Glomerular filtration rate measured using the Patlak plot technique and contrast‐enhanced dynamic MRI with different amounts of gadolinium‐DTPA

Abstract

We determined the optimum gadolinium (Gd)‐DTPA dose and time window for calculating the glomerular filtration rate (GFR) using contrast‐enhanced (CE) dynamic MRI and the Patlak plot technique. Twelve adult volunteers with healthy kidneys were included in the study. As a reference method the GFR was measured by iopromide plasma clearance. A three‐dimensional gradient‐echo (GRE) sequence with a flip angle of 50° was used for MRI. Signal was measured using a body surface coil with four elements. Each volunteer was examined on four days using 2 mL, 4 mL, 8 mL, or 16 mL of Gd‐DTPA 0.5 mmol/mL dissolved with sodium chloride (NaCl) 0.9% to a total of 60 mL. The injection rate was 1 mL/second. A Patlak plot was calculated from the kidney and aorta signals. The mean reference GFR was 133 mL/min (min‐max, 116–153 mL/min). The best correlation of GFR calculated from MRI data compared to the reference method was found in a time window 30–90 seconds after aortic signal rise using 16 mL Gd‐DTPA. Pearson's correlation coefficient was r = 0.83, and the standard deviation (SD) from the line of regression was 10.5 mL/minute. We found a significantly lower average GFR(MR) using 16 mL Gd‐DTPA compared to 4 mL and 2 mL in the late time window 60–120 seconds post aortic rise. A dose of 16 mL Gd‐DTPA was optimal for measuring GFR using dynamic MRI and the Patlak plot technique. The slope should be measured in a time window of 30–90 seconds post aortic rise. J. Magn. Reson. Imaging 2005.