Time-resolved contrast-enhanced magnetic resonance angiography of the lower extremity

The aim of this prospective study was to evaluate the feasibility and clinical use of time-resolved magnetic resonance angiography (MRA) of the lower extremity compared to intraarterial digital subtraction angiography (IA-DSA). Twenty-two patients suffering from peripheral arterial occlusive disease underwent MRA and IA-DSA. MRA examinations were performed on a 1.5 T system equipped with a 4-element-array coil. The area from the distal abdominal aorta to the distal lower limb was covered by 2-3 examination steps. A T1-weighted gradient echo sequence with a temporal resolution of 7-10 s was used. Single-dose contrast material (0.1 mm/kg) was injected with a flow rate of 2 mL/s, followed by a 40 mL saline flush. Pre and post contrast images were subtracted, and the subtracted data set was postprocessed with maximum intensity projection (MIP). In all patients diagnostic images could be obtained. Problems with venous overlay or incomplete arterial filling were not present. Sensitivity for the detection of relevant stenoses (> 50%) was 96.7%, specificity was 97%. Concerning the detection of occlusions, sensitivity was 97.8%, specificity was 99.2%. Time-resolved contrast-enhanced MRA of the lower extremity is a robust procedure with high accuracy in the detection of relevant stenoses and occlusions.