Does Covert Cerebral Small Vessel Disease Modulate Early Change in Glymphatic Flow from DTI-ALPS?

Le résumé fourni par la source

Diffusion tensor image analysis along the perivascular space (DTI-ALPS) has emerged as a method for non-invasively assessing glymphatic flow from magnetic resonance diffusion-weighted images. This index has been applied to the study of neurodegenerative and other brain disorders. It has been found to decrease in most studies of neurodegenerative conditions. Decreases in DTI-ALPS also have been found in healthy adults with age. Changes by sex are less consistently observed but seem to suggest females have higher indices. We explored in a healthy adult cohort whether DTI-ALPS is affected by age and sex, or serves as a surrogate/biomarker of the presence of early, covert small vessel disease (SVD) (white matter hyperintensities, lacunes, microbleeds or enlarged perivascular spaces), and vascular risk factors (VRFs) like diabetes, hypertension, hyperlipidemia, or smoking. Separate linear regressions found a slower decrease in DTI-ALPS with age in females than males (-0.0034±0.0013 units/year vs -0.0048 ±0.0011 units/year, p<0.020 between slopes). DTI-ALPS was associated with SVD in one-way ANOVA testing (F=4.72, p=0.032) but not the presence of one or more VRFs (F=0.955, p=0.330). However, in a multivariable linear model only age was significant (-0.0041 units/year, p = 0.007). The other examined factors (sex, presence of SVD or VRF, and age×sex interaction) were all not significant. In conclusion, only older age was significantly associated with lower DTI-ALPS, suggesting a reduction in glymphatic flow with age. However, male sex, the presence of mild-to-moderate SVD pathology nor VRFs were linked to decreased glymphatic flow in a sample drawn from healthy community-dwelling adults.

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