Use of diffusion-tensor imaging in traumatic spinal cord injury to identify concomitant traumatic brain injury.

OBJECTIVE: To characterize and differentiate cerebral white matter (WM) changes related selectively to traumatic brain injury (TBI) or spinal cord injury (SCI) in patients with SCIs in order to improve diagnostic accuracy of TBI in people with SCI.

DESIGN: Diffusion-tensor imaging (DTI)-derived fractional anisotropy (FA) data in WM tracts were compared between a healthy control and 2 patient groups. Between-subject comparisons of FA were performed using region of interest (ROI) analysis and tract-based spatial statistics.

SETTING: A large, urban inpatient SCI program.

PARTICIPANTS: Three groups: SCI and concomitant TBI (SCI with TBI, n=7); SCI without TBI (SCI only, n=15); and healthy control subjects (n=12).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURE: FA was used as a measure of cerebral WM integrity.

RESULTS: ROI analyses showed reduced FA in the genu and splenium of the corpus callosum and forceps minor in patients with SCI with TBI compared with both healthy controls and patients with SCI only. ROI analyses did not show evidence of FA differences in patients with SCI only compared with controls. Tract-based spatial statistics did not demonstrate between-group differences in FA.

CONCLUSIONS: DTI is a sensitive tool to detect TBI-related WM damage in patients with SCI who have suffered concomitant TBI. No WM abnormalities on DTI could be attributed to SCI alone, although this finding should be further explored in future studies. Therefore, DTI may be a valuable tool to identify TBI in the SCI population. Further research to produce normative FA values is needed to allow identification of TBI in individual patients with SCI.