Unenhanced Velocity-Selective MR Angiography (VS-MRA): Initial Clinical Evaluation in Patients With Peripheral Artery Disease.

Abstract

Safe and accurate imaging of the peripheral arterial system is important for diagnosis and treatment planning of patients with peripheral artery disease (PAD). To evaluate image quality and diagnostic performance of unenhanced magnetic resonance angiography (MRA) based on velocity-selective (VS) magnetization preparation (termed VS-MRA). Prospective. Thirty-one symptomatic PAD patients underwent VS-MRA. Twenty-four of them underwent clinical digital subtraction angiography (DSA) examination, 18.8 ± 5.2 days after the MR scans. 1.5T MRI that included VS-MRA (homemade research sequence) and phase-contrast flow imaging (clinical sequence). Image quality (0: nondiagnostic, 3: excellent) and stenosis severity (0: normal, 3: occlusion) of VS-MRA images were assessed independently by three reviewers. Arterial signal-to-noise-ratio (SNR) and artery-to-muscle contrast-to-noise ratio (CNR) were calculated. The sensitivity and specificity of VS-MRA were calculated for the detection of significant stenosis (>50%) with DSA as the reference standard. Interobserver agreement among the three reviewers was evaluated by using Cohen κ-statistics. The image quality score of VS-MRA was 2.7 ± 0.5 for Reader 1, 2.8 ± 0.5 for Reader 2, and 2.8 ± 0.4 for Reader 3; SNR and CNR were 37.8 ± 12.5 and 30.5 ± 11.8, respectively. Segment-based analysis revealed that VS-MRA had sensitivities of 85.3%, 74.5%, and 78.4%, respectively, for the three reviewers, and specificities of 93.5%, 96.8%, and 95.2%. The interobserver agreement for the stenosis grading was good, as demonstrated by Cohen κ values of 0.76 (Reader 1 vs. Reader 2), 0.82 (Reader 1 vs. Reader 3), and 0.79 (Reader 2 vs. Reader 3). Unenhanced VS-MRA allows clear depiction of the peripheral arteries and accurate stenosis grading, as evidenced by high image quality scores and strong agreement with DSA. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:744-751.