Noncontrast QISS MRA at 3T vs CT Angiography for Lower Extremity Peripheral Arterial Disease

This comparative diagnostic study enrolled 32 patients with suspected lower extremity peripheral arterial disease and evaluated QISS (quiescent-interval single-shot) MRA at 3T magnetic field strength compared with CTA, assessing image quality and diagnostic accuracy for stenosis detection.

QISS MRA at 3T demonstrated comparable image quality and diagnostic performance to CTA, with higher sensitivity specifically in calcified arterial segments where CTA blooming artifact degrades lumen assessment. Interobserver agreement was strong for both modalities. The noncontrast nature of QISS MRA eliminated contrast-related risk in the study population, which included patients with renal impairment.

QISS MRA’s technical advantage in calcified vessels reflects a fundamental difference between CT and MRI contrast mechanisms: CTA uses iodinated contrast and X-ray attenuation to visualize the arterial lumen, and dense calcium causes blooming artifact that obscures adjacent lumen. QISS MRA uses the MRI signal of flowing blood without contrast, making it immune to calcium artifact — directly relevant in the elderly, diabetic patients most likely to have advanced calcification and PAD.

This study complements the Varga-Szemes et al. (2017) validation in a different patient population and MRI field strength (3T vs 1.5T), providing additional evidence that noncontrast QISS MRA is a viable alternative to CTA for PAD evaluation.

We rate the evidence limited. A small comparative diagnostic study in 32 patients demonstrating that QISS MRA at 3T is a reliable alternative to CTA for lower extremity PAD evaluation, particularly in calcified vessels — confirmatory data for a useful noncontrast imaging alternative.