Quantitative comparison of 21 protocols for labeling hippocampal subfields and parahippocampal subregions in in vivo MRI: Towards a harmonized segmentation protocol

• Published in: NeuroImage (Orlando, Fla.) Vol. 111; pp. 526 - 541
• Main Authors: Yushkevich, Paul A., Amaral, Robert S.C., Augustinack, Jean C., Bender, Andrew R., Bernstein, Jeffrey D., Boccardi, Marina, Bocchetta, Martina, Burggren, Alison C., Carr, Valerie A., Chakravarty, M. Mallar, Chételat, Gaël, Daugherty, Ana M., Davachi, Lila, Ding, Song-Lin, Ekstrom, Arne, Geerlings, Mirjam I., Hassan, Abdul, Huang, Yushan, Iglesias, J. Eugenio, La Joie, Renaud, Kerchner, Geoffrey A., LaRocque, Karen F., Libby, Laura A., Malykhin, Nikolai, Mueller, Susanne G., Olsen, Rosanna K., Palombo, Daniela J., Parekh, Mansi B., Pluta, John B., Preston, Alison R., Pruessner, Jens C., Ranganath, Charan, Raz, Naftali, Schlichting, Margaret L., Schoemaker, Dorothee, Singh, Sachi, Stark, Craig E.L., Suthana, Nanthia, Tompary, Alexa, Turowski, Marta M., Van Leemput, Koen, Wagner, Anthony D., Wang, Lei, Winterburn, Julie L., Wisse, Laura E.M., Yassa, Michael A., Zeineh, Michael M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2015; Elsevier Limited
• Subjects: Adult; Biomedical materials; Boundaries; Brain research; CA1; CA2; CA3; Clinical Protocols - standards; Dentate gyrus; Entorhinal cortex; Hippocampal subfields; Hippocampus; Hippocampus - anatomy & histology; Humans; Image Processing, Computer-Assisted - methods; Image Processing, Computer-Assisted - standards; Labels; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Magnetic Resonance Imaging - standards; Manuals; Marking; Medial temporal lobe; Parahippocampal gyrus; Parahippocampal Gyrus - anatomy & histology; Perirhinal cortex; Segmentation; Subiculum; Substructures; Surgical implants; Unified protocol; Segmentation; Unified protocol; Perirhinal cortex; Parahippocampal gyrus; Medial temporal lobe; Hippocampal subfields; CA1; Dentate gyrus; CA3; Magnetic resonance imaging; CA2; Entorhinal cortex; Subiculum; Hippocampus
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2015.01.004

An increasing number of human in vivo magnetic resonance imaging (MRI) studies have focused on examining the structure and function of the subfields of the hippocampal formation (the dentate gyrus, CA fields 1−3, and the subiculum) and subregions of the parahippocampal gyrus (entorhinal, perirhinal, and parahippocampal cortices). The ability to interpret the results of such studies and to relate them to each other would be improved if a common standard existed for labeling hippocampal subfields and parahippocampal subregions. Currently, research groups label different subsets of structures and use different rules, landmarks, and cues to define their anatomical extents. This paper characterizes, both qualitatively and quantitatively, the variability in the existing manual segmentation protocols for labeling hippocampal and parahippocampal substructures in MRI, with the goal of guiding subsequent work on developing a harmonized substructure segmentation protocol. MRI scans of a single healthy adult human subject were acquired both at 3T and 7T. Representatives from 21 research groups applied their respective manual segmentation protocols to the MRI modalities of their choice. The resulting set of 21 segmentations was analyzed in a common anatomical space to quantify similarity and identify areas of agreement. The differences between the 21 protocols include the region within which segmentation is performed, the set of anatomical labels used, and the extents of specific anatomical labels. The greatest overall disagreement among the protocols is at the CA1/subiculum boundary, and disagreement across all structures is greatest in the anterior portion of the hippocampal formation relative to the body and tail. The combined examination of the 21 protocols in the same dataset suggests possible strategies towards developing a harmonized subfield segmentation protocol and facilitates comparison between published studies. •We compare 21 manual protocols for labeling hippocampal and parahippocampal subfields.•21 research groups applied their own manual segmentation protocol to the same anatomy.•Fuzzy similarity metrics used to quantify disagreement between protocols•Greatest disagreement is along the CA1/subiculum boundary, anterior hippocampus.•We propose a strategy for developing a harmonized segmentation protocol.