title: Survey of protocols for the manual segmentation of the hippocampus: preparatory steps towards a joint EADC-ADNI harmonized protocol.
abstract: Manual segmentation from magnetic resonance imaging (MR) is the gold standard for evaluating hippocampal atrophy in Alzheimer's disease (AD). Nonetheless, different segmentation protocols provide up to 2.5-fold volume differences. Here we surveyed the most frequently used segmentation protocols in the AD literature as a preliminary step for international harmonization. The anatomical landmarks (anteriormost and posteriormost slices, superior, inferior, medial, and lateral borders) were identified from 12 published protocols for hippocampal manual segmentation ([Abbreviation] first author, publication year: [B] Bartzokis, 1998; [C] Convit, 1997; [dTM] deToledo-Morrell, 2004; [H] Haller, 1997; [J] Jack, 1994; [K] Killiany, 1993; [L] Lehericy, 1994; [M] Malykhin, 2007; [Pa] Pantel, 2000; [Pr] Pruessner, 2000; [S] Soininen, 1994; [W] Watson, 1992). The hippocampi of one healthy control and one AD patient taken from the 1.5T MR ADNI database were segmented by a single rater according to each protocol. The accuracy of the protocols' interpretation and translation into practice was checked with lead authors of protocols through individual interactive web conferences. Semantically harmonized landmarks and differences were then extracted, regarding: (a) the posteriormost slice, protocol [B] being the most restrictive, and [H, M, Pa, Pr, S] the most inclusive; (b) inclusion [C, dTM, J, L, M, Pr, W] or exclusion [B, H, K, Pa, S] of alveus/fimbria; (c) separation from the parahippocampal gyrus, [C] being the most restrictive, [B, dTM, H, J, Pa, S] the most inclusive. There were no substantial differences in the definition of the anteriormost slice. This survey will allow us to operationalize differences among protocols into tracing units, measure their impact on the repeatability and diagnostic accuracy of manual hippocampal segmentation, and finally develop a harmonized protocol.
authors.affiliation: LENITEM-Laboratory of Epidemiology, Neuroimaging and Telemedicine IRCCS - S. Giovanni di Dio - Fatebenefratelli Brescia, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Boccardi
authors.forename: Rossana
authors.initials: R
authors.lastname: Ganzola
authors.forename: Martina
authors.initials: M
authors.lastname: Bocchetta
authors.forename: Michela
authors.initials: M
authors.lastname: Pievani
authors.forename: Alberto
authors.initials: A
authors.lastname: Redolfi
authors.forename: George
authors.initials: G
authors.lastname: Bartzokis
authors.forename: Richard
authors.initials: R
authors.lastname: Camicioli
authors.forename: John G
authors.initials: JG
authors.lastname: Csernansky
authors.forename: Mony J
authors.initials: MJ
authors.lastname: de Leon
authors.forename: Leyla
authors.initials: L
authors.lastname: deToledo-Morrell
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Killiany
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehéricy
authors.forename: Johannes
authors.initials: J
authors.lastname: Pantel
authors.forename: Jens C
authors.initials: JC
authors.lastname: Pruessner
authors.forename: H
authors.initials: H
authors.lastname: Soininen
authors.forename: Craig
authors.initials: C
authors.lastname: Watson
authors.forename: Simon
authors.initials: S
authors.lastname: Duchesne
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Jack
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Frisoni
mesh_terms: D026683:Advisory Committees; D000465:Algorithms; D000544:Alzheimer Disease / Q000473:pathology*; D001284:Atrophy; D001931:Brain Mapping / Q000592:standards*; D006306:Health Surveys; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity