Changes in Cerebral Volume and White Matter Integrity in Adults on Hemodialysis and Relationship to Cognitive Function

Abstract

<b><i>Introduction:</i></b> Patients on hemodialysis (HD) have a significant burden of cognitive impairment. Characterizing the cerebral structural changes in HD patients compared to healthy controls and evaluating the relationship of cerebral structural integrity with cognitive performance in HD patients can help clarify the pathophysiology of the cognitive impairment in HD patients. <b><i>Methods:</i></b> In this cross-sectional study, in-center HD patients ≥50 years of age underwent brain structural and diffusion MRIs and cognitive assessment using the NIH Toolbox cognition battery. The cerebral imaging measures of the HD participants were compared to imaging from age-matched controls. Gray matter volume, white matter volume, and white matter integrity determined by diffusion tensor imaging parameters (including fractional anisotropy [FA]) were measured in both cohorts to determine differences in the cerebral structure between HD participants and healthy controls. The association between cognitive performance on the NIH Toolbox cognition battery and cerebral structural integrity was evaluated using multiple linear regression models. <b><i>Results:</i></b> We compared imaging measures form 23 HD participants and 15 age-matched controls. The HD participants had decreased gray matter volumes (526.8 vs. 589.5 cm³, <i>p</i> &#x3c; 0.01) and worsened white matter integrity overall (FA values of 0.2864 vs. 0.3441, <i>p</i> &#x3c; 0.01) within major white matter tracts compared to healthy controls. Decreases in white matter integrity in the left superior longitudinal fasciculus was associated with lower executive function scores (<i>r</i>^<i>2</i> = 0.24, <i>p</i> = 0.02) and inferior longitudinal fasciculus with lower memory scores (<i>r</i> = 0.25 and <i>p</i> = 0.03 for left and <i>r</i>² = 0.21 and <i>p</i> = 0.03 for right). <b><i>Conclusions:</i></b> HD patients have a pattern of decreased white matter integrity and gray matter atrophy compared to controls. Decreases in white matter integrity were associated with decreased cognitive performance in the HD population.