title: Reference standard space hippocampus labels according to the European Alzheimer's Disease Consortium-Alzheimer's Disease Neuroimaging Initiative harmonized protocol: Utility in automated volumetry.
abstract: BACKGROUND
  A harmonized protocol (HarP) for manual hippocampal segmentation on magnetic resonance imaging (MRI) has recently been developed by an international European Alzheimer's Disease Consortium-Alzheimer's Disease Neuroimaging Initiative project. We aimed at providing consensual certified HarP hippocampal labels in Montreal Neurological Institute (MNI) standard space to serve as reference in automated image analyses.
  
  
  METHODS
  Manual HarP tracings on the high-resolution MNI152 standard space template of four expert certified HarP tracers were combined to obtain consensual bilateral hippocampus labels. Utility and validity of these reference labels is demonstrated in a simple atlas-based morphometry approach for automated calculation of HarP-compliant hippocampal volumes within SPM software.
  
  
  RESULTS
  Individual tracings showed very high agreement among the four expert tracers (pairwise Jaccard indices 0.82-0.87). Automatically calculated hippocampal volumes were highly correlated (rL/R= 0.89/0.91) with gold standard volumes in the HarP benchmark data set (N = 135 MRIs), with a mean volume difference of 9% (standard deviation 7%).
  
  
  CONCLUSIONS
  The consensual HarP hippocampus labels in the MNI152 template can serve as a reference standard for automated image analyses involving MNI standard space normalization.
authors.affiliation: Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Mainz, Germany. Electronic address: dominik.wolf@unimedizin-mainz.de.
authors.forename: Dominik
authors.initials: D
authors.lastname: Wolf
authors.affiliation: Laboratory of Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK.
authors.forename: Martina
authors.initials: M
authors.lastname: Bocchetta
authors.affiliation: Department of Radiology, Mayo Clinic and Foundation, Rochester, MN, USA.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Preboske
authors.affiliation: Laboratory of Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; LANVIE-Laboratory of Neuroimaging of Aging, Department of Psychiatry, University of Geneva, Switzerland.
authors.forename: Marina
authors.initials: M
authors.lastname: Boccardi
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Clinical Dementia Research Group, Rostock, Germany. Electronic address: michel.grothe@dzne.de.
authors.forename: Michel J
authors.initials: MJ
authors.lastname: Grothe
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D005260:Female; D006624:Hippocampus / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards*; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000592:standards*; D008297:Male; D059906:Neuroimaging / Q000379:methods / Q000592:standards*; D009929:Organ Size; D010363:Pattern Recognition, Automated / Q000379:methods / Q000592:standards*; D012015:Reference Standards
keywords: Automated volumetry; EADC-ADNI harmonized protocol; Hippocampus; Reference standard space hippocampus labels