Diffusion-tensor imaging implicates prefrontal axonal injury in executive function impairment following very mild traumatic brain injury.
OBJECTIVE
To determine whether frontal white matter diffusion abnormalities can help predict acute executive function impairment after mild traumatic brain injury (mTBI).


METHODS
This study had institutional review board approval, included written informed consent, and complied with HIPAA. Diffusion-tensor imaging and standardized neuropsychologic assessments were performed in 20 patients with mTBI within 2 weeks of injury and 20 matched control subjects. Fractional anisotropy (FA) and mean diffusivity (MD) images (imaging parameters: 3.0 T, 25 directions, b = 1000 sec/mm(2)) were compared by using whole-brain voxelwise analysis. Spearman correlation analyses were performed to evaluate associations between diffusion measures and executive function.


RESULTS
Multiple clusters of lower frontal white matter FA, including the dorsolateral prefrontal cortex (DLPFC), were present in patients (P < .005), with several clusters also demonstrating higher MD (P < .005). Patients performed worse on tests of executive function. Lower DLPFC FA was significantly correlated with worse executive function performance in patients (P < .05).


CONCLUSIONS
Impaired executive function following mTBI is associated with axonal injury involving the DLPFC.
Lipton
Michael L
ML
Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA. mlipton@aecom.yu.edu
Gulko
Edwin
E
Zimmerman
Molly E
ME
Friedman
Benjamin W
BW
Kim
Mimi
M
Gellella
Erik
E
Gold
Tamar
T
Shifteh
Keivan
K
Ardekani
Babak A
BA
Branch
Craig A
CA
D000058:Accidental Falls; D000063:Accidents, Traffic; D000328:Adult; D016880:Anisotropy; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000473:pathology*; D020833:Diffuse Axonal Injury / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000293:injuries*