Fig. 1

Axial and coronal T1-weighted anatomical images and corresponding diffusion tensor (DTI) images showing the trigeminal nerve root entry zone in a single subject. The DTI image is color-coded for direction of greatest water movement. The outline of the trigeminal nerve region used for total nerve analysis is also shown in red shading on the T1-weighted anatomical image and outlined in white on DTI images. To the right is an example of the regions selected for the rostral (red), middle (yellow) and caudal (green) third of the nerve at the maximal cross-sectional area