Background and objectivesThe diffusion tensor image analysis along the perivascular space (DTI-ALPS) index is an important imaging biomarker for assessing glymphatic system function. However, the cortical and white matter metrics associated with changes in the DTI-ALPS index have not been fully elucidated, and the relationship between these two types of metrics remains controversial.MethodsWe computed the index in 815 healthy participants from the AOMIC dataset. Surface-based morphometry (SBM) a