Use of Diffusion Tensor Imaging to Examine Subacute White Matter Injury Progression in Moderate to Severe Traumatic Brain Injury

Objective: To demonstrate subacute progression of white matter (WM) injury (4.5mo-2.5y postinjury) in patients with traumatic brain injury using diffusion-tensor imaging. Design: Prospective, repeated-measures, within-subjects design. Setting: Inpatient neurorehabilitation program and teaching hospital MRI department. Participants: Brain-injured adults (N=13) with a mean Glasgow Coma Scale score of 7.67 +/- 4.16. Interventions: Not applicable. Main Outcome Measures: :Fractional anisotropy (FA) values were measured at 4.5 and 29 months postinjury in right and left frontal and temporal deep WM tracts and the anterior and posterior corpus callosum. Results: FA significantly decreased in frontal and temporal tracts: right frontal (.38 +/-.06 to.30 +/-.06; P<.005), left frontal (.37 +/-.06 to.32 +/-.06; P<.05), right temporal (.28 +/-.05 to .22 +/-.018; P<.005), and left temporal (.28 +/-.05 to .24 +/-.02; P<.05). No significant changes were in the corpus callosum. Conclusions: Preliminary results demonstrate progression of WM damage as evidenced by interval changes in diffusion anisotropy. Future research should examine the relationship between decreased FA and long-term clinical outcome.