Development of diffusion analysis along the perivascular space (DTI-ALPS) index during childhood and adolescence: Evidence from two longitudinal cohorts

Brain glymphatic activity, as indicated by diffusion analysis along the perivascular space (DTI-ALPS) index, has been discovered to participate in the pathogenesis of atypical development. However, little is known about the physiological developmental trajectory of the DTI-ALPS index during childhood and adolescence. Here, we evaluated DTI-ALPS index developmental characteristics and investigated its potential association with sex in 627 participants from two longitudinal cohorts. The global DTI-ALPS (gDTI-ALPS) index showed a positive cross-sectional relationship with age in both cohorts even after adjusting for sex. The annual net increase in the gDTI-ALPS index in both cohorts ranged from 0.003 to 0.005. Increases in the gDTI-ALPS index with age were also observed in the longitudinal analysis. Moreover, regional DTI-ALPS index analysis revealed the increment of DTI-ALPS mainly involved in the anterior brain regions, with the peak value of the regional DTI-ALPS index moving forward with age. Sex had no significant moderating effect on DTI-ALPS index. Our results suggest DTI-ALPS index development is a dynamic process during childhood and adolescence, particularly within the anterior brain regions, which may represent glymphatic system maturation during this critical period. The global and regional DTI-ALPS index could serve as a sensitive biomarker for monitoring this process.