Premium
Characterization of hippocampal subfields using ex vivo MRI and histology data: Lessons for in vivo segmentation
Author(s) -
Flores Robin,
Berron David,
Ding SongLin,
Ittyerah Ranjit,
Pluta John B.,
Xie Long,
Adler Daniel H.,
Robinson John L.,
Schuck Theresa,
Trojanowski John Q.,
Grossman Murray,
Liu Weixia,
Pickup Stephen,
Das Sandhitsu R.,
Wolk David A.,
Yushkevich Paul A.,
Wisse Laura E. M.
Publication year - 2020
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.23172
Subject(s) - hippocampal formation , subiculum , coronal plane , hippocampus , anatomy , neuroscience , diffusion mri , segmentation , biology , magnetic resonance imaging , psychology , pathology , dentate gyrus , computer science , medicine , artificial intelligence , radiology
Hippocampal subfield segmentation on in vivo MRI is of great interest for cognition, aging, and disease research. Extant subfield segmentation protocols have been based on neuroanatomical references, but these references often give limited information on anatomical variability. Moreover, there is generally a mismatch between the orientation of the histological sections and the often anisotropic coronal sections on in vivo MRI. To address these issues, we provide a detailed description of hippocampal anatomy using a postmortem dataset containing nine specimens of subjects with and without dementia, which underwent a 9.4 T MRI and histological processing. Postmortem MRI matched the typical orientation of in vivo images and segmentations were generated in MRI space, based on the registered annotated histological sections. We focus on the following topics: the order of appearance of subfields, the location of subfields relative to macroanatomical features, the location of subfields in the uncus and tail and the composition of the dark band, a hypointense layer visible in T2‐weighted MRI. Our main findings are that: (a) there is a consistent order of appearance of subfields in the hippocampal head, (b) the composition of subfields is not consistent in the anterior uncus, but more consistent in the posterior uncus, (c) the dark band consists only of the CA‐stratum lacunosum moleculare, not the strata moleculare of the dentate gyrus, (d) the subiculum/CA1 border is located at the middle of the width of the hippocampus in the body in coronal plane, but moves in a medial direction from anterior to posterior, and (e) the variable location and composition of subfields in the hippocampal tail can be brought back to a body‐like appearance when reslicing the MRI scan following the curvature of the tail. Our findings and this publicly available dataset will hopefully improve anatomical accuracy of future hippocampal subfield segmentation protocols.