General Aims
The overall aim of this group is to develop a candidate protocol for segmentation of hippocampal and parahippocampal subregions applicable to in vivo human imaging, which would facilitate a direct comparison between the results obtained from different labs. This is an open working group and we therefore invite anyone who is interested to join and encourage feedback on this effort.
The more input we get from various fields (anatomists, ex vivo imagers, and in vivo imagers across a range of field strengths), the better!
Given substantial differences in subfield anatomy within the hippocampal head, body, and tail, we are developing 3T segmentation protocols separately for each area. Upon completion of the 3T harmonized protocol, it will be adjusted for other applications, such as 7T structural images, which may involve adding more granular rules on top of the 3T protocol.
The Boundary Working Group itself is composed of several smaller working groups and a steering committee (David Berron, Valerie Carr, Ana Daugherty, Renaud La Joie, Rosanna Olsen, and Laura Wisse).
Contact: laura.wisse@med.lu.se
Active boundary groups
Head Group
This working group is developing segmentation rules for both the inner and outer boundaries of the hippocampal head, an incredibly complex area given substantial anatomical changes along the anterior-posterior axis of the region and inter-subject variability in hippocampal digitations. The development of segmentation rules are guided by the labeled histology produced by the histology group.
- Members: Marshall Dalton, Robin de Flores, Trevor Steve, Renaud La Joie
- Lead: Marshall Dalton
Tail Group
The Tail Group is working to develop boundary rules for both outer boundaries of the hippocampal tail. Given that the SRLM is not visible on MRI in many tail slices, it is challenging to develop boundary rules between subfields in this region. As such, this group is focusing solely on the outer boundaries of the hippocampal tail.
- Members: Robin de Flores, Nicole Gervais, Anne Maass and Jonathan Shine.
- Lead: Robin de Flores
MTL Cortex Group
The MTL Cortex Group is working to develop boundary rules for the different portions of the medial temporal lobe beyond hippocampus including the entorhinal cortex, perirhinal cortex (BA35 & BA36) and the parahippocampal gyrus. As with the hippocampus proper, the development of segmentation rules are guided by the labeled histology produced by the histology group
- Members: Jenna Adams, Tammy Tran, Hannah Baumeister, Negar Mazloum-Farzaghi, Thanh Doan, Anika Wuestefeld, Anne Maass
- Lead: Jenna Adams
Completed boundary groups
Body: Ranging Group
As a first step of harmonized protocol development, we started with the body of the hippocampus gives its relatively simple anatomy. This working group aims to develop and test specific rules to reliably determine which slices should be considered as hippocampal body using a variety of high-resolution MR images.
- Members: Daniela Jesseca  Palombo, Attila Keresztes, Robin de Florès, Joshua Lee, Lorenzo Pasquini, Elliott Johnson, Elizabeth Marie Mulligan, Meg Schlichting, and Yushan Huang
- Lead: Ana Daugherty
Body: Outer Boundary Group
This working group aimed to precisely develop and test tracing guidelines with respect to the outer boundaries of the hippocampus with surrounding structures and CSF spaces. The guidelines were modeled after the recently validated EADC-ADNI Harmonized Hippocampal Protocol (HarP) for volumetric segmentation of the whole hippocampus, and adapted to the specificities of our high-resolution images.
- Members: Robert S.C. Amaral, David Berron, Prabesh Kanel, John Pluta, and Trevor Steve
- We also thank Marina Boccardi and Martina Bocchetta, who consulted with the group regarding their experiences with HarP
- Lead: Renaud LaJoie
Body: Inner Boundary Group
This working group was created to develop and test geometric heuristic rules to identify boundaries between subfields within the hippocampal body. Notably, the protocol development process was guided by labeled histological samples provided by the histology group.
- Members: David Berron, Valerie Carr, Robin de Flores, Nikolai Malykhin, and Rosanna Olsen
- Lead: Ana Daugherty