title: Age-related regional brain T2-relaxation changes in healthy adults.
abstract: OBJECTIVE
  To determine normal T2-relaxation values from different brain areas in healthy adults, assess age-related T2-relaxation changes in those sites, and evaluate potential gender-related T2-relaxation value differences.
  
  
  METHODS
  We performed proton-density and T2-weighted imaging in 60 healthy adults (male: 38, age range = 31-64 years, mean age ± SD = 46.1 ± 9.3 years; female: 22, age range = 37-66 years, mean age ± SD = 49.5 ± 8.3 years), using a 3.0 Tesla MRI scanner. T2-relaxation values were calculated voxel-by-voxel from proton-density and T2-weighted images, and whole-brain T2-relaxation maps were constructed and normalized to a common space. A set of regions-of-interest were outlined within the basal ganglia, limbic, frontal, parietal, temporal, occipital, thalamic, hypothalamic, cerebellar, and pontine regions using mean background images derived from normalized and averaged T2-weighted images of all individuals, and regional T2-relaxation values were determined from these regions-of-interest and normalized T2-relaxation maps. Pearson's correlations were calculated between T2-relaxation values and age, and male-female differences evaluated with independent-samples t-tests.
  
  
  RESULTS
  T2-relaxation values typically increased with age in multiple brain sites; only a few regions showed declines, including the putamen and ventral pons. Sex-related differences in T2-relaxation values appeared in basal ganglia, frontal, temporal, occipital, and cerebellar regions; males showed higher values over females in these sites.
  
  
  CONCLUSIONS
  Establishment of normative adult T2-relaxation values over different brain areas, with age and sex as co-factors, offers baseline values against which disease-related tissue changes can be assessed.
authors: Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, California 90095-1763, USA.
authors: Rajesh
authors: R
authors: Kumar
authors: Sean
authors: S
authors: Delshad
authors: Mary A
authors: MA
authors: Woo
authors: Paul M
authors: PM
authors: Macey
authors: Ronald M
authors: RM
authors: Harper
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012737:Sex Factors