title: White Matter Changes May Precede Gray Matter Loss in Elderly with Subjective Memory Impairment.
abstract: A limited number of studies addressed MRI-based neurodegenerative changes in subjective memory impairment (SMI). We investigated changes in white matter (WM) microstructures as well as gray matter (GM) macrostructures in subjects with SMI of high and low risk for progression.
  
  
  
  A modeling scale (score range, 0-6) developed for prediction of SMI progression was used to divide SMI subjects (n = 46) into two groups: a high risk of progression (score ≥3; n = 19) and a low risk of progression (score ≤2; n = 27). Cross-sectional comparisons were performed using a region-of-interest-based diffusion tensor imaging (DTI) analysis, cortical thickness analysis, and hippocampal volumetry.
  
  
  
  The high-risk group had more microstructural disruption shown by lower fractional anisotropy in the hippocampus, parahippocampal gyrus, supramarginal gyrus, and parts of frontotemporal lobes. On the other hand, GM macrostructural changes did not differ between the groups and were not associated with modeling scale scores.
  
  
  
  SMI subjects with a high risk of progression had more WM microstructural disruption than those with a low risk, and the changes were not explained by GM atrophy. Our findings suggest that the degree of microstructural alterations in SMI may be distinctive according to the risk factors and may precede GM atrophy.
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Yun Jeong
authors.initials: YJ
authors.lastname: Hong
authors.forename: Chan-Mi
authors.initials: CM
authors.lastname: Kim
authors.forename: Eun Hye
authors.initials: EH
authors.lastname: Jang
authors.forename: Jihye
authors.initials: J
authors.lastname: Hwang
authors.forename: Jee Hoon
authors.initials: JH
authors.lastname: Roh
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000368:Aged; D016880:Anisotropy; D001284:Atrophy; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D003430:Cross-Sectional Studies; D059026:Diagnostic Self Evaluation; D056324:Diffusion Tensor Imaging; D018450:Disease Progression; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology; D066128:Gray Matter / Q000000981:diagnostic imaging* / Q000473:pathology; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D056784:Leukoencephalopathies / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000000981:diagnostic imaging*; D008875:Middle Aged; D009929:Organ Size; D020534:Parahippocampal Gyrus / Q000000981:diagnostic imaging / Q000473:pathology; D010296:Parietal Lobe / Q000000981:diagnostic imaging / Q000473:pathology; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology; D066127:White Matter / Q000000981:diagnostic imaging* / Q000473:pathology