Relationship between the renal apparent diffusion coefficient and glomerular filtration rate: Preliminary experience

Purpose: To investigate the relationship between ADC values measured by diffusion-weighted MRI (DWI) and the split glomerular filtration rate (GFR). Materials and Methods: DWI (b = 0 and 500 seconds/mm(2)) was performed with a 1.5T MR unit in 55 patients. The ADCs were calculated with ROIs positioned in the renal parenchyma, and the split GFRs were measured by Tc-99(m)-DTPA scintigraphy using Gates' method. The I 10 kidneys were divided into four groups: normal renal function (GFR 40 mL . minute(-1)), mild renal impairment (40 > GFR >= 20 mL . minute(-1)), moderate renal impairment (20 > GFR >= 10 mL . nimute(-1)), and severe renal impairment (GFR < 10 mL . minute(-1)). The renal ADCs between four groups were statistically compared by analysis of variance (ANOVA), and the relationship between ADCs and GFR was examined using Pearson's correlation test. Results: The mean renal ADCs of the four groups were 2.87 +/- 0.11, 2.55 +/- 0.17, 2.29 +/- 0.10, and 2.20 +/- 0.11 x 10(-3)mm(2)/second, respectively. There was a statistically significant difference in renal ADCs among the four groups (P < 0.001). There was a positive correlation between the ADCs and split GFR (r = 0.709). Conclusion: The ADCs were significantly lower in impaired kidneys than in normal kidneys, and there was a positive correlation between the ADCs and GFR.