Carotid stenosis: embolic risk assessment by sonographic plaque morphology and plaque vascularization

Background The risk of embolization originating from carotid artery stenosis is dependent not only on the grade of stenosis but also on the composition of the corresponding arteriosclerotic plaque. In particular, the presence of ulcerations, inflammation, a thin fibrous cap, a large necrotic lipid core, in addition to vascularization within the plaque emanating from the vasa vasorum and associated intraplaque hemorrhage, are signs of a vulnerable arteriosclerotic lesion. Objectives This article gives an overview based on the sonographic characteristics of carotid stenosis that can be used to estimate the associated increased stroke risk. Materials and Methods Duplex ultrasound not only determines the degree of stenosis based on hemodynamic criteria but also makes it possible to assess sonomorphological characteristics of a vulnerable plaque on B-mode ultrasound, and, in particular, plaque vascularization using contrast-enhanced ultrasound (CEUS). Results and Conclusions Based on current evidence, hypoechogenicity, the size of the plaque area, surface irregularities, and ulceration on B-mode ultrasound, in addition to plaque vascularization of the carotid stenosis on CEUS, are sonographic indications for vulnerable carotid stenosis with increased embolic risk. This additional imaging information should help us to select patients with carotid stenosis and increased embolic risk who may benefit from invasive therapy.