Predicting vulnerable carotid plaques by detecting wall shear stress based on ultrasonic vector flow imaging

Carotid plaque vulnerability is a significant factor in the risk of cardio-cerebrovascular events, with intraplaque neovascularization (IPN) being a crucial characteristic of plaque vulnerability. This study investigates the value of ultrasound vector flow imaging (V-Flow) for measuring carotid plaque wall shear stress (WSS) in predicting the extent of IPN. We enrolled 140 patients into three groups: 53 in the plaque group (72 plaques), 23 in the stenosis group (27 plaques), and 64 in the control group. V-Flow was employed to measure WSS parameters, including the average WSS (WSS Mean) and the maximum WSS (WSS Max), across three plaque locations: mid-upstream, maximum thickness, and mid-downstream. Contrast-enhanced ultrasound (CEUS) was utilized in 76 patients to analyze IPN and its correlation with WSS parameters. 1. WSS Max in the stenosis group was significantly higher than that in the control and plaque groups at the maximum thickness part (p < 0.05); WSS Mean in the stenosis group was significantly lower than that in the control group at the mid-upstream and mid-downstream segments (p < 0.05); and WSS Mean in the plaque group was significantly lower than that of the control group at all three locations (p < 0.05). 2. CEUS revealed that plaques with neovascularization enhancement exhibited significantly higher WSS values (p < 0.05), with a positive correlation between WSS parameters and IPN enhancement grades, particularly WSS Max at the thickest part (r = 0.508). 3. ROC curve analysis of WSS parameters for evaluating IPN showed that the efficacy of WSS Max in evaluating IPN was better than that of WSS Mean (p < 0.05), with an AUC of 0.7762, 0.6973; 95% CI of 0.725 - 0.822, 0.642 - 0.749, respectively; Cut-off was 4.57 Pa, 1.12 Pa; sensitivity was 74.03%, 63.64%; specificity was 75.00%, 68.18%. V-Flow effectively measures WSS in carotid plaques. WSS Max provides a promising metric for assessing IPN, offering potential insights into plaque characteristics and showing some potential in predicting plaque vulnerability.