Objective    To investigate the usual aging-related changes in diffusivity and anisotropy of the brain by diffusion tensor imaging (DTI).     Methods    Average diffusion coefficient (ADC) and fractional anisotropy (FA) maps of brain were gained by DTI. We measured ADC and FA values of interested structures for the changes in diffusivity and anisotropy

and attempted to discover the underlying microstructure changes.     Results     In young (20-39 years of age) and old (more than 60 years of age) groups without brain disease-related aging

ADC and FA values of symmetric structures had no statistical significance (P0.05). ADC values in the old group were higher than those in the young group (P0.05)

except the values in bilateral genu of internal capsules. Meanwhile

FA values of the old group were lower in all ROIs than those in the young group (P0.05).     Conclusion    DTI reflects the changes in diffusivity and anisotropy of brain caused by usual aging

and the underlying changes of microstructure and integrity.