title: Expansion of corticomedullary junction high-susceptibility region (CMJ-HSR) with aging: a clue in the pathogenesis of Alzheimer's disease?
abstract: BACKGROUND
  Susceptibility-weighted imaging (SWI) microscopy on a 7.0T system demonstrated the corticomedullary junction (CMJ) to be a high-susceptibility region (HSR) in young normal subjects, suggesting that functional alteration of cortical microcirculation could be assessed with this imaging method.
  
  
  METHODS
  Focused microscopic studies were performed on the parietal association cortex in 74 normal volunteers (ages 20-79 years; 35 female, 39 male) using a SWI algorithm on a system constructed based on General Electric Signa LX (Waukesha, WI, USA), equipped with a 900-mm clear bore superconducting magnet operating at 7.0T.
  
  
  RESULTS
  There was a clear-cut reduction in the thickness of the normal-appearing cortex (cortex, R2 = .5290, P < .001) and expansion of CMJ-HSR (R(2) = .6919, P < .001). The sum of cortex thickness and CMJ-HSR thickness was essentially constant, suggesting that the observed expansion of CMR-HSR with aging likely occurred within the cortical mantle.
  
  
  CONCLUSIONS
  CMJ-HSR expands significantly as a function of aging. Since CMJ-HSR represents a functionally distinct area with relatively slow venous flow, the observed expansion is believed to reflect alteration in cerebral microcirculation with increased age, providing another clue for pathogenesis of Alzheimer's disease.
authors.affiliation: Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan. tnakada@bri.niigata-u.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakada
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Matsuzawa
authors.forename: Hironaka
authors.initials: H
authors.lastname: Igarashi
authors.forename: Ingrid L
authors.initials: IL
authors.lastname: Kwee
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D000465:Algorithms; D000544:Alzheimer Disease / Q000473:pathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged