1Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
A three-dimensional anatomical atlas of the human brainstem based on ultra-high resolution (125-255 m) DTI at 11.7T is developed. DTI contrasts in our study revealed unprecedented level of microscopic neuroanatomical details in the postmortem brainstem, comparable to histological myelin-staining. Tractography enabled reconstruction of fine fiber tracts, including interleaved fascicles of the corticospinal and transverse pontine fibers, and decussation of pyramidal tract fibers. Additionally, strong grey-white matter contrasts in ADC maps allowed precise reconstruction of grey matter nuclei. We also demonstrate mapping of the high-resolution postmortem DTI data to an in vivo whole brain atlas to construct a 3D brainstem atlas registered to the MNI stereotaxic space.