title: Diffusion-weighted MR and apparent diffusion coefficient in the evaluation of severe brain injury.
abstract: OBJECTIVE
  To study apparent diffusion coefficient (ADC) maps in severely brain-injured patients.
  
  
  METHODS
  Four deeply comatose patients with severe brain injury were investigated with single-shot, diffusion-weighted, spin-echo echoplanar imaging. The tetrahedral diffusion gradient configuration and four iterations of a set of b-values (one time of 0 mm2/s, and four times of 1000 mm2/s) were used to create isotropic ADC maps with high signal-to-noise ratio. ADC values of gray and white matter were compared among patients and 4 reference subjects.
  
  
  RESULTS
  One patient was diagnosed as clinically brain dead after the MR examination. The patient's ADC values of gray and white matter were significantly lower than those of 3 other brain-injured patients. In addition the ADC value of white matter was significantly lower than that of gray matter.
  
  
  CONCLUSIONS
  The patient with fatal outcome shortly after MR examination differed significantly from other patients with severe brain injury but non-fatal outcome, with regard to ADC values in gray and white matter. This might indicate a prognostic value of ADC maps in the evaluation of traumatic brain injury.
authors.affiliation: Department of Neuroradiology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Nakahara
authors.forename: K
authors.initials: K
authors.lastname: Ericson
authors.forename: B M
authors.initials: BM
authors.lastname: Bellander
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology; D001926:Brain Death / Q000175:diagnosis; D001930:Brain Injuries / Q000175:diagnosis*; D020207:Coma, Post-Head Injury / Q000175:diagnosis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis