MR-based glymphatic function: association between DTI-ALPS and perivascular space

Motivation: The glymphatic system is presumed to be associated with perivascular space (PVS). Goal(s): To identify the relationship between the glymphatic system (ALPS index), PVS, and cerebral white matter hyperintensities (WMH) according to age. Approach: Participants indicated for brain MRI for cognitive decline (n=611) were retrospectively included. The glymphatic function was assessed by ALPS index calculated from diffusion tensor imaging along the perivascular space (DTI-ALPS). PVS volumes were automatically quantified via deep learning segmentation model. FLAIR WMH were also automatically quantified. Results: ALPS index showed a significant negative correlation with WMH and PVS in the age group of 50–59. Impact: WMH show a negative correlation with ALPS index, indicating poor glymphatic function. However, only age group of 50–59 shows such relationship. This suggests that aging and enlarged PVS might have diminished glymphatic function as reflected in decreased ALPS index.