[Contribution of contrast enhanced ultrasonography in the characterization of carotid lesions]

Abstract

Harmonic mode ultrasound with injection of a contrast enhancement agent allows visualization of mobile microbubbles in the carotid plaque corresponding to neovessels secondary to an inflammation or hypoxia. These neovessels could be considered "precursor" markers of the vulnerable plaque. The aim of this work was to give an update on ultrasound contrast imaging acquisition in the exploration of carotid artery both for atheromatous lesions and for large vessel vasculitis. A precise description of the material to be used, the image acquisition methodology and the environmental conditions is discussed, emphasizing the pitfalls to be avoided as well as proper image interpretation. Microbubbles in a plaque are significantly associated with an increase in cardiovascular events (infarction and acute coronary syndrome) and ipsilateral cerebral ischemic events. Wall irregularities, microfissures and ulcer plaque detection are facilitated by the use of contrast compared to the CT scan. No studies have yet validated contrast enhanced ultrasound in the exploration of asymptomatic carotid stenosis. Contrast enhanced ultrasound also allows to detect vasculitis of the large vessels active phases by the presence of microbubbles in the carotid wall thickening and to monitor the regression under appropriate medical treatment. Future validation studies or even registries are needed to allow better use of this tool in everyday clinical practice.

Keywords: Arteritis; Artérite; Carotid plaque; Contrast enhanced ultrasound; Neovascularization; Néovascularisation; Plaque carotidienne; Échographie de contraste.