Researchers used arterial spin labeling MRI to track cerebral blood flow (CBF) in 281 patients with reversible cerebral vasoconstriction syndrome (RCVS) over five years. Acute RCVS patients showed significantly lower global brain perfusion than healthy controls, with the most prominent reductions in posterior brain regions. Strikingly, CBF normalized within two weeks of headache onset. A distinct window of abrupt CBF fluctuation was identified between days 2–16 and 7–21 after onset, consistently detected across multiple statistical models. Ultrasound-measured flow velocities in the middle cerebral and internal carotid arteries correlated strongly with CBF during the acute phase, reinforcing the link between large-vessel constriction and downstream perfusion changes. These findings offer the most detailed spatiotemporal map of RCVS perfusion to date.
