Assessment of neovascularization in atherosclerotic carotid sinus plaques using quantitative contrast-enhanced ultrasound perfusion imaging

Abstract

Aim. To assess the prospects of using quantitative contrast-enhanced ultrasound perfusion imaging of atherosclerotic carotid sinus plaques.Material and methods. The study included 5 men and 1 woman (59-76 years old, median 72) with symptomatic coronary sinus atherosclerosis. The inclusion criterion was history of ischemic stroke due to internal carotid artery lesion (NASCET >60%). We performed contrast-enhanced ultrasound perfusion imaging of the carotid arteries, endarterectomy, studying pathomorphology of the removed plaque with the calculation of the neovascular density and the total number of neovessels with a diameter <40 μm. Neovascularization was assessed by quantitative contrast-enhanced ultrasound 20 seconds after the 1 ml infusion of Sonovia (Bracco, Italy) and subsequent application of the flash. The analysis of dynamics of ultrasonic signal intensity in the atherosclerotic plaque was carried out by creating the curves of the ultrasonic signal intensity (dB)/time (s) over 3 segments of the cross section of the internal carotid artery long axis. The automatic calculation of the intensity dynamics took into account the parameter values in the studied areas within 20 s after the flash. The calculated coefficients (A, B, β) of the exponential equation for 3 atherosclerotic segments were recorded.Results. Perfusion and neovascularization were assessed in 27 segments of atherosclerotic plaques. The correlation relationships between the ultrasonic parameters of plaque perfusion and the severity of neovascularization were assessed according to the histological data. Significant correlations of the exponential curve coefficient β and histological parameters characterizing the prevalence of “young” vessels (<40 microns) in the atherosclerotic plaque were revealed. Spearman’s R for the density of neovessels was 0,54; for the number of neovessels with a diameter <40 μm. —0,66 (p<0,01).Conclusion. Diagnosis of atherosclerotic plaque neovascularization becomes possible to quantify, assessing not only the presence of neovascular vessels, but also the perfusion intensity. The novel approach replaces the qualitative and semi-quantitative method for calculating the number of carotid plaques neovessels in vivo.

Keywords

• carotid stenosis
• perfusion
• neovascularization
• quantitative analysis