Absolute renal blood flow quantification by dynamic MRI and Gd-DTPA

The aim of this study was to demonstrate the feasibility of the absolute re nal blood flow quantification using MRI and injection of contrast media. Us ing a T1-weighted fast gradient sequence following an intravenous bolus inj ection of Gd-DTPA, dynamic images of the kidney were obtained in patients w ith well-functioning native kidneys (n = 7) or transplant (n = 9), with sig nificant renal artery stenosis (n = 4) and with renal failure (n = 7). Afte r signal intensity calibration, the absolute renal perfusion was equal to t he wash-in slope of the renal transit curve divided by the contrast medium concentration at the peak of the bolus in the aorta. The cortical blood flo w was 2.54 +/- 1.16 ml/min per gram in well-functioning kidneys decreasing to 1.09 +/- 0.75 ml/min per gram in case of renal artery stenosis (p = 0.04 ) and to 0.51 +/- 0.34 ml/min per gram in case of renal failure (p < 0.001) . These measurements were in agreement with previous results obtained by ot her methods. A standard MRI imaging sequence and a simple model can provide realistic quantitative data on renal perfusion. This work justifies furthe r studies to compare this model with a gold standard for renal blood flow m easurements.