title: Diffusion-weighted imaging for the evaluation of diffuse axonal injury in closed head injury.
abstract: OBJECTIVE
  The purpose of this work was to compare diffusion-weighted imaging (DWI) with conventional MRI in the detection of shearing injuries in acute closed head injuries.
  
  
  METHODS
  Twenty-five patients (19 male, 6 female) were examined within 48 h of trauma. Conventional MRI included T2-weighted fast spin echo, fluid-attenuated inversion recovery (FLAIR), and T2*-weighted gradient echo sequences. Full tensor DWI with calculation of apparent diffusion coefficient (ADC) maps was also performed. Lesions were identified and compared on all sequences.
  
  
  RESULTS
  Four hundred twenty-seven lesions were counted by the combined use of all sequences. DWI identified 70 lesions not seen on conventional MRI. DWI identified 310 shearing injuries, followed by T2/FLAIR (n = 248) and T2* (n = 202). The majority of DWI-positive lesions showed decreased diffusion (65%).
  
  
  CONCLUSIONS
  DWI is valuable in closed head injury because it identifies additional shearing injuries not visible on T2/FLAIR or T2* sequences. Furthermore, DWI/ADC maps differentiate between lesions with decreased or increased diffusion. DWI is less sensitive than T2* imaging for detecting hemorrhagic lesions.
authors.affiliation: Department of Radiology, Neuroradiology Section, and MGH-NMR Center, Massachusetts General Hospital, Harvard Medical School, Charlestown-Boston, USA. thierry@nmr.mgh.harvard.edu
authors.forename: Thierry A G M
authors.initials: TA
authors.lastname: Huisman
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
authors.forename: Klaus
authors.initials: K
authors.lastname: Hergan
authors.forename: R Gilberto
authors.initials: RG
authors.lastname: Gonzalez
authors.forename: Pamela W
authors.initials: PW
authors.lastname: Schaefer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D020833:Diffuse Axonal Injury / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D016489:Head Injuries, Closed / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies