title: Ultra-early study of edema formation in cerebral contusion using diffusion MRI and ADC mapping.
abstract: OBJECTIVE
  Our previous studies have reported that heterogeneous mechanisms exist in early edema formation in cerebral contusion, and cytotoxic edema plays an important role within 48 hours post-trauma. It is remains unclear, when edema begins to develop following injury. In order to determine the time course of edema development, diffusion imaging and ADC (apparent diffusion co-efficient) mapping was performed in 10 patients within 24 hours post-trauma with cerebral contusion.
  
  
  METHODS
  Diffusion imaging and ADC mapping were performed employing 1.0 T echo planar MRI. ADC values were indicated as a ration relative to the values of intact brain areas.
  
  
  RESULTS
  Within 3 hours post-trauma, diffusion MRI showed no remarkable changes, and the ADC values were within normal limit (ADC ratio (=contused/normal brain) = 1.00 +/- 0.21, (mean +/- SD)). At 6 hours post-trauma, diffusion images demonstrated a low intensity core in the contusion proper and a high intensity rim in the peripheral area of contusion. The ADC value increased in the contusion proper (ADC ratio = 1.26 +/- 0.13) and decreased in the peripheral area (ADC ratio = 0.58 +/- 0.19).
  
  
  CONCLUSIONS
  These findings indicated that early cellular swelling in the peripheral area of contusion begins within 6 hours following injury. This delayed occurrence of contusion-induced cellular swelling suggests that the CBF does not decrease to ischemic level immediately following injury.
authors.affiliation: Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Maeda
authors.forename: Y
authors.initials: Y
authors.lastname: Katayama
authors.forename: T
authors.initials: T
authors.lastname: Kawamata
authors.forename: S
authors.initials: S
authors.lastname: Koyama
authors.forename: J
authors.initials: J
authors.lastname: Sasaki
mesh_terms: D001929:Brain Edema / Q000209:etiology* / Q000503:physiopathology*; D001930:Brain Injuries / Q000150:complications* / Q000175:diagnosis* / Q000378:metabolism; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D013997:Time Factors