LAUSR

OBJECTIVES Non-contrast-enhanced quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) and invasive carbon dioxide (CO2) angiography are suggested as nephroprotective methods for accurate staging of peripheral arterial disease (PAD) in patients with chronic renal insufficiency (CRI). The aim of our study was to compare the image quality of both examinations. METHODS 16 consecutive PAD patients with highly impaired renal function (estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73 m²) who underwent 3 T MRA with QISS and catheter angiography with CO2 within 90 days were retrospectively included. Subjective image quality was determined using a five-point Likert scale (1, non-diagnostic; 5, excellent) and presence of significant (≥50%) stenoses of pelvic and lower extremity arteries (21-segment-model) was evaluated per-region and per-segment, respectively, in random order by four independent readers with different levels of experience. CO2 angiography of an experienced interventional radiologist was considered the standard reference method. RESULTS 167 segments were available for direct comparison with a prevalence of ≥50% stenoses of 28.1%. QISS-MRA yield was: sensitivity 91.5%, specificity 94.2%, positive predictive value 86.0% and negative predictive value 96.6%, with an intraclass correlation coeffcient (ICC) of 0.88. Median values of qualitative imaging parameters for QISS-MRA were as follows: arterial signal intensity: 4 (pelvis), 5 (thigh), 5 (calf); venous overlay: 4, 5, 5; susceptibility artifacts: 5, 5, 5; motion artifacts: 4, 5, 5; ECG-related artifacts: 5, 5, 5. ICC-values for image quality were 0.74, 0.73, 0.93, 0.69 and 0.79, respectively. Arterial opacification at CO2 angiography was rated 3, 4, 3, with an ICC of 0.63. CONCLUSIONS Image quality of non-invasive unenhanced MR angiography with QISS was preferred over invasive CO2 angiography, whilst taking into account that it offers high diagnostic performance for the detection and ruling out of PAD.