NONINVASIVE MEASUREMENT OF RENAL HEMODYNAMIC FUNCTIONS USING GADOLINIUM-ENHANCED MAGNETIC-RESONANCE-IMAGING

A technique for the assessment of single kidney hemodynamic functions utilizing a novel MR pulse sequence in conjunction with MR contrast ma terial administration scribed. Renal extraction fraction (EF) is deriv ed measuring the concentration of the incoming contrast agent in the r enal artery and the outgoing concentration in the renal vein. The glom erular filtration rate (GFR) can then be determined by the product of EF and renal plasma flow. A modified inversion recovery MR pulse seque nce is used to measure the T-1 of moving blood. This pulse sequence us es a spatially nonselective inversion pulse. A series of small flip an gle detection pulses are then used to monitor the recovery of longitud inal spin magnetization in an image plane intersecting the renal vesse ls. The recovery rate is measured in each vessel and the T-1 of blood determined. These T-1 measurements are then used to determine the rati o of contrast concentration in the renal arteries and veins. Blood flo w measurements can be obtained simultaneously with T-1 measurements by inserting flow-encoding magnetic field gradients into the pulse seque nce. Preliminary results in human volunteers suggest the feasibility o f noninvasively determining hemodynamic functions with magnetic resona nce.