title: Age-related structural changes in the young adult brain shown by magnetic resonance diffusion tensor imaging.
abstract: OBJECTIVE
  Structure of the brain is generally thought to remain stationary over the course of young adulthood. However, there is some evidence that microstructural changes of the brain do occur during this period. Magnetic resonance diffusion tensor imaging (DTI) provides quantitative measures of structural changes in the brain. We used DTI to detect possible age-related structural changes in the brains of young adults.
  
  
  METHODS
  Twenty-five healthy adults in their 20s and 30s were studied using DTI. Maps of mean diffusivity and fractional anisotropy (FA) were created for subsequent histogram and region-of-interest analyses, and the results were correlated with the respective ages of the subjects.
  
  
  RESULTS
  The histogram analysis revealed a significant increase in the mean FA value (r = 0.407, P < .05) and a significant decrease in FA peak height (r = -0.578, P < .002) with increasing age. No age-related changes were observed in indices derived from mean diffusivity maps. Region-of-interest analysis showed no focal white matter regions with significant FA change.
  
  
  CONCLUSIONS
  Quantitative DTI revealed age-related structural changes in the brains of young adults. Changes on FA histograms observed in this study were considered to be related to changes in the relative volumes of gray and white matter and may represent maturational changes.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Japan. tyoshiura@syd.odn.ne.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.forename: Futoshi
authors.initials: F
authors.lastname: Mihara
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tanaka
authors.forename: Osamu
authors.initials: O
authors.lastname: Togao
authors.forename: Takayuki
authors.initials: T
authors.lastname: Taniwaki
authors.forename: Akiko
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nakao
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Noguchi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kuwabara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000328:Adult; D000375:Aging / Q000473:pathology*; D001921:Brain / Q000033:anatomy & histology* / Q000098:blood supply; D001933:Brain Stem / Q000033:anatomy & histology; D002531:Cerebellum / Q000033:anatomy & histology; D003337:Corpus Callosum / Q000033:anatomy & histology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008833:Microcirculation / Q000033:anatomy & histology; D010296:Parietal Lobe / Q000033:anatomy & histology; D013702:Temporal Lobe / Q000033:anatomy & histology