7T MR DTI and Tractography of a 1-Week Postmortem Fixed Human Brainstem-Cerebellum: Novel Imaging Methodology Producing Extraordinary Images

Diffusion-tensor imaging (DTI) is routinely used to estimate the pattern, orientation, and directionality of white matter tracts in human living subjects. However, diffusion imaging of ex-vivo brain specimens is complex due to the diffusivity properties of fixed brain tissue. We developed a novel methodology for tractography of a 1-week postmortem fixed human brainstem and cerebellum specimen utilizing a deterministic fiber tracking algorithm on a 7T MR DTI diffusion scheme registered to an MNI space through landmark-based affine registration. The results showed highly detailed tractography images and agreement between left and right crossing and non-crossing fibers.