Brain Magnetic Resonance Imaging Findings in Children and Young Adults With CKD

Background: The neuroanatomic basis for cognitive impairment in chronic kidney disease (CKD) is incompletely characterized. We performed advanced quantitative structural magnetic resonance imaging (MRI) to determine whether CKD affects brain structure and whether poorer neurocognitive performance in CKD is associated with structural brain differences. Study Design: Cross-sectional. Setting & Participants: 85 individuals with CKD stages 2 to 5 and 63 healthy controls, aged 8 to 25 years Predictors: CKD versus control, estimated glomerular filtration rate (eGFR), and kidney transplant status were analyzed as predictors of MRI findings. MRI volumes in 19 prespecified regions of gray matter (GM), white matter (WM), and cerebrospinal fluid were analyzed as predictors of neurocognitive performance (median z scores) in 7 prespecified domains. Outcomes: 19 prespecified brain regions of interest (ROIs) in 7 prespecified domains. Neurocognitive performance in 7 prespecified domains. Measurements: ROI volumes were compared in CKD versus controls using unadjusted t tests and analysis of covariance (ANCOVA). Associations of ROI volumes with eGFR and kidney transplant status in participants with CKD were analyzed using ANCOVA and linear regression. Associations of neurocognitive performance and ROI volumes were analyzed by linear regression. Results: Participants with CKD had lower whole-brain, cortical, and left parietal GM volumes than controls in unadjusted analyses, but no differences were found in adjusted analysis. In participants with CKD, lower eGFR was associated with higher WM volume in whole-brain (P = 0.05) and frontal (P = 0.04) ROIs, but differences were not significant after multiple comparisons correction. Kidney transplant recipients had lower GM volumes in whole-brain (P = 0.01; Q = 0.06), frontal (P = 0.02; Q = 0.08), and left and right parietal (P = 0.01; Q = 0.06; and P = 0.03; Q = 0.1) ROIs and higher whole-brain WM volume (P = 0.04; Q = 0.1). Neurocognitive performance in the CKD group was not associated with ROI volumes. Limitations: Unable to assess changes in brain structure and kidney function over time; analysis limited to prespecified ROIs and neurocognitive domains. Conclusions: CKD in children and young adults may be associated with lower GM and higher WM volumes in some ROIs. Differences were relatively subtle in the CKD group as a whole, but were more prominent in recipients of a kidney transplant. However, neurocognitive performance was not explained by differences in brain ROI volumes, suggesting a functional rather than structural basis for neurocognitive impairment in CKD.