title: White matter microstructural changes in pure Alzheimer's disease and subcortical vascular dementia.
abstract: OBJECTIVE
  Recent studies have demonstrated that Alzheimer's disease (AD) and subcortical vascular dementia (SVaD) have white matter (WM) microstructural changes. However, previous studies on AD and SVaD rarely eliminated the confounding effects of patients with mixed Alzheimer's and cerebrovascular disease pathologies. Therefore, our aim was to evaluate the divergent topography of WM microstructural changes in patients with pure AD and SVaD.
  
  
  METHODS
  Patients who were clinically diagnosed with AD and SVaD were prospectively recruited. Forty AD patients who were Pittsburgh compound B (PiB) positive [PiB(+) AD] without WM hyperintensities and 32 SVaD patients who were PiB negative [PiB(-) SVaD] were chosen. Fifty-six cognitively normal individuals were also recruited (NC). Tract-based spatial statistics of diffuse tensor imaging were used to compare patterns of fractional anisotropy (FA) and mean diffusivity (MD).
  
  
  RESULTS
  Compared with the NC group, the PiB(+) AD group showed decreased FA in the bilateral frontal, temporal and parietal WM regions and the genu and splenium of the corpus callosum as well as increased MD in the left frontal and temporal WM region. PiB(-) SVaD patients showed decreased FA and increased MD in all WM regions. Direct comparison between PiB(+) AD and PiB(-) SVaD groups showed that the PiB(-) SVaD group had decreased FA across all WM regions and increased MD in all WM regions except occipital regions.
  
  
  CONCLUSIONS
  Our findings suggest that pure AD and pure SVaD have divergent topography of WM microstructural changes including normal appearing WM.
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroscience Center, Samsung Medical Center, Seoul, Korea.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: H K
authors.initials: HK
authors.lastname: Kwon
authors.forename: J-M
authors.initials: JM
authors.lastname: Lee
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: H J
authors.initials: HJ
authors.lastname: Kim
authors.forename: N-Y
authors.initials: NY
authors.lastname: Jung
authors.forename: S T
authors.initials: ST
authors.lastname: Kim
authors.forename: K H
authors.initials: KH
authors.lastname: Lee
authors.forename: D L
authors.initials: DL
authors.lastname: Na
authors.forename: S W
authors.initials: SW
authors.lastname: Seo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D000814:Aniline Compounds; D015140:Dementia, Vascular / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013844:Thiazoles; D066127:White Matter / Q000473:pathology*
chemical_list: C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D000814:Aniline Compounds; D013844:Thiazoles
keywords: Alzheimer's disease; diffuse tensor imaging; subcortical vascular dementia; white matter microstructural changes