title: Establishing magnetic resonance images orientation for the EADC-ADNI manual hippocampal segmentation protocol.
abstract: OBJECTIVE
  An effort to define and validate a Harmonized Protocol for standard hippocampal segmentation is being carried out. We wished to estimate the effect of magnetic resonance image (MRI) spatial orientation on manual hippocampal segmentations to define optimal standard orientation of MRIs for hippocampal volumetry.
  
  
  METHODS
  Three expert tracers segmented twice the hippocampi of 10 ADNI subjects on MRI slices oriented perpendicular to the anterior-posterior commissure (AC-PC) line and the long hippocampal axes plane, following internationally harmonized landmarks. We computed intra and interrater reliability figures for total volumes and similarity coefficients.
  
  
  RESULTS
  Total volume reliability was similar for both orientations. Similarity coefficients were significantly higher for the AC-PC orientation (exact P = 0.002).
  
  
  CONCLUSIONS
  These data show that AC-PC orientation is slightly more reliable for manual segmentations, possibly due to better visualization of the cerebrospinal fluid spaces separating hippocampal head and amygdala. A Delphi panel of experts has used these data to decide on the optimal orientation for a Harmonized Protocol for hippocampal segmentation.
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: Martina
authors.initials: M
authors.lastname: Bocchetta
authors.forename: Liana G
authors.initials: LG
authors.lastname: Apostolova
authors.forename: Gregory
authors.initials: G
authors.lastname: Preboske
authors.forename: Nicolas
authors.initials: N
authors.lastname: Robitaille
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pasqualetti
authors.forename: Louis D
authors.initials: LD
authors.lastname: Collins
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: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D059925:Anatomic Landmarks / Q000473:pathology*; D005060:Europe; D019983:Guideline Adherence; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000592:standards*; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D015588:Observer Variation; D017410:Practice Guidelines as Topic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Hippocampus; harmonized protocol; magnetic resonance imaging; manual segmentation; standard operating procedures