAR Calculations in Transmit-Only-Receive-Only RF systems: A Comparison of Detuning Methods for Rx Array Coils and their Implementation in EM Simulations Matthias Malzacher1, Jorge Chacon-Caldera1, Mathias Davids1, and Lothar R. Schad1 1Computer Assisted Clinical Medicine,Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany The accurate simulation of SAR is important to guarantee patient safety in MRI measurements especially for local variations. Although most clinical RF systems are hybrid systems (separate Transmit (Tx) and Receive (Rx) coils), the effect of the Rx coils on Tx power consumption, B1+-homogeneity and SAR have been seldom investigated. Rx coils present highly conductive surfaces which affect the RF field distribution. In this work, we evaluate the performance of several detuning concepts and their realization in the EM simulations concerning Tx power consumption, B1+-homogeneity and SAR for a hybrid setup at 3T.

 641 Plasma 4 Sensitivity analysis of Peripheral Nerve Stimulation modeling: Which model parameters actually matter? Valerie Klein1, Mathias Davids1,2, Bastien Guérin2,3, Lothar R. Schad1, and Lawrence L. Wald2,3,4 1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, 2A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 3Harvard Medical School, Boston, MA, United States, 4Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States Peripheral nerve stimulation (PNS) has become the main limitation for MRI with high-performance gradients. Recently, we proposed a simulation framework to predict PNS thresholds for arbitrary coil geometries to directly address PNS considerations during the coil prototyping phase. In order to ensure robust modeling of PNS (and thus convergence of the coil optimization phase), we analyze the sensitivity of our framework to key simulation parameters such as the temporal and spatial resolution of the induced electric fields, dielectric tissue parameters of our body models, and the location of the neurodynamic model compartments along the nerve fibers.

 642 Plasma 5 Validating and Measuring Transfer Functions of Straight Wires using a Combination of an Electro-optic Field Sensor and Simulation Thomas Lottner1, Simon Reiss1, Ali Caglar Özen1,2, Michael Bock1, and Andreas Bitzer1,3 1Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2German Consortium of Translational Cancer Research Freiburg Site, German Cancer Research Center (DKFZ), Heidelberg, Germany, 3BIOLAB Technology AG, Zürich, Switzerland To investigate deep brain stimulators, pacemakers or other elongated structures the transfer function was proposed to characterize these devices. A electro-optic E-field sensor is used to acquire 2D field data of copper wires excited at one tip for 64 and 123MHz. The data is compared to simulations and transfer functions are calculated from these simulations. These are compared to experimentally acquired transfer functions.

 643 Plasma 6 Imaging Conditions and Image Quality for Patients with MR-conditional Implantable Medical Devices: Normal Volunteer Study Kagayaki Kuroda1, Saeko Sunohara1, Satoshi Yatsushiro2, Toshiki Saito3, Nao Kajiwara3, Tomohiko Horie3, Toshiki Kazama3, Tetsu Niwa3, and Yutaka Imai3 1Course of Electric and Electronic Engineering, Graduate School of Engineering, Tokai University, Hiratsuka, Japan, 2Graduate School of Science and Technology, Tokai University, Hiratsuka, Japan, 3Department of Radiology, School of Medicine, Tokai University, Isehara, Japan Actual SAR values measured by calorimetry varied for a factor of 2.3 among three different scanners (two 1.5T and one 3T) even at identical console SAR settings. Console B1+RMS values also deviate for a factor of 1.2 between the two 1.5T. Image quality assessment performed by three radiologists suggested that the image quality change due to the console SAR setting was not critical at a 1.5-T scanner, but was so at a 3-T scanner. Therefore attention should be paid to the variation of the actual SAR even if the console SAR is at a condition specified for an implantable medical device.

 644 Plasma 7 Wireless MR-Compatibility Control of Active Implantable Medical Devices Berk Silemek1, Volkan Açıkel2, Uğur Yılmaz1, and Ergin Atalar1,3 1National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey, 2REHIS Power Amplifier Technologies, Aselsan, Ankara, Turkey, 3Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey In this study, we proposed a prototype implant that can be controlled wirelessly to change the connection impedance between the lead and the case. To show the effect of the connection impedance between the lead and the case, the tip temperature increase was calculated for 3 different lead lengths by placing a capacitance between the lead and the case.  Two different case to lead connection impedance values were switched in this work as proof of a concept and tip temperature heating was changed during the scanning.  It is demonstrated that by changing the impedance, the lead tip heating properties can be changed allowing safe scanning. it can be useful for avoiding excessive heating if resonance condition occurs due to environmental factors inside human body and position inside the scanner.

 645 Plasma 8 Experimental implementation of test-field diversity method for RF-induced heating assessment of medical implants Earl Zastrow1, Aiping Yao1,2, and Niels Kuster1,2 1IT'IS Foundation, Zurich, Switzerland, 2ETH-Zurich, Zurich, Switzerland We summarize the experimental implementation of test-field diversity (TFD) method for radiated immunity testing of medical implants. The TFD method is used to provide a diverse and well-characterized incident conditions to the implant during radiated immunity test. As an illustrative example, the TFD is used for in vitro validation of a Tier 3 model that describes RF-induced heating of a commercial medical implant at 64 MHz. Results shown a dynamic range of 10 dB for the tip deposited power can be obtained experimentally. The experimental instrumentation and the practical considerations of the method are discussed.

 646 Plasma 9 SMART tracking: SiMultaneous Anatomical imaging and Real-Time needle tracking Frank Zijlstra1 and Peter R Seevinck1 1Image Sciences Institute, UMC Utrecht, Utrecht, Netherlands We propose a passive needle tracking method for MR-guided interventions. We combined undersampled 2D radial multi-echo acquisitions, the white marker phenomenon, and simulations and template matching of artifacts around the needle tip to achieve real-time (10 Hz) tracking of the needle tip, while simultaneously being able to reconstruct anatomical images using a sliding window reconstruction. The method is demonstrated to smoothly track the insertion of a needle in porcine tissue while also showing deformations in the anatomical image caused by the needle insertion. These results bridge a gap between active and passive tracking of needles.

 647 Plasma 10 MRI Safety Assessment of Orthopedic Implants on the Bone Surface via the Induced Tangential E-Fields Manuel Murbach1, Earl Zastrow1, Esra Neufeld1, Theodoros Samaras2, Wolfgang Kainz3, and Niels Kuster1,4 1ITIS Foundation, Zurich, Switzerland, 2Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece, 3Center for Devices and Radiological Health (CDRH), US Food and Drug Administration (FDA), Silver Spring, MD, United States, 4Swiss Federal Institute of Technology (ETH), Zurich, Switzerland Orthopedic implant manufacturers produce a large portfolio of on-bone devices. Current implant RF safety standards, e.g., ASTM F2182-11a and TS/ISO 10974, do not take advantage of very well-defined data on relevant RF exposures of these devices, i.e., E-fields tangential to the bone-surface. In our approach presented here, we explore the use of the bone-surface-averaged tangential E-field as a close approximation of the incident field impacting an on-bone orthopedic device. The relevant surface-averaged tangential E-fields are less than half of the corresponding peak volume-averaged E-fields, which allows for realistic but not overly conservative assessment of RF implant safety in MRI.

 648 Plasma 11 A Reproducible and Lower-Cost Thermo-Acoustic Ultrasound System for Detection of RF-Induced Lead Tip Heating in MRI Neerav Dixit1, Pascal Stang2, John Pauly1, and Greig Scott1 1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Procyon Engineering, San Jose, CA, United States Thermo-acoustic ultrasound (TAUS) has been shown to be able to detect the peaks in local SAR indicative of RF-induced lead tip heating in an MRI setting. Here, we detail a reproducible TAUS acquisition system consisting entirely of commercially accessible electronics that can interface with an MRI scanner. This system achieves comparable performance to our previously demonstrated acquisition system with lower cost electronics, while also providing additional functionality that could aid in the development of a robust TAUS pre-scan to assess the risk of RF-induced lead tip heating in MRI.

 649 Plasma 12 An Aerosol-Deposited Wireless Resonant Marker for Catheter Tracking in Interventional MRI Caroline D. Jordan1, Bradford R. H. Thorne1, Arjun Wadhwa2, Vincent Fratello2, Alastair J. Martin1, Xiaoliang Zhang1,3, and Steven W. Hetts1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Quest Integrated, LLC, Kent, WA, United States, 3UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, CA, United States Catheter visualization and guidance under MRI guidance can be challenging, and conventional MR tracking coils decrease the flexibility and increase the profile of catheters. We used aerosol jet deposition to print a capacitor and an inductor with a double helix geometry on a polymer catheter. bSSFP sequences with flip angles 5°, 15°, and 90°, and a B1+ map were acquired at 3T, and CNR and amplification were measured. The marker demonstrated good CNR and B1+ signal amplification, suggesting that fabrication of complete 3D printed LC circuits for use as markers on catheters is feasible and can exhibit good tracking characteristics.

 650 Plasma 13 Actively-tracked metallic electrophysiology catheters and guidewires with miniature floating radio-frequency traps: Theory, Design and Validation Ehud J Schmidt1, Eric S Meyer1, Ronald D Watkins2, Hassan Elahi1, Wolfgang Loew3, Jeffrey Schweitzer4, Gregory Olson4, Aravindan Kolandaivelu1, and Henry R Halperin1 1Cardiology, Johns Hopkins University, Baltimore, MD, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 4Abbott Inc., Saint Paul, MN, United States Metal-reinforced catheters have improved steerability and pushability. Currently, long (>wavelength/8) metallic-braided or metallic-tube-reinforced active MRI-compatible devices do not exist, due to risks of heating of surrounding tissue. Metallic-backbone devices may be possible if  heating-sources are attenuated.  Concentric-tube RF traps were miniaturized (“MBaluns)” by using leaky (loosely-wound) solenoids in-place of the external tube, providing transverse magnetic fields to attenuate (a) surface electric-fields on metals and (b) common-mode propagation on internal-cables.  We validated (1) a 1.1mm outer-diameter (OD) active metallic-tube-based guidewire and (2) a 2.6mm OD metallic-braid-based electrophysiology catheter via; Electromagnetic modeling, Network-Analyzer electrical tests, phantom imaging and navigation into swine hearts.

 651 Plasma 14 AN ACTIVE BIOPSY NEEDLE DESIGN FOR MRI GUIDED PROSTATE BIOPSY Korel Dursun YILDIRIM1, Ibrahim Davut MAHCICEK1, and Ozgur KOCATURK1 1Biomedical Engineering, Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey In this work, we present a novel low profile and active biopsy needle for MRI guided prostate interventions. We show that using conductive ink printed non-planar RF antenna components does not compromise overall device profile while maintaining required mechanical properties for clinical grade devices. We confirmed that the biopsy needle design is conspicious under MRI while maintaining RF induced heating below the allowed limits. This work demonstrates the feasibility of developing ultra low profile active interventional devices and potentially enables physicians to perform MRI guided prostate interventions.

 652 Plasma 15 MRI-guided robotic arm (MgRA) drives optogenetic activation of the rat corpus callosum Yi Chen1,2, Pais Roldán Patricia1,2, Xuming Chen1, and Xin Yu1,3 1Research Group of Translational Neuroimaging and Neural Control, High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Graduate Training Centre of Neuroscience, University of Tuebingen, Tuebingen, Germany, 3The Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany An MRI-compatible robotic arm was developed to provide a precise fiber positioning for optogenetic fMRI of the rat brain. Corpus callosum connects two hemispheres through a thin sheet of spreading fiber bundle with only a few hundred micron thickness in the brain. This work shows that MgRA can guide fiber optic to precisely target the callosal fiber bundles. The optogenetically driven callosal axonal fiber-mediated neural activity leads to strong antidromic activation in the hemisphere with callosal neurons expressing ChR2 by fMRI.

Electronic Power Pitch Poster

### Poster: Motion & Image Analysis Highlights

 Power Pitch Theater B - Exhibition Hall Wednesday 9:15 - 10:15

 653 Plasma 16 The spatial distribution of arterial and venous vessels in the human brain Michaël Bernier1, Stephen C Cunnane2, and Kevin Whittingstall3 1Nuclear medecine and radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada, 2Medecine, Université de Sherbrooke, Sherbrooke, QC, Canada, 3Diagnostic radiology, Université de Sherbrooke, Sherbrooke, QC, Canada Although human cerebrovascular system is the basis of most non-invasive measures of neural activity, its structure is poorly understood owing to the difficulty in identifying, segmenting and separating venous and arterial vessels.  To resolve this, we used Susceptibility Weighting Imaging (SWI) and Magnetic Resonance Angiography Time-of-Flight (MRA-TOF) to develop a probabilistic template of vascular architecture in the MNI space using an iterative back projection approach. This template is then paired with an anatomical atlas illustrates how some grey-matter areas are more vascularized than others. This could be the first steps toward a region-based vascular regression tool for the analysis hemodynamic-based measures of brain activity, such as fMRI.

 654 Plasma 17 A spatiotemporal fetal MRI atlas for multi-organ segmentation and growth analysis Tong Zhang1, Maria Deprez1, Paul Aljabar1, Robert Wright1, Alice Davidson1, Mary Rutherford1, Jo V. Hajnal1, and Julia A. Schnabel1 1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom We propose a comprehensive framework for spatiotemporal multi-organ fetal MR atlasing and segmentation. Volumetric fetal brain and trunk image data for 78 healthy fetuses acquired at different gestational age were reconstructed separately from motion corrupted MRI scans to 0.75mm isotropic resolution using slice-to-volume reconstruction. For each week, an affine template was generated from 15 subjects by averaging them in the atlas space. This template was further improved by non-linear registration of all the subjects using B-spline free-form deformations. For consistency, the template at each week was rigidly transformed. The annotated organs of the atlas include brain, lung, heart, and spine.

 655 Plasma 18 Accelerated high b-value diffusion-weighted MRI for higher-order diffusion analysis using a phase-constrained low-rank tensor model Lianli Liu1, Adam Johansson2, James M. Balter2, Jeffrey A. Fessler1, and Yue Cao2 1Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States, 2Radiation Oncology, University of Michigan, Ann Arbor, MI, United States DWI acquired with b-values greater than 1000 s/mm2 and higher-order diffusion analyses based on such DWI series have the potential to improve tumor differentiation, while the extended sampling of b-values makes the acquisition time inconveniently long. We propose an acceleration scheme that sparsely samples k-space and reconstructs images using a new low-rank tensor model which exploits both global and local low-rank structure. Under an acceleration factor of 8, parameter mapping results on one simulated and 7 patient datasets show improved accuracy over another low-rank tensor model that exploits global correlation only, and comparable accuracy to clinically used four-fold GRAPPA reconstruction.

 656 Plasma 19 Construction of Spatiotemporal Infant Cortical Surface Atlas of Rhesus Macaque Fan Wang1, Chunfeng Lian1, Jing Xia1, Zhengwang Wu1, Dingna Duan1, Li Wang1, Dinggang Shen1, and Gang Li1 1Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States Rhesus macaque is a widely used animal model helping understand neural development in the human brain. Available adult macaque brain atlases are not suitable for infant studies, due to their dramatic brain difference. Building age-matched atlases is thus highly desirable yet still lacking. In this study, using MRI scans for 32 healthy rhesus monkeys, we constructed the first spatiotemporal cortical surface atlas for macaques aged from 2 weeks to 24 months, which were further equipped with developmental-trajectory-based parcellation maps. These surface atlases and parcellation maps will greatly facilitate the early brain development studies of macaques.

 657 Plasma 20 Efficient Super-Resolution in Intracranial Vessel Wall Magnetic Resonance Imaging using 3D Deep Densely Connected Neural Networks Yuhua Chen1,2, Zhaoyang Fan2, Feng Shi2, Zixiao Tian2, Anthony Christodoulou2, Yibin Xie2, and Debiao Li2 1Department of Bioengineering, UCLA, Los Angeles, CA, United States, 2Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States Spatial resolution is of paramount importance for intracranial vessel wall (IVW) MR imaging because the vessel wall is submillimeter thin. However, high spatial resolution typically comes at the expense of long scan time, small spatial coverage and low signal-to-noise ratio (SNR). If we can reconstruct a high-resolution (HR) image from a low-resolution (LR) input, we can potentially achieve larger spatial coverage, higher SNR and better spatial resolution in a shorter scan. In this work, we propose a new Single Image Super-Resolution(SISR) technique which recovers an HR image from an LR image using 3D Densely Connected Super-Resolution Networks (DCSRN). We compared our network with state-of-art deep learning network in restoring 4x down-graded images and ours are faster and better.

 658 Plasma 21 Simultaneous Relaxometry and Segmentation of Human Brain through a Deep Neural Network Peng Cao1, Jing Liu1, Shuyu Tang1, Andrew Leynes1, and Peder Larson1 1Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, United States This study demonstrated a method for 3D simultaneous relaxometry and segmentation of human brain tissues through a deep neural network. Ranges of T1 and T2 values for gray matter, white matter and cerebrospinal fluid (CSF) were used as the prior knowledge. The proposed method can directly generate brain T1 and T2 maps in conjunction with segmentation of gray matter, white matter and CSF, and in particular was robust for relaxometry/segmentation in the challenging region of deep brain nuclei.

 659 Plasma 22 Combining Multi-Site/Study MRI Data: A Novel Linked-ICA Denoising Method for Removing Scanner and Site Variability from Multi-Modal MRI Data Huanjie Li1,2, Staci Gruber1, Stephen M Smith3, Scott E Lukas1, Marisa Silveri1, Kevin P Hill4, William D. S Killgore5, and Lisa D Nickerson1 1Imaging Center, Harvard Medical School, McLean Hospital, Belmont, MA, United States, 2Dalian University of Technology, Dalian, China, 3Oxford University, Oxford, United Kingdom, 4Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, United States, 5University of Arizona, Tucson, AZ, United States Large multi-site studies that pool magnetic resonance imaging (MRI) data across research sites present exceptional opportunities to advance neuroscience and enhance reproducibility of neuroimaging research. However, inconsistent MRI data collection platforms and scanning sequences both introduce systematic variability that can confound the true effect of interest and make the interpretation of results obtained from combined data difficult. Unfortunately, methods to address this problem are scant. In this study, we propose a novel denoising approach for multi-site, multi-modal MRI data that implements a data-driven linked independent component analysis to efficiently identify scanner/site-related effects for removal.

 660 Plasma 23 Real-time simultaneous shim and motion measurement and correction in CEST MRI using Double volumetric Navigators (DvNavs) Gizeaddis L. Simegn1, Andre J.W. Van der Kouwe1,2,3, Borjan Gagoski3,4, Frances Robertson1,5, Ernesta Meintjes1,5, and Ali Alhamud1,5 1MRC/UCT Medical Imaging Research Unit, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa, 2Athinoula A. Martinos Center for Biomedical imaging/MGH, Charlestown, MA, United States, 3Department of Radiology, Harvard Medical School, Boston, MA, United States, 4Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA, United States, 5Cape Universities Body Imaging Centre (CUBIC-UCT), Cape Town, South Africa In Chemical Exchange Saturation Transfer (CEST) MRI, images are acquired by applying saturation RF pulses at multiple frequencies of small increments to generate the CEST-spectrum. This makes CEST sensitive to motion and field inhomogeneity. Several factors can also vary the shim prepared by the scanner. To date, no study has been conducted to evaluate and correct shim fluctuation during CEST acquisition. In this study, we implement CEST with Double volumetric Navigators (DvNavs) to evaluate and update in real-time motion, zero and first-order shim parameters. The results show the ability of the DvNavs to correct shim and motion during CEST acquisition.

 661 Plasma 24 Real-time motion and dynamic transmit/receive B1 correction of CEST in the human brain at 7T Sami Auno1,2, Esau Poblador Rodriguez1,3, Philipp Moser1,3, Andre v.d.Kouwe4, Stephan Gruber1, Siegfried Trattnig1,3, and Wolfgang Bogner1 1High-Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2Department of Physics, University of Helsinki, Helsinki, Finland, 3Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, 4Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States Movement during MR imaging may cause significant motion artifacts that can impair the experiment. This is especially true in CEST imaging, which relies on comparison between images recorded at different time points during the experiment. We implemented a real-time motion correction method and a retrospective receiver sensitivity(B1-) correction based on volumetric EPI navigators interleaved with the CEST measurements. We tested these methods on phantoms and healthy volunteers. Together with adequate B0 and B1+ corrections, motion and sensitivity corrections may completely restore CEST data fidelity in the presence of involuntary head motion, thereby facilitating CEST imaging of restless patients.

 662 Plasma 25 Brainstem abnormalities in structural MRI of young children with Autism Spectrum Disorder: evaluation of inter-method agreement. Paolo Bosco1, Alessia Giuliano1, Jonathan Delafield-Butt2, Filippo Muratori3, Sara Calderoni3, and Alessandra Retico1 1INFN, Pisa, Italy, 2Humanities and Social Science, University of Strathclyde, Glasgow, United Kingdom, 3IRCCS Stella Maris, Pisa, Italy Structural MRI studies have pointed out the potential role of the brainstem in the pathophysiology of ASD. However, the findings in volume alterations in subjects with ASD are controversial. In this study, structural MRI was used to measure brainstem volume in a group of 152 young children with and without ASD, with five different methods (FSL-FIRST, ANTs, FS 5.3, FS 6.0, FS 6.0 with substructures). One out of five (FSL-FIRST) showed poor agreement with the other segmentation methods, which, by contrasts, consistently showed Pearson correlations greater than 0.93 and average Dice indexes greater than 0.76 in comparison among each other.

 663 Plasma 26 Automatic Segmentation of 3D Perivascular Spaces in 7T MR Images Using Multi-Channel Fully Convolutional Network Chunfeng Lian1, Mingxia Liu1, Jun Zhang1, Xiaopeng Zong1, Weili Lin1, and Dinggang Shen1 1Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States Advanced 7T MR imaging improves the visualization of perivascular spaces (PVSs) in human brains. However, accurate PVS segmentation for quantitative morphological studies is still challenging, since PVSs are very thin tubular structures with low contrast in noisy MR images. We proposed a new multi-channel fully convolutional network (mFCN) to automatically segment 3D PVSs. Our mFCN method adopts multi-channel inputs to complementarily provide enhanced tubular structural information and detailed image information. Multi-scale image features are automatically learned to delineate PVSs, without requirement of any pre-defined regions of interest (ROIs). The proposed method outperforms existing automatic/semi-automatic methods with a large margin.

 664 Plasma 27 Motion artifact quantification and localization for whole-body MRI Thomas Kuestner1,2, Marvin Jandt2, Annika Liebgott2,3, Lukas Mauch2, Petros Martirosian1, Fabian Bamberg3, Konstantin Nikolaou3, Sergios Gatidis3, Bin Yang2, and Fritz Schick1 1Section on Experimental Radiology, University Hospital of Tuebingen, Tuebingen, Germany, 2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, 3Department of Radiology, University Hospital of Tuebingen, Tuebingen, Germany Motion is still one of the major extrinsic factors degrading image quality. Automated detection of these artifacts is of interest, (i) if suitable prospective or retrospective correction techniques are not available/applicable, (ii) if human experts who judge the achieved quality are not present, or (iii) if a manual quality analysis of large databases from epidemiological cohort studies is impracticable. A convolutional neural network assesses and localizes the motion artifacts. This work extends the previously published method by proposing a general architecture for a whole-body scenario with varying contrast weightings. High accuracies of >90% were achieved in a volunteer study.

 665 Plasma 28 Tract-Based Cluster Analysis Pedro Angel Luque Laguna1,2, Francisco de Santiago Requejo1,2, Steven Williams2, Laura H. Goldstein3, Marco Catani1, and Flavio Dell'Acqua1,2,4 1Natbrainlab, Forensic and Neurodevelopmental Science, King's College London, London, United Kingdom, 2Department of Neuroimaging, King's College London, London, United Kingdom, 3Department of Psychology, King's College London, London, United Kingdom, 4The Sackler Institute for Translational Neurodevelopment, King's College London, London, United Kingdom The use of a-priori anatomical information can effectively improve statistical analysis of neuroimaging data. In this work, we introduce a new method called Tract-Based Cluster Analysis (TBCA) that exploits the rich anatomical information present in a whole-brain tractogram to inform the cluster-level inference analysis of voxel-based images. The method is based on the novel concept of hyper-voxel which incorporates local and global anatomical information derived from tractography data. When applied to real clinical data TBCA demonstrates clear benefits compared to previous cluster-level inference approaches.

 666 Plasma 29 SEGUE: a Speedy rEgion-Growing algorithm for Unwrapping Estimated phase Anita Karsa1 and Karin Shmueli1 1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom MRI phase images are increasingly used, for example for Susceptibility Mapping, and distortion correction in functional and diffusion MRI. However, measured phase images contain wraps, because the phase is defined only between 0 and 2π. PRELUDE is the current gold-standard method for robust, 3D, spatial phase unwrapping, but its computation time can become very long (e.g. 10 hours), especially at high field and outside the brain. Here, we developed a new method, SEGUE, that produced similar results to PRELUDE in multi-echo brain and head-and-neck images, successfully unwrapped some regions where PRELUDE failed and was between 1.6 and 83 times faster.

 667 Plasma 30 The Role of Partial Volume Modelling in Longitudinal Automated Multiple Sclerosis Lesion Segmentation Mário João Fartaria1,2,3, Tobias Kober1,2,3, Cristina Granziera4,5,6, and Meritxell Bach Cuadra2,3,7 1Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, 2Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 3Signal Processing Laboratory (LTS 5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 4Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States, 5Neuroimmunology Unit, Neurology, Department of Clinical Neurosciences, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 6Neurology Department and Neuroimaging Laboratory, Basel University Hospital, Basel, Switzerland, 7Medical Image Analysis Laboratory (MIAL), Centre d'Imagerie BioMédicale (CIBM), Lausanne, Switzerland Longitudinal analyses in Multiple Sclerosis are often performed to assess disease progression and evaluate treatment response. The number of new and enlarged lesions as well as total lesion volume variations over time are imaging biomarkers used in MS follow-up assessment. Here, we evaluate the performance of an in-house prototype algorithm for lesion detection and volume estimation in a longitudinal scenario. Our algorithm can be run with or without partial volume modelling. Both detection and volume estimation improved using the partial volume model with respect to manual delineations, especially in small lesions and at lesion borders.

Electronic Power Pitch Poster

### Poster: Applications of Diffusion MRI

 Power Pitch Theater A - Exhibition Hall Wednesday 14:45 - 15:45

 743 Plasma 1 Building a probabilistic atlas of the human corticospinal tract from 410 healthy participants by using enhanced bundle-specific tractography. Chenot Quentin1, Nathalie Tzourio-Mazoyer1, François Rheault2, Maxime Descoteaux2, and Laurent Petit1 1Groupe d’Imagerie Neurofonctionnelle, Institut des Maladies Neurodégénératives (GIN-IMN) - UMR 5293, CNRS, CEA Université de Bordeaux, Bordeaux, France, 2Sherbrooke Connectivity Imaging Lab (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada Current limitations of diffusion-weighted tractography algorithms face the complexity of white matter fiber crossings, especially for the cortico-lateral projections of the cortico-spinal tract (CST) in the human brain. In this work, to improve cortico-spinal tracking in crossing areas we combined accurate anatomical region positioning along the CST in each individual with a new bundle-specific tractography algorithm. We thus built a probabilistic atlas of the whole-fanning CST in 410 healthy participants.

 744 Plasma 2 Validation of dentato-rubro-thalamic tract in squirrel monkey brain Yurui Gao1,2, Kurt Schilling1,2, Iwona Stepniewska3, Guozhen Luo4,5, Bennett Landman2,6, Hong Yu7, Daniel Claassen8, Benoit Dawant6, and Adam Anderson1,2 1Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 2Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 3Psychology, Vanderbilt University, Nashville, TN, United States, 4Physics and Astronomy, Vanderbilt University, Nashville, TN, United States, 5Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, United States, 6Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, United States, 7Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, United States, 8Neurology, Vanderbilt University Medical Center, Nashville, TN, United States The dentato-rubro-thalamic-tract (DRTT) has recently been suggested as a target for tremor control in deep brain stimulation and stereotactic radiosurgery, however, its efficacy has been challenged because different approaches to diffusion MRI (dMRI) tractography exhibited significantly different sensitivity in detecting the DRTT. We implemented a framework to quantitatively evaluate the performance of dMRI tractography by comparing the dMRI tracts to the histological DRTT identified from Nissl-stained sections in the same squirrel monkey brain. The Jaccard index between our dMRI tractography strategy and the histological DRTT is above 0.7. In the future, other tractography strategies can be tested using this framework.

 745 Plasma 3 Assessing the asynchronous macrostructural changes in white matter tracts of the developing brain Elinor Thompson1, Matteo Bastiani2, Matthew Brookes1, Saad Jbabdi2, and Stamatios N. Sotiropoulos1,2 1Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, United Kingdom, 2Wellcome Centre for Integrative Neuroscience - Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, Oxford, United Kingdom We have developed an approach to elucidate the macrostructural changes of individual white matter tracts in neonatal brains, using deformation-based morphometry. Many studies have investigated how microstructure changes during development, however it is not clear how to disentangle changes in tissue microstructure from macrostructural volume changes. The latter is particularly challenging in the absence of longitudinal data from the same subject, which is the norm given the difficulty in scanning neonates. We propose an approach that is aimed towards this problem. Results are presented from analysis carried out on publicly available diffusion MRI data from the developing Human Connectome Project.

 746 Plasma 4 An accurate and efficient infarction segmentation method for diffusion weighted images using a deep convolutional neural network Hanjing Kong1, Fei Gao2, Wenjian Huang1, Weihai Xu3, Yining Huang4, and Jue Zhang1,2 1Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 2College of Engineering, Peking University, Beijing, China, 3Department of Neurology, Peking Union Medical College Hospital, Beijing, China, 4Department of Neurology, Peking University First Hospital, Beijing, China Accurate identification of infarcted regions of the brain is critical in management of stroke patients. An efficient and accurate method based on a deep convolutional neural network for segmentation of infarcts in the diffusion-weighted images is proposed.

 747 Plasma 5 Selective degeneration of crossing fibres and its relationship with fractional anisotropy Jordan A. Chad1,2, Ofer Pasternak3, David H. Salat4, and J. Jean Chen1,2 1Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Departments of Psychiatry and Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States, 4MGH/HST Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States Selective degeneration of crossing fibres has been reported in diffusion MRI studies of Alzheimer’s disease alongside increased fractional anisotropy (FA). Similar albeit more subtle selective degeneration has been suggested in healthy aging, but increased FA with age has not been reported on cross-sectional studies of aging. In this work, we use DTI tractography to measure selective degeneration of crossing fibres in healthy aging among 212 subjects. Increased FA with age is found in this cohort only after applying free water elimination (FWE), suggesting that increasing extracellular water in aging may introduce variability that obscure finer structural phenomena in cross-sectional designs.

 748 Plasma 6 Quantifying diameter overestimation of undulating axons from synthetic DW-MRI Alonso Ramirez-Manzanares1, Mario Ocampo-Pineda2, Jonathan Rafael-Patiño3, Giorgio Innocenti3,4,5, Jean-Philippe Thiran3, and Alessandro Daducci2,3,6 1Computer Science, Centro de Investigación en Matemáticas A.C., Guanajuato, Mexico, 2University of Verona, Verona, Italy, 3Signal Processing Lab (LTS5), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 4Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden, 5Brain and Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 6University Hospital Center (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland This study aims to provide to the research community quantitative measurements about the axon diameter overestimation due to the straight-cylinder assumption usually made in state-of-the-art models for diameter mapping with DW-MRI. Our methodology uses a Monte Carlo diffusion simulator to compute the diffusion weighted magnetic resonance signals of undulating axons. We use in our experiments plausible tissue values, we also explore a broad parameter set that depicts undulation. The results of this study provide useful information to understand the differences between the estimators from histology vs. the estimated diameters when using the model assumption of simple shaped axons.

 749 Plasma 7 Diffusion Anisotropy of the Extra-Axonal Environment is Linked to Axon Alignment Emilie T. McKinnon1,2,3, Jens H. Jensen1,3, and Joseph A. Helpern1,3 1Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Department of Neurology, Medical University of South Carolina, Charleston, SC, United States, 3Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, United States A better understanding of the complex water diffusion dynamics in the extra-axonal environment may aid in the mathematical modeling of the diffusion MRI signal and have application to pathologies that specifically impact glial cells and the surrounding extracellular space. Here we employ a novel method of combining diffusion MRI data for weak and strong diffusion weightings to show that extra-axonal water diffusion anisotropy strongly correlates with intra-axonal diffusion anisotropy and takes on large values in voxels with highly aligned axons. This connection suggests that the geometrical alignment of axonal fibers is important for both intra-axonal and extra-axonal water diffusion.

 750 Plasma 8 Multishot high-resolution brain diffusion-weighted imaging using phase regularized reconstruction Yuxin Hu1,2, Xiaole Wang3, Evan G. Levine1,2, Qiyuan Tian1,2, Valentina Taviani4, Frank Ong5, Shreyas Vasanawala1, Jennifer A McNab1, Bruce L. Daniel1,6, and Brian Hargreaves1,2,6 1Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Electrical Engineering, Stanford University, Stanford, CA, United States, 3Biomedical Engineering, Tsinghua University, Beijing, China, 4GE Healthcare, Menlo Park, CA, United States, 5Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, United States, 6Department of Bioengineering, Stanford University, Stanford, CA, United States Multishot imaging has been shown to provide high resolution diffusion-weighted images (DWIs) with reduced distortion, however, significant aliasing artifacts and signal cancellation still occur due to the mismatch of the motion-induced phase between different shots. The reconstruction becomes non-convex and intractable to solve when this phase is included into the forward model. The goal of this work is to solve this problem by circumventing the challenging phase estimation step. The brain and breast examples demonstrate that this can be efficiently achieved using a locally low-rank reconstruction approach.

 751 Plasma 9 Reversible white matter restricted diffusion in patients with cerebral malaria via ADC measurement on a 0.35T MR scanner Yuchuan Zhuang1, Sarah Mohajeri Moghaddam 2, Samuel D Kampondeni 2,3, Madalina Tivarus 2, Gretchen L Birbeck 4, Michael J Potchen 2, and Jianhui Zhong2 1Electrical and Computer Engineering, University of Rochester, Rochester, NY, United States, 2Department of Imaging Sciences, University of Rochester, Rochester, NY, United States, 3Malawi MRI Center, Queen Elizabeth Central Hospital, Blantyre, Malawi, 4Department of Neurology, University of Rochester, Rochester, NY, United States White matter abnormalities are commonly identified on cerebral malaria patients. We proposed a method to overcome technical limitations of low-field MRI, and quantitatively calculate the ADC and b0 maps, enabling discrimination of the true restricted diffusion from T2 shine-through. A unique pattern of reversible restricted diffusion was identified in some patients.

 752 Plasma 10 Evaluation of Standardized and Study-Specific Diffusion Tensor Imaging Templates of the Adult Human Brain Shengwei Zhang1 and Konstantinos Arfanakis1 1Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States DTI templates of the adult human brain are commonly used in neuroimaging, and their characteristics influence the accuracy of the application. The purpose of this work was to compare eight available standardized DTI templates to each other, as well as to study-specific templates, in terms of template characteristics and performance in spatial normalization and detection of small inter-group FA differences. The IIT v.3.0 template was shown to combine a number of desirable characteristics, and allows higher inter-subject spatial normalization accuracy and detection of smaller inter-group FA differences, compared to other templates, including study-specific templates, for both younger and older adults.

 753 Plasma 11 Characterization of Axonal Pathology Independent of Fiber Crossings in Multiple Sclerosis Using High-Gradient Diffusion MRI Qiuyun Fan1, Aapo Nummenmaa1, Thomas Witzel1, Ned Ohringer1, Lawrence L Wald1, Eric Klawiter2, and Susie Y Huang1 1Massachusetts General Hospital, Boston, MA, United States, 2Neurology, Massachusetts General Hospital, Boston, MA, United States Axonal damage is thought to be the substrate of disability in multiple sclerosis. We have recently introduced a method based on the spherical mean framework that provides per-voxel axon diameter and volume fraction that is independent of fiber crossings/dispersion. We apply this approach to estimate whole brain axon diameter and density in a group of patients with MS to healthy controls. Widespread alterations in axon diameter and density were found throughout the NAWM and lesions of MS patients that may reflect diffuse axonal loss and swelling in the setting of chronic demyelination.

 754 Plasma 12 Anatomy-constrained automated fiber tract reconstruction for surgery planning: a validation study in language-related white matter tracts Matteo Mancini1,2, Sjoerd Vos1,2,3, Vejay Vakharia2,4, Rachel Sparks1,2, Karin Trimmel4, Gavin P. Winston3,4,5, John Duncan2,3,4, and Sebastian Ourselin1,2,4,6 1Translational Imaging Group, University College London, London, United Kingdom, 2Wellcome EPSRC Centre for Interventional and Surgical Sciences (WEISS), University College London, London, United Kingdom, 3Epilepsy Society MRI Unit, Chalfont St Peter, United Kingdom, 4Department of Clinical and Experimental Epilepsy, University College London, London, United Kingdom, 5Neuroimaging of Epilepsy Laboratory, Montreal Neurological Institute, McGill University, Montreal, Canada, 6Dementia Research Centre, University College London, London, United Kingdom Diffusion MRI and tractography hold great potential for surgery planning, but fiber tract reconstruction requires an expert rater. In this work, we set up an automated reconstruction pipeline based on anatomical criteria that does not require manual intervention and we validated it on epilepsy patients with specific focus on language-related bundles. We first compared the results with the ones obtained from human raters and then further validated them using task fMRI. The fiber tracts reconstructed from the pipeline were in line with the agreement between different human raters and showed good overlap with function.

 755 Plasma 13 Rapid Single Shot Whole Lung Acquisition of for Hyperpolarized Gas MRI Biomarkers of Airspace Enlargement. Alexei Ouriadov1,2, Dante PI Capaldi1,2, David McCormack3, and Grace Parraga1,2,3 1Robarts Research Institute, London, ON, Canada, 2Department of Medical Biophysics, Western University, London, ON, Canada, 3Division of Respirology, Department of Medicine, Western University, London, ON, Canada Hyperpolarized gas pulmonary MRI provides physiologically relevant biomarkers of obstructive lung disease including emphysema, bronchopulmonary dysplasia, congenital lobar emphysema and alpha-1 antitrypsin deficiency.  Recently, a stretched-exponential-model combined with under-sampling in the imaging and diffusion directions was proposed for the evaluation of hyperpolarized gas multiple b-value diffusion-weighted MRI.  The major advantage of this method is the possibility to significantly speed up the data acquisition using acceleration factors between 7 and 10.  We hypothesize that this method can be extended to provide whole lung hyperpolarized gas MRI-based emphysema biomarkers including static-ventilation, T2* ADC and morphometry maps with high spatial image resolution.

 756 Plasma 14 The intracellular component of VERDICT (Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumors) MRI distinguishes Gleason 4 pattern better than Apparent Diffusion Coefficient Mrishta Brizmohun Appayya1, Edward W Johnston1, Arash Latifoltojar1, James O’Callaghan1, Elisenda Bonnet-Carne2, Hayley Pye3, Dominic Patel3, Susan Heavey3, Alistair Grey4, Sebastien Ourselin3, David Hawkes3, Caroline Moore4, Hayley Whitaker3, Alexander Freeman4, David Atkinson3, Daniel Alexander3, Eleftheria Panagiotaki3, and Shonit Punwani2 1Centre of Medical Imaging, UCL, London, United Kingdom, 2Centre for Medical Imaging, UCL, London, United Kingdom, 3UCL, London, United Kingdom, 4UCLH, London, United Kingdom VERDICT (Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumours) MRI combines a diffusion-weighted MRI acquisition with a three-compartment mathematical model that describes signal from i) intracellular water (fIC), ii) water in extracellular-extravascular space (fEES) and iii) water in the microvasculature (fvasc). In contrast to VERDICT, clinical ADC is derived from a mono-exponential model. Upon comparison between VERDICT parameters and clinical ADC, we showed that fIC was better able to discriminate between Gleason ≥3+4 histology pattern and Gleason ≤3+3/benign histology. We also showed that image quality of VERDICT-MRI maps and clinical ADC was comparable.

 757 Plasma 15 Validation of the VERDICT MRI Framework using a Novel Computational Model of Diffusion and Flow in Real-World Tumours. Ben Hipwell1, Tom Roberts1, Paul Sweeney2, Morium Ali2, Angela D'Esposito3, Eleftheria Panagiotaki2, Mark Lythgoe2, Daniel Alexander2, Rebecca Shipley2, and Simon Walker-Samuel2 1Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom, 2University College London, London, United Kingdom, 3University of Bologna, Bologna, Italy Compartmental models are increasingly being used to quantify diffusion MRI signals from tumours. We have developed a complex, multiscale mathematical modelling platform for simulating tumour pathophysiology, using high-resolution optical imaging data from complete tumour samples. Diffusion MRI signals from these tumours were simulated, including vascular flow and intra- and extracellular diffusion. These data were fitted to the VERDICT  compartmental model, and the resulting parameters compared against ground truth simulation values. Cell radius and intra/extracellular fractional volume parameters and respective ground truth values were strongly correlated. A more complex relationship was found in vascular volume fractions.

Electronic Power Pitch Poster

### Poster: CV PowerBeat: Part 2

 Power Pitch Theater B - Exhibition Hall Wednesday 14:45 - 15:45

 758 Plasma 16 Double DANTE: an improved method for high-resolution intracranial vessel wall imaging Bram F Coolen1, Jasper Schoormans1, Ernst S Kooreman1,2, Qinwei Zhang3, Olivia Viessmann4, Gustav J Strijkers1, Aart J Nederveen3, Guillaume Gilbert5, and Jeroen CW Siero6,7 1Department of Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands, 2Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands, 3Department of Radiology, Academic Medical Center, Amsterdam, Netherlands, 4A.A. Martinos Center for Biomedical Imaging, MGH, Harvard Medical School, Boston, MA, United States, 5MR Clinical Science, Philips Healthcare, Markham, ON, Canada, 6Department of Radiology, Utrecht Medical Center, Utrecht, Netherlands, 7Spinoza Centre for Neuroimaging, Amsterdam, Netherlands We present the use of Double DANTE as an improved method for DANTE prepared 3D TSE imaging of intracranial arteries. DANTE preparation inherently leads to banding artifacts, which become increasingly visible at high-resolution imaging. We show that Double DANTE strongly reduces banding separation without changes in the DANTE pulse train duration, and more importantly, without compromising flow suppression of blood or CSF. Double DANTE therefore enables high-quality intracranial vessel wall MRI at 0.6mm isotropic resolution.

 759 Plasma 17 Clinical value of dark-blood late gadolinium enhancement without additional magnetization preparation Robert J. Holtackers1,2, Caroline M. van de Heyning2,3,4, Muhummad S. Nazir2,3, Imran Rashid2,3, Ioannis Ntalas2,3, Haseeb Rahman3,5, René M. Botnar2,6, and Amedeo Chiribiri2 1Department of Radiology, Maastricht University Medical Centre, Maastricht, Netherlands, 2School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 3Department of Cardiology, St Thomas' Hospital, London, United Kingdom, 4Department of Cardiology, Antwerp University Hospital, Antwerp, Belgium, 5British Heart Foundation Centre of Excellence, King's College London, London, United Kingdom, 6Pontificia Universidad Católica de Chile, Escuela de Ingeniería, Santiago, Chile Late gadolinium enhancement (LGE) MRI often suffers from poor scar-to-blood contrast when used for detection of (sub)endocardial scar due to the bright signal of adjacent blood. We sought to validate a novel dark-blood LGE technique in a large cohort of 250 patients at both 1.5T and 3T.  Combining left ventricular blood nulling with phase-sensitive inversion-recovery significantly improved both image quality and diagnostic confidence compared to conventional bright-blood LGE. As no additional magnetization preparation is used, clinical application on current MRI systems is readily available without the need for extensive simulations, software modifications and/or additional training.

 760 Plasma 18 Feasibility of Free-Breathing Fetal Cine Cardiac MRI based on Doppler Ultrasound, Compressed Sensing and Motion Compensation Kostas Haris1,2, Erik Hedström1,3, Fabian Kording4,5, Sebastian Bidhult1,6, Frederik Testud7, Katarina Steding-Ehrenborg1,8, Christian Ruprecht4,5, Einar Heiberg1,6, Håkan Arheden1, and Anthony Aletras1,2 1Lund University, Skåne University Hospital, Department of Clinical Sciences Lund, Clinical Physiology, Lund, Sweden, 2Laboratory of Computing, Medical Informatics and Biomedical-Imaging Technologies, School of Medicine, Aristotle University, Thessaloniki, Greece, 3Lund University, Skåne University Hospital, Department of Clinical Sciences Lund, Diagnostic Radiology, Lund, Sweden, 4Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 5North medical GmbHMartinistraße 52, 20246, Hamburg, Germany, 6Faculty of Engineering, Lund University, Department of Biomedical Engineering, Lund, Sweden, 7Siemens Healthcare AB, Malmö, Sweden, 8Lund University, Department of Health Sciences, Physiotherapy, Lund, Sweden We investigated the feasibility of free-breathing fetal cine cardiac MRI using Doppler Ultrasound retrospective binning combined with continuous tiny golden angle radial sampling and compressed sensing via the tyGRASP reconstruction method. Motion due to maternal respiration and fetal movement was estimated by registration applied to reconstructed images of low temporal resolution. K-space radial profiles containing motion were either corrected or rejected from the reconstruction process. The reconstruction results demonstrated good image and diagnostic quality showing that the absence of fetal ECG can be bypassed in a computationally efficient way by Doppler Ultrasound even in the presence of motion.

 761 Plasma 19 Geometrical Characterization of Marfan and Bicuspid Aortic Valve Patients Using Finite Element Methods Julio Sotelo1,2, Andrea Guala3, Lydia Dux-Santoy3, Aroa Ruiz-Muñoz3, Arturo Evangelista3, Joaquín Mura1, Cristian Tejos1,2,4, Daniel E Hurtado4,5, José Rodríguez-Palomares3, and Sergio Uribe1,4,6 1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 3Department of Cardiology, Hospital Universitari Vall d´Hebron, Vall d´Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain, 4Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile, 5Department of Structural and Geotechnical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 6Department of Radiology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile BAV patients and patients with MFS are predisposed to develop geometrical changes in the aorta. The geometrical assessment of the aorta using MRI in these patients generates an operator dependency and variability given by the 2D planer reformatting of the data. In this work, we propose finite element Laplace formulation, which allows us to obtain 3D maps of geometrical parameters in the aorta, avoiding the 2D reformatting process of the MRI data. We apply our method on volunteers, BAV and MFS patients. Our method allows applying it to any type of volumetric segmentation from MR or CT.

 762 Plasma 20 Myocardial T1 And T2 Mapping Using MR Fingerprinting: Comparison to clinical standards Shivani Pahwa1, Jesse Hamilton2, Joseph Adedigba3, Sanjay Sridaran4, Satyam Ghodasara5, Rahul Thomas6, Sadeer G Al-Kindi6, Gregory O'Connor5, Sanjay Rajagopalan6, Mark Griswold3, Vikas Gulani1, and Nicole Seiberlich3 1Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, United States, 2Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 3Case Western Reserve University, Cleveland, OH, United States, 4Case Western Reserve University School of Medicine, Cleveland, OH, United States, 5Case Western Reserve University School of Medcine, Cleveland, OH, United States, 6Cardiology, University Hospitals Cleveland Medical Center, Cleveland, OH, United States Myocardial T1 and T2 relaxation times obtained with MRF were compared to values from traditional mapping sequences (MOLLI and T2-prep bSSFP) and evaluated for repeatability and reproducibility in 50 normal volunteers, as per SCMR consensus guidelines. MRF compared favorably with traditional sequences without significant proportional or systemic differences with fair to excellent repeatability and reproducibility, while providing better image quality.

 763 Plasma 21 Pericardial Enhancement in Recurrent and Constrictive Pericarditis: Correlation with Pathology in 52 Patients James Glockner1 1Radiology, Mayo Clinic, Rochester, MN, United States Pericardial late gadolinium enhancement was correlated with pathologic specimens in 52 patients who had pericardiectomy performed for constrictive or chronic pericarditis. Pericardial LGE is an indicator of pericardial inflammation; however, it does not reliably distinguish inflammation from fibrosis: LGE was seen in 9/10 patients with pericardial fibrosis and minimal or no pericardial inflammation. Pericardial edema or early pericardial enhancement may be more useful biomarkers for pericardial inflammation.

 764 Plasma 22 Quantitative myocardial perfusion using multi-echo Dixon for respiratory motion correction and arterial input function estimation Markus Henningsson1, Alexandre Farias1,2,3, Adriana Dolores Maria Villa1, Cian Scannell1, Torben Schneider4, and Amedeo Chiribiri1 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Federal University of Minas Gerais, Belo Horizonte, Brazil, 3Federal Center for Technological Education of Minas Gerais, Belo Horizonte, Brazil, 4Philips Healt Systems, London, United Kingdom A quantitative myocardial first-pass perfusion approach is proposed using multi-echo Dixon acquisition. The fat images (unaffected by contrast bolus) are used to estimate respiratory motion and the transformations are applied to the corresponding diagnostic water images. The three echo images are also used to perform T2* correction of the arterial input function. Evaluation was performed in 8 patients during free-breathing rest perfusion. Motion correction reduced quantiation variability, while T2* correction of the arterial input function reduced the myocardial blood flow by 0.7ml/g/min across all patients.

 765 Plasma 23 Automated 4D Flow Conservation Utilizing Adjacency Matrices Carson Anthony Hoffman1, Oliver Wieben1,2, and Gabe Shaughnessy1 1Medical Physics, University of Wisconsin Madison, Madison, WI, United States, 2Radiology, University of Wisconsin Madison, Madison, WI, United States 4D flow magnetic resonance imaging (MRI) can provide a way to analyze both the anatomical and hemodynamic properties related to complex vessel networks. Using basic principles related to flow conservation the entire vessel networks data can be used to help improve local flow calculations. A Bayesian approach is utilized with a Markov Chain Monte Carlo where flow conservation is enforced to obtain, for a complete vascular network, estimates of mean flow and flow uncertainty. The estimated data results in a lower flow uncertainty overall and can allow for localization of potential erroneous branches in the initial data.

 766 Plasma 24 Rapid Carotid Artery T2 and T1 Mapping Using a Radial TSE and IR-FLASH Approach Maria I Altbach1,2, Sagar Mandava3, Kevin J Johnson4, Zhitao Li3, Mahesh B Keerthivasan3, Jennifer Becker1, Ali Bilgin1,2,3, and Craig Weinkauf5 1Department of Medical Imaging, University of Arizona, Tucson, AZ, United States, 2Department of Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 3Electrical and Computer Engineering, University of Arizona, Tucson, AZ, United States, 4Siemens Medical Solutions, Tucson, AZ, United States, 5Department of Surgery, University of Arizona, Tucson, AZ, United States Defining carotid plaque characteristics predictive of stroke using non-invasive MR imaging is clinically relevant, but has been mostly limited to qualitative visualization of signal intensity in multi-contrast MR images. Here we present two robust and fast T2 and T1 mapping techniques based on radial data acquisition and demonstrate them in terms of carotid plaque characterization.

 767 Plasma 25 Improved phase unwrapping algorithm for automatic cine DENSE strain analysis using phase predictions and region growing Daniel Auger1, Xiaoying Cai1, Changyu Sun1, and Frederick Epstein1,2 1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Radiology, University of Virginia, Charlottesville, VA, United States Displacement encoding with stimulated echoes (DENSE) measures myocardial displacements using the signal phase. Phase wrapping generally occurs during systolic phases, thus spatiotemporal phase unwrapping algorithms are required to compute motion trajectories and strain. Current DENSE analysis methods are aided by user-defined myocardial contours. A fully automatic DENSE analysis method is proposed where phase predictions using multiple pathways and region growing are used to simultaneously unwrap and segment the myocardium. Compared to a prior automatic method, this method selects fewer extramyocardial pixels, reducing the computation time, and has a greater phase unwrapping success rate.

 768 Plasma 26 Myocardial Edema Imaging – A Comparison of Three Techniques Yanjie Zhu1,2, Lixian Zou1, Yucheng Chen3, Dong Liang1, Xin Liu1, and Yiu-Cho Chung4 1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 3Department of Cardiology, West China Hospital, Chengdu, China, 4Siemens Healthcare Pte Ltd., Singapore, Singapore Myocardial edema is commonly imaged using T2 based imaging technique, such as T2w-TSE, T2p-bSSFP and T2 mapping. Noting its elevated T1 and T2 value, a single-shot technique using T2 prepared STIR called T2STIR-bSSFP has been proposed for edema imaging. This study compared the contrast of T2p-bSSFP, T2 mapping and the newly proposed T2STIR-bSSFP methods via simulation, phantom experiment and patient study. The results showed that T2STIR-bSSFP has the highest contrast in myocardial edema image among the three methods at a shot scan time. It may provide a fast edema imaging technique for the whole heart covering.

 769 Plasma 27 Prediction for development of cerebral hyperperfusion after carotid endarterectomy using cerebral oxygen extraction fraction map based on quantitative susceptibility mapping at 7T Jun-ichi Nomura1, Ikuko Uwano2, Makoto Sasaki2, Kohsuke Kudo3, Fumio Yamashita2, Kenji Ito2, Shunrou Fujiwara1, Yoshiyasu Matsumoto1, Kohki Oikawa1, Kohei Chida1, Kazunori Terasaki4, Masakazu Kobayashi1, Kenji Yoshida1, and Kuniaki Ogasawara1 1Neurosurgery, Iwate Medical university, Morioka, Japan, 2Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical university, Yahaba, Japan, 3Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan, 4Cyclotron Reserch Center, Iwate Medical university, Takizawa, Japan The aim of this study was to validate whether preoperative QSM-based OEF (OEFQSM) map at 7T could predict the development of postoperative hyperperfusion (HP) after carotid endarterectomy (CEA) in patients with internal carotid artery stenosis. In quantitative assessment, OEFQSM was significantly higher in the presence group than that in the absence group of HP. Receiver operating characteristic analysis showed the OEFQSM was a good indicator for predicting the development of HP after CEA when the suitable cut-off value. Finally, the present study demonstrated that preoperative OEFQSM map at 7T can identify patients at risk for HP after CEA.

 770 Plasma 28 Investigating the use of non-contrast enhanced Magnetic Resonance Multi-Sequence Thrombus Imaging (MSTI) to direct therapy in patients with acute iliofemoral Deep Vein Thrombosis Justinas Silickas1, Prakash Saha1, Alberto Smith1, Stephen Black2, Adam Gwozdz1, Marcelo Andia Kohnenkampf3, Ashish Patel1, Bijan Modarai1, Rene Botnar4, and Alkystis Phinikaridou4 1Academic Department of Vascular Surgery, King's College London, London, United Kingdom, 2Vascular Surgery Department, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom, 3School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, 4School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom Deep vein thrombosis (DVT) affects 1 in 1000 people and when the ilio-femoral segment is involved, over half will develop post-thrombotic syndrome (PTS). PTS can be debilitating for the patients and carries a huge health cost burden. Thrombolysis reduces the incidence of PTS, but is only successful in 60% of patients. There is no reliable method of identifying thrombi susceptible to lysis. We have developed a non-contrast-enhanced magnetic resonance multi-sequence thrombus imaging (MSTI) protocol that provides information on the structural composition of the thrombus and may be a reliable method of predicting thrombus lysability.

 771 Plasma 29 Strain Measurements from 3D Isotropic Cine MRI: Relation with Fibrosis in a Duchenne Patient Population Freddy Odille1,2, Shufang Liu1,3, Bailiang Chen2, Aurélien Bustin1,3, Jacques Felblinger1,2, and Laurent Bonnemains1,4 1IADI, INSERM U947 & Université de Lorraine, Nancy, France, 2CIC-IT 1433, INSERM, Université de Lorraine and CHRU Nancy, Nancy, France, 3Compter Science Department, Technical University Munich, Munich, Germany, 4Department of Cardiothoracic Surgery, CHU Strasbourg and University of Strasbourg, Strasbourg, France A method is proposed for myocardial strain estimation, based on 3D isotropic cine MRI. A free-breathing, motion-corrected super-resolution acquisition is used to obtain the 3D isotropic cine dataset. Then the left ventricular (LV) myocardium is manually segmented using a sparse segmentation technique. Finally a registration-based technique is used to obtain displacement fields that best match diastolic and systolic 3D isotropic masks of the LV, and subsequent Lagrangian strain estimates. The method was evaluated in 20 Duchenne muscular dystrophy patients. Segment-wise analysis showed that the proposed radial strain estimates correlated well with the presence of fibrosis.

 772 Plasma 30 Optimized respiratory-resolved motion-compensated 3D Cartesian coronary MRA Teresa M Correia1, Giulia Ginami1, Radhouene Neji2, Gastao Cruz1, Rene Botnar1, and Claudia Prieto1 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom Conventionally, free-breathing whole-heart 3D coronary MR angiography (CMRA) uses navigator-gated acquisitions to reduce respiratory motion, by acquiring data only at a specific respiratory phase, which leads to prolonged scan times. Respiratory-resolved reconstruction approaches have been proposed to achieve 100% scan efficiency using mainly non-Cartesian acquisitions and exploiting sparsity in the respiratory dimension. Here, a robust framework for Cartesian imaging is proposed, which provides high-quality respiratory-resolved images by incorporating motion information from image navigators (iNAV) to increase the sparsity in the respiratory dimension. Furthermore, iNAV motion information is used to compensate for 2D translational motion within each respiratory phase.

Electronic Power Pitch Poster

### Poster: Techniques & Applications of Microcirculation Imaging

 Power Pitch Theater A - Exhibition Hall Wednesday 17:15 - 18:15

 853 Plasma 1 Simultaneous measurements of global cerebral blood flow with 2D pseudo-continuous multi-TI arterial spin labeling and 15O-H2O PET in a hybrid PET/MR system Oriol Puig Calvo1, Ulrich Lindberg1, Mark B Vestergaard1, Egill Rostrup1, Adam E Hansen1, Henrik B.W. Larsson1, Ian Law1, and Otto M Henriksen1 1Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark Arterial spin labeling (ASL) provides easy-access non-invasive quantification of regional cerebral blood (CBF) but its accuracy is not established. The aim of the study was to compare simultaneous measurements of absolute CBF obtained by ASL MRI and 15O-H2O PET CBF measurements in healthy subjects using a hybrid PET/MR system. Simultaneous 15O-H2O PET and ASL MRI were performed in resting state, hypoperfusion and hyperperfusion. Overall highly significant positive and linear correlation of ASL MRI and H2O PET in gCBF was observed across all perfusion states, confirming the ability of ASL MRI to quantify gCBF in good agreement with PET.

 854 Plasma 2 Advanced lesion symptom mapping analyses and implementation as BCBtoolkit Chris Foulon1, Leonardo Cerliani1, Serge Kinkingnéhun1, Richard Levy2, Charlotte Rosso3, Marika Urbanski1, Emmanuelle Volle1, and Michel Thiebaut de Schotten1 1BCBlab, Paris, France, 2Frontlab, Institut du Cerveau et de la Moelle épinière, Paris, France, 3Centre de Neuroimagerie de Recherche CENIR, Paris, France Even when focal, brain lesions have local and remote effects that impact functionally and structurally connected circuits. We developed a free open-source software (BCBtoolkit) that gathers different methods to estimate these effects on structural (using healthy controls tractography) and functional networks, using T1-images and fMRI data, and relate them to behavioral impairment. We applied these methods to 37 patients with a chronic focal brain lesion and 54 healthy controls in the context of category fluency. Our methods revealed a large set of directly and indirectly disconnected brain regions that had significantly impacted the performance.

 855 Plasma 3 Validation of Cerebrovascular Reactivity by Arterial Spin Labeling MRI in Moyamoya Disease with Simultaneously Measured 15O-PET and Phase-contrast MRI Yosuke Ishii1,2, Thoralf Thamm1, Jia Guo1, Mohammad Mehdi Khalighi3, Mirwais Wardak1, Dawn Holley1, Harsh Gandhi1, Jun Hyung Park1, Bin Shen1, Gary K Steinberg4, Fred T Chin1, Greg Zaharchuk1, and Audrey Peiwen Fan1 1Radiology, Stanford University, Stanford, CA, United States, 2Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan, 3Applied Science Lab, GE Healthcare, Menlo Park, CA, United States, 4Neurosurgery, Stanford University, Stanford, CA, United States We validated cerebrovascular reactivity (CVR) in Moyamoya disease measured by arterial spin labeling (ASL) simultaneously with 15O-positron emission tomography (PET) using hybrid PET/MRI scanner. We compared the three types of ASL including standard-delay, multi-delay with extended post-label delay, and velocity selective ASL (VS-ASL). To quantify absolute PET cerebral blood flow (CBF) without arterial blood samples, we scaled the static PET maps using simultaneously collected phase-contrast (PC) MRI. Multi-delay ASL showed the strongest correlation with PC-PET on both baseline and post-ACZ CBF (R2 = 0.48 and 0.66 respectively). Multi-delay ASL and VS-ASL showed similar good correlations with PC-PET on CVR.

 856 Plasma 4 Adaptations in cerebral physiology due to chronic anaemia measured with Turbo-QUASAR ASL Lena Vaclavu1, Moss Y Zhao2, Esben Thade Petersen3, John C Wood4, Henk JMM Mutsaerts1,5,6, Charles B Majoie1, Ed T vanBavel7, Bart J Biemond8, Michaell A Chappell2, and Aart J Nederveen1 1Radiology & Nuclear Medicine, Academic Medical Center, Amsterdam, Netherlands, 2Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom, 3Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark, 4Cardiology and Radiology, Children's Hospital of Los Angeles, Los Angeles, CA, United States, 5Kate Gleason College of Engineering, Rochester Institute of Technology, Rochester, NY, United States, 6Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 7Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, Netherlands, 8Haematology, Internal Medicine, Academic Medical Center, Amsterdam, Netherlands In this work, we applied a novel ASL method (Turbo-QUASAR) to evaluate the effects of life-long anaemia on cerebral physiology by comparing patients with Sickle Cell Disease to healthy controls. Turbo-QUASAR enables simultaneous assessment of cerebral blood flow (CBF), cerebral blood volume (aCBV) and arterial transit time (ATT) as well as tissue T1 and M0. We found normal ATT in the presence of elevated CBF in patients. In addition we found increased aCBV in patients. Acetazolamide administration shortened ATT with no change in aCBV suggesting maximal dilation and reserves being accessed by faster ATT. aCBV was inversely related to haemoglobin.

 857 Plasma 5 Noninvasive MRI measurements of oxygen extraction fraction reduction in response to blood transfusion in adults with sickle cell anemia Meher Juttukonda1, Lori C Jordan2, Larry T Davis1, Chelsea A Lee2, Niral J Patel2, Sumit Pruthi1, and Manus J Donahue1 1Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 2Pediatrics - Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, United States Blood transfusions are often administered for secondary stroke prevention in adults with sickle cell anemia (SCA). We utilized noninvasive MRI methods to evaluate how oxygen extraction fraction (OEF) and cerebral blood flow (CBF) adjust after transfusion in adults with SCA. OEF reduced on average, while CBF did not change significantly. The OEF reduction paralleled increases in hematocrit but was unrelated to the reduction in hemoglobin-S. This implies that most patients receiving transfusions operate near autoregulatory reserve capacity even after transfusion, and improving oxygen delivery by increasing hematocrit can be visualized noninvasively with OEF-MRI.

 858 Plasma 6 Relationship between the Degree of Unilateral Intracranial Artery Stenosis and Cerebral Perfusion: a High-resolution Intracranial Vessel Wall Imaging Study Song Liu1,2, Tianyi Qian3, Jinxia Zhu3, Wen Shen2, and Shuang Xia2 1First Clinical College,Tianjin Medical University, Tianjin, China, 2Department of Radiology,Tianjin First Central Hospital, Tianjin, China, 3Siemens Healthcare,MR Collaborations NE Asia, Beijing, China High-resolution vessel wall imaging(HR-VWI) is an novel technique used to assess intracranial artery stenosis, and it has been useful in clinical practice. In addition, time-to-maximum (Tmax) maps, derived from PWI, are increasingly being used in studies of ischemic stroke, such as EPITHET and DEFUSE-2 . Our study aimed to investigate how the degree of stenosis of the MCA or ICA affects brain tissue perfusion. The results showed that the degree of MCA or ICA stenosis was positively correlated with the Tmax delay volume, and different degrees of ICA or MCA stenosis presented with different perfusion delay volumes.

 859 Plasma 7 Identifying ischemic zone patterns and origins using multi-delay arterial spin labeling in vasospasm Swati Rane1, Daniel Hippe1, Michael Levitt1, Louis Kim1, and Jalal B Andre1 1University of Washington Medical Center, Seattle, WA, United States Our goal was to evaluate a multi-delay, pseudocontinuous arterial spin labeling (ASL) approach to detect focal delayed cerebral ischemia in patients with vasospasm. We show that inferences on vascular origins based on ASL and standardized perfusion territories correlated well with expert reader reads that rely on an invasive catheter-based digital subtraction angiography (DSA) examination. Importantly, ASL identified possible ischemic zones due to distal vasospasm, which are nearly undetectable on conventional DSA. Thus, use of ASL may prevent unnecessary DSA examinations and improve patient prognosis.

 860 Plasma 8 Non-contrast fingerprinting perfusion imaging reveals hemodynamic deficits in cerebrovascular diseases Pan Su1,2, Peiying Liu1, Yang Li1,2, Zixuan Lin1,3, Lynsey Keator4, Ye Qiao1, Judy Huang5, Argye E. Hillis4,6,7, and Hanzhang Lu1 1The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States, 3Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 6Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 7Cognitive Science, Johns Hopkins University, Baltimore, MD, United States Perfusion imaging plays an important role in management decisions for a variety of cerebrovascular diseases. Most clinical perfusion MRI of stroke requires the use of contrast agent. However, contrast-agent perfusion cannot be used or fails to be used in 10-20% of patients. Therefore, an alternative technique to Gd-perfusion will benefit a substantial number of patients in clinical practice. Recently, a MR-Fingerprinting (MRF) ASL was developed for simultaneous estimations of CBF and bolus timing. In this study, we demonstrated the clinical utility of MRF-ASL in two types of cerebrovascular diseases, ischemic stroke and Moyamoya disease.

 861 Plasma 9 High-Resolution, Non-contrast Pseudo-Continuous Arterial Spin-Labeling (PCASL) MR-Angiography compared to standard clinical MRI in the detection of intracranial vessel pathologies with emphasis on intracranial arteriovenous shunts. Tilman Schubert1, oliver Wieben2, Patrick Turski2, Huimin Wu3, and Kevin Johnson2 1Radiology, Basel University Hospital, Basel, Switzerland, 2University of Wisconsin Madison, Madison, WI, United States, 3William Beaumont Hospital, Royal Oak, MI, United States The detection of intracranial AV-shunts may be difficult with non-invasive imaging. Due to the nature of spin-labeled protons, ASL-based MRA is likely to be highly specific for AV-shunting. We sought to determine the sensitivity and specificity of ASL-based MRA in a group of 32 patients, among those 14 with AV-shunts. Furthermore, the diagnostic performance for vascular pathology not associated with AV-shunting was assessed. We found ASL-based MRA to be more specific with an equivalent sensitivity compared to a clinical MRA-exam for intracranial AV-shunts. All vascular pathology not associated with AV-shunting were detected with ASL-based and clinical MRA.

 862 Plasma 10 Characteristics of Plaques and Lenticulostriate Arteries in Stroke Patients by Whole-Brain Vessel Wall Magnetic Resonance Imaging Fang Wu1, Zhaoyang Fan2, Tianyi Qian3, Qi Yang1, and Debiao Li2 1Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China, 2Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States, 3MR Collaboration NEA, Siemens Healthcare, Beijing, China The aim of our study was to investigate the plaque characteristics and the lenticulostriate artery (LSA) status in artery-to-artery (A-to-A) embolism and branch atheromatous disease (BAD) using whole-brain high-resolution MRI. The results showed that patients with A-to-A embolism presented more frequently hyperintense plaques (HIP), plaque surface irregularity, and severe stenosis than patients with BAD. A signiﬁcant reduction in the number and lengths of LSA branches in patients with BAD compared to A-to-A embolism was also found. Multivariate analysis further demonstrated that HIP was independently associated with A-to-A embolism, whereas the reduction in LSA branches was independently associated with BAD.

 863 Plasma 11 Comparison of velocity-selective and pulsed ASL perfusion MRI in patients with suspected cerebral cortical ischemia Divya S Bolar1,2, Bruce R Rosen1,2, and Pamela W. Schaefer1 1Radiology, Massachusetts General Hospital, Boston, MA, United States, 2MGH/HST Martinos Center for Biomedical Imaging, Charlestown, MA, United States Traditional pulsed ASL (PASL) suffers from arterial transit delay (ATD) effects, often resulting in inaccurate perfusion measurements in cerebral ischemia. Velocity selective ASL (VSASL), on the other hand, accurately measures perfusion independent of ATD. In this study, we compare VSASL and PASL perfusion in 27 patients with suspected cerebral cortical ischemia. Normal perfusion on VSASL and PASL had nearly perfect negative predictive value for ischemia, abnormal PASL perfusion had a high false positive rate for ischemia (25-35%), and abnormal VSASL perfusion had a ~0% false positive rate for ischemia.

 864 Plasma 12 Intravoxel Incoherent Motion (IVIM) Perfusion Imaging in Hyperacute Stroke: Initial Results Christian Federau1, Max Wintermark2, Soren Christensen3, David Marcellus2, Guangming Zhu2, Maarten Lansberg3, Gregory Albers3, and Jeremy Heit2 1University Hospital Basel, Basel, Switzerland, 2Neuroradiology, Stanford University, Stanford, CA, United States, 3Neurology, Stanford University, Stanford, CA, United States Intravoxel Incoherent Motion (IVIM) MR perfusion is of particular interest in stroke because it derives intrinsic microvascular perfusion information, and might therefore include information regarding collateral blood flow without being influenced by time delay in blood arrival, which is a limitation of other perfusion techniques. In this preliminary work in 23 patients with hyperacute stroke, we found the IVIM microvascular perfusion paramteters were significantly reduced in the infarct core but not in the penumbra, compared to the contralateral side, suggesting that at time of imaging, microvascular perfusion is maintained through collateral blood flow in the penumbra.

 865 Plasma 13 Superselective 4D MR Angiography with Pseudo-Continuous Arterial Spin Labelling Combined with CENTRA-Keyhole (SS-4D-PACK) Used to Visualize Brain Arteriovenous Malformations Osamu Togao1, Akio Hiwatashi1, Makoto Obara2, Michael Helle3, Koji Yamashita1, Daichi Momosaka1, Tatsuhiro Wada4, Hiroo Murazaki4, Marc Van Cauteren2, and Hiroshi Honda1 1Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan, 2Philips Japan, Tokyo, Japan, 3Philips Research, Hamburg, Germany, 4Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan In the present study, we demonstrated the utility of superselective 4D-MR angiography with pCASL combined with CENTRA-keyhole (SS-4D-PACK) for the visualization of brain AVMs. This method enables a time-resolved and vessel-selective angiography within 5 minutes without a use of contrast agents. It was showed that almost perfect vessel selectivity was achieved with SS-4D-PACK. Although CNRs were slightly reduced in SS-4D-PACK due to a labeling loss during superselective label focusing, this was acceptable since visualization was well preserved. SS-4D-PACK can be a non-invasive clinical tool for assessing brain AVMs.

 866 Plasma 14 Impaired cerebrovascular reactivity assessed by BOLD hypercapnic fMRI is associated with increased risk of stroke in patients with symptomatic intracranial atherosclerotic stenosis Jeremy Papassin1, Olivier Heck2, Naila BOUDIAF3, Eric CONDAMINE4, Johan PIETRAS4, Florence TAHON2, Olivier DETANTE1, and Alexandre KRAINIK2,3,4 1Department of Neurology, University Hospital Grenoble Alpes, Grenoble, France, 2Neuroradiology, University Hospital of Grenoble Alpes, Grenoble, France, 3Univ. Grenoble Alpes, Inserm, Grenoble Institute of Neurosciences, Grenoble, France, 4Univ. Grenoble Alpes, Inserm, CNRS, University Hospital Grenoble Alpes, IRMaGe, Grenoble, France Intracranial atherosclerotic stenosis (IAS) remains at risk of recurrent ischemic events despite intensive medical management. Cerebrovascular reactivity (CVR) assessed by hypercapnic challenge using BOLD functional MRI (CVR BOLD fMRI) estimates cerebrovascular reserve and may allow to identify patients at higher risk of recurrent ischemic events. 19 patients referred for unilateral symptomatic IAS were studied to estimate the relationships between baseline characteristics, recurrence of ischemic events, and CVR. During follow-up, recurrent ischemic events were more frequent in patients with impaired CVR. CVR mapping may help to better select among IAS patients those at higher risk to discuss additional treatment.

 867 Plasma 15 Resting-State BOLD MRI for Evaluating Cerebrovascular Reserve in Stroke Patients Kamil Taneja1, Hanzhang Lu1, Argye Beth Hillis2, and Peiying Liu1 1Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States The early stage of hemodynamic failure in ischemic cerebrovascular diseases is characterized by diminished cerebrovascular reserve. Tissues at this stage are at high risk for stroke. Assessment of cerebrovascular reserve by cerebrovascular reactivity (CVR) measurement usually requires the administration of vasoactive challenges (e.g., acetazolamide or CO2), which is often difficult or impractical in stroke patients. In this study, we demonstrate that CVR can be mapped in stroke patients without a physiological challenge but using the natural fluctuations of the resting-state BOLD signal. Results indicate that this technique can assess CVR in lesion, peri-lesional, and healthy tissue in a reproducible manner.

Electronic Power Pitch Poster

### Poster: fMRI: Signal Characteristics & Analysis

 Power Pitch Theater B - Exhibition Hall Wednesday 17:15 - 18:15

 868 Plasma 16 Blood pressure correlated fluctuations of BOLD origin in fMRI signals: A multi-echo 7T study. Joseph Whittaker1, Ian Driver2, Marcello Venzi1, and Kevin Murphy1 1School of Physics and Astronomy, Cardiff University Brain Research imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom, 2School of Psychology, Caridiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom Previously we have reported that fluctuations in fMRI signals at approximately 0.1Hz are highly correlated with blood pressure fluctuations at the same frequency. A multi-echo resting-state fMRI experiment was performed at 7T to separate the effect of changes in transverse relaxation (R2*) and longitudinal magnetisation (S0) in these fluctuations. We demonstrate that the magnitudes of correlations with blood pressure are significantly greater for R2* signals, compared with corresponding S0 signals. These data suggest that there is a significant proportion of BOLD dependent signal variance in fMRI that is of non-neuronal origin.

