Cerebral hyperperfusion on arterial spin labeling MRI after reperfusion therapy is related to hemorrhagic transformation

Early detection of hemorrhagic transformation after reperfusion therapy is crucial in acute stroke treatment. Here, we evaluated the relationship between hemorrhagic transformation and post-reperfusion hyperperfusion using pulsed arterial spin labeling (ASL) perfusion MRI and 123 I-iodoamphetamine single-photon emission-computed tomography. Patients who developed hemorrhagic transformation showed significantly higher cerebral blood flow in the affected lesion after thrombolysis and/or endovascular intervention. Focal hyperperfusion (ipsilateral to contralateral ratio >1.5) was associated with hemorrhagic transformation after reperfusion (odds ratio, 9.3; 95% confidence interval, 1.4–64.0). Our findings suggest that post-reperfusion hyperperfusion on ASL could represent a reliable marker of hemorrhagic transformation.