Diffusion-weighted imaging in the assessment of renal function in patients with diabetes mellitus type 2

Investigation of functional magnetic resonance (MR) imaging role in early diagnosis of diabetic nephropathy (DN) in patients with diabetes mellitus (DM) type 2, by quantification of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values.

10 healthy volunteers and 91 DM type 2 patients were scanned using diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) sequences. Patients were divided into four groups based on the estimated glomerular filtration value (eGFR). ADC and FA values, calculated in six regions of interest in each kidney (cortex and medulla), were compared to eGFR and laboratory parameters of renal function.

ADC values of DM patients were higher in the cortex than in the medulla (p < 0.01), while FA values were higher in the medulla (p = 0.284). Creatinine, cystatin C negatively correlated with ADC (cortex, medulla, parenchyma). Medullary FA were lower in DM patients and positively correlated with the eGFR (p = 0.049). Tractography showed disturbed structure in patients with impaired renal function.

Medullary FA value is a more sensitive parameter than parenchymal ADC in the early detection of renal damage in DM patients. ADC and FA values are significant in the diagnosis of DN; further research is needed for the update and refinement of the established recommendations.