title: Correlation between degree of white matter hyperintensities and global gray matter volume decline rate.
abstract: BACKGROUND
  Whether the degree of white matter hyperintensities (WMHs) shows a significant correlation with the rate of global gray matter volume decline over a period following initial baseline measurement remains unclear. The purpose of the present study was to reveal the relationship between the degree of WMHs at baseline and the rate of global gray matter volume decline by applying a longitudinal design.
  
  
  METHODS
  Using a 6-year longitudinal design and magnetic resonance images of the brains of 160 healthy individuals aged over 50 years and living in the community, we analyzed the correlation between degree of WMHs using Fazekas scaling at baseline and rate of global gray matter volume decline 6 years later. To obtain the rate of global gray matter volume decline, we calculated global gray matter volume and intracranial volume at baseline and at follow-up using a fully automated method.
  
  
  RESULTS
  The annual percentage change in the gray matter ratio (GMR, APC(GMR)), in which GMR represents the percentage of gray matter volume in the intracranial volume, showed a significant positive correlation with the degree of deep WMHs and periventricular WMHs at baseline, after adjusting for age, gender, present history of hypertension, and diabetes mellitus.
  
  
  CONCLUSIONS
  Our results suggest that degree of WMHs at baseline predicts the rate of gray matter volume decline 6 years later and that simple visual scaling of WMHs could contribute to predicting the rate of global gray matter volume decline.
authors.affiliation: Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Aobaku, Sendai, Japan. ytaki@idac.tohoku.ac.jp
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Taki
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kinomura
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sato
authors.forename: Ryoi
authors.initials: R
authors.lastname: Goto
authors.forename: Kai
authors.initials: K
authors.lastname: Wu
authors.forename: Ryuta
authors.initials: R
authors.lastname: Kawashima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukuda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size