Tract-specific Mapping of Diffusion Anisotropy Index
Kuo L, Wedeen V, Tsai J, Tseng H, Weng J, Huang S, Reese T, Chen J, Tseng W
National Taiwan University
To visualize white matter tracts reconstructed from diffusion MRI, it is customary to use RGB color-coding representation to show the orientation of each track. This representation method, however, is subject to the selection of the reference coordinates, and seems redundant to visualize a 3D object. Tract-specific mapping of diffusion anisotropy (DA) index could reveal the integrity of underlying axonal fibers, and should be effective in localizing pathological changes of individual tracts. In this study, we tested this hypothesis by applying such tract representation method to patients with brain tumors, to see whether the affected tracts were infiltrated by tumors or not. Reduction of DA was found in specific locations of the tracts that passed through the tumor. In contrast, no change in DA was noted in the tracts that were merely displaced by the tumor.