Arterial transit artifacts on arterial spin labeling MRI can predict cerebral hyperperfusion after carotid endarterectomy: an initial study

Objectives To investigate whether preoperative arterial spin labeling (ASL) MRI can predict cerebral hyperperfusion after carotid endarterectomy (CEA) in patients with carotid stenosis. Methods Consecutive patients with carotid stenosis who underwent CEA between May 2015 and July 2021 were included. For each patient, a cerebral blood flow ratio (rCBF) map was obtained by dividing postoperative CBF with preoperative CBF images from two pseudo-continuous ASL scans. Hyperperfusion regions with rCBF > 2 were extracted and weighted with rCBF to calculate the hyperperfusion index. According to the distribution of the hyperperfusion index, patients were divided into hyperperfusion and non-hyperperfusion groups. Preoperative ASL images were scored based on the presence of arterial transit artifacts (ATAs) in 10 regions of interest corresponding to the Alberta Stroke Programme Early Computed Tomography Score methodology. The degree of stenosis and primary and secondary collaterals were evaluated to correlate with the ASL score. Logistic regression and receiver operating characteristic curve analyses were performed to assess the predictive ability of the ASL score for cerebral hyperperfusion. Results Of 86 patients included, cerebral hyperperfusion was present in 17 (19.8%) patients. Carotid near occlusion, opening of posterior communicating arteries with incomplete anterior semicircle, and leptomeningeal collaterals were associated with lower ASL scores ( p < 0.05). The preoperative ASL score was an independent predictor of cerebral hyperperfusion (OR = 0.48 [95% CI [0.33–0.71]], p < 0.001) with the optimal cutoff value of 25 points (AUC = 0.98, 94.1% sensitivity, 88.4% specificity). Conclusions Based on the presence of ATAs, ASL can non-invasively predict cerebral hyperperfusion after CEA in patients with carotid stenosis. Key Points • Carotid near occlusion, opening of posterior communicating arteries with incomplete anterior semicircle, and leptomeningeal collaterals were associated with lower ASL scores. • The ASL score performed better than the degree of stenosis, type of CoW, and leptomeningeal collaterals, as well as the combination of the three factors for the prediction of cerebral hyperperfusion. • For patients with carotid stenosis, preoperative ASL can non-invasively identify patients at high risk of cerebral hyperperfusion after carotid endarterectomy without complex post-processing steps.