title: Correlation between volume and morphological changes in the hippocampal formation in Alzheimer's disease: rounding of the outline of the hippocampal body on coronal MR images.
abstract: BACKGROUND
  The aim of this study was to investigate whether the outline of the hippocampal body becomes rounded on coronal magnetic resonance imaging (MRI) as the volume of the hippocampal formation decreases in Alzheimer's disease (AD).
  
  
  METHODS
  Institutional review board approval of the study protocol was obtained, and all subjects provided informed consent for the mini-mental state examination (MMSE) and MRI. The MRI and MMSE were prospectively performed in all 103 subjects (27 men and 76 women; mean age ± standard deviation, 77.7 ± 7.8 years) who had AD or were concerned about having of dementia and who consulted our institute over 1 year. The subjects included 14 non-dementia cases (MMSE score ≥ 28) and 89 AD cases (MMSE score ≤ 27). The total volume of the bilateral hippocampal formation (VHF) was assessed with a tracing method, and the ratio of the VHF to the intracranial volume (RVHF) and the rounding ratio (RR) of the hippocampal body (mean ratio of its short dimension to the long dimension in the bilateral hippocampal body) were calculated. Using Spearman's correlation coefficient, the correlations between RR and VHF and between RR and RVHF were assessed.
  
  
  RESULTS
  Correlation coefficients between RR and VHF and between RR and RVHF were -0.419 (p < 0.01) and -0.418 (p < 0.01), respectively. There was a significant negative correlation between RR and the volume of the hippocampal formation.
  
  
  CONCLUSIONS
  The outline of the body of the hippocampal formation becomes rounded on coronal images as its volume decreases in AD.
authors.affiliation: Department of Radiology, Ohshima Clinic, 4-1-14 Sakurada Nishi, Yamagata 990-2321, Japan. miadchi@beach.ocn.ne.jp
authors.forename: Michito
authors.initials: M
authors.lastname: Adachi
authors.forename: Shinobu
authors.initials: S
authors.lastname: Kawakatsu
authors.forename: Takamichi
authors.initials: T
authors.lastname: Sato
authors.forename: Fumi
authors.initials: F
authors.lastname: Ohshima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000544:Alzheimer Disease / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity