Abstract

Long COVID is increasingly associated with persistent neurological and cognitive symptoms, yet its underlying mechanisms remain unclear. Vascular dysregulation, endothelial dysfunction, and microvascular injury have been proposed as contributors. In this study, arterial spin labeling (ASL) MRI was used to quantify cerebral blood flow (CBF) and the spatial coefficient of variation (sCOV), a proxy of arterial transit time and vascular efficiency, in 186 adults from an Argentine cohort (145 long COVID and 41 controls), approximately 2 years post-infection.

After adjustment for age, sex, and white matter hyperintensity volume, long COVID participants showed significantly higher global gray matter sCOV, with consistent regional trends across multiple lobes, while mean CBF and white matter hyperintensity volumes did not significantly differ between groups. These findings indicate widespread cerebrovascular dysfunction in long COVID in the absence of overt perfusion deficits and support sCOV as a sensitive, noninvasive biomarker of cerebrovascular health.