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INTRODUCTION: Diabetic patients with peripheral arterial disease (PAD) are challenging to assess. Non-contrast magnetic resonance angiography (MRA) offers a safe alternative in patients with renal impairment. The study objective is to evaluate accuracy of lower limb quiescent-interval single-shot (QISS) MRA and pedal QISS-arterial spin-labelled (ASL) MRA for detection of significant stenosis in diabetic patients with PAD. METHODS: Combined QISS and QISS-ASL MRA was performed in 32 diabetic PAD patients (20 male, 12 female; mean 69 years; 8 with critical ischaemia). Two readers assessed haemodynamically significant (>50%) stenosis and diagnostic confidence on MRA, against digital subtraction angiography (DSA) as the reference standard, with subgroup analysis of patients with severe renal impairment (n = 7). Inter-reader agreement of stenosis and diagnostic confidence were evaluated. Test-retest reproducibility was evaluated in 10 subjects who underwent repeat MRA on a different day. RESULTS: At DSA, 262/645 segments (40.6%) had haemodynamically significant stenoses. MRA accuracy was 78.1% (478/612) and 75.6% (464/614), sensitivity 64.7% (161/249) and 77.5% (193/249), and specificity 87.3% (317/363) and 74.2% (271/365) for 2 readers. MRA accuracy was 80.9% and 80.7% for readers 1 and 2, respectively, in patients with severe renal impairment. QISS MRA but not pedal QISS-ASL MRA was considered of diagnostic image quality. Inter-reader agreement was moderate for stenosis (ĸ = 0.60) and diagnostic confidence (ĸ = 0.41). Test-retest reproducibility was high (ĸ = 0.87) and moderate (ĸ = 0.54) for individual readers. CONCLUSIONS: Quiescent-interval single-shot MRA has reasonable accuracy in a diabetic PAD population with high burden of disease, providing a non-contrast option in patients with renal impairment. QISS-ASL MRA requires further optimisation to be clinically feasible.

Objective: Non-contrast magnetic resonance angiography (NC-MRA) is an attractive technique for imaging peripheral arterial disease (PAD) in diabetic patients where arterial calcification and renal impairment are common. Our purpose was to evaluate patient perception of lower limb NC-MRA and compare this perception to that of digital subtraction angiography (DSA). Materials and Methods: Thirty-one diabetic patients (18 male, 13 female, mean age=69 years) with symptomatic PAD (critical ischemia, n=10) referred for DSA were prospectively recruited, and 1.5T quiescent-interval single-shot NC-MRA was performed before DSA (intervention performed during DSA, n=23). Patients rated anxiety, pain, discomfort, willingness to repeat (Likert scale: 1 most favorable to 7 least favorable), and difficulty compared to expectations (-3 better to +3 worse). Results: Twenty-nine patients’ results were analyzed (DSA under general anesthesia, n=1; incomplete NC-MRA due to morbid obesity, n=1). NC-MRA and DSA median scores were 1 vs. 3, 1 vs. 2, 2 vs. 2, and 1 vs. 1 for anxiety, pain, discomfort, and willingness to repeat, respectively. The median score for difficulty compared to expectations was 0 (as expected) for both examinations. The anxiety and pain scores for NC-MRA were significantly lower than those for DSA (p=0.006 and p=0.001, respectively). Reasons for the less favorable NC-MRA experience included machine noise (n=3), pain from coil pressure (n=3), and claustrophobia (n=1). Conclusion: NC-MRA was well tolerated overall, and better than DSA for anxiety and pain. Although DSA is commonly required for intervention in PAD, NC-MRA may inform disease management and potentially obviate DSA where conservative management, or open surgery, are indicated. Reduced acoustic noise, lighter receiver coils, and wider scan bores may improve procedural tolerance.

Target Audience Clinicians and basic scientists with an interest in non-invasive imaging of peripheral arterial disease. Purpose Imaging diabetic patients with peripheral arterial disease (PAD) is critical for revascularization planning. PAD in diabetic patients is commonly distal, and imaging of the pedal arteries is desirable to identify potential bypass targets. Concomitant renal impairment may contribute to difficulties with conventional imaging. Quiescent interval single shot (QISS) MRA is a recently described non-contrast enhanced technique with high reported accuracy. However, it is challenging to perform in the feet, due to inhomogeneous shim and slow arterial flow, with QISS with arterial spin labeling (QISS-ASL) described to improve pedal artery visualization. The purpose of this study was to evaluate feasibility and accuracy of a combined QISS/QISS-ASL approach (cQISS-MRA) for evaluating diabetic patients with symptomatic PAD, using DSA as the reference standard. Methods 15 diabetic patients (7M, 8F, mean 72y, range 42-91y, eGFR 7-91 ml/min/1.73m2) with symptomatic PAD were prospectively recruited for cQISS-MRA at 1.5T (Siemens, Avanto) 0-36 days prior to clinically required DSA. Initially, pedal QISS-ASL MRA was performed with a 12-channel head coil. Subsequently, QISS MRA of infrarenal aorta to feet was performed with peripheral, body and spine array coils. Common parameters for QISS MRA and QISS-ASL MRA were: FA 90°, in plane resolution 1 x 1mm2, BW 658 Hz/Px, acceleration factor 2 (GRAPPA). For QISS MRA: TR/TE 3.5/1.4ms, sl 3mm (additional 1.2mm imaging through calf), FOV 400 x 260, 9 stations, 48 sl, total acquisition 432 RR intervals, quiescent interval 350ms. For QISS-ASL: TR/TE 3.7/1.6ms, quiescent interval 228ms, FOV 400 x 240, sl 1.2mm, 2 stations, 128 sl, total acquisition 256 RR intervals. DSA was performed with iodinated contrast (n=14) or carbon dioxide (CO2, n=1) with coverage determined by clinical indication. MRA and DSA images were anony