Deafferentation in thalamic and pontine areas in severe traumatic brain injury

J Neuroradiol. 2015 Jul;42(4):202-11. doi: 10.1016/j.neurad.2014.03.001. Epub 2014 Jul 2.


Purpose: Severe traumatic brain injury (TBI) is characterized mainly by diffuse axonal injuries (DAI). The cortico-subcortical disconnections induced by such fiber disruption play a central role in consciousness recovery. We hypothesized that these cortico-subcortical deafferentations inferred from diffusion MRI data could differentiate between TBI patients with favorable or unfavorable (death, vegetative state, or minimally conscious state) outcome one year after injury.

Methods: Cortico-subcortical fiber density maps were derived by using probabilistic tractography from diffusion tensor imaging data acquired in 24 severe TBI patients and 9 healthy controls. These maps were compared between patients and controls as well as between patients with favorable (FO) and unfavorable (UFO) 1-year outcome to identify the thalamo-cortical and ponto-thalamo-cortical pathways involved in the maintenance of consciousness.

Results: Thalamo-cortical and ponto-thalamo-cortical fiber density was significantly lower in TBI patients than in healthy controls. Comparing FO and UFO TBI patients showed thalamo-cortical deafferentation associated with unfavorable outcome for projections from ventral posterior and intermediate thalamic nuclei to the associative frontal, sensorimotor and associative temporal cortices. Specific ponto-thalamic deafferentation in projections from the upper dorsal pons (including the reticular formation) was also associated with unfavorable outcome.

Conclusion: Fiber density of cortico-subcortical pathways as measured from diffusion MRI tractography is a relevant candidate biomarker for early prediction of one-year favorable outcome in severe TBI.

Keywords: Diffusion MRI; Pons; Thalamus; Tractography; Traumatic brain injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Diffuse Axonal Injury / pathology*
  • Diffusion Tensor Imaging / methods*
  • Female
  • Humans
  • Image Interpretation, Computer-Assisted / methods
  • Male
  • Pons / injuries*
  • Pons / pathology*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Thalamus / injuries*
  • Thalamus / pathology*
  • White Matter / injuries
  • White Matter / pathology