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Abstract: FR-PO426

Hemodialysis Can Contribute to Acute Changes in Cerebral Volume and White Matter Structure

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Dacey, Madeleine Therese, Lawson Health Research Institute, London, Ontario, Canada
  • Gomes, Janice, Lawson Health Research Institute, London, Ontario, Canada
  • Poirier, Stefan E., Lawson Health Research Institute, London, Ontario, Canada
  • Anazodo, Udunna C., Lawson Health Research Institute, London, Ontario, Canada
  • McIntyre, Christopher W., Lawson Health Research Institute, London, Ontario, Canada
Background

Cerebral atrophy, silent cerebral infarcts, and leukoaraiosis are common brain injuries in chronic kidney disease (CKD) patients undergoing hemodialysis (HD), but their etiology is poorly understood. To elucidate the acute effects of HD on the brain, we used a novel system designed in-house to perform magnetic resonance (MR) imaging during HD. Diffusion tensor imaging (DTI) is an MR modality used to characterize white matter (WM) structure. Mean diffusivity (MD) is a DTI metric associated with cellularity and edema in WM. We predict that HD will induce a transient increase in MD and cerebral volume volume, potentially due to osmotic stress and edema.

Methods

12 CKD patients receiving hemodialysis ≥3 times/week underwent diffusion and T1 weighted MR scans (Siemens 3T Biograph mMR) prior to and in the last 60 minutes of HD. The MR data were processed to correct for noise, motion, and artifacts prior to tensor fitting. Spatially normalized scalar maps were compared pairwise using tract-based spatial statistics (TBSS) and a general linear model with threshold-free contrast enhancement. Cerebrospinal fluid (CSF), WM, and gray matter (GM) volumes were extracted from T1 maps in CAT12 and compared before and during HD by Wilcoxon paired t-tests (α=0.05).

Results

During dialysis, MD was elevated (p<0.05) in regions of the superior corona radiata (fig. A) and peripheral WM near the cingulate gyrus (fig. B). CSF volume decreased by an average of 50.2 ± 12.2 ml (p<0.05) while the GM volume increased by an average of 28 ± 11.1 ml (p<0.05), as shown in figure C.

Conclusion

Increased MD in conjunction with increased brain volume suggests cerebral edema, potentially caused by osmotic stresses associated with HD. Further investigations are ongoing to determine if edema contributes to the brain injury and cognitive impairment observed in HD patients.

The regions with significantly increased MD (p<0.05) during HD are shown in red in A and B. C gives the volumes of WM, GM, and CSF before and during HD.

Funding

  • Private Foundation Support