FIG. 2.

Representative control spinal cord images of T9 vertebra level obtained from DTI and DWI: diffusion anisotropy, Asd, and AI (a, b); diffusivity transverse to the white-matter tract, λ_⊥ and D_∥ (c, d); and diffusivity parallel to the fiber tract, λ_⊥ and D_⊥. (e, f ). Cerebral spinal fluid (CSF ) is clearly seen in the λ_⊥, D_⊥, λ_∥ and D_‖ maps, enabling the identification of the cord parenchyma. Regions of dorsal white matter (DWM), ventral-lateral white matter (VLWM), and gray matter (GM) are readily visualized in the anisotropy maps, as well as in all other diffusion index maps. The manually segmented ROI of GM and VLWM were used to quantify the group-averaged parameters of each region. The pixel-based whisker plots show the principal diffusion direction obtained by DTI scheme (g, with Asd background) based on the calculation of tensor eigenvectors in each pixel. Color image is available online at www.liebertonline.com/neu.