Objective To calculate the diffusion tensor image analysis along the perivascular space(DTI-ALPS) index, evaluate the function of the glymphatic system, observe the changes in the DTI-ALPS index during the aging process, and find the relationship between the DTI-ALPS index and correlates of certain executive functions that reflect mental flexibility, based on DTI-ALPS. Methods The FSL toolbox was used to extract the DTI-ALPS index of the dominant hemisphere of the brain of adult subjects in the NKI Rockland Sample data set, and the correlations between the DTI-ALPS index and age and design fluency practical accuracy were analyzed, respectively. Differences in DTI-ALPS index among different age groups and the mediating effect of DTI-ALPS index between age and design fluency practical accuracy were analyzed. Results The DTI-ALPS index was negatively correlated with age (r=-0.288, P<0.001), but there was a local peak of recovery in the 60-69 age group (P<0.01).The DTI-ALPS index was positively correlated with the design fluency practical accuracy (r=0.258, P=0.001).The mediating effect of DTI-ALPS index between age and design fluency practical accuracy was statistically significant (P<0.05), and the mediating effect accounted for 22.1% of the total effect. Conclusion  The DTI-ALPS index showed an overall downward trend during the aging process, but there is a local peak of recovery in the 60-69 age group. At the same time, the DTI-ALPS index might be related to certain executive functions that could reflect thinking flexibility. 

Aging, Glymphatic system, Diffusion tensor image analysis along the perivascular space, Human