Age-related changes in fractional anisotropy in corpus callosum with MR diffusion tensor imaging

Objective: To analyze age-related changes in fractional anisotropy (FA) in sub-regions of corpus callosum on diffusion tensor imaging(DTI). Methods: DTI was obtained from 171 healthy individuals (80 men, 91 women; age 12 to 73 years; median age 44 years). All the subjects were stratified into the following seven age groups(10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79 years). Corpus callosum was divided into 5 subregions(I-V region). DTI FA values of sub-regions of corpus callosum were measured. Mean FA values changes in corpus callosum sub-regions with advancing age were evaluated with hierarchical polynomial regression analyses. Results: The mean FA value in the V region was the highest within the same age group. The corresponding values from group 1 to 7 were 0.77 ± 0.06, 0.80 ± 0.03, 0.79 ± 0.03, 0.79 ± 0.03, 0.78 ± 0.03, 0.77 ± 0.03, 0.77 ± 0.03, respectively. The mean FA value in the IK region was the lowest within the same age group. The corresponding values from group 1 to 7 were 0.51 ± 0.08, 0.59 ± 0.06, 0.59 ± 0.06, 0.56 ± 0.07, 0.55 ± 0.07, 0.52 ± 0.07, 0.43 ± 0.07, respectively. The change of FA values in subregions of the corpus callosum on DTI followed an inverted U-shaped curve with advancing age(ROIl-ROI5, R² = 0.162, 0.214, 0.164, 0.098, 0.070, respectively, all P < 0.05). FA peak appeared at 20 to 30 years old in all regions. Conclusions: The study demonstrated age-related changes in FA value in sub-regions of the corpus callosum on DTI as following a curve, reflecting the age-related changes of physiological processes, which could serve as a basis for corpus callosum research. (authors)