Assessment of gadolinium-enhanced time-resolved three-dimensional MR angiography for evaluating renal artery stenosis

OBJECTIVE. The purpose of this study was to assess the image quality of gad olinium-enhanced time-resolved three-dimensional (3D) MR angiography and to evaluate its accuracy in revealing renal artery stenosis. SUBJECTS AND METHODS. Thirty-nine patients underwent MR angiography using a n ultrafast 3D Fourier transform spoiled gradient-recalled acquisition in t he steady state (TR/TE range, 2.6/0.7-0.8). Five seconds after administrati on of 15-20 mL gadodiamide hydrate, four or five consecutive data sets with imaging times of 7.0-7.6 sec were acquired during a single breath-hold A t iming examination was not performed. Image quality was assessed using quant itative analysis (signal-to-noise, contrast-to-noise, and venous-to-arteria l enhancement ratios) and qualitative analysis (presence of venous overlap, presence of artifacts, and degree of renal arterial enhancement). MR angio graphy depiction of the renal artery stenosis was evaluated using conventio nal angiography as the standard of reference. RESULTS. On the best arterial phase, average aortic signal-to-noise ratio ( +/- SD) was 74.5 +/- 24.4, aorta-to-inferior vena cava contrast-to-noise ra tio was 70.8 +/- 23.4, and inferior vena cava-to-aorta venous-to-arterial e nhancement ratio was 0.03 +/- 0.01. No venous overlap was seen in 35 of 39 patients. Substantial enhancement of renal arteries was seen in all patient s without any noticeable artifacts. MR angiography correctly depicted the d egree of stenosis in 44 of 47 normal arteries, 13 of 16 mildly stenotic art eries, five of five moderately stenotic arteries, three of four severely st enotic arteries, and one of one occluded artery. Sensitivity and specificit y for revealing greater than 50% stenosis was 100%. CONCLUSION. Time-resolved 3D MR angiography can provide high-quality arteri ograms. Its performance in revealing renal artery stenosis is comparable wi th that of conventional angiography.