The Diagnostic Value of QISS MRA in Lower-Extremity Arteriosclerosis: A Comparison with CT Angiography
Gang Wu1, Tianjing Zhang2, Peter Schmitt3, and Xiaoming Li4

1Tongji Hospital, Huazhong university of science and technology, Wuhan, China, People's Republic of, 2Shanghai, China, People's Republic of, 3Erlangen, Germany, 4Wuhan, China, People's Republic of


The Diagnostic Value of QISS MRA in Lower-Extremity Arteriosclerosis: A Comparison with CT Angiography

one abstract

four figures

Purpose: To compare image quality and diagnostic value of Quiescent Interval Single Shot (QISS) sequence at 3T for the evaluation of lower-extremity arteriosclerosis relative to CT angiography. Materials and Methods: 39 consecutive patients (26 male, 13 female, age range 31-81 years, average age 60.6 years) with clinically suspected lower-extremity arteriosclerosis underwent QISS MRA and CTA. DSA correlation was available in 14 patients. With ECG-gating, saturation of imaging slice and tracking saturation of venous signal were applied after R-wave. A TI of 345 ms between slice saturation and the center of k-space allowed for inflow of non-saturated blood spins before the acquisition of a single-shot 2D image. Data acquisition of lower extremity and lower pelvis consisted of nine stations. Coronal MIP of the whole lower-extremity artery was generated by splicing the coronal MIP of each station. Two radiologists with 10 and 8 years of experience compared MRA image with CTA according to a 4-point Likert scale. They measured SNR for each MRA and CTA case, and MRA SNR was compared with CTA. Stenosis was rated in accordance with stenotic degree as follows:0-normal;1-1%~24%;2-25%~49%;3-50%~74%;4-75%~99%;5-completely occluded. Two readers in consensus rated each stenotic segment on the MIP. Kappa test was used to reveal the intra-modality agreement between MRA and CTA in stenosis rating. In a subgroup of 14 patients, DSA was available. Sensitivity and specificity of CTA and MRA in detecting obvious stenosis (≥50%) were compared, with DSA serving as reference standard. Results: Image quality of QISS MRA and CTA were rated as excellent without statistically significant differences (3.79±0.52 vs 3.87±0.41, P=0.491)(Figure 1). SNR of MRA was significantly higher than that of CTA (155.19±24.89 vs 57.30±23.90). Intramodality agreement between MRA and CTA was high for the stenosis rating (Kappa=0.831±0.018). The specificity of MRA was higher than that of CTA, not reaching statistical significance (93.67% vs 91.46%, P=0.594). The sensitivity difference between MRA and CTA was not significant (90.79% vs 91.78%, P=0.830). Conclusion: Performance of QISS in diagnosing lower-extremity arteriosclerosis is not inferior to CTA. Because QISS needs no contrast and does not apply radiation, it is a promising examination, especially for those patients with renal insufficiency.


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CTA and QISS images

intramodality agreement in stenosis rating

sensitivity comparing between QISS and CTA

specificity comparing between QISS and CTA

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)