The age-related changes of normal adult brain structure: analysis with diffusion tensor imaging

Objective: To quantify the anisotropy and average diffusion coefficient (DCavg) changes of normal adult brain, and to reflect the brain structure changes with advancing age by using diffusion tensor imaging (DTI). Methods: One hundred and six normal adults were examined with DTI. The fractional anisotropy (FA), 1-volume ratio (1-VR), relative anisotropy (RA), and average diffusion coefficient (DCavg) of different anatomic sites were measured and correlated with the age, respectively, and compared among groups. Results: The FA, 1-VR, and RA showed negative correlation with age and DCavg positive correlation with age in genu (rFA=-0.491, PFA=0.000; r1-VR=-0.508, P1-VR=0.000; rRA=-0.494, PRA=0.000; rDCavg=0.263, PDCavg=0.006) and splenium (rFA=-0.569, PFA=0.000; r1-VR=-0.531, P1-VR=0.000; rRA=-0.535, PRA=0.000; rDCavg=0.475, PDCavg=0.000) of corpus callosum, centrum semiovale (rFA=-0.562, PFA=0.000; r1-VR=-0.588, P1-VR=0.000; rRA-0.561, PRA=0.000; rDCavg=0.337, PDCavg=0.000), and thalamus (rFA=-0.210, PFA=0.031; r1-VR=-0.203, P1-VR=0.036; rRA=-0.213, PRA=0.028; rDCavg=0.354, PDCcag=0.000). While FA, 1-VR, RA, and DCavg in lentiform neucleus showed positive correlation with age (rFA= 0.287, PFA=0.003; r1-VR=0.290, P1-VR=0.003; rRA=0.283, PRA=0.003; rDCcag=0.325, PDCavg=0.001). Conclusion: DTI can reflect the microstructure changes with advancing age noninvasively. (authors)