[Morphologic and functional assessment of renal artery stenosis: use of combined MR angiography and MR renography--preliminary report].
PURPOSE: To assess the possibility of use of multiphase magnetic resonance angiography for simultaneous acquiring of angiographic images and curves of contrast enhancement of renal cortex, medulla and pyelocalyceal system and evaluation of quality of obtained images. MATERIAL AND METHODS: Twenty-four patients suspected of having renal artery stenosis underwent power-injection of 30 ml of Gd-DTPA (3 ml/sec). From 10 to 360 seconds after the beginning of the injection, 3D MRA sequence was performed multiple times. Acquisition time of single phase of MR examination was 7.5-8 sec (TR = 5 ms, TE = 1:6 ms, single 7 cm thick slab with 35 partitions, 164 x 512 matrix). First three phases were used to obtain angiographic images. All phases were used to obtain curves of renal cortical, medullary and pyelocaliceal enhancement. Two readers evaluated quality of MRA images, as well as, quality of enhancement curves. RESULTS: 21 of 24 MRA examinations were of good, 2 of fair and none of poor quality. Quality of enhancement curves was good in 22 cases. It was suboptimal in 2 cases because of irregular breath-holding. Maximum number of acquisitions per minute was 4-5. Eight accessory, 2 obstructed and 9 stenosed renal arteries were visualized. Renographic curves were abnormal in 8 patients. CONCLUSIONS: MRA sequence with short acquisition time enables simultaneous acquisition of angiographic images and renographic curves of good quality. With further reduction in acquisition time it may be possible to obtain more points on MR renographic curves.