title: Longitudinal changes in diffusion tensor imaging parameters of the corpus callosum between 6 and 12 months after diffuse axonal injury.
abstract: Magnetic resonance diffusion tensor imaging (MR-DTI) is used increasingly to detect diffuse axonal injury (DAI) after traumatic brain injury (TBI).
  
  
  
  To investigate changes in the diffusion tensor imaging parameters of the corpus callosum 6 and 12 months after TBI, to optimize the timing of follow-up DTI investigations. A secondary goal was to study the relationship between DTI parameters and outcome.
  
  
  
  Longitudinal prospective study.
  
  
  
  MR-DTI was performed in 15 patients with suspected DAI, 6 and 12 months post-injury. Sixteen controls were also examined. Fractional anisotropy (FA) and diffusivity (trace) in the corpus callosum were analysed. The outcome measures were the extended Glasgow Outcome Scale and the Barrow Neurological Institute Screen for Higher Cerebral Functions, assessed at 6 and 12 months.
  
  
  
  FA decreased and trace increased at 6 and 12 months compared to controls. Trace continued to increase even further between 6 and 12 months, while FA remained unchanged. Patients with the worst outcomes had lower FA and higher trace compared to patients with better outcomes.
  
  
  
  DTI parameters have not reached a stable level at 6 months after DAI, but continue to change, probably reflecting an incessant microstructural alteration of the white matter.
authors.affiliation: a Department of Neurosurgery.
authors.forename: Johan
authors.initials: J
authors.lastname: Ljungqvist
authors.affiliation: a Department of Neurosurgery.
authors.forename: Daniel
authors.initials: D
authors.lastname: Nilsson
authors.affiliation: b Department of Medical Physics and Biomedical Engineering.
authors.forename: Maria
authors.initials: M
authors.lastname: Ljungberg
authors.affiliation: c Department of Clinical Neuroscience and Rehabilitation , Sahlgrenska University Hospital , Goteborg , Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Esbjörnsson
authors.affiliation: a Department of Neurosurgery.
authors.forename: Catherine
authors.initials: C
authors.lastname: Eriksson-Ritzén
authors.affiliation: a Department of Neurosurgery.
authors.forename: Thomas
authors.initials: T
authors.lastname: Skoglund
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003337:Corpus Callosum / Q000000981:diagnostic imaging*; D020833:Diffuse Axonal Injury / Q000000981:diagnostic imaging*; D056324:Diffusion Tensor Imaging; D005260:Female; D005500:Follow-Up Studies; D015600:Glasgow Coma Scale; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D055815:Young Adult
keywords: MRI; Traumatic brain injury; axonal injury; outcome measures