Figure 6:

Geometric distortion in axial spin-echo (SE) echo-planar imaging (EPI) (top row) and diffusion-prepared (bottom row) diffusion tensor images when compared with anatomic magnetization-prepared rapid acquisition gradient-echo (MPRAGE) images in same participant wearing metallic dental braces. Edges of brain structures obtained from coregistered MPRAGE images are shown in red contour lines on mean diffusion-weighted images from corresponding diffusion tensor imaging (DTI) approaches. Mismatch between red contour lines and edge of structures shown in diffusion tensor images illustrates geometric distortion artifacts (eg, in frontal area indicated by arrow). Mean Jaccard index (JI) is calculated for each slice and is listed under each image. SE EPI DTI showed significantly lower JI in each corresponding slice (P < .01).