Diffusion-weighted imaging of the kidneys and its relationship with residual renal function in continuous ambulatory peritoneal dialysis patients.

Abstract

The objective of our study was to prospectively evaluate renal diffusion as shown by diffusion-weighted imaging (DWI) and its relationship with the residual renal function (RRF) in continuous ambulatory peritoneal dialysis (CAPD) patients. Forty CAPD patients and 40 healthy volunteers were recruited, and all underwent conventional and fat-saturated echo-planar DWI with three b values (0, 300, 600 s/mm(2)). The renal parenchymal thickness and apparent diffusion coefficients (ADCs) were measured, and both were compared between the two groups. The relationships between ADC values and clinical indexes--which included RRF, serum creatinine value, cystatin C value, and urine output--were analyzed. Compared with the renal parenchymal thickness and ADC values in control subjects, these values in CAPD patients were significantly decreased (p < 0.0001). In CAPD patients, the ADC values were positively correlated with RRF (r = 0.447, p = 0.004). A mild linear correlation was also found between the ADC values and cystatin C value (r = -0.352, p = 0.026). The renal diffusion function as shown by DWI is impaired in CAPD patients and correlates with RRF.