The significance of ultrasonographic characteristics in the comprehensive radiological assessment of «high risk» carotid stenoses

Abstract

Background. The prevalence of asymptomatic carotid stenosis (ACS) requires the existence of an algorythm to identify patients at risk of ischemic stroke. Assessment of carotid atherosclerotic plaque (AP) based on its morphology and composition in addition to the quantitative parameter «stenosis» is possible using a complex of radiological studies including ultrasonographic ones, that can be deepened by new ultrasound techniques. Purpose – define ultrasonographic criteria for vulnerable carotid plaque based on evaluation of plaque characteristics using current ultrasonic techniques. Materials and methods. The study is based on the analysis of data obtained from 105 patients aged 41 to 84, diagnosed with stenosis of the internal carotid artery (ICA) according to ultrasonography (US). Examination methods – clinical, duplex US with the inclusion of shear wave elastography (SWE) and superb microvascular imaging (SMI) techniques to assess plaque stiffness and plaque microvascularisation; brain MRI, MSСT angiography (MSCTA), statistical. Two age-matched group were formed: a group with symptomatic carotid stenosis (SCS), 55 patients, and a group with asymptomatic carotid stenosis (ACS), 50 patients. Results. Statistically significant differences in the groups of patients with and without stroke were determined according to the following parameters of carotid plaques: quantitative criteria – maximum thickness (p = 0,02), with an AP thickness of more than 3.5 mm, the risk of stroke increases 2.2 times (p = 0,03), stenosis degree according to the NASCET protocol (p = 0,01 in the right ICA), plaque stiffness indicator according to SWE data (p = 0,001); qualitative criteria – type of plaque echogenicity according to the Gray-Weale classification (p = 0,001), presence of microvascularization according to SMI data (p = 0,04). Correlation of AP stiffness indicators according to SWE and MSCTA data (ρ = 0,60; р = 0,004) was established, as well as between AP stiffness according to SWE data and echo- type of AP (τ = 0,56; р = 0,006). Conclusions. Determination of plaque thickness greater than 3.5 mm, low plaque stiffness according to SWE data, the presence of microvascularization according to SMI data it is advisable to add to the complex of radiological assessment of carotid stenosis with a high risk of ischemic events, in addition to the standard US criteria of stenosis degree and AP echo-type.