Standard dose Gd-DTPA dynamic MR of renal arteries.
Renal MR contrast enhancement depends on the timing of image acquisition. Limited human trials have demonstrated efficacy of renal artery stents on salvage of renal function. This study assessed the ability of dynamic gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) administration to demonstrate renal artery stenosis and renal stent patency compared to conventional angiography as the gold standard. Twenty subjects referred for renal angiography underwent 22 dynamic MR studies, including 7 with renal artery stenting (Palmaz P204 or P201, Johnson & Johnson, Sydney, Australia). All were examined with conventional angiography and after dynamic Gd-DTPA infusion. Coronal MR images of the kidneys were acquired using a GE Signa 1.5-T magnet (General Electric Medical Systems, Milwaukee, WI) (fast spoiled gradient echo [FSPGR]; TE=4.2 msec, TR=68-150 msec, flip angle=75 degrees) 0 to 600 seconds after iv bolus injection of 15 ml of Gd-DTPA during sequential breath-hold acquisitions, 13 to 32 seconds each. All 51 renal arteries (13 stenosed, 38 normal) were detected with dynamic MRI. Severity of renal artery stenosis was classified correctly with an accuracy of 98% (95% confidence interval [CI]: 85-100), yielding 98% specificity and 100% sensitivity. All nine renal stents were visualized with 100% accurate patency documentation. FSPGR MRI with bolus Gd-DTPA administration can provide adequate time and spatial resolution to demonstrate renal artery stenosis.