MR angiography with parallel acquisition for assessment of the visceral arteries: comparison with conventional MR angiography and 64-detector-row computed tomography.

The purpose of the study was to retrospectively compare three-dimensional gadolinium-enhanced magnetic resonance angiography (conventional MRA) with MRA accelerated by a parallel acquisition technique (fast MRA) for the assessment of visceral arteries, using 64-detector-row computed tomography angiography (MDCTA) as the reference standard. Eighteen patients underwent fast MRA (imaging time 17 s), conventional MRA (29 s) and MDCTA of the abdomen and pelvis. Two independent readers assessed subjective image quality and the presence of arterial stenosis. Data were analysed on per-patient and per-segment bases. Fast MRA yielded better subjective image quality in all segments compared with conventional MRA (P = 0.012 for reader 1, P = 0.055 for reader 2) because of fewer motion-induced artefacts. Sensitivity and specificity of fast MRA for the detection of arterial stenosis were 100% for both readers. Sensitivity of conventional MRA was 89% for both readers, and specificity was 100% (reader 1) and 99% (reader 2). Differences in sensitivity between the two types of MRA were not significant for either reader. Interobserver agreement for the detection of arterial stenosis was excellent for fast (kappa = 1.00) and good for conventional MRA (kappa = 0.76). Thus, subjective image quality of visceral arteries remains good on fast MRA compared with conventional MRA, and the two techniques do not differ substantially in the grading of arterial stenosis, despite the markedly reduced acquisition time of fast MRA.