 869 Plasma 17 Determination of white matter cerebrovascular reactivity (CVR) and CVR compliance time responses to surgical revascularization using time regression analysis of hypercapnic BOLD fMRI data Sarah K Lants1, Meher R Juttukonda1, Spencer L Waddle2, Jennifer M Watchmaker3, Lori C Jordan4, Larry T Davis1, Matthew R Fusco5, and Manus J Donahue1 1Dept. of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 2Quantitative and Physical Biology Program, Vanderbilt University Medical Center, Nashville, TN, United States, 3Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States, 4Dept. of Neurology, Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, 5Dept. of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, United States We applied a novel time-regression analysis to hypercapnic BOLD imaging data in a cohort of moyamoya patients with progressive steno-occlusion of the intracranial arteries before and after surgical revascularization with the overall goal of elucidating gray and white matter differences in cerebrovascular reactivity (CVR)-weighted responses and vascular compliance time measures. We observed differences between gray and white matter reactivity time delays, as well as depth-dependent differences in reactivity and time delays within the white matter. Additionally, we observed that the improvement in both white and gray matter hemodynamics following surgical revascularization was closely related to pre-surgical CVR-weighted metrics.

 870 Plasma 18 Differentiating neural and non-neural fMRI signals using CBV-BOLD fMRI Laurentius Huber1, Daniel A Handwerker2, Sean Marrett2, Javier Gonzalez-Castillo1, Anrew Hall1, Dimo Ivanov3, Maria Guidi4, and Peter A Bandettini1 1SFIM, NIMH, Bethesda, MD, United States, 2FMRIF, NIMH, Bethesda, MD, United States, 3MBIC, Maastricht, Netherlands, 4MPI-CBS, Leipzig, Germany fMRI is noisy and suffers from signal origin ambiguities. We propose a straightforward method that can classify the origin of neurally- and non-neurally-driven signal fluctuations by means of simultaneously acquired BOLD and CBV fMRI-data. For neurally-driven fMRI-signal fluctuations, BOLD and CBV are synchronized. For non-neurally-driven fluctuations, however, abnormal temporal correlations are seen. Upon identification of the non-neural components, they can be filtered out. This helps to remove artifacts and improve the specificity and interpretability of fMRI activation maps. Moreover, we show that it can remove venous signal components in ultra-high-resolution fMRI and improve the spatial specificity across cortical laminae.

 871 Plasma 19 Local neuronal synchronization and global functional disconnection are signatures of propofol-induced unconsciousness Anthony G Hudetz1, Zirui Huang1, Xiaolin Liu2, and George A Mashour1 1University of Michigan, Ann Arbor, MI, United States, 2Medical College of Wisconsin, Milwaukee, WI, United States Information processing in the brain occurs through a hierarchy of temporal receptive windows (TRWs). Anesthetic drugs induce a reversible suppression of consciousness and thus offer a unique opportunity to investigate the state-dependence of TRWs. Here we demonstrate that sedation with propofol is accompanied by the prolongation of the brain’s intrinsic functional timescales, i.e. enlarged TRWs. This is accomplished by an increase of local and regional signal synchronization, which in turn disrupts information exchange among distant brain regions. Finally, we show that the brain’s information processing timescales exhibit distinct dynamic signatures in sedation, deep anesthesia, and disorders of consciousness.

 872 Plasma 20 Absolute quantification of resting oxygen metabolism and cerebral physiology following acute exposure to repeated sub-concussive collisions: A calibrated MRI approach ALLEN A. CHAMPAGNE1, NICOLE S. COVERDALE1, MIKE GERMUSKA2, and DOUGLAS J. COOK1,3 1Centre of Neuroscience studies at Queen's University, Kingston, ON, Canada, 2Cardiff University Brain Research Imaging Centre, Cardiff, United Kingdom, 3Department of Surgery at Queen's University, Kingston, ON, Canada Athletes involved in collision sports can sustain up to ~1400 head impacts, within a single season. In this study, we explore the physiological nature of sub-concussive impacts using a calibrated MRI method, which combines hypercapnic and hyperoxic breathing manipulations. Collegiate football players were scanned at pre-season baseline and following three weeks of practices and one game. Relative to baseline, we observed global increased resting oxygen extraction fraction (OEF0) and cerebral metabolic rate of oxygen consumption (CMRO2|0) in the grey-matter, with significant differences found within the frontal lobe (P<0.05). These results emphasize the need to regulate exposure to head impacts in sports.

 873 Plasma 21 Evaluation of task-induced δCMRO2 with a simultaneous acquisition of CBV, CBF and BOLD signals during normoxia and hypoxia conditions Yaoyu Zhang1,2, Yayan Yin1,3, Long Qian1, Yang Fan4, Bing Wu1,4, and Jia-Ηοng Gao1,3 1Center for MRI Research, Peking University, Beijing, China, 2Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China, 3Beijing City Key Lab for Medical Physics and Engineering, Peking University, Beijing, China, 4MR Research China, GE Healthcare, Beijing, China Existing studies have reported various results regarding CMRO2 behaviors during hypoxia. In this study, a simultaneous acquisition of CBV, CBF and BOLD signals was implemented to evaluate task-induced δCMRO2 under both normoxia and hypoxia conditions. Of 40 subjects who completed two runs of block-designed, black-and-white checkerboard visual tasks (normoxia and hypoxia) and a CO2 challenge, we found δCMRO2 increase significantly during hypoxia. We reckon that the simultaneous acquisition technique makes it possible for all necessary data to be acquired in one run of task, thus minimizing motion and physiological artifacts caused by separate data acquisitions through task repetitions.

 874 Plasma 22 Using measured Haemodynamic Response Functions in Population Receptive Field mapping at 7 T Michael Asghar1, Denis Schluppeck2, and Susan Francis2 1SPMIC, University of Nottingham, Nottingham, United Kingdom, 2University of Nottingham, Nottingham, United Kingdom In order to combat overfitting in computational encoding models, one method is to reduce the number of fit parameters. In population receptive field (pRF) mapping, a haemodynamic response function (HRF) is parameterized from the fMRI timeseries, and this may inflate model fits (r2). Here, we show that measured HRF estimates from a brief set of separate HRF measurement scans can be included in the pRF fitting procedure, reducing the degrees of freedom. We show that model fits between our “HRF-informed” pRF and the traditional fitted HRFs are comparable, suggesting that this method is more representative of the ground truth.

 875 Plasma 23 Visual temporal frequency preference shows a distinct cortical architecture using fMRI Yuhui Chai1, Daniel Handwerker1, Sean Marrett1, Andrew Hall1, Javier Gonzalez-Castillo1, Peter Molfese1, and Peter Bandettini1 1National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States The functional architecture of temporal frequency preference of human visual system is not well characterized. We collected fMRI data with visual stimuli varying flicker frequency from 1 to 40 Hz. Using model fit and K-means clustering on frequency tuning curve we were able to show evidence for a temporal frequency specific architecture of visual system.

 876 Plasma 24 A Probabilistic Atlas of Digit Somatotopy in the Human Primary Somatosensory Cortex Ayan Sengupta1, Denis Schluppeck2, Eleanor Barrat1, Julien Besle3, Susan Francis1, and Rosa Sanchez Panchuelo1 1Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 2School of Psychology, University of Nottingham, Nottingham, United Kingdom, 3Department of Psychology, American University of Beirut, Beirut, Lebanon A probabilistic atlas of the digit representations of the left and right hand in primary somatosensory cortex is formed. The atlas is generated in volume and surface standardized space from somatotopic maps of 21 right-handed subjects obtained using a travelling wave paradigm with vibrotactile stimuli. Metrics quantify the likelihood of a given position being assigned to a digit (full probability map) and the most probable digit for a position (maximum probability map), with the atlas validated using a leave-one-out cross validation procedure. This probabilistic atlas quantifies variability in healthy subjects and can be used as a reference in patient studies.

 877 Plasma 25 Modeling Motor Task Activation from Task-free fMRI with Machine Learning: Predictions and Accuracy in Individual Subjects Elizabeth Zakszewski1, Alexander Cohen1, Chen Niu2, Xiao Ling2, Oiwi Parker Jones3, Saad Jbabdi3, Ming Zhang2, Maode Wang2, and Yang Wang1 1Medical College of Wisconsin, Milwaukee, WI, United States, 2First Affiliated Hospital of Xi'An Jiaotong University, Shaanxi Xi'an, China, 3Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, Oxford, United Kingdom This study is aimed to apply a newly developed machine learning approach to predict individual motor performance from resting state functional MRI. Our data demonstrate that resting state fMRI even using conventional EPI protocols can predict individual motor performance. Our results suggest that the novel machine learning model could more accurately predict motor function at the individual level, compared to the independent component analysis method.

 878 Plasma 26 Performing Sparse Regularization and Dimension Reduction Simultaneously in CCA-Based Data Fusion Zhengshi Yang1, Xiaowei Zhuang1, Christopher Bird1, Karthik Sreenivasan1, Virendra Mishra1, Sarah J Banks1, and Dietmar Cordes1,2 1Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States, 2University of Colorado, Boulder, CO, United States Principal component analysis is commonly used in data fusion for dimension reduction prior to performing fusion analysis. However, PCA does not address that a large proportion of voxels may be irrelevant to extract joint information in data fusion. We implemented sparse PCA to suppress irrelevant voxels while simultaneously reducing the data dimension. Results show that introducing sparsity to data fusion provides better group discrimination.

 879 Plasma 27 Evidence of Dense Functional Connectivity in the Human Brain Ankita Saha1, Ishaan Batta2, and Rahul Garg1 1Department of Computer Science and Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Center for Biomedical Image Computing and Analytics, University of Pennsylvania, Philadelphia, PA, United States Aimed at studying the nature of voxel-wise interactions in the brain, this study finds the evidence of dense functional connectivity in the brain using resting state fMRI data from over 700  subjects. To study the nature of these interactions, we used a bipartite graph embedding algorithm on the connectivity network obtained with multiple pre-processing strategies with respect to global signal regression. We also analyzed interactions between and whithin grey and white matter. The results point to a dense non-bipartite network covering 74.63% of the brain leading to new insights towards understanding the human functional connectome.

 880 Plasma 28 Matrix Tri-Factorization for BOLD-fMRI Michael Hütel1, Andrew Melbourne1, and Sebastien Ourselin1 1UCL, London, United Kingdom We present Matrix Tri-Factorization as a means to obtain an individual's BOLD-fMRI decomposition into unique neuronal activation patterns, spatial network maps and their corresponding hemodynamic response functions. We validate our proposed method on the motor cortex localization task of the Human Connectome Project 1200 Subject Release and show that neural activation patterns from our proposed Unsupervised Machine Learning technique resemble the given motor task profiles.

 881 Plasma 29 Effect size and result overlap between individual and group results in fMRI studies Peter Van Schuerbeek1, Chris Baeken2,3, and Johan De Mey4 1Radiology, UZ Brussel (VUB), Brussels, Belgium, 2Psychiatry, UZ Brussel, Brussel, Belgium, 3Psychiatry and Medical Psychology, UGent, Ghent, Belgium, 4Radiology, UZ Brussel, Brussels, Belgium In the fMRI literature, most authors reported solely the significance of their findings which hampered the critical interpretation of the found results and power analyses for subsequent studies. To reveal the effect size and overlap between individual subject activation maps, we reanalyzed data from multiple fMRI studies. For each of the 44 contrasts tested, our study revealed fairly strong effect sizes and reasonable overlap between the individual results. However, the overlap between the individual results and the results of the corresponding group analysis was rather poor. This observation supports the call that reporting significance solely, is not enough.

 882 Plasma 30 Cross-vendor harmonization of T2-Relaxation-Under-Spin-Tagging (TRUST) MRI for the assessment of cerebral venous oxygenation Dengrong Jiang1, Peiying Liu2, Yang Li2,3, Deng Mao2,3, Cuimei Xu2, and Hanzhang Lu1,2,4 1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States, 4F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States Cerebral venous oxygenation (Yv) is an important physiological parameter and has potential clinical application in many diseases. T2-relaxation-under-spin-tagging (TRUST) is a commonly used MRI method to measure Yv. Harmonization of TRUST across MRI vendors is important for dissemination and multi-center studies of brain oxygenation as a disease biomarker. In this work, we harmonized TRUST pulse sequence components and imaging parameters across two major MRI vendors, Philips and Siemens. We showed that Yv measured on the two vendors were highly compatible and strongly correlated, had excellent reproducibility, and can reliably detect oxygenation changes associated with physiological challenges on both scanners.

Electronic Power Pitch Poster

### Poster: Neurodegeneration

 Power Pitch Theater A - Exhibition Hall Thursday 9:00 - 10:00

 973 Plasma 1 Data-driven modelling of diffusion MRI changes in Amyotrophic Lateral Sclerosis (ALS) indicates evolution of distal prior to proximal corticospinal tract pathology Matt C Gabel1, Stella Tsermentseli2, Laura H Goldstein3, Ammar Al-Chalabi3, Alexandra L Young4, Daniel C Alexander4, Nigel Leigh5, and Mara Cercignani1 1Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, United Kingdom, 2Department of Psychology, Social Work and Counselling, University of Greenwich, London, United Kingdom, 3Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom, 4Centre for Medical Image Computing, University College London, London, United Kingdom, 5Trafford Centre for Biomedical Research, Brighton and Sussex Medical School, Brighton, United Kingdom In order to investigate the likely progression of neurodegeneration in amyotrophic lateral sclerosis (ALS) patients, we applied a novel mathematical model to multi-site diffusion MRI data.  Our results indicate directional evolution of disease in the corticospinal tracts (CSTs) of ALS patients, in a distal to proximal manner.

 974 Plasma 2 Progressive Cortical Thinning in Specific Motor Regions in Different Clinical Stages of Patients with Amyotrophic Lateral Sclerosis Haining Li1, Qiuli Zhang1, Xiao Ling1, Guirong Zhang1, Ling Yang1, and Ming Zhang1 1Department of Medical Imaging, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China Staging system for ALS is important for clinical practice. Howerer, the validation of the mechanism that underneath the proposed stages in ALS remains unclear. We used surface-based cortical morphology and more precise anatomical evaluation for 72 patients at different stages and 88 controls, confirmed the consecutive involvement of cortical thinning in PrG along disease progression. Moreover, the extensive but similar PrG involvement in patients at stage 2 and stage 3, highlighted a critical therapeutic window from stage 1 to stage 2, and also underlined the incorporation of cortical evaluation as additional features to King’s clinical stages for promising clinical management.

 975 Plasma 3 Increased brain entropy in supplementary motor area and precuneus in amyotrophic lateral sclerosis Liqin Yang1, Yifang Bao1, Yuxin Li1, and Daoying Geng1 1Huashan Hospital, Fudan University, Shanghai, China Amyotrophic Lateral Sclerosis (ALS) is a fatal disease, but no fully validated and clinically specific biomarkers have been identified yet. We studied the brain entropy (BEN) of ALS patients using resting state functional magnetic resonance imaging (rs-fMRI) on fifty-six ALS patients without cognitive impairments and forty-six age- and sex-matched healthy controls. We found increased low frequency entropy in SMA/SMF and increased whole frequency entropy in precuneur/PCC regions in ALS patients. The results may improved our understanding of ALS and provide new biomarkers for diagnosis of ALS.

 976 Plasma 4 Impaired oxygen metabolism in the brain during visual stimulation in premanifest Huntington's Disease patients detected by 3D-TRIP MRI at 7T Peter Klinkmueller1,2,3, Martin Kronenbuerger4,5, Xinyuan Miao2,3, Russell L. Margolis5, Peter C. M. van Zijl2,3, Christopher A. Ross4,5,6, and Jun Hua2,3 1Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 6Department of Neuroscience and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, United States Huntington’s disease (HD) is a neurodegenerative disease caused by a single genetic mutation. Neurovascular abnormalities have been implicated in the pathophysiology of HD. Here, dynamic responses in BOLD, cerebral-blood-flow (CBF) and -volume (CBV) during visual stimulation were measured using 3D-TRiple-acquisition-after-Inversion-Preparation (3D-TRIP) MRI in premanifest HD patients and healthy controls, from which cerebral-metabolic-rate-of-oxygen (CMRO2) response was estimated. Decreased ΔCMRO2 and increased ΔCBV were observed in HD patients compared to controls, which correlated with genetic measures. The results suggested potential value of ΔCMRO2 as a biomarker for HD, and may shed light on the pathophysiology in HD in terms of mitochondrial deficiency.

 977 Plasma 5 The Impact of Leukoencephalopathy on the White Matter Tracts of Long-Term Survivors of Childhood Acute Lymphoblastic Leukemia Treated with Chemotherapy Only Noah D. Sabin1, Yin Ting Cheung2, Wilburn E. Reddick1, Deepa Bhojwani3, Wei Liu4, John O. Glass1, Tara M. Brinkman2, Scott N. Hwang1, Deokumar Srivastava4, Ching-Hon Pui5, Leslie L. Robison2, Melissa M. Hudson2, and Kevin R. Krull2 1Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, United States, 2Epidemiology & Cancer Control, St. Jude Children's Research Hospital, Memphis, TN, United States, 3Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Los Angeles, CA, United States, 4Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, United States, 5Oncology, St. Jude Children's Research Hospital, Memphis, TN, United States Survivors of acute lymphoblastic leukemia (ALL) can develop neurocognitive deficits and leukoencephalopathy. On-therapy and follow-up MRI examinations of the brain for 173 ALL survivors were reviewed for leukoencephalopathy. At follow-up, the survivors also underwent neurocognitive testing and brain diffusion tensor imaging (DTI). DTI parameters were associated with leukoencephalopathy in multiple regions of the brain. Although there were no associations between neurocognitive performance and leukoencephalopathy, increased mean diffusivity (MD) in certain fiber tracts was associated with neurocognitive impairment. DTI, in particular MD, may better detect loss of white matter integrity associated with neurocognitive deficits in ALL survivors than leukoencephalopathy.

 978 Plasma 6 CO2-challenge measured with dual echo arterial spin labeling as a whole brain biomarker to assess the effect of amyloid deposition in HCHWA-D on the cerebrovascular reactivity. Sophie Schmid1,2, Jasper Verbree1, Merlijn C.E. van der Plas1,2, Ellis S. van Etten3, Ingeborg Rasing3, Pauline H. Croll4, Madeline Redelijkheid2,4, Gerda Labadie4, Gisela M. Terwindt3, Marieke J.H. Wermer3, Mark A. van Buchem4, and Matthias J.P. van Osch1,2 1C.J. Gorter Center, Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Leiden Institute of Brain and Cognition (LIBC), Leiden, Netherlands, 3Neurology, Leiden University Medical Center, Leiden, Netherlands, 4Radiology, Leiden University Medical Center, Leiden, Netherlands In this study a CO2-challenge was applied to test the effect of amyloid deposition in HCHWA-D, a hereditary form of cerebral amyloid angiopathy (CAA), on the cerebrovascular reactivity (CVR). With dual echo arterial spin labeling, providing cerebral blood flow (CBF) and BOLD images, the CVR was measured in grey and white matter and the CO2-challenge was evaluated as a whole brain biomarker. The effect of the CO2-challenge was best measured with CBF in the grey matter. Future research should prove whether it is sensitive enough to detect treatment induced changes in (pre-)symptomatic CAA patients.

 979 Plasma 7 Connectomics Correlates of Neurocognitive Deficits in Gulf War Illness Patients: A Resting State fMRI Study Kaundinya Gopinath1, Unal Sakoglu2, Bruce Crosson3,4, and Robert Haley5 1Department of Radiology, Emory University, Atlanta, GA, United States, 2University of Houston Clear-Lake, Houston, TX, United States, 3VA RR&D Center of Excellence, Atlanta VAMC, Decatur, GA, United States, 4Department of Neurology, Emory University, Atlanta, GA, United States, 5Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States Around 200,000 veterans of the 1991 Gulf War (GW) suffer from GW illness (GWI), which is characterized by multiple deficits in cognitive, emotion, sensory and interoception domains. In this study we examined resting state fMRI data from 23 GWI patients and 30 age-matched controls with group independent components analysis (ICA). Deficits in neurocognitive assessment scores of different brain function domains in GWI veterans strongly correlated with impaired functional connectivity within and between specific brain function networks engaged during performance of the corresponding neuropsychological tests, thereby elucidating brain mechanisms underlying cognitive deficits in GWI.

 980 Plasma 8 Interaction of vascular and glymphatic systems in brain waste clearance after diabetes Quan Jiang1,2,3, Hiani Hu4, Guangliang Ding1, Esmaeil Davoodi-Bojd1, Yimin Shen4, Li Zhang1, Lian Li1, Qingjiang Li1, Michael Chopp1,2,3, and Zhenggang Zhang1,2,3 1Neurology, Henry Ford Health System, Detroit, MI, United States, 2Physics, Oakland University, Rochester, MI, United States, 3Neurology, Wayne State University, Detroit, MI, United States, 4Radiology, Wayne State University, Detroit, MI, United States The recently discovered glymphatic system has become an exciting area of research because of it plays an important role in neurological diseases.  However, the interaction between the vascular and the glymphatic systems in terms of waste clearance from the brain is not clear. In addition to the glymphatic system, our preliminary MRI results suggest that the venous system involves in waste removal and waste clearance increases after diabetes. Current study provide the first investigation of the interaction between the vascular and the glymphatic systems in brain waste clearance after diabetes.

 981 Plasma 9 Detection of Medication-Induced Changes in Thalamic GABA in Patients with Parkinson’s Disease Using J-Edited Spectroscopy Paula Trujillo1, Ya-Chen Lin2, Nelleke van Wouwe1, Kalen Petersen1, Adam J. Stark1, Nivedita Kukreti1, Hakmook Kang2, Manus J. Donahue1,3, and Daniel O. Claassen1 1Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, 2Biostatistics, Vanderbilt University, Nashville, TN, United States, 3Radiology, Vanderbilt University Medical Center, Nashville, TN, United States A major neurochemical regulator of the thalamocortical network is GABA. We used J-edited MRS with compartment correction to evaluate the pharmacological effect of Dopamine agonist (DAA) therapy on thalamic GABA in patients with Parkinson’s disease (PD). Our findings suggest that DAA alters GABA release in PD patients, and that medication-induced changes may be associated to the presence of impulsive behaviors. These results provide evidence that J-edited MRS can be used to measure subcortical neurotransmitter concentration non-invasively, allowing the investigation of the pharmacological effects in GABAergic activity in humans.

 982 Plasma 10 Environmental Paraquat and HFE genetics as factors in the development of Parkinson’s disease Miranda A Salvo1, Carson J Purnell1, Qing X Yang2, James R Connor1, and Mark D Meadowcroft1,2 1Neurosurgery, The Pennsylvania State University - College of Medicine, Hershey, PA, United States, 2Radiology, The Pennsylvania State University - College of Medicine, Hershey, PA, United States The herbicide paraquat (PQ) is believed to have a neurotoxic role in the development of Parkinson’s disease (PD) as there is increased risk of exposure in rural areas. The HFEH63D polymorphism has been shown to cause brain abnormalities and disrupt iron homeostasis, key components of PD etiology. This work hypothesized that HFEH67D carrier status would augment PQ induced PD histological and imaging metrics. The R2 and histology data from PQ treated mice provide evidence that PQ had a marked effect in the WT but not HFEH67D mice, suggesting that the H67D polymorphism imparts a neuroprotective role in PD.

 983 Plasma 11 Magnetic resonance spectroscopic imaging based biomarkers of Parkinson’s disease with mild cognitive impairment registered to MNI152 brain atlas after chemical shift correction Sevim Cengiz1, Dilek Betul Arslan1, Ani Kicik2, Emel Erdogdu3, Muhammed Yildirim1, Zeynep Tufekcioglu4, Basar Bilgic4, Hasmet Hanagasi4, Aziz Mufit Ulug1, Hakan Gurvit4, Tamer Demiralp2,5, and Esin Ozturk-Isik1 1Biomedical Engineering Institute, Bogazici University, Istanbul, Turkey, 2Hulusi Behcet Life Sciences Research Center, Istanbul University, Istanbul, Turkey, 3Psychology and Cognition Research Institute, Bremen University, Bremen, Germany, 4Department of Neurology, Istanbul University, Istanbul, Turkey, 5Department of Physiology, Istanbul University, Istanbul, Turkey Mild cognitive impairment in Parkinson’s disease (PD-MCI) is one of the most significant risk factors for Parkinson’s disease dementia. In this study, we defined proton magnetic resonance spectroscopic imaging (1H-MRSI) based biomarkers of PD-MCI. After chemical shift misregistration correction and registration to MNI152 brain atlas of multi-voxel 1H-MRSI data, 101 regions defined in MNI structural and Harvard-Oxford cortical and subcortical structural atlases were analyzed for metabolic differences between PD-MCI, cognitively normal PD (PD-CN) and healthy controls. Temporal occipital fusiform cortex, and posterior divisions of parahippocampal gyrus and right temporal fusiform cortex were indicated as the main regions for metabolic differences.

 984 Plasma 12 Disrupted Grey Matter Network Morphology in Parkinson's Disease Xueling Suo1, Du Lei2, Nannan Li3, Lan Cheng3, Fuqin Chen1, Running Niu1, Rong Peng3, and Qiyong Gong1 1Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China, 2Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom, 3Department of Neurology, West China Hospital of Sichuan University, Chengdu, China To use graph theory approaches and high resolution T1-weighted structural magnetic resonance imaging to explore the brain grey matter morphological network in patients with Parkinson's disease (PD). The individual morphological brain networks were constructed by estimating interregional similarity in the distribution of regional grey matter volume of 90 brain regions. The higher clustering coefficient and local efficiency in the PD patients relative to healthy controls were found, indicating that brain morphological networks are closer to regularization, which was different from previous functional connectome studies, suggesting relatively fixed structural network organization can produce diverse functional network patterns.

 985 Plasma 13 Altered brain network structure during urethane-induced sleep states in a rat model of early-stage Parkinson’s disease Ekaterina Zhurakovskaya1, Jaakko Paasonen1, Juuso Leikas2, Aaro Jalkanen2, Tiina Pirttimäki1, Rubin Aliev3,4, Heikki Tanila1, Markus Forsberg2, and Olli Gröhn1 1A.I.Virtanen Institute, University of Eastern Finland, Kuopio, Finland, 2School of Pharmacy, University of Eastern Finland, Kuopio, Finland, 3Moscow Institute of Physics and Technology, Moscow, Russian Federation, 4Institute of Theoretical and Experimental Biophysics, Pushchino, Russian Federation 6-hydroxydopamine (6-OHDA) striatal lesion is a well-established rat model of early-stage Parkinson’s disease.  The aim of the study was to compare connectivity patterns between 20 6-OHDA lesion rats and 10 sham controls under urethane anesthesia, modelling natural sleep, by using functional magnetic resonance imaging (fMRI). We found that functional connectivity patterns were disturbed in lesion animals. The decrease in functional connectivity, however, occurred only in rapid eye movement (REM)-like state. Furthermore, thalamocortical functional connectivity was correlating with striatal dopamine depletion ratio, making these changes possible early diagnostic markers for Parkinson’s disease.

 986 Plasma 14 Effect of motor planning and dopaminergic medication on cerebellar network connectivity during dual motor tasking in Parkinson's disease Silvina G Horovitz1, David Benninger2, Traian Popa1, Valerie Voon3, Mark Hallett1, and Cecile Gallea1,4 1HMCS, NINDS - NIH, Bethesda, MD, United States, 2Neurologie, CHUV, Lausanne, Switzerland, 3Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom, 4ICM-CRICM, UPMC/INSERM, UMR_975, CNRS 7225, Paris, France We investigated cerebellar deficits in dual-motor-tasking in Parkinson’s disease (PD) patients. Eighteen PD patients (scanned ON and OFF dopaminergic medication) and 18 matched controls performed simultaneous finger movements in a coupled or individuated fashion, and with different visual cues at 3T. We showed that cerebello-striatal network interactions play a role in symptomatic dual tasks in PD, and is influenced by dopaminergic medication. Our data suggest that  cerebellar-striatal loop is involved in planning fine dexterous tasks without interacting with the cortical motor areas.

 987 Plasma 15 Multimodal quantitative MRI biomarkers: identification of the specific damage in Progressive Supranuclear Palsy versus Parkinson’s disease Nadya Pyatigorskaya1,2,3, Rahul Gaurav1, Lydia Yahia-cherif1, Claire Ewenczyk4, Cecile Gallea1, Romain Valabregue1, Fatma Gargouri1, Eric Bardinet1, Isabelle Arnulf3,5, Cyril Poupon6, Marie Vidailhet3,4, and Stephane Lehericy1,2,3 1Centre de NeuroImagerie de Recherche – CENIR, ICM, Paris, France, 2Neuroradiology department, APHP, Pitié-Salpêtrière hospital, Paris, France, 3UMR S 1127, CNRS UMR 7225, ICM, UPMC Univ Paris, Paris, France, 4Clinique des mouvements anormaux, Département des Maladies du Système Nerveux, Hôpital Pitié-Salpêtrière, PARIS, France, 5Service des pathologies du Sommeil, Hôpital Pitié-Salpêtrière, APHP, Paris, France, 6NeuroSpin, CEA, Gif-Sur-Yvette, France We used quantitative multimodal MRI to investigate the region-specific damage in progressive supranuclear palsy (PSP) in order to generate a precise in-vivo model of neurodegeneration at various levels of the central nervous system. Additionally, we aimed to test the markers for differentiating the PSP from Parkinson disease (PD) patients and from healthy subjects. PSP patients showed extensive volume decrease and microstructural diffusion changes in the brainstem and the basal ganglia in agreement with previous pathological studies. These results suggest the possibility of direct non-invasive assessment of brain damage in PSP even in small brainstem nuclei.

Electronic Power Pitch Poster

### Poster: Body: Power Potpourri

 Power Pitch Theater B - Exhibition Hall Thursday 9:00 - 10:00

 988 Plasma 16 Imaging collateral ventilation in patients with advanced Chronic Obstructive Pulmonary Disease – relative sensitivity of 3He and 129Xe MRI Helen Marshall1, Guilhem J Collier1, Chris S Johns1, Ho-Fung Chan1, Graham Norquay1, Rod A Lawson1, and Jim M Wild1 1University of Sheffield, Sheffield, United Kingdom The success of lung volume reduction with endobronchial valves in patients with Chronic Obstructive Pulmonary Disease (COPD) depends on the absence of collateral ventilation into the target lung segment.  Collateral ventilation can be assessed using time-resolved 3He MRI, but providing this clinical application with 129Xe MRI would be desirable.  Two patients with severe COPD were scanned with time-resolved 3He and 129Xe MRI.  In both patients, collateral ventilation visualised using 3He MRI was not observed with 129Xe MRI. Although the small sample size is a limitation, this suggests that 129Xe MRI may not be suitable for the assessment of collateral ventilation.

 989 Plasma 17 Quantitative geometric assessment of regional airway collapse in neonates via retrospectively respiratory-gated 1H UTE MRI Nara S. Higano1,2, Alister J. Bates1,3, Erik B. Hysinger4, Robert J. Fleck5, Andrew D. Hahn6, Sean B. Fain6,7, Paul S. Kingma8, and Jason C. Woods1,2,4,5 1Center for Pulmonary Imaging Research, Cincinnati Children's Hospital, Cincinnati, OH, United States, 2Physics, Washington University in St. Louis, St. Louis, MO, United States, 3Upper Airway Center, Cincinnati Children's Hospital, Cincinnati, OH, United States, 4Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, OH, United States, 5Radiology, Cincinnati Children's Hospital, Cincinnati, OH, United States, 6Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 7Radiology, University of Wisconsin - Madison, Madison, WI, United States, 8Neonatology and Pulmonary Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States Neonatal airway malacia (dynamic larynx, trachea, and/or bronchi collapse) is a common airway complication often associated with preterm birth and congenital abnormalities but has not been extensively studied. This condition is currently diagnosed through visual bronchoscopy, which can be unreliable and poses increased risks to patients. We address these issues with an innovative technique using retrospectively respiratory-gated ultrashort echo time MRI and geometric analysis of moving airway anatomy for regional, quantitative evaluation of dynamic airway collapse in quiet-breathing, non-sedated neonates. This method has the potential to yield more accurate and objective assessment of neonatal airway collapse than current techniques allow.

 990 Plasma 18 Hyperpolarized [1-13C]Pyruvate Magnetic Resonance Imaging of Placentae Associated With Intrauterine Growth Restriction Lanette J Friesen-Waldner1, Conrad P Rockel1, Kevin J Sinclair1, Trevor P Wade1,2, Lauren Smith1, Mohamed Moselhy1, Cheryl Vander Tuin3, Albert P Chen4, Barbra de Vrijer5,6,7, Timothy RH Regnault3,5,6,7, and Charles A McKenzie1,2,6,7 1Medical Biophysics, Western University, London, ON, Canada, 2Robarts Research Institute, London, ON, Canada, 3Physiology and Pharmacology, Western University, London, ON, Canada, 4GE Healthcare, Toronto, ON, Canada, 5Obstetrics and Gynaecology, Western University, London, ON, Canada, 6Children's Health Research Institute, London, ON, Canada, 7Lawson Research Institute, London, ON, Canada Intrauterine growth restriction (IUGR) is associated with impaired placental metabolism and transport.  Hyperpolarized carbon-13 (HP13C) MRI was used to detect metabolic differences between control and IUGR placentae in pregnant guinea pigs, and to determine the impact of maternal hyperoxygenation on placental metabolism.  Area under the curve (AUC) was calculated for lactate, alanine, and bicarbonate and expressed as a ratio relative to pyruvate AUC.  The ratio of alanine to pyruvate AUC decreased significantly in IUGR versus control placentae.  Maternal hyperoxygenation resulted in significant increases in ratios of alanine and bicarbonate to pyruvate AUCs for both control and IUGR placentae.

 991 Plasma 19 Glycogen Synthesis Mapping Using In Vivo Deuterium Metabolic Imaging (DMI) Henk M. De Feyter1, Peter B. Brown1, Kevin L. Behar2, Douglas L. Rothman1,3, and Robin A. de Graaf1,3 1Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States, 2Department of Psychiatry, Yale University, New Haven, CT, United States, 3Department of Biomedical Engineering, Yale University, New Haven, CT, United States Deuterium Metabolic Imaging (DMI) is a novel approach providing high spatial resolution metabolic data from both animal models and human subjects. DMI relies on 2H MRSI in combination with administration of 2H-labeled substrates. We show how DMI combined with administration of [6,6’-2H2]-glucose can image liver glycogen synthesis in rats and human subjects. In rats at 11.7T, DMI revealed differences in liver glycogen synthesis between glucose administrations through an intravenous and intraperitoneal route. At 4T, we showed that DMI is feasible in humans and could detect labeling of liver glycogen after oral intake of [6,6’-2H2]-glucose.

 992 Plasma 20 High-Resolution Multishot Diffusion-Weighted Body and Breast MRI using Locally Low-rank regularization Yuxin Hu1,2, Evan G. Levine1,2, Catherine J. Moran1, Valentina Taviani3, Shreyas Vasanawala1, Bruce L. Daniel1,4, and Brian Hargreaves1,2,4 1Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Electrical Engineering, Stanford University, Stanford, CA, United States, 3GE Healthcare, Menlo Park, CA, United States, 4Department of Bioengineering, Stanford University, Stanford, CA, United States Multishot imaging has been shown to provide high resolution diffusion-weighted images (DWIs) with reduced distortion, however, significant aliasing artifacts and signal cancellation still occur due to the mismatch of the motion-induced phase between different shots. Several proposed SENSE-based methods without using navigators work well for brain DWI. However, these methods may fail when phase variations are more complex, in body DWI. In this work, we circumvent the challenging phase estimation step and efficiently solve this problem by using a locally low-rank reconstruction approach. The proposed reconstruction enables high resolution imaging with reduced geometric distortion compared with other approaches.

 993 Plasma 21 Prediction of Breast Cancer Molecular Subtypes Using Conventional Feature Extraction and Two Machine Learning Architectures Based on DCE-MRI Yang Zhang1, Siwa Chan2, Jeon-Hor Chen1,3, Daniel Chow1, Peter Chang4, Melissa Khy1, Dah-Cherng Yeh2, Xinxin Wang1, and Min-Ying Su1 1Department of Radiological Sciences, University of California, Irvine, CA, United States, 2Tzu-Chi General Hospital, Taichung, Taiwan, 3E-Da Hospital and I-Shou University, Kaohsiung, Taiwan, 4Department of Radiology, University of California, San Francisco, CA, United States Two different convolutional neural network architectures were applied to differentiate subtype breast cancer based on 5 DCE-MRI time frame images: (1) a conventional serial convolutional neural network; (2) a convolutional long short term memory (CLSTM) Network. In addition, a logistic classifier was trained using morphology and texture features, selected using a random forest algorithm. For CNN, a bounding box based on the automated tumor segmentation was used to create a cropped image of the tumor as network input.  A total of 94 cancers were analyzed, including 14 triple negative, 29 HER2-positive, and 51 Hormonal-positive, HER2-negative. Upon 10-fold validation, the differentiation accuracy is 0.81-0.86 using serial CNN, and 0.88-0.95 using the CLSTM.

 994 Plasma 22 A diffusion MRI based computer-guided assistance approach for the diagnosis of breast lesions with high accuracy and without the need for contrast agents. Mariko Goto1, Denis Le Bihan1,2, Koji Sakai1, and Kei Yamada1 1Radiology, Kyoto prefectural university of medicine, Kyoto, Japan, 2NeuroSpin, Gif-sur-Yvette, France This prospective study included 37 patients with 39 breast lesions. DWI images were acquired at 2 b values (200, 1500s/mm²) on a 3T-MRI scanner with a dedicated 16-channel breast coil. From the images a non-Gaussian diffusion based absolute quantitative biomarker, so-called Signature Index (S-index), was calculated by comparing tissue signals to a library of tissue reference signals to provide a classification of tumor types. The median S-index for malignant lesions was significantly higher (p < 0.0001) than for benign lesions, and the overall S-index diagnostic performance was significantly higher than BI-RADS (AUC=0.96 and 0.83, respectively), without contrast agents.

 995 Plasma 23 Changes in Pancreatic Stiffness in Obese Adults Receiving an Oral Glucose Load, as Measured by Magnetic Resonance Elastography Ruoyun Ji1, Yu Shi1, Yanqing Liu1, Lizhuo Cang1, Min Wang1, and Qiyong Guo1 1Shengjing Hospital of China Medical University, Shen Yang, China When applying MR elastography (MRE) in pancreas, the waves propagated in individuals with high Body Mass Index (BMI) tend to travel longer distances with more challenges. In this study, we performed MRE in 18 obese subjects before and after an administration of a 75 g oral glucose load (OGL), and we found that 40Hz had better wave image quality than 60Hz and was more sensitive to detect the stiffness decrease after OGL.

 996 Plasma 24 L-Carnitine Shows Beneficial Effects on Cardiac Metabolism and Function: A Hyperpolarized MRS and Langendorff Perfusion Study Dragana Savic1, Vicky Ball1, Kerstin Timm1, Lisa C. Heather1, and Damian J. Tyler1 1University of Oxford, Oxford, United Kingdom L-carnitine acts as a buffer of acetyl-CoA units in the mitochondria, as well as facilitating transport of fatty acids. In addition, L-carnitine levels are decreased in the diabetic heart. The purpose of this study was to investigate the effect of L-carnitine supplementation on cardiac function and metabolism in the diabetic rat heart. We show that daily injections of L-carnitine can alter cardiac metabolism in the in-vivo diabetic rat heart, and can improve functional recovery as well as fatty acid oxidation rates post ischemia. Such studies allow a better understanding of the interactions between metabolism and function in the diabetic heart and may provide new insight into novel therapeutics.

 997 Plasma 25 MRI Cine-Tagging of Cardiac-Induced Motion: Diagnostic Performance for Noninvasive Staging of Liver Fibrosis Thierry Lefebvre1, Léonie Petitclerc1,2,3, Laurent Bilodeau1,3, Giada Sebastiani4, Hélène Castel5, Claire Wartelle-Bladou5, Bich Ngoc Nguyen6,7, Guillaume Gilbert3,8, and An Tang1,3 1Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada, 2Leiden University Medical Centre (LUMC), Leiden, Netherlands, 3Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montreal, QC, Canada, 4Department of Medicine, Division of Gastroenterology, McGill University Health Centre (MUHC), Montreal, QC, Canada, 5Department of Gastroentology and Hepatology, Université de Montréal, Montreal, QC, Canada, 6Department of Pathology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada, 7Department of Pathology and Cellular Biology, Université de Montréal, Montreal, QC, Canada, 8MR Clinical Science, Philips Healthcare Canada, Markham, ON, Canada Elastography techniques for staging liver fibrosis assess the right liver and require additional hardware. MRI cine-tagging evaluates the strain of liver tissue and shows promise for staging liver fibrosis without additional hardware. It can be performed routinely during MRI examinations. Strain showed high correlation with fibrosis stages (ρ = -0.60, P < 0.001). AUC was 0.78 to distinguish fibrosis stages F0 vs. ≥ F1, 0.78 for ≤ F1 vs. ≥ F2, 0.87 for ≤ F2 vs. ≥ F3, and 0.87 for ≤ F3 vs. F4. Larger studies in cohorts with specific liver disease are required to validate this technique.

 998 Plasma 26 Improved Speed and Image Quality for Imaging of Liver Lesions with Auto-calibrated Wave Encoded Variable Density Single-Shot Fast Spin Echo. Jamil Shaikh1, Feiyu S. Chen2, Valentina S. Taviani3, Kim Nhien Vu1, and Shreyas S. Vasanawala1 1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering and Radiology, Stanford University, Stanford, CA, United States, 3Global MR Applications and Workflow, GE Healthcare, Menlo Park, CA, United States Abdominal T2-weighted imaging is conventionally lengthy, but single shot approaches significantly improve current acquisition times. For single shot fast spin echo (SSFSE), axial imaging speed and sharpness are constrained by limited parallel imaging acceleration.  Here, SSFSE technique with wave encoding and variable-density sampling (wSSFSE) was developed to enable higher accelerations and improve overall image quality. The purpose of this study is to assess image quality, delineation of anatomical structures, lesion conspicuity, and speed improvements with wSSFSE.

 999 Plasma 27 A Fully Convolutional Neural Network for 3D Volumetric Liver Lesion Segmentation Sean Sall1, Anitha Krishnan1, Jesse Lieman-Sifry1, Felix Lau1, Matthieu Le1, Matt DiDonato1, Albert Hsiao2, Claude Sirlin2, John Axerio-Cilies1, and Daniel Golden1 1Arterys, San Francisco, CA, United States, 2Radiology, UC San Diego Health, La Jolla, CA, United States We present an automated approach to liver lesion segmentation in abdominal MRI scans. We use a 3D fully convolutional neural network to segment liver lesions; segmentations are then used to estimate longest linear diameter (LLD) and volume. We show that the median LLD error is 2.01 mm and that these estimates are within limits of clinically usability as part of a semi or fully-automated workflow.  Automating lesion segmentation may pave the way for tracking lesion volume and tumor burden as well as treatment response.

 1000 Plasma 28 High spatial and temporal free breathing T1 contrast enhanced imaging using a novel 4D variable density, elliptical centric radial stack-of-stars sharing approach Gabriele M. Beck1, Suthambhara Nagaraj2, Joao Silva Canaveira Tourais3, Jan Hendrik Wuelbern4, and Johannes M. Peeters1 1Philips Healthcare, Best, Netherlands, 2Philips Healthcare, Bangalore, India, 3Technical University Eindhoven, Eindhoven, Netherlands, 4Philips Research Europe, Hamburg, Germany Non-Cartesian acquisitions combined with parallel imaging and compressed sensing have been proposed for high spatial and temporal resolution free breathing motion robust 4D contrast enhanced applications. While these approaches provide substantial reduction of contrast blurring and motion robustness, the sampling in itself may still provide limitations to capture the temporal image content. Our approach focuses on the optimization of the 4D sampling strategy with a unique 4D variable density, elliptical-centric radial stack of stars sharing approach. This approach reduces not only the minimum scan time of the 4D scan but also provide possibilties to optimally adjust and capture temporal information like motion and contrast enhancement.

 1001 Plasma 29 Higher-Resolution Prostate Diffusion MRI with Minimized Echo Time using Eddy Current Nulled Convex Optimized Diffusion Encoding (ENCODE) Zhaohuan Zhang1,2, Kevin Moulin1, Eric Aliotta1, Sepideh Shakeri1, Sohrab A. Mirak1, Daniel B. Ennis1,2, and Holden H. Wu1,2 1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States Higher-resolution prostate DWI has the potential to improve prostate cancer diagnosis, but suffers from additional SNR reduction due to increased TE at longer EPI readouts for current diffusion encoding schemes. In this work, we evaluated the newly proposed Eddy Current Nulled Convex Optimized Diffusion Encoding to achieve eddy-current-free diffusion encoding with minimized TE for prostate diffusion MRI using standard and higher-resolution protocols. The ENCODE higher-resolution protocol achieves higher scores for image sharpness and contrast compared to standard-resolution prostate DWI.

 1002 Plasma 30 Evaluating the Accuracy of Multi-component T2 and Fractions for Luminal Water Imaging of the Prostate using 3D GRASE with Inner Volume Selection Rachel W. Chan1, Angus Z. Lau1,2, Garry Detzler1, Vivekanandan Thayalasuthan1, Robert K. Nam3, and Masoom A. Haider1 1Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Division of Urology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada Prostate cancer can be detected using a multi-component T2 mapping technique termed luminal water imaging (LWI). The purpose of our study is: i) to accelerate the LWI acquisition by using inner volume selection (IVS) in GRASE and ii) to assess the accuracy of estimated T2 values and fractions. Simulations, phantom and in-vivo prostate experiments were performed. Results show that the estimated parameters should be interpreted with caution in noisy scenarios and at low fractions of the long T2 component. Results demonstrate that GRASE with IVS is effective for accelerating prostate LWI by at least a factor of three.

Electronic Power Pitch Poster

### Poster: Tissue Microstructure

 Power Pitch Theater A - Exhibition Hall Thursday 14:15 - 15:15

 1092 Plasma 1 Probing microstructure with different tomographic methods: Comparing dMRI and X-ray scattering-derived parameters in mouse and human brains Marios Georgiadis1,2, Dmitry S. Novikov1, Manuel Guizar-Sicairos3, Marianne Liebi3,4, Vivianne Lutz-Bueno3, Benjamin Ades-Aron1, Timothy M. Shepherd1, Aileen Schroeter2, Markus Rudin2, and Els Fieremans1 1NYU Langone Medical Center, New York, NY, United States, 2ETH Zurich, Zurich, Switzerland, 3Paul Scherrer Institute, Villigen, Switzerland, 4Chalmers University of Technology, Gothenburg, Sweden Despite MRI’s coarse resolution, diffusion MRI (dMRI) enables probing cellular microstructure. Advanced dMRI acquisition and biophysical modeling can provide microstructural metrics related to disease processes, and spherical harmonics (SH)-based orientation distribution function (ODF). Yet, these still need structural validation, and a gold standard for quantifying microstructure, particularly fiber dispersion, is missing. X-ray scattering directly probes tissue microstructure, exploiting the ~17nm myelin repeat distance, and can also represent ODF in a SH basis. Here, we show good correspondence between SH coefficients from dMRI and X-ray scattering on a mouse brain, with analysis on human samples and histological validation to follow.

 1093 Plasma 2 Diffusion-time dependence of diffusional kurtosis in the mouse brain using pulsed and oscillating gradients Manisha Aggarwal1, Kyle Martin2, Matthew Smith2, and Peter Calabresi2 1Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States Non-vanishing excess kurtosis and diffusion-time dependence are two key hallmarks of non-Gaussian or restricted water diffusion in complex brain tissue microenvironments. However, the relation between diffusional kurtosis and diffusion time in the brain remains elusive. In this work, we investigated the time-dependence of diffusional kurtosis in the mouse brain using pulsed- and oscillating-gradient (PGSE and OGSE) diffusion kurtosis imaging (DKI). The results of this work reveal unique tissue contrasts based on the time-dependence of diffusional kurtosis in both gray and white matter, with sensitivity to probe region-selective microstructural changes due to cuprizone-induced demyelination.

 1094 Plasma 3 Biophysical modeling of the gray matter: does the “stick” model hold? Jelle Veraart1, Els Fieremans1, Umesh Rudrapatna2, Derek K Jones2, and Dmitry S Novikov1 1Center for Biomedical Imaging, NYU School of Medicine, New York, NY, United States, 2CUBRIC, Cardiff University, Cardiff, United Kingdom The use of term “neurites” implies that many biophysical models of diffusion in the white matter can be applied in the gray matter as well.  However, the validity of representing dendrites as a collection of zero-radius impermeably sticks, a widely adopted representation of myelinated axons, has not been evaluated yet.  By evaluating the diffusion-weighted signal decay as a function of the $b$-value up to $b=25000\,\mathrm{ms/\mu\,m^2}$ in the living human brain, we show that a more accurate representation of the diffusion in neuronal processes in the gray matter must account for a fast proton exchange between the intra- and extra-cellular compartments.

 1095 Plasma 4 Mean lung alveolar dimension mapping with hyperpolarized 3He and 129Xe diffusion-weighted MRI Ho-Fung Chan1, Guilhem J. Collier1, and Jim M. Wild1 1Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom Lung morphometry parameters can be derived from multiple b-value hyperpolarized gas diffusion-weighted (DW)-MRI using the cylinder (CM) and stretched exponential (SEM) models. Mean alveolar diameter (LAlv) and diffusive length scale (LmD) are calculated from the CM and SEM, respectively. This work compares the parameters LAlv and LmD derived from a range of subjects with both 3He and 129Xe DW-MRI. Excellent linear agreement is observed between the LAlv and LmD parameters for both gases. This indicates these parameters are equivalently representative indices of mean alveolar diameter dimension within the range of experimental conditions considered.

 1096 Plasma 5 A compartment based model for non-invasive cell body imaging by diffusion MRI Marco Palombo1, Noam Shemesh2, Andrada Ianus1,2, Daniel C. Alexander1, and Hui Zhang1 1Computer Science Department and Centre for Medical Imaging Computing, University College London, London, United Kingdom, 2Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal This study aims to open a new window onto brain tissue microstructure by proposing a new technique to estimate cell body (namely soma) size/density non-invasively. Using Monte-Carlo simulation and data from rat brain, we show that soma’s size and density have a specific signature on the direction-averaged DW-MRI signal at high b values. Simulation shows that, at reasonably short diffusion times, soma and neurites can be approximated as two non-exchanging compartments, modelled as “sphere” and “sticks” respectively. Fitting this simple compartment model to rat data produces maps with contrast consistent with published histological data.

 1097 Plasma 6 GPU-based Monte-Carlo simulation of diffusion in astrocytes reconstructed from confocal microscopy Khieu Van NGUYEN1, Edwin Hernandez Garzon1, and Julien Valette1 1Molecular Imaging Research Center (MIRCen), Commissariat à l'Energie Atomique, Fontenay-aux-Roses, France, Fontenay aux Roses, France Here we implement a GPU-based Monte-Carlo simulation of diffusion to efficiently simulate diffusion-weighting in realistic, complex cellular structures such as astrocytes as directly derived from confocal microscopy. This opens new possibilities to better understand intracellular diffusion, validate diffusion models, and create dictionaries of intracellular diffusion signatures.

 1098 Plasma 7 What is the feasibility of estimating axonal conduction velocity from in vivo microstructural MRI? Mark Drakesmith1 and Derek K Jones1 1CUBRIC, Cardiff University, Cardiff, United Kingdom Microstructural MRI provides non-invasive measures of the microstructure of white-matter axons, including diameter and g-ratio. These can theoretically be used to infer axonal conduction velocity (CV). However, several other morphological and physiological parameters also contribute to CV, which are not accessible through MRI. Using sensitivity analysis on a comprehensive model of axon electrophysiology, we test the feasibility of modelling CV and associated uncertainty using only MRI-accessible parameters. Results show 88.5% of the variance in CV is accounted for by axon diameter and g-ratio and uncertainty due to non-imageable parameters can be easily modelled by a simple linear function.  When these measurements can be made reliably  it is feasible to obtain estimates of axonal CVs from micro-structural parameters obtained from MRI.

 1099 Plasma 8 Measurement of Intra-Axonal Water Diffusivity in Normal Human White Matter Bibek Dhital1, Marco Reisert1, Elias Kellner1, and Valerij G. Kiselev1 1Clinic for Radiology, Medical Physics, Faculty of Medicine, Medical Center - University of Freiburg, Germany, Freiburg, Germany How to measure the intra-axonal diffusion coefficient in the normal human brain? This contribution reports on such a measurement performed with minimum model assumptions. The result is about $2\,\rm\mu m^2/ms$, which constructively limits the scope of acceptable biophysical models for interpretation of diffusion MRI in terms of tissue microstructure. A side finding is the width of axonal orientation distribution in the most coherent fiber bundles, which is estimated as $19^\circ$ for the standard deviation. The core of the method is the suppression of signal from water that can move in the plane transverse to the principal fiber direction.

 1100 Plasma 9 Accurate Estimation of Microscopic Diffusion Anisotropy Using Multi-shell Double Diffusion Encoding Andrada Ianus1,2, Sune N. Jespersen3,4, Ivana Drobnjak2, 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, 3Center of Functionally Integrative Neuroscience (CFIN), Aarhus University, Aarhus, Denmark, 4Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark Advanced diffusion MRI acquisitions, such as double diffusion encoding (DDE), have been used to provide estimates of microscopic anisotropy, and the majority of DDE studies to date have acquired data at a single b-value. This study shows in simulations and ex-vivo experiments that the D(O)DE derived microscopic anisotropy metric strongly depends on the choice of b-value and proposes a multi shell estimation scheme which provides accurate measurements.

 1101 Plasma 10 From physical chemistry to human brain biology: unconstrained inversion of 5-dimensional diffusion-T2 correlation data Chantal M.W. Tax1, João P. de Almeida Martins2,3, Filip Szczepankiewicz3,4, Carl-Fredrik Westin5, Maxime Chamberland1, Daniel Topgaard2, and Derek K Jones1 1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 2Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, 3Random Walk Imaging AB, Lund, Sweden, 4Clinical sciences, Lund, Lund University, Lund, Sweden, 5Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States Studying the diffusion MRI signal as a function of more experimental parameters allows to establish correlations between different chemical and physical properties and to disentangle different compartments. Such measurements are common in the field of physical chemistry to characterise heterogeneous media, but are rendered impractical on human scanners due to hardware limitations. Here, we leverage ultra-strong gradients to acquire a 5-dimensional in-vivo human brain correlation dataset, which allows the characterisation of microstructural features through unconstrained inversion.

 1102 Plasma 11 Echo Time Dependence of Double Diffusion Encoding Measurements of Microscopic Diffusion Anisotropy Grant Yang1,2 and Jennifer McNab2 1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States In this study, double diffusion encoding (DDE) MRI measurements of microscopic fractional anisotropy (μFA) are compared at two different echo times (TE).  At longer TE, higher mean μFA values were measured in single fiber regions but not in crossing fiber regions.  Consistent with prior work on the TE dependence of fractional anisotropy (FA) the largest differences were found in regions known to be highly myelinated such as the genu of the corpus callosum.

 1103 Plasma 12 Validity extension of stimulated echoes to imaginary signals arising for double diffusion encoding of closed pores Kerstin Demberg1, Frederik Bernd Laun2, Peter Bachert1, and Tristan Anselm Kuder1 1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany We extend diffusion-weighted acquisitions using the stimulated echo acquisition mode (STEAM) to imaginary signals. In classical diffusion encoding, only real signals arise; however, for special applications of double diffusion encoding (DDE), complex signals arise, as shown here for diffusion pore imaging, a method that allows determining the shape of arbitrary closed pores filled with an NMR-detectable medium. It is shown that the phase information of complex signals is preserved under application of stimulated echoes: We show the analytically derived signal for DDE with STEAM and use Monte Carlo simulations for validation. Consequently STEAM can be employed for diffusion pore imaging.

 1104 Plasma 13 Measurement of diffusion exchange in yeast with Diffusion Exchange Spectroscopy (DEXSY) James Olav Breen-Norris1, Bernard Siow1,2, Ben Hipwell1, Thomas A. Roberts1, Mark F. Lythgoe1, Andrada Ianus3, Daniel C. Alexander3, and Simon Walker-Samuel1 1Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, United Kingdom, 2The Francis Crick Institute, London, United Kingdom, 3Centre for Medical Imaging Computing, Department of Computer Science, UCL, London, United Kingdom We demonstrate the feasibility of measuring diffusion exchange using Diffusion Exchange Spectroscopy (DEXSY), in yeast. We show data acquired from yeast suspensions with a 9.4 T Varian scanner using two different sets of DEXSY scan parameters in order to probe different diffusion lengths.

 1105 Plasma 14 Differences between treated glioblastoma and metastatic brain neoplasms revealed by non-Gaussian diffusion MRI and 18F-FET-PET Farida Grinberg1,2, Francesco D’Amore1, Ganna Blazhenets1, Ezequiel Farrher1, Karl-Josef Langen1,3,4, and N. Jon Shah1,2,4 1Institute of Neuroscience and Medicine 4, Research Centre Juelich, Juelich, Germany, 2Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany, 3Center of Integrated Oncology (CIO), Universities of Cologne and Bonn, Cologne, Germany, 4JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany Metastatic brain tumours constitute the majority of all brain tumours in adult population. Differentiation of metastases from primary brain tumours such as malignant gliomas may be a diagnostic problem and is important because of different treatment strategies. Recently, and advanced diffusion MRI method, diffusion kurtosis imaging, has been shown to provide information on tumour grade of cerebral gliomas. The purpose of this work was to study  the potential of two non-Gaussian diffusion methods, including diffusion kurtosis imaging and gamma-distribution-function imaging, in differentiation of the brain metastases and high-grade tumours.

 1106 Plasma 15 Simulation of diffusion in axons with harmonic and stochastic trajectories Jan Brabec1, Samo Lasic2, and Markus Nilsson1 1Clinical Sciences Lund, Radiology, Lund University, Lund, Sweden, 2Random Walk Imaging, Lund, Sweden We investigated effects on the diffusion MRI signal from harmonic and stochastic variations in the trajectories of thin axon-like structures. Trajectories with different types of variations exhibited characteristically different diffusion spectra (time-dependence) that, for low frequencies, bare similarities with those from restricted diffusion environments. Non-straight trajectories can thus bias axon diameter estimation. Results also indicated that observable effects of structural disorder may not be specific for extracellular diffusion but may also be found for intra-axonal spaces.

Electronic Power Pitch Poster

### Poster: Preclinical fMRI: Neuroscience & Emerging Techniques

 Power Pitch Theater B - Exhibition Hall Thursday 14:15 - 15:15

 1107 Plasma 16 Functional MRI mapping the optogenetic activation of the lateral hypothalamus driven by an MRI-guided robotic arm (MgRA) Yi Chen1,2, Pais Roldán Patricia1,2, Xuming Chen1, Michael Frosz3, and Xin Yu1,4 1Research Group of Translational Neuroimaging and Neural Control, High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Graduate Training Centre of Neuroscience, University of Tuebingen, Tuebingen, Germany, 3The Max Planck Institute for the Science of Light, Erlangen, Germany, 4The Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany A multiple degree-of-freedom robotic controlling system was developed to guide the fiber optic targeting lateral hypothalamus in the rat brain inside the high field (14.1T) MRI scanner. Optogenetic activation of the LH leads to highly reliable functional fMRI activation patterns in the LH and its projecting regions including LPO, MPA, MPOL and StA across animals. The MgRA provides a MR-compatible brain intervention strategy to target deep brain nuclei for optogenetic activation or calcium recordings with high precision and flexibility.

 1108 Plasma 17 Multi-centre resting-state fMRI comparison reveals common functional networks in the mouse brain. Joanes Grandjean1, Carola Canella2,3, Cynthia Anckaerts4, Gülebru Ayrancı5, Ludovico Coletta2,3, Daniel Gallino5, Natalia Gass6, Neele Hübner7, Silke Kreitz8, Anna E Mechling7, Sandra Strobelt8, Tong Wu9,10, Isabel Wank8, Mallar Chakravarty5,11, Wei-Tang Chang1, Dominik von Elverfeldt7, Laura-Adela Harsan12, Andreas Hess8, Georgios Keliris4, Markus Rudin13,14, Alexander Sartorius6, Tianzi Jiang9,15,16, Annemie Van der Linden4, Marleen Verhoye4, Wolfgang Weber-Fahr6, Nicole Wenderoth17, Valerio Zerbi17, and Alessandro Gozzi2 1Singapore Bioimaging Consoritum, Agency for Science, Technology and Research, Singapre, Singapore, 2Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, Rovereto, Italy, 3Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy, 4Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium, 5Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada, 6Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany, 7Department of Radiology, University of Freiburg, Freiburg, Germany, 8Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany, 9Queensland Brain Institute, The University of Queensland, Brisbane, Australia, 10Max Planck University College London Centre for Computational Psychiatry and Ageing Research, University College London, London, United Kingdom, 11Departments of Psychiatry and Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada, 12Department of Biophysics and Nuclear Medicine, University Hospital Strasbourg, Strasbourg, France, 13Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland, 14Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland, 15Institute of Automation, Chinese Academy of Sciences, Beijing, China, 16School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China, 17Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland Functional imaging studies in rodent have gained considerable momentum over the past years, holding the promise to provide a crucial translational tool to comprehend the functional signatures of the healthy and diseased brain. Mouse resting-state (rs-)fMRI has been adopted by numerous laboratories world-wide, yet, variations in equipment, animal handling and data analysis protocols render the comparison of results between studies difficult. We have carried out a multi-centre comparison comprising 12 mice rs-fMRI datasets analysed through a common pipeline and identified the major resting-state networks expressed across datasets. We provide a detailed investigation into the reproducibility and robustness of the protocols.

 1109 Plasma 18 Brain-wide functional organization of the hippocampus along the dorsoventral axis: an optogenetic fMRI study Russell W. Chan1,2,3, Eddie C. Wong1,2, Alex T. L. Leong1,2, Xunda Wang1,2, Celia M. Dong1,2, Karim E. Hallaoui1,2, and Ed X. Wu1,2 1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China, 3Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States Hippocampus plays a prominent role in central nervous system functions. It receives convergent projections and sends reciprocal divergent projections, forming an interactive cortico-hippocampal-cortical network. However, the precise brain-wide functional organization of different hippocampal activities along dorsoventral axis remains unknown. Using optogenetic fMRI, we revealed that functional organization of low frequency hippocampal activities along dorsoventral axis exhibits a gradual change from regions mainly involved in cognition and sensory processing to regions also involved in motor control and anxiety-related behavior. Additionally, hippocampal activities generally transit from long-range propagation to downstream cortical/subcortical regions to local intra-hippocampal propagation with increasing frequencies.

 1110 Plasma 19 Simultaneous fMRI and Fast-Scan Cyclic Voltammetry: Methodological Considerations and In Vivo Oxygen Measurements Lindsay Walton1, Matthew Verber2, R. Mark Wightman2, and Yen-Yu Ian Shih1 1Biomedical Research Imaging Center and Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States fMRI is based on the dogma that neuronal activity couples to local hemodynamic changes; however, exceptions to this rule exist with little explanation why. Additional neurophysiological context, such as concurrent release of vasoactive neurotransmitters, is required to discern how other underlying factors contribute to evoked hemodynamic responses. Fast-scan cyclic voltammetry (FSCV) is a minimally-invasive technique capable of detecting neurotransmitters and tissue oxygen with high temporal and spatial resolution. Here, we design a multimodal platform to perform simultaneous fMRI and FSCV, prove its feasibility in vitro, and expand its use to characterize evoked oxygen detection in vivo.

 1111 Plasma 20 Neural activity pattern(s) underlying brain interhemispheric propagation: An optogenetic fMRI study Alex T. L. Leong1,2, Xunda Wang1,2, Russell W. Chan1,2, Karim El Hallaoui1,2, and Ed X. Wu1,2 1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China The sensory system is topographically organized by highly interconnected excitatory thalamo-cortical and interhemispheric cortical-cortical projections. However, little is known at present regarding the existence of spatiotemporal neural activity pattern(s) that may dictate the propagation of activity between cortices at both hemispheres. Here, we employed a novel paired-pulse optogenetic fMRI stimulation paradigm to reveal a temporally-specific neural activity pattern initiated from the somatosensory thalamus that could drive activity propagation from the ipsilateral to contralateral cortex. We found that propagation from the ipsilateral to contralateral somatosensory cortex was facilitated when paired optogenetic stimulation pulses were spaced at 100ms, but not 50ms.

 1112 Plasma 21 Dynamic Autoregulation in Pharmacological Mouse fMRI Revisited: Abrupt Changes in Systemic Blood Pressure Elicit Significant BOLD Effects in the Murine Brain Henning Matthias Reimann1, Mihail Todiras2, Erdmann Seeliger3, Michael Bader2,4,5, Andreas Pohlmann1, and Thoralf Niendorf1,6 1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany, 2Max Delbrueck Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany, 3Institute of Vegetative Physiology, Charité – University Medicine, Berlin, Germany, 4DZHK (German Centre for Cardiovascular Research), Berlin, Germany, 5Department of Endocrinology, Charité – University Medicine, Berlin, Germany, 6Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany Pharmacological fMRI (phfMRI) is widely utilized to study the effect of specific drugs on brain circuitries and neurotransmitter systems. Some drugs induce elevations in mean arterial blood pressure (MABP) which can increase cerebral blood flow (CBF) and translate into blood oxygenation level-dependent (BOLD) effects. Dynamic autoregulation buffers abrupt changes in MABP to keep CBF relatively constant in a particular range, which was previously defined in rats as 60-120 mmHg and sanguinely applied to mice. By pharmacologically challenging and monitoring the MABP during fMRI we show that these limits of dynamic autoregulation do not apply to mice. Therefore murine phfMRI studies should be interpreted with caution.

 1113 Plasma 22 Focused ultrasound-mediated disruption of the blood-brain barrier for targeted delivery of neurotransmitters to the rat brain Nick Todd1, Yongzhi Zhang1, Lino Becerra2, David Borsook2, Margaret Livingstone3, and Nathan McDannold1 1Brigham and Women's Hospital, Boston, MA, United States, 2Boston Children's Hospital, Boston, MA, United States, 3Harvard Medical School, Boston, MA, United States Here we present a novel approach to non-invasive neuromodulation that affects neuronal activity by delivering neurotransmitter chemicals to targeted areas of the brain. This is achieved by using focused ultrasound to open the blood-brain barrier in a targeted brain region such that a systemically injected neuroactive chemical will enter into the brain parenchyma only at the intended site. We demonstrate the proof of concept in a rodent model by delivering GABA to the somatosensory cortex to suppress activation from hindpaw stimulation, and by delivering glutamate to the thalamus to enhance activation downstream in the cortex from hindpaw stimulation.

 1114 Plasma 23 Simultaneous fMRI and multispectral fiber-photometry for concurrent triple-modality measurement of genetically encoded calcium activity, CBV and BOLD Wei-Ting Zhang1, Tzu-Hao Chao1, Sung-Ho Lee1, Brittany Michelle Katz1, Esteban Oyarzabal1, Guohong Cui2, and Yen-Yu Ian Shih1 1Biomedical Research Imaging Center and Department of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Neurobiology Laboratory, National Institute of Environmental Health Sciences, NIH, RTP, NC, United States We demonstrate the experimental setup and the use of multispectral fiber-photometry during fMRI in vivo for concurrent measurements of GCaMP6f, CBV, and BOLD. The fluorescent intensity of GCaMP6f and Rhodamine B, a red fluorescent dye which represents CBV, increased during spontaneous motion in the freely moving animal. GCaMP6f, CBV, and BOLD increased when forepaw electric stimulation was given in the simultaneous fMRI and fiber-photometry. We conclude that simultaneous multispectral fiber-photometry and functional MRI is a powerful tool which has an advantage in both temporal and spatial dimensions. Rhodamine B could be a surrogate CBV indicator in the regions of interest.

 1115 Plasma 24 CBV fMRI study of the olfactory and visual processing in same mice Fuqiang Zhao1, Xiangjun Meng1, Lynn Hyde2, Sherry Lu3, Matthew E Kennedy4, Andrea K Houghton1, Jeffrey L Evelhoch1, and Catherine D. G. Hines1 1Merck & Co., Inc., West Point, PA, United States, 2Merck & Co., Inc., Rahway, NJ, United States, 3Merck & Co., Inc., South San Francisco, CA, United States, 4Merck & Co., Inc., Boston, MA, United States fMRI offers an excellent opportunity to study neural activations in the central nervous system. In this study, cerebral blood volume (CBV) fMRI with USPIO was used to measure simultaneous odorant and visual stimulation-induced neural activations in mice. Olfactory responses were observed in the olfactory bulb, anterior olfactory nucleus (AON), and piriform cortex (PC), while visual responses were observed in the lateral geniculate nuclei, visual cortex, and cingulate cortex. The neural phenomenon of “post-inhibition excitation rebound” was observed in the responses in AON and PC, and the fMRI phenomenon of “post-stimulus undershoot” was observed in the visual responses.

 1116 Plasma 25 Distinct structure-function relationships at different hierarchical levels of structural connectivity in the rat brain. Milou Straathof1, Michel R T Sinke1, Theresia J M Roelofs1,2, Erwin L A Blezer1, Oliver Schmitt3, Willem M Otte1,4, and Rick M Dijkhuizen1 1Biomedical MR Imaging and Spectroscopy group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands, 2Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands, 3Department of Anatomy, University of Rostock, Rostock, Germany, 4Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands The relationship between functional and structural connectivity strength in the brain remains uncertain. We compared high-field resting-state fMRI, diffusion-based tractography and neuronal tracer data to robustly characterize the rat connectome. Our study revealed that strong structural connectivity is not required for strong functional connectivity. We found distinct structure-function relationships at different hierarchical levels in the rat brain: functional connectivity strength correlated moderately with diffusion-based structural connectivity strength, but did not significantly correlate with neuronal tracer-based structural connectivity strength. Hereby we demonstrate the importance of examining or appraising connectivity at different hierarchical levels for reliable assessment of neural network organization.

 1117 Plasma 26 Functional connectivity under six anesthesia protocols and the awake condition in rat brain Jaakko Paasonen1, Petteri Stenroos1, Raimo A Salo1, Vesa Kiviniemi2, and Olli Gröhn1 1A.I.V. Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 2Department of Radiology, Oulu University Hospital, Oulu, Finland Most preclinical resting-state functional magnetic resonance imaging studies are performed in anesthetized animals, but the confounding effects of anesthesia on the measured functional connectivity (FC) are poorly understood. Therefore, we measured FC under six anesthesia protocols and compared the findings with data obtained from awake rats. Connectivity patterns obtained under propofol and urethane anesthesia were most similar to that observed in awake rats. FC patterns in the α-chloralose and isoflurane-medetomidine combination groups had moderate to good correspondence with that in the awake group. The FC patterns in the isoflurane and medetomidine groups differed most from that in the awake rats.

 1118 Plasma 27 Quasiperiodic Patterns in BOLD fMRI Reflect Neuromodulatory Input Anzar Abbas1, Maysam Nezafati2, Isak Thomas2, and Shella Keilholz1,2 1Neuroscience, Emory University, Atlanta, GA, United States, 2Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States The mechanisms behind spontaneous activations in the BOLD signal are not understood. Quasiperiodic patterns are reliably recurring spatiotemporal events that involve spontaneous fluctuations of brain regions. We hypothesize that quasiperiodic patterns are regulated by neuromodulatory inputs from a subcortical driver. Pharmaceutical modulation of the locus coeruleus resulted in reduction of the strength and frequency of quasiperiodic patterns in the BOLD signal. This indicates a direct relationship between the locus coeruleus and quasiperiodic patterns. These findings suggest that spontaneous activity in the brain may be arising from controlled neuromodulatory input, allowing for a clearer understanding of the mechanisms that drive it.

 1119 Plasma 28 Validation of spinal cord fMRI with LFP and spike activity in non-human primates Tung-Lin Wu1,2, Pai-Feng Yang1,3, Feng Wang1,3, Zhaoyue Shi1,2, Arabinda Mishra1,3, Ruiqi Wu1, Li Min Chen1,3, and John C Gore1,2,3 1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 2Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 3Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States Stimulus-driven and resting-state fMRI BOLD signals have previously been reported in the spinal cord to delineate its functional architecture. However, validation of these resting-state findings has yet to be performed. In this study, we compared spinal fMRI results with electrophysiology (LFP and spike activity) in non-human primates and found that 1) signals elicited by stimulation occur predominantly in the ipsilateral dorsal horn and only in the appropriate segments 2) resting-state dorsal-dorsal functional connectivity is significantly greater than that in dorsal-to-intermediate-gray-matter, and 3) resting-state functional connectivity is spatially constrained to two spinal segments.

 1120 Plasma 29 Diffusion fMRI reveals thalamo-cortical circuitry using forepaw stimulation in rats Daniel Nunes1, Andrada Ianus1,2, Cristina Chavarrias1, and Noam Shemesh1 1Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal, 2Department of Computer Science, Centre for Medical Image Computing, London, United Kingdom Diffusion fMRI (dfMRI) has been suggested as an alternative means for mapping activity more directly than its BOLD fMRI counterpart. However, it remains unclear whether dfMRI can deliver information not revealed by BOLD. Here, isotropic diffusion encoding dfMRI was used for mapping activity elicited by electrical forepaw stimulation. Data-driven analysis revealed that active voxels are localized within functionally distinct cortical units in dfMRI, while BOLD maps only evidenced widespread signals in the primary somatosensory cortex. Furthermore, dfMRI extracted the expected thalamocortical brain circuitry whereas BOLD fMRI did not, suggesting a potential role for dfMRI in direct detection of activity.

 1121 Plasma 30 Orthonasal versus retronasal glomerular activity in rat olfactory bulb by fMRI Basavaraju G Sanganahalli1,2,3, Garth J Thompson1,2, Peter Herman1,2,3, Gordon M Shepherd4, Justus V Verhagen5, and Fahmeed Hyder1,2,3,6 1Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States, 2Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, United States, 3Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, United States, 4Neuroscience, Yale University, New Haven, CT, United States, 5The John B. Pierce Laboratory, Yale University, New Haven, CT, United States, 6Biomedical Engineering, Yale University, New Haven, CT, United States Animals perceive their olfactory environment not only from odors originating in the external world (orthonasal route), but also from odors released in the oral cavity while eating food (retronasal route). We delivered odorants via the orthonasal and retronasal routes and measured whole olfactory bulb (OB) glomerular activity responses by fMRI. Our fMRI BOLD activation maps from the whole OB revealed gross spatial activation patterns that are largely independent of stimulus route, except for lower efficacy of retronasal stimuli as compared to orthonasal stimuli. This different encoding likely alters the odor perception for food vs. smelling.