title: Decline of fiber tract integrity over the adult age range: a diffusion spectrum imaging study.
abstract: OBJECTIVE
  We applied a novel diffusion spectrum imaging (DSI) acquisition to determine associations between aging and subcortical fiber tract integrity.
  
  
  METHODS
  We studied 35 cognitively healthy subjects (17 women), spanning the adult age range between 23 and 77 years, using anatomical MRI and a novel DSI acquisition scheme at 3 Tesla. The study was approved by the local institutional review board. DSI data were analyzed using tractography and complementary voxel-based analysis of generalized fractional anisotropy (GFA) maps. We determined the effects of age on generalized fractional anisotropy in selected fiber tracts as well as in a whole brain voxel-based analysis. For comparison, we studied the effects of age on regional gray and white matter volumes.
  
  
  RESULTS
  We found a significant reduction in anterior corpus callosum fiber tract integrity with age (P < 0.001), as well as significant GFA reduction throughout the subcortical white matter (P < 0.05, false discovery rate [FDR] corrected). GFA decline was accompanied by significant gray matter atrophy in frontal and temporal association cortex (P < 0.05, FDR corrected).
  
  
  CONCLUSIONS
  Our data suggest that normal aging leads to a regionally specific decline in fiber tract integrity. DSI may become a useful biomarker in healthy and pathological aging.
authors.affiliation: Department of Psychosomatic Medicine, University Medicine Rostock, Rostock, Germany; DZNE, German Center for Neurodegenerative Diseases, Rostock, Germany.
authors.forename: Stefan J
authors.initials: SJ
authors.lastname: Teipel
authors.forename: Maximilian
authors.initials: M
authors.lastname: Lerche
authors.forename: Ingo
authors.initials: I
authors.lastname: Kilimann
authors.forename: Kieran
authors.initials: K
authors.lastname: O'Brien
authors.forename: Michel
authors.initials: M
authors.lastname: Grothe
authors.forename: Peter
authors.initials: P
authors.lastname: Meyer
authors.forename: Xingfeng
authors.initials: X
authors.lastname: Li
authors.forename: Peter
authors.initials: P
authors.lastname: Sänger
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Hauenstein
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D066127:White Matter / Q000473:pathology*; D055815:Young Adult
keywords: aging; diffusion spectrum imaging; generalized fractional anisotropy; genetics; neurodegeneration; white matter microstructure