Diffusion tensor imaging of the renal cortex in diabetic patients: correlation with urinary and serum biomarkers

To demonstrate role of diffusion tensor imaging of the kidney in diabetic patients and to correlate renal fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the renal cortex with urinary and serum biomarkers of diabetes.

Prospective study was conducted upon 42 diabetic patients (28 males, 14 females; mean age = 33 years) and 17 age- and sex-matched volunteers. Diabetic patients were micro-normoalbuminuric (n = 27) and macroalbuminuric (n = 15). Patients and volunteers underwent diffusion tensor imaging of the kidney. The FA and ADC of the renal cortex were calculated from 3 regions of interests of both kidneys.

The mean FA and ADC of the renal cortex in diabetic patients (0.36 ± 0.10 and 1.74 ± 0.16 × 10^-3 mm²/s) was significantly different (p = 0.001) from that of volunteers (0.26 ± 0.02 and 1.88 ± 0.03 × 10^-3 mm²/s). The cut-off renal FA and ADC used to differentiate diabetic patients from volunteers were 0.28 and 1.89 × 10^-3 mm²/s with AUC of 0.791 and 0.773 and accuracy of 71% and 76%. The FA and ADC calculated in the renal cortex in patients with macroalbuminuria (0.43 ± 0.10 and 1.63 ± 0.19 × 10^-3 mm²/s) was significantly different (p = 0.001) from that of patients with micro-normoalbuminuria (0.35 ± 0.12 and 1.80 ± 0.18 × 10^-3 mm²/s). The FA and ADC of the renal cortex in diabetic patients correlated with urinary albumin (r = 0.530; p = 0.001, r = -0.421; p = 0.006), urinary NAG (r = 0.376; p = 0.014, r = -0.245; p = 0.01), urinary TGF-β1 (r = 0.287; p = 0.065, r = -0.214; p = 0.175), and serum creatinine (r = 0.381; p = 0.013, r = -0.349; p = 0.023).

The FA and ADC of the renal cortex may help in differentiation of diabetic kidney from volunteers and prediction of the presence of macroalbuminuria in diabetic patients and correlated with some of the urinary and serum biomarkers of diabetes.