MR VELOCITY MAPPING MEASUREMENT OF RENAL-ARTERY BLOOD-FLOW IN PATIENTS WITH IMPAIRED KIDNEY-FUNCTION

Renal blood flow (RBF) was measured in 9 patients with chronic impaire d kidney function using MR velocity mapping and compared to PAH cleara nce and Tc-99m-DTPA scintigraphy. An image plane suitable for flow mea surement perpendicular to the renal arteries was chosen from 2-dimensi onal MR angiography. MR velocity mapping was performed in both renal a rteries using an ECG-triggered gradient echo pulse sequence previously validated in normal volunteers. Effective renal plasma flow was calcu lated from the clearance rate of PAH during constant infusion and the split of renal function was evaluated by Tc-99m-DTPA scintigraphy. A r eduction of RBF was found, and there was a significant correlation bet ween PAH clearance multiplied by 1/(1-hematocrit) and RBF determined b y MR velocity mapping. Furthermore a significant correlation between t he distribution of renal function and the percent distribution of RBF was found.