title: Long-term white matter changes after severe traumatic brain injury: a 5-year prospective cohort.
abstract: OBJECTIVE
  Extensive white matter damage has been documented in patients with severe traumatic brain injury, yet how this damage evolves in the long term is not well understood. We used DTI to study white matter changes at 5 years after traumatic brain injury.
  
  
  METHODS
  There were 8 healthy control participants and 13 patients with severe traumatic brain injury who were enrolled in a prospective observational study, which included clinical assessment and brain MR imaging in the acute setting (< 6 weeks) and 2 years and 5 years after injury. Only subjects with mild to moderate disability or no disability at 1 year were included in this analysis. DTI parameters were measured in 20 different brain regions and were normalized to values obtained in an age-matched control group.
  
  
  RESULTS
  In the acute setting, fractional anisotropy was significantly lower in the genu and body of the corpus callosum and in the bilateral corona radiata in patients compared with control participants, whereas radial diffusivity was significantly (P < .05) higher in these tracts. At 2 years, fractional anisotropy in these tracts had further decreased and radial diffusivity had increased. No significant changes were detected between 2 and 5 years after injury. The baseline radial diffusivity and fractional anisotropy values in the anterior aspect of the brain stem, genu and body of the corpus callosum, and the right and left corona radiata were significantly (P < .05) associated with neurocognitive sequelae (including amnesia, aphasia, and dyspraxia) at year 5.
  
  
  CONCLUSIONS
  DTI changes in major white matter tracts persist up to 5 years after severe traumatic brain injury and are most pronounced in the corpus callosum and corona radiata. Limited structural change is noted in the interval between 2 and 5 years.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: J
authors.initials: J
authors.lastname: Dinkel
authors.forename: A
authors.initials: A
authors.lastname: Drier
authors.forename: O
authors.initials: O
authors.lastname: Khalilzadeh
authors.forename: V
authors.initials: V
authors.lastname: Perlbarg
authors.forename: V
authors.initials: V
authors.lastname: Czernecki
authors.forename: R
authors.initials: R
authors.lastname: Gupta
authors.forename: F
authors.initials: F
authors.lastname: Gomas
authors.forename: P
authors.initials: P
authors.lastname: Sanchez
authors.forename: D
authors.initials: D
authors.lastname: Dormont
authors.forename: D
authors.initials: D
authors.lastname: Galanaud
authors.forename: R D
authors.initials: RD
authors.lastname: Stevens
authors.forename: L
authors.initials: L
authors.lastname: Puybasset
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011446:Prospective Studies; D015599:Trauma Severity Indices; D055815:Young Adult