Elevated peak width of skeletonized mean diffusivity in patients with end-stage kidney disease: evidence of diffuse white matter microstructural injury

Background Peak width of skeletonized mean diffusivity (PSMD) is a diffusion tensor imaging-based marker of diffuse white matter microstructural injury that has been associated with cerebral small vessel disease (CSVD). This study aimed to investigate whether patients with end-stage kidney disease (ESKD) exhibit altered PSMD compared with healthy controls. Methods We prospectively enrolled 38 ESKD patients and 38 age- and sex-matched healthy controls. Diffusion tensor imaging (DTI) was performed using a three-tesla MRI scanner in patients with ESKD and healthy controls. We obtained PSMD based on DTI in several steps, including preprocessing, skeletonization, application of a custom mask, and histogram analysis. We compared PSMD between the groups and performed correlation analyses between PSMD and clinical factors. Results PSMD was higher in patients with ESKD than in healthy controls (2.945 ± 0.361 vs. 2.552 ± 0.458 × 10 −4 mm 2 /s, p  r  = 0.370, p  = 0.022). In exploratory subgroup analyses, no statistically significant differences in PSMD were observed according to dialysis modality or the presence of diabetes mellitus. Conclusion We demonstrated that patients with ESKD exhibited higher PSMD than healthy controls, suggesting diffuse white matter microstructural injury that may be related to CSVD. PSMD may be a useful imaging marker for characterizing diffuse white matter abnormalities in this population, although further studies incorporating conventional CSVD markers, vascular risk–matched controls, and clinical outcome measures are warranted.