title: Comparison of manual direct and automated indirect measurement of hippocampus using magnetic resonance imaging.
abstract: OBJECTIVE
  Objective quantification of brain structure can aid diagnosis and therapeutic monitoring in several neuropsychiatric disorders. In this study, we aimed to compare direct and indirect quantification approaches for hippocampal formation changes in patients with mild cognitive impairment and Alzheimer's disease (AD).
  
  
  METHODS
  Twenty-one healthy volunteers (mean age: 66.2), 21 patients with mild cognitive impairment (mean age: 66.6), and 10 patients with AD (mean age: 65.1) were enrolled. All subjects underwent extensive neuropsychological testing and were imaged at 1.5T (Vision, Siemens, Germany; T1w coronal TR=4 ms, Flip=13 degrees , FOV=250 mm, Matrix=256 x 256, 128 contiguous slices, 1.8mm). Direct measurement of the hippocampal formation was performed on coronal slices using a standardized protocol, while indirect temporal horn volume (THV) was calculated using a watershed algorithm-based software package (MeVis, Germany). Manual tracing took about 30 min, semi-automated measurement less than 3 min time.
  
  
  RESULTS
  Successful direct and indirect quantification was performed in all subjects. A significant volume difference was found between controls and AD patients (p<0.001) with both the manual and the semi-automated approach. Group analysis showed a slight but not significant decrease of hippocampal volume and increase in temporal horn volume (THV) for subjects with mild cognitive impairment compared to volunteers (p<0.07). A significant correlation (p<0.001) of direct and indirect measurement was found.
  
  
  CONCLUSIONS
  The presented indirect approach for hippocampus volumetry is equivalent to the direct approach and offers the advantages of observer independency, time reduction and thus usefulness for clinical routine.
authors.affiliation: Department of Radiology, German Cancer Research Center, Heidelberg, Germany. f.giesel@dkfz.de
authors.forename: Frederik L
authors.initials: FL
authors.lastname: Giesel
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Thomann
authors.forename: Horst K
authors.initials: HK
authors.lastname: Hahn
authors.forename: Maria
authors.initials: M
authors.lastname: Politi
authors.forename: Bram
authors.initials: B
authors.lastname: Stieltjes
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Weber
authors.forename: Johannes
authors.initials: J
authors.lastname: Pantel
authors.forename: I D
authors.initials: ID
authors.lastname: Wilkinson
authors.forename: Paul D
authors.initials: PD
authors.lastname: Griffiths
authors.forename: Johannes
authors.initials: J
authors.lastname: Schröder
authors.forename: Marco
authors.initials: M
authors.lastname: Essig
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000473:pathology; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009483:Neuropsychological Tests