Contrast Carotid Ultrasound for the Detection of Unstable Plaques with Neoangiogenesis: A Pilot Study

Abstract

Contrast carotid ultrasonography may allow the identification of microvessels with neoangiogenesis at the base of carotid plaques, and differentiate symptomatic from asymptomatic plaques.

Current Strategies and Possible Perspectives of Ultrasonic Risk Stratification of Ischemic Stroke in Internal Carotid Artery Disease

“…Systematic histopathological validation revealed a direct positive correlation between contrast enhancement using this semi-quantitative grading scale and histology [44,45]. Furthermore, wholly consistent with the concept that more vulner- able plaque contains a higher degree of neovascularization, recent retrospective studies revealed the association between plaque enhancement on contrast-enhanced ultrasound imaging and clinical symptoms including cerebrovascular events in patients with carotid atherosclerosis [19,46,47]. Therefore, contrast-enhanced ultrasound examination of the carotid artery may provide a novel, noninvasive clinical tool to identify and quantify the presence and the extent of arterial plaque neovascularization in patients at risk for developing symptomatic atherosclerosis, thus permitting more reliable assessment of cardiovascular risk.…”

“…2, 3). Recent studies have shown that the grayscale values of symptomatic versus asymptomatic plaques differ significantly [19]. Visual scores, however, have the disadvantage of relatively high subjectivity, which is illustrated by a rather poor interrater and intrarater correlation [20].…”

“…Several studies have shown that this ectopic neovascularization (angiogenesis) is inherently linked with plaque vulnerability and plaque rupture, initiated and triggered by vascular cell leakage, inflammatory cell recruitment, and intraplaque hemorrhage [11,41]. Different reports using real-time contrast-enhanced ultrasound imaging techniques to directly visualize the microvasculature of the adventitial and intraplaque angiogenesis of the carotid artery in humans have recently been published [19,42,43]. Normally, contrast-enhanced ultrasound examinations in carotid vascular clinical studies are performed using a high-end ultrasound system equipped with a linear array, vascular probe with transmission frequencies ranging from 4 to 10 MHz, a low mechanical index, and dedicated contrast imaging software utilizing pulse inversion or harmonic techniques.…”

Contrast-enhanced ultrasound imaging of the vasa vasorum of carotid artery plaque

“…Ultrasound contrast agents have been administrated in millions of patients and are safe and side effects are extremely rare [11] . The presence of ultrasound contrast agents in carotid artery plaque represents the presence of the vasa vasorum in carotid artery plaque (Figures 1 and 2) because the ultrasound contrast agents (SonoVue) are strict intravascular tracers, and the appearance of contrast enhancement of CEUS was shown to correlate with the presence and degree of the vasa vasorum in carotid artery plaque which were assessed by histology [12,13] .…”

“…There are too many criterions about assessment of the vasa vasorum in carotid artery plaque with CEUS at the present [4][5][6][7][8][9]12,13] , which includes quantitative criterion, semi-quantitative criterion and qualltative criterion [4][5][6][7][8][9] , therefore, the criterion of assessment of the vasa vasorum in carotid artery plaque with CEUS is inconsistent among all kinds of clinical studies [4][5][6][7][8][9]12,13] . Thus, the clinical value of the vasa vasorum in carotid artery plaque with CEUS yet remain sure accurately, therefore, the criterion about assessment of the vasa vasorum in carotid artery plaque with CEUS should be assessed in the future studies.…”