title: Voxel-wise co-analysis of macro- and microstructural brain alteration in mild cognitive impairment and Alzheimer's disease using anatomical and diffusion MRI.
abstract: OBJECTIVE
  To determine if a voxel-wise "co-analysis" of structural and diffusion tensor magnetic resonance imaging (MRI) together reveals additional brain regions affected in mild cognitive impairment (MCI) and Alzheimer's disease (AD) than voxel-wise analysis of the individual MRI modalities alone.
  
  
  METHODS
  Twenty-one patients with MCI, 21 patients with AD, and 21 cognitively normal healthy elderly were studied with MRI. Maps of deformation and fractional anisotropy (FA) were computed and used as dependent variables in univariate and multivariate statistical models.
  
  
  RESULTS
  Univariate voxel-wise analysis of macrostructural changes in MCI showed atrophy in the right anterior temporal lobe, left posterior parietal/precuneus region, WM adjacent to the cingulate gyrus, and dorsolateral prefrontal regions, consistent with prior research. Univariate voxel-wise analysis of microstructural changes in MCI showed reduced FA in the left posterior parietal region extending into the corpus callosum, consistent with previous work. The multivariate analysis, which provides more information than univariate tests when structural and FA measures are correlated, revealed additional MCI-related changes in corpus callosum and temporal lobe.
  
  
  CONCLUSIONS
  These results suggest that in corpus callosum and temporal regions macro- and microstructural variations in MCI can be congruent, providing potentially new insight into the mechanisms of brain tissue degeneration.
authors: University of California, San Francisco, CA; Veterans Affairs Medical Center, San Francisco, CA.
authors: Valerie A
authors: VA
authors: Cardenas
authors: Duygu
authors: D
authors: Tosun
authors: Linda L
authors: LL
authors: Chao
authors: P Thomas
authors: PT
authors: Fletcher
authors: Sarang
authors: S
authors: Joshi
authors: Michael W
authors: MW
authors: Weiner
authors: Norbert
authors: N
authors: Schuff
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000209:etiology / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013702:Temporal Lobe / Q000473:pathology*
keywords: MANOVA; deformation morphometry; fractional anisotropy; multimodality imaging; multivariate statistics; univariate statistics