Cerebral white matter injury in hemodialysis patients: a cross-sectional tract-based spatial statistics and fixel-based analysis

Background End-stage renal disease (ESRD) patients with maintenance hemodialysis (HD) are often accompanied by damage to brain white matter (WM) and cognitive impairment. However, whether this damage is caused by maintenance HD or renal dysfunction is unclear. Purpose To investigate the natural progression of WM damage in patients with ESRD and the effects of HD on WM using Tract-based spatial statistics (TBSS) and fixel-based analysis (FBA). Population Eighty-one ESRD patients including 41 with no dialysis (ND) and 40 with HD and forty-six healthy controls (HCs) were enrolled in this study. Field Strength/Sequence A 3 T, single-shot spin–echo echo planar imaging (EPI). Assessment The difference of WM among the three groups (ESRD patients with HD, ESRD patients without HD and HCs) were analyzed using Tract-based spatial statistics (TBSS) and fixel-based analysis (FBA), pairwise comparison was then used to compare the difference of WM between two groups. Relationship between WM and neurocognitive assessments/clinical data were analyzed in ESRD patients with or without HD. Statistical Tests Group t-test, Chi-square Test, Kruskal–Wallis test, Mann–Whitney U-Test, Spearman’ correlation analysis, non-parametric permutation testing. Results The damage of WM in ESRD with ND and ESRD HD appeared around the lateral ventricles similarly used for TBSS while FBA reflected the changes had extended to adjacent WM in anterior hemisphere, with larger region in ESRD HD compared to ESRD ND and the brainstem was also widely affected in ESRD HD. The levels of MoCA score were lower in ESRD HD group. RD in body of corpus callosum (BCC) were negatively correlated with MoCA score in both groups. FDC in left Thalamo-prefrontal projection (T_PREFL), left and right cingulum (CGL and CGR) were positively correlated with MoCA score in both groups. Creatinine (Cr) was positively correlated with FDC in some frontal projection fibers in striatum and thalamus, CG and fronto-pontine tract (FPT), Cr was positively correlated with FD mainly in premotor projection fibers in striatum and thalamus in ESRD HD group. Cr was negatively correlated with MD and RD in regions of corona radiata ESRD ND group. Data Conclusion FBA is more sensitive in detecting differences between ESRD patients and HCs. When ESRD patients receive maintenance HD, the degree of WM damage may not be aggravated, however, the range of damaged WM can be expanded, especially in anterior hemisphere and brainstem, some of these changes in anterior hemisphere may contribute to cognitive decline.