title: Whole-brain apparent diffusion coefficient in traumatic brain injury: correlation with Glasgow Coma Scale score.
abstract: OBJECTIVE
  Patients with traumatic brain injury (TBI) and low Glasgow coma scale (GCS) scores may have severe injury associated with cellular disruption that can be studied with whole-brain apparent diffusion coefficient (ADC) histograms. We retrospectively studied this hypothesis and correlated ADC with GCS.
  
  
  METHODS
  Twenty-one patients (37.81 +/- 41.3 years) with TBI were enrolled: Group A had normal MR imaging findings but low GCS scores (n = 6). Group B had brain stem injury with low GCS scores (n = 6). Group C had cortical lesions with normal GCS scores (n = 5), and group D had cortical lesions with low GCS scores (n = 4). Eleven control subjects were enrolled (32.7 +/- 19.2 years). Whole-brain ADC maps and histograms were generated and normalized for each subject. Mean and peak ADCs were determined. A one-sided t test was performed for each parameter. Average GCS scores and corresponding peak and mean ADCs were correlated.
  
  
  RESULTS
  Peak histogram values significantly differed between controls and groups A, B, and D (P <.0019, P <.00129, and P <.0148, respectively). In groups A and D, values were significantly skewed compared with control values. Mean ADC was significantly different between the control ADC and group A (P <.013) but not group C. In each group, peak ADC and GCS score were strongly correlated (R(2) = 0.67).
  
  
  CONCLUSIONS
  Whole-brain peak ADCs and GCS scores are significantly correlated in patients with TBI. Although conventional MR images were normal, ADC independently indicated TBI and better represents the degree of neurologic dysfunction.
authors.affiliation: Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, USA.
authors.forename: Kathirkamanathan
authors.initials: K
authors.lastname: Shanmuganathan
authors.forename: Rao P
authors.initials: RP
authors.lastname: Gullapalli
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Mirvis
authors.forename: Steven
authors.initials: S
authors.lastname: Roys
authors.forename: Prasad
authors.initials: P
authors.lastname: Murthy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001924:Brain Concussion / Q000175:diagnosis / Q000503:physiopathology; D001930:Brain Injuries / Q000175:diagnosis* / Q000503:physiopathology; D001933:Brain Stem / Q000293:injuries / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000293:injuries / Q000473:pathology / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging; D045604:Extracellular Fluid / Q000502:physiology; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D012016:Reference Values; D013223:Statistics as Topic