title: Diffusion tensor imaging as potential biomarker of white matter injury in diffuse axonal injury.
abstract: OBJECTIVE
  Multiple biomarkers are used to quantify the severity of traumatic brain injury (TBI) and to predict outcome. Few are satisfactory. CT and conventional MR imaging underestimate injury and correlate poorly with outcome. New MR imaging techniques, including diffusion tensor imaging (DTI), can provide information about brain ultrastructure by quantifying isotropic and anisotropic water diffusion. Our objective was to determine if changes in anisotropic diffusion in TBI correlate with acute Glasgow coma scale (GCS) and/or Rankin scores at discharge.
  
  
  METHODS
  Twenty patients (15 male, five Female; mean age, 31 years) were evaluated. Apparent diffusion coefficients (ADCs) and fractional anisotropy (FA) values were measured at multiple locations and correlated with clinical scores. Results were compared with those of 15 healthy control subjects.
  
  
  RESULTS
  ADC values were significantly reduced within the splenium (Delta18%, P =.001). FA values were significantly reduced in the internal capsule (Delta14%; P <.001) and splenium (Delta16%; P =.002). FA values were significantly correlated with GCS (r = 0.65-0.74; P <.001) and Rankin (r = 0.68-0.71; P <.001) scores for the internal capsule and splenium. The correlation between FA and clinical markers was better than for the corresponding ADC values. No correlation was found between ADC of the internal capsule and GCS/Rankin scores.
  
  
  CONCLUSIONS
  DTI reveals changes in the white matter that are correlated with both acute GCS and Rankin scores at discharge. DTI may be a valuable biomarker for the severity of tissue injury and a predictor for outcome.
authors.affiliation: MGH-NMR Center, Division of Neuroradiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors.forename: Thierry A G M
authors.initials: TA
authors.lastname: Huisman
authors.forename: Lee H
authors.initials: LH
authors.lastname: Schwamm
authors.forename: Pamela W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Koroshetz
authors.forename: Neetha
authors.initials: N
authors.lastname: Shetty-Alva
authors.forename: Yelda
authors.initials: Y
authors.lastname: Ozsunar
authors.forename: Ona
authors.initials: O
authors.lastname: Wu
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
mesh_terms: D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology; D001925:Brain Damage, Chronic / Q000145:classification / Q000175:diagnosis* / Q000401:mortality; D020833:Diffuse Axonal Injury / Q000145:classification / Q000175:diagnosis* / Q000401:mortality; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015996:Survival Rate