title: Brain volumes in healthy adults aged 40 years and over: a voxel-based morphometry study.
abstract: OBJECTIVE
  Gender and age effect on brain morphology have been extensively investigated. However, the great variety in methods applied to morphology partly explain the conflicting results of linear patterns of tissue changes and lateral asymmetry in men and women. The aim of the present study was to assess the effect of age, gender and laterality on the volumes of gray matter (GM) and white matter (WM) in a large group of healthy adults by means of voxel-based morphometry. This technique, based on observer-independent algorithms, automatically segments the 3 types of tissue and computes the amount of tissue in each single voxel.
  
  
  METHODS
  Subjects were 229 healthy subjects of 40 years of age or older, who underwent magnetic resonance (MR) for reasons other than cognitive impairment. MR images were reoriented following the AC-PC line and, after removing the voxels below the cerebellum, were processed by Statistical Parametric Mapping (SPM99). GM and WM volumes were normalized for intracranial volume.
  
  
  RESULTS
  Women had more fractional GM and WM volumes than men. Age was negatively correlated with both fractional GM and WM, and a gender x age interaction effect was found for WM, men having greater WM loss with advancing age. Pairwise differences between left and right GM were negative (greater GM in right hemisphere) in men, and positive (greater GM in left hemisphere) in women (-0.56+/-4.2 vs 0.99+/-4.8; p=0.019).
  
  
  CONCLUSIONS
  These results support side-specific accelerated WM loss in men, and may help our better understanding of changes in regional brain structures associated with pathological aging.
authors.affiliation: Laboratory of Epidemiology and Neuroimaging, IRCCS San Giovanni di Dio, FBF, Brescia, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Riello
authors.forename: Francesca
authors.initials: F
authors.lastname: Sabattoli
authors.forename: Alberto
authors.initials: A
authors.lastname: Beltramello
authors.forename: Matteo
authors.initials: M
authors.lastname: Bonetti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bono
authors.forename: Andrea
authors.initials: A
authors.lastname: Falini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Magnani
authors.forename: Giorgio
authors.initials: G
authors.lastname: Minonzio
authors.forename: Enrico
authors.initials: E
authors.lastname: Piovan
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Alaimo
authors.forename: Monica
authors.initials: M
authors.lastname: Ettori
authors.forename: Samantha
authors.initials: S
authors.lastname: Galluzzi
authors.forename: Enrico
authors.initials: E
authors.lastname: Locatelli
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Noiszewska
authors.forename: Cristina
authors.initials: C
authors.lastname: Testa
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Frisoni
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000033:anatomy & histology* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012737:Sex Factors