Association of symptomatic atherosclerotic carotid arteries with plaque areas showing low densities on computed tomographic angiography

Intraplaque hemorrhage is a key feature of vulnerable carotid atherosclerotic plaque (CAP), associated with low densities (<25 Hounsfield units [HU]) on computed tomographic angiography (CTA). This study aimed to analyze CAP on routine CTA performed in patients with symptomatic and asymptomatic carotid stenosis undergoing carotid endarterectomy (CEA) by assessing HU of