Poster E120, Monday, March 26, 2:30-4:30 pm, Exhibit Hall C
Fractional Anisotropy Asymmetries of White Matter Tracts in Traumatic Brain Injury
Andrei A. Vakhtin1,2, Wesson J. Ashford1,2, Miguel T. Robinson1, Dana Waltzman3, Max Wintermaker2,1, Ansgar J. Furst1,2; 1Veterans Affairs Palo Alto Health Care, 2Stanford University, 3Centers for Disease Control and Prevention
Group comparisons of white matter (WM) integrity measures between traumatic brain injury (TBI) and healthy individuals have limited implications for assessing individual patients’ scans. We examined the utility of fractional anisotropy (FA) asymmetry levels in contralateral WM tracts for detecting neurological disorders on an individual level, focusing on TBI. Diffusion tensor imaging data from 50 neurologically healthy participants (age = 46.8 +/- 10.6 yrs.), 4 mild TBI (age = 46.8 +/- 1.0 yrs.), and 4 moderate TBI (age = 47.5 +/- 1.7 yrs.) patients were subjected to automated fiber quantification, extracting 18 tracts and 100 FA values along them. A multiple sclerosis (MS; age = 63) patient was included for methodological verification due to known WM abnormalities. Patients’ asymmetry indices along contralateral WM tract pairs were z-scored using the healthy group’s variance, and assessed via peak magnitudes and tract fractions exceeding 95th percentiles of the healthy group’s distribution. The MS patient displayed aberrant asymmetry levels (z > 1.65) in segments of the thalamic radiation (17%), corticospinal tract (38%), and cingulum (19%). All TBI patients displayed varying patterns of significant FA asymmetry levels among the 9 tract pairs relative to the control group, possibly reflecting different injury mechanisms. Average peak asymmetry across tracts was consistently elevated across TBI severity (mild z = 2.14; moderate z = 2.14), and highest in the MS patient (z = 2.96). Tract-specific FA asymmetry levels have the potential to localize WM abnormalities following trauma, allowing for patient-specific inferences and targeted treatments.
Topic Area: METHODS: Neuroimaging