Poster E119, Monday, March 26, 2:30-4:30 pm, Exhibit Hall C
Fiber Tract Asymmetry: A novel approach to assessing white matter integrity with Diffusion Tensor Imaging (DTI)
Ansgar Furst1,2, Andrei Vakhtin1,2, Miguel T. Robinson1, Dana Waltzman3, Max Wintermark2,1, Wesson J. Ashford1,2; 1Veterans Affairs Palo Alto Health Care System, 2Stanford University, 3Centers for Disease Control and Prevention
Diffusion Tensor Imaging (DTI) is widely used in neuroimaging as a proxy for white matter integrity. Fractional Anisotropy (FA) is the most commonly reported DTI measure often averaged across different regions-of-interest (ROI) or across fiber tract volumes. We introduce here a novel approach that allows for the automated segmentation of 18 major fiber tracts, bilaterally. Based on pathology observed in trauma, stroke and neurodegenerative diseases we hypothesized that cerebral structural/functional decline typically does not occur in a symmetrical fashion (i.e. lesions, infarcts and hypometabolism are not mirrored contralaterally) and therefore propose a measure of white matter health based on Fiber Tract Asymmetry (FTA). We validated FTA on a convenience sample of 170 patients (Age: M: 46.0, SD: 11.0; Gender: 17 Females) seen by the War Related Illness and Injury Study Center (WRIISC), Palo Alto. Ninety-nine (57.2 %) of these patients had sustained mild and 17 (9.8 %) moderate Traumatic Brain Injury (TBI). We entered FTA values for all patients into a Generalized Linear Model with Age and TBI severity as independent variables. Generalized Linear Model Fit Estimates (Maximum Likelihood) indicated that both Age and TBI severity significantly accounted for median FTA variance in several tracts including the Cingulum, Superior & Inferior Longitudinal Fasciculus and the Thalamic Radiation. These findings suggest that FTA captures white matter health through individual comparisons of homologous brain structures.
Topic Area: METHODS: Neuroimaging