title: Traumatic brain injury and the post-concussion syndrome: A diffusion tensor tractography study.
abstract: OBJECTIVE
  The aim of the present study is to evaluate diffusion tensor tractography (DTT) as a tool for detecting diffuse axonal injury in patients of acute, mild, and moderate traumatic brain injury (TBI), using two diffusion variables: Fractional anisotropy (FA) and mean diffusivity (MD). The correlation of these indices with the severity of post-concussive symptoms was also assessed.
  
  
  METHODS
  Nineteen patients with acute, mild, or moderate TBI and twelve age- and sex-matched healthy controls were recruited. Following Magnetic Resonance Imaging (MRI) on a 3.0-T scanner, DTT was performed using the 'fiber assignment by continuous tracking' (FACT) algorithm for fiber reconstruction. Appropriate statistical tools were used to see the difference in FA and MD values between the control and patient groups. In the latter group, the severity of post-concussive symptoms was assessed six months following trauma, using the Rivermead Postconcussion Symptoms Questionnaire (RPSQ).
  
  
  RESULTS
  The patients displayed significant reduction in FA compared to the controls (P < 0.05) in several tracts, notably the corpus callosum, fornix, bilateral uncinate fasciculus, and bilateral superior thalamic radiations. Changes in MD were statistically significant in the left uncinate, inferior longitudinal fasciculus, and left posterior thalamic radiation. A strong correlation between these indices and the RPSQ scores was observed in several white matter tracts.
  
  
  CONCLUSIONS
  Diffusion tensor imaging (DTI)-based quantitative analysis in acute, mild, and moderate TBI can identify axonal injury neuropathology, over and above that visualized on conventional MRI scans. Furthermore, the significant correlation observed between FA and MD indices and the severity of post-concussive symptoms could make it a useful predictor of the long-term outcome.
authors.affiliation: Department of NMR and Radiological Imaging, Institute of Nuclear Medicine and Allied Sciences (INMAS), New Delhi, India.
authors.forename: Maria M
authors.initials: MM
authors.lastname: D'souza
authors.affiliation: Department of NMR and Radiological Imaging, Institute of Nuclear Medicine and Allied Sciences (INMAS), New Delhi, India.
authors.forename: Richa
authors.initials: R
authors.lastname: Trivedi
authors.affiliation: Department of NMR and Radiological Imaging, Institute of Nuclear Medicine and Allied Sciences (INMAS), New Delhi, India.
authors.forename: Kavita
authors.initials: K
authors.lastname: Singh
authors.affiliation: Department of Radiodiagnosis, Government Medical College, Patiala, Punjab, India.
authors.forename: Hemal
authors.initials: H
authors.lastname: Grover
authors.affiliation: Department of Neurosurgery, Post Graduate Institute of Medical Education and Research, Ram Manohar Lohia Hospital, New Delhi, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Choudhury
authors.affiliation: Department of NMR and Radiological Imaging, Institute of Nuclear Medicine and Allied Sciences (INMAS), New Delhi, India.
authors.forename: Prabhjot
authors.initials: P
authors.lastname: Kaur
authors.affiliation: Department of NMR and Radiological Imaging, Institute of Nuclear Medicine and Allied Sciences (INMAS), New Delhi, India.
authors.forename: Pawan
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of NMR and Radiological Imaging, Institute of Nuclear Medicine and Allied Sciences (INMAS), New Delhi, India.
authors.forename: Rajendra Prashad
authors.initials: RP
authors.lastname: Tripathi
keywords: Diffusion tensor imaging; diffusion tensor tractography; mild and moderate traumatic brain injury; post-concussive symptoms; tractography