title: Age-Related Sex-Specific Changes in Brain Metabolism and Morphology.
abstract: With a large database, we aimed to evaluate sex-specific distinctive changes in brain glucose metabolism and morphology during normal aging using MRI and (18)F-FDG PET.
  
  
  METHODS
  A total of 963 cognitively healthy adults were included in this study. All subjects completed a medical questionnaire, took the mini-mental state examination, and underwent brain MRI and whole-body (18)F-FDG PET. The MR and PET images were statistically analyzed using 3-dimensional stereotactic surface projection. All images were corrected for whole-brain pixel value to identify the brain regions with significant changes, and regions of interest were set up with reference to Brodmann areas. We evaluated morphologic and glucose metabolic changes by cross-sectional analysis. The baseline database consisted of subjects from 30 to 40 y old, and the age-step for comparison was 5-y ranges. We also compared sex-specific differences in MR and PET images in each age group.
  
  
  RESULTS
  Regarding age-related changes, in both sexes brain atrophy was observed in the lateral frontal and parietal regions and glucose hypometabolism in the medial frontal regions. There were significant differences in these parameters between the sexes; parallel changes in volume and metabolism were manifested in the medial frontal cortex in men and in the lateral and medial temporal cortex in women. By contrast, metabolism-dominant reductions were manifested in the lateral and medial parietal cortex in men and in the ventrolateral prefrontal cortex, including the Broca area, in women. These differences became insignificant in individuals 66 y or older.
  
  
  CONCLUSIONS
  Our brain mapping study with a large number of reference human brain data demonstrated age-related parallel changes between morphology and metabolism in the medial frontal regions and sex-specific hypometabolism in the parietal (male) and ventrolateral prefrontal (female) cortices. These findings may suggest an aging vulnerability in sex-specific brain regions: the parietal cortex for visuospatial ability in men and the Broca area for speech processing in women.
authors.affiliation: Diagnostic Imaging Application Group, PET Business Promotion Department, Development Bureau, Hamamatsu Photonics K.K., Hamamatsu, Japan Department of Biofunctional Imaging, Medical Photonics Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kakimoto
authors.affiliation: Diagnostic Imaging Application Group, PET Business Promotion Department, Development Bureau, Hamamatsu Photonics K.K., Hamamatsu, Japan Hamamatsu Medical Imaging Center, Hamamatsu Medical Photonics Foundation, Hamamatsu, Japan; and.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ito
authors.affiliation: Diagnostic Imaging Application Group, PET Business Promotion Department, Development Bureau, Hamamatsu Photonics K.K., Hamamatsu, Japan Hamamatsu Medical Imaging Center, Hamamatsu Medical Photonics Foundation, Hamamatsu, Japan; and.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okada
authors.affiliation: Hamamatsu Medical Imaging Center, Hamamatsu Medical Photonics Foundation, Hamamatsu, Japan; and.
authors.forename: Sadahiko
authors.initials: S
authors.lastname: Nishizawa
authors.affiliation: Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Minoshima
authors.affiliation: Department of Biofunctional Imaging, Medical Photonics Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan ouchi@hama-med.ac.jp.
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Ouchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D019412:Anatomy, Cross-Sectional; D001921:Brain / Q000033:anatomy & histology* / Q000254:growth & development*; D001923:Brain Chemistry; D005260:Female; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000254:growth & development; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000254:growth & development; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012016:Reference Values; D012727:Sex Characteristics
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose
keywords: 18F-FDG PET; brain atrophy; cognitive aging; glucose metabolism; structural MR imaging