title: Role of diffusion-weighted magnetic resonance imaging in diffuse axonal injury.
abstract: OBJECTIVE
  To determine whether the signal changes on magnetic resonance imaging (MRI), including fluid attenuated inversion recovery (FLAIR), T2*-weighted gradient echo (GE) imaging, and diffusion-weighted imaging (DWI) in diffuse axonal injury (DAI) patients correlate with the clinical outcome.
  
  
  METHODS
  We diagnosed patients with DAI based on the following criteria: 1) a loss of consciousness from the time of injury that persisted beyond 6 h; 2) no apparent hemorrhagic contusion on computed tomography (CT); 3) the presence of white matter injury on MRI. Twenty-one DAI patients were analyzed (19 M, 2 F, mean age 34 years) with MRI (FLAIR, T2*-weighted GE imaging, and DWI).
  
  
  RESULTS
  325 abnormalities were detected by MRI within a week after injury. The T2*-weighted GE imaging was significantly more sensitive than FLAIR and DWI in diagnosing DAI. DWI detected only 32% of all lesions, but could depict additional shearing injuries not visible on either T2*-weighted GE imaging or FLAIR. The mean number of lesions in brainstem detected by DWI in the favorable group (good recovery/moderately disabled) was significantly smaller than in the unfavorable group (severely disabled/vegetative survival/death). This trend was not observed on the T2*-weighted GE imaging and FLAIR findings.
  
  
  CONCLUSIONS
  DWI cannot detect all DAI-related lesions, but is a potentially useful imaging modality for both diagnosing and assessing patients with DAI.
authors.affiliation: Department of Neurosurgery, Nagasaki University Graduate School of Medicine, Nagasaki, Japan. ezaki-nsu@umin.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Ezaki
authors.forename: K
authors.initials: K
authors.lastname: Tsutsumi
authors.forename: M
authors.initials: M
authors.lastname: Morikawa
authors.forename: I
authors.initials: I
authors.lastname: Nagata
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003937:Diagnosis, Differential; D020833:Diffuse Axonal Injury / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D016489:Head Injuries, Closed / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric