Correlation between ADC Values and Split Renal Function by Renal Isotope Scan in Assessment of Nephropathy

Background Early assessment of renal structure and function is crucial for the proper management and treatment of renal disease. DW-MRI show the Brownian motion of water molecules using the ADC values yielding information on water diffusion in the extracellular and extravascular space and capillary perfusion. Aim of the Work to study the ability of DWI in assessing and evaluating the individual renal function by correlating the ADC values calculated with split GFR obtained from dynamic renal scan among cases and healthy control group. Patients and Methods This prospective study was conducted on 30 patients and 30 control healthy group. Both MR examination and dynamic renal scan were performed on 30-case group, only MR examination was done on 30-healthy control group. DWI (b = 0, 200, 800 s/mm2) was done on 1.5T MRI unit. ADC map was calculated for every kidney. Split GFRs were measured from 99-Tcm DTPA scintigraphy. Results our study revealed that ADC values of normal control group is lower than that of case group. Cut off value of ADC, that discriminate between case and control group (using average ADC value of both kidneys), was ≤2.1 x10-3 mm2/s with Sensitivity = 87% and Specificity = 47%. We classified renal dysfunction, according to the total GFR measured from the dynamic renal scan and comparing it with the standard normalized GFR ranges according to age and sex in to 3 groups : suboptimal, decompensated and deteriorated renal dysfunction, the mean ADC values were 2.07 ± 0.21, 2.01 ± 0.13 and 1.45 ± 0.19 x10-3 mm2/s respectively. Conclusion There is a positive relationship between the ADC values and split GFR. DWI has a potential value for evaluating individual renal function, and may provide functional and morphological information at the same time.