title: A preliminary report of brain edema in patients with uremia at first hemodialysis: evaluation by diffusion-weighted MR imaging.
abstract: OBJECTIVE
  The dynamics of brain-water content associated with hemodialysis in patients with severe azotemia remains obscure. To investigate whether either interstitial or cytotoxic edema is responsible for dialysis disequilibrium syndrome (DDS), we used diffusion-weighted MR imaging (DWI) to measure the apparent diffusion coefficient (ADC), which is sensitive for detecting tissue water dynamics.
  
  
  METHODS
  Eight consecutive patients with end stage renal disease (ESRD) and blood urea nitrogen level of more than 100 mg/dL (160.9 +/- 53.1 mg/dL) were recruited. Conventional MR images, DWI, and clinical manifestations were obtained before and after the 1st hemodialysis. The ADC values were determined for regions of normal-appearing gray and white matter and for regions of hyperintensity of white matter on T2-weighted MR imaging.
  
  
  RESULTS
  Foci of bright areas of white matter were found in all patients on T2-weighted images. The ADC values of the patients with ESRD, in white matter and gray matter before and after hemodialysis, were greater than those of the healthy controls (P < .005). Regarding the impact of hemodialysis, the ADC of frontal lobe white matter increased significantly after hemodialysis (1.09 +/- 0.11 versus 1.03 +/- 0.11, P = .036). We did not find the specific area of brain edema reported in posterior leukoencephalopathy and the osmotic demyelination syndrome.
  
  
  CONCLUSIONS
  These results suggest that severe azotemia in end stage renal disease leads to interstitial brain edema reflected as increased ADC, and the further increased ADC reflects that edema associated with 1st hemodialysis is interstitial rather than cytotoxic in nature.
authors.affiliation: Division of Nephrology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: C L
authors.initials: CL
authors.lastname: Chen
authors.forename: P H
authors.initials: PH
authors.lastname: Lai
authors.forename: K J
authors.initials: KJ
authors.lastname: Chou
authors.forename: P T
authors.initials: PT
authors.lastname: Lee
authors.forename: H M
authors.initials: HM
authors.lastname: Chung
authors.forename: H C
authors.initials: HC
authors.lastname: Fang
mesh_terms: D000328:Adult; D000368:Aged; D053099:Azotemia / Q000175:diagnosis* / Q000628:therapy; D001921:Brain / Q000473:pathology; D001929:Brain Edema / Q000175:diagnosis*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005921:Glomerulonephritis / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009395:Nephritis, Interstitial / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D012016:Reference Values; D006435:Renal Dialysis; D012680:Sensitivity and Specificity; D014511:Uremia / Q000175:diagnosis* / Q000628:therapy