title: Age-related changes in normal-appearing brain tissue and white matter hyperintensities: more of the same or something else?
abstract: OBJECTIVE
  Cerebral white matter (WM) hyperintensities are a frequent finding in elderly people, and lowering of cerebral magnetization transfer ratio (MTR) has been observed. The aim of this study was to assess the relationship between age-related WM hyperintensities and MTR changes in the brain.
  
  
  METHODS
  We performed MR imaging in a group of young subjects, a group of elderly individuals with minimal WM hyperintensities, and a group of elderly individuals with abundant WM hyperintensities. In addition, we performed volumetric MTR analysis of the whole brain and of the normal-appearing WM (NAWM) in these groups.
  
  
  RESULTS
  Volumetric MTR parameters differed between elderly and young patients. Mean MTR +/- standard error of the mean (SEM) was 34.0% +/- 0.12% in the young, 33.0% +/- 0.08% in the elderly with minimal WM hyperintensities, 32.8% +/- 0.09%) in the group with abundant WM hyperintensities. Peak height (number of voxels +/- SEM) was 122 +/- 1.2 in the young, 99 +/- 1.5 in the elderly with minimal WM hyperintensities, and 98 +/- 1.6 in the group with abundant WM hyperintensities. Mean MTR of NAWM was lower in the elderly compared with the young (36.7% +/- 0.12%) but did not differ between subjects with minimal (36.0% +/- 0.11%) and those with abundant WM hyperintensities (35.9% +/- 0.13%).
  
  
  CONCLUSIONS
  Our results show that aging gives rise to changes in normal-appearing brain tissue. These changes, which can be detected on magnetization transfer imaging, seem to have no relationship with age-related WM hyperintensities and might have a different etiology.
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, Netherlands.
authors.forename: Aart
authors.initials: A
authors.lastname: Spilt
authors.forename: Tychon
authors.initials: T
authors.lastname: Geeraedts
authors.forename: Anton J M
authors.initials: AJ
authors.lastname: de Craen
authors.forename: Rudi G J
authors.initials: RG
authors.lastname: Westendorp
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Blauw
authors.forename: Mark A
authors.initials: MA
authors.lastname: van Buchem
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male