title: Age-related alterations in white matter microstructure measured by diffusion tensor imaging.
abstract: Cerebral white matter (WM) undergoes various degenerative changes with normal aging, including decreases in myelin density and alterations in myelin structure. We acquired whole-head, high-resolution diffusion tensor images (DTI) in 38 participants across the adult age span. Maps of fractional anisotropy (FA), a measure of WM microstructure, were calculated for each participant to determine whether particular fiber systems of the brain are preferentially vulnerable to WM degeneration. Regional FA measures were estimated from nine regions of interest in each hemisphere and from the genu and splenium of the corpus callosum (CC). The results showed significant age-related decline in FA in frontal WM, the posterior limb of the internal capsule (PLIC), and the genu of the CC. In contrast, temporal and posterior WM was relatively preserved. These findings suggest that WM alterations are variable throughout the brain and that particular fiber populations within prefrontal region and PLIC are most vulnerable to age-related degeneration.
authors.affiliation: MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA 02129-2060, USA. salat@nmr.mgh.harvard.edu
authors.forename: D H
authors.initials: DH
authors.lastname: Salat
authors.forename: D S
authors.initials: DS
authors.lastname: Tuch
authors.forename: D N
authors.initials: DN
authors.lastname: Greve
authors.forename: A J W
authors.initials: AJ
authors.lastname: van der Kouwe
authors.forename: N D
authors.initials: ND
authors.lastname: Hevelone
authors.forename: A K
authors.initials: AK
authors.lastname: Zaleta
authors.forename: B R
authors.initials: BR
authors.lastname: Rosen
authors.forename: B
authors.initials: B
authors.lastname: Fischl
authors.forename: S
authors.initials: S
authors.lastname: Corkin
authors.forename: H Diana
authors.initials: HD
authors.lastname: Rosas
authors.forename: A M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D016880:Anisotropy; D001284:Atrophy / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology; D003337:Corpus Callosum / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000473:pathology; D008297:Male; D008569:Memory Disorders / Q000473:pathology* / Q000503:physiopathology; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D019636:Neurodegenerative Diseases / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests