Advance Ultrasound Techniques for the Assessment of Plaque Vulnerability in Symptomatic and Asymptomatic Carotid Stenosis: a Multimodal Ultrasound Study

Background: Advanced carotid ultrasound techniques may be useful in characterizing plaque vulnerability, but comprehensive studies are still lacking. The aim of this study was to identify factors associated with vulnerable plaques using advanced ultrasound techniques.

Methods: This is a prospective observational study of patients with >50% internal carotid stenosis (ICA). All patients underwent conventional ultrasound, superb microvascular imaging (SMI) and shear wave elastography (SWE) examinations. Plaque size, echogenicity, stiffness and intraplaque neovascularization (IPN) were assessed and compared between symptomatic and asymptomatic groups. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of SWE and SMI of the vulnerable plaques.

Results: The final analysis included 123 patients (78.9% male; mean age, 66±8 years), 65 were enrolled in the symptomatic group, and 58 were enrolled in the asymptomatic group. The mean elasticity was 78.1±25.4 kPa for asymptomatic and 51.5±18.3 kPa for symptomatic plaques. Symptomatic plaques showed higher visual IPN grades on SMI than asymptomatic plaques (P<0.001). Multivariate regression analysis showed that plaque stiffness (PS) (OR 0.95, 95% CI, 0.919-0.974) and IPN level (OR 4.17, 95% CI, 2.008-8.664) were independently associated with symptomatic plaques. The combination of the two factors had a preferable accuracy to discriminate symptomatic plaques (AUC 0.89, 95% CI, 0.827-0.944).

Conclusions: Advanced carotid ultrasound techniques can identify plaque characteristics that are associated with ischemic events and may be potentially indicative of plaque vulnerability. These factors may ultimately be used in the clinical management of carotid stenosis.