Quantitative assessment of hyperperfusion using arterial spin labeling to predict hemorrhagic transformation in acute ischemic stroke patients with mechanical endovascular therapy

Objectives This study was aimed to quantitatively assess hyperperfusion using arterial spin labeling (ASL) to predict hemorrhagic transformation (HT) in acute ischemic stroke (AIS) patients. Methods This study enrolled 98 AIS patients with anterior circulation large vessel occlusion within 24 h of symptom onset. ASL was performed before mechanical endovascular therapy. On pre-treatment ASL maps, a region with relative cerebral blood flow (CBF) ≥ 1.4 was defined as an area of hyperperfusion. The maximum CBF (CBF max ) of hyperperfusion was calculated for each patient. A non-contrast CT scan was performed during the subacute phase for the evaluation of HT. Good clinical outcome was defined as a 90-day modified Rankin scale score of 0–2. Results The CBF max of hyperperfusion (odds ratio, 1.023; 95% confidence interval [CI], 1.005–1.042; p = 0.012) was an independent risk factor for the status of HT. The CBF max of hyperperfusion for HT showed an area under the curve of 0.735 (95% CI, 0.588–0.882) with optimal cutoff value, sensitivity, and specificity being 146.5 mL/100 g/min, 76.9%, and 69.6%, respectively. There was a statistically significant relationship between HT grades (from no HT to PH2) and CBF max of hyperperfusion with a Spearman rank correlation of 0.446 ( p = 0.001). In addition, low CBF max of hyperperfusion were associated with good functional outcome (95% CI, 17.130–73.910; p = 0.002). Conclusions High CBF max of hyperperfusion was independently associated with subsequent HT and low CBF max of hyperperfusion linked to good functional outcome. There was a positive correlation between HT grade and CBF max. Clinical relevance statement Arterial spin labeling is a noninvasive and contrast agent–independent technique, which is sensitive in detecting hyperperfusion. This study shows that the cerebral blood flow of hyperperfusion is associated with clinical prognosis, which will benefit more patients. Key Points • Quantitative assessment of hyperperfusion using pre-treatment arterial spin labeling to predict hemorrhagic transformation and prognosis in acute ischemic stroke patients. • The maximum cerebral blood flow of hyperperfusion was associated with hemorrhagic transformation and clinical prognosis and higher maximum cerebral blood flow of hyperperfusion was associated with higher grade hemorrhagic transformation. • The maximum cerebral blood flow of hyperperfusion can predict hemorrhagic transformation which enables timely intervention to prevent parenchymal hematoma.