Abstract
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.