Ultrasonography of carotid plaque for the prevention of stroke

Abstract

A carotid ultrasonography is a non-invasive technique that provides an accurate and reliable characterization of the broad spectrum of carotid arteriosclerosis, from the intima-media thickness to the atherosclerotic plaque. Carotid ultrasonography has become a useful tool for identifying patients at high risk of stroke and selecting those who can benefit most from revascularization therapies such as carotid endarterectomy and stenting. In addition to the degree of stenosis, plaque echomorphology has emerged in recent years as an important contributory factor to stroke risk. Changes in plaque echogenicity, as measured by the quantitative computer-assisted ultrasonography index, could be a marker of plaque instability as well as an indicator of plaque remodeling, thereby providing the means for monitoring anti-atherosclerosis drugs such as statins.

Keywords::

• carotid atherosclerosis
• carotid endarterectomy
• carotid plaque
• carotid stenosis
• carotid ultrasound
• echolucency
• plaque echomorphology
• stenting
• stroke prevention

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Carotid ultrasonography (CU) is a non-invasive technique that provides us with an accurate and reliable characterization of the broad spectrum of carotid arteriosclerosis, from the intima-media thickness (IMT) to the atherosclerotic plaque.

• • Carotid IMT has been linked to subclinical cardiovascular risk, improving the classification of the Framingham Risk Score (FRS).

• • Plaque echomorphology has emerged in recent years as an important contributor to stroke risk. CU studies have shown that hypoechoic and anechoic plaques carry a higher risk of cerebrovascular events than echogenic plaques. Similarly, heterogeneous plaques that present a complex pattern of echogenicity under ultrasound have been more frequently associated with the occurrence of neurological symptoms than homogeneous lesions. Plaque echomorphometry has emerged as a potential tool for improving the selection of patients who would benefit from revascularization (carotid endarterectomy (CEA) and carotid artery stenting (CAS)) and for measuring the degree of carotid stenosis.

• • The use of a quantitative computer-assisted ultrasonographic index of texture and echogenicity such as the gray-scale median (GSM) has greatly improved the correlation between plaque characterization, plaque histological components and clinical features, enabling a better identification of patient stroke risk. Furthermore, changes in plaque echogenicity by GSM could be a marker of plaque remodeling and stabilization.

• • Novel ultrasound techniques, such as three-dimensional (3D) analysis and contrast-enhanced ultrasound (CEUS), promise a better characterization of plaque anatomy and neovascularization. Both techniques are potential tools for establishing a more accurate assessment of stroke risk, thereby enabling a better selection of proper prevention therapies.

• • Ultrasound has shown that statins might have a dual beneficial effect on carotid plaque by reducing the size of the plaque and by remodeling the plaque, that is, by changing the plaque’s echogenicity, decreasing its lipid content and thickening the fibrous cap.

• • Given that it is highly predictive of stroke risk, the degree of carotid stenosis remains the key measurement for influencing revascularization decision-making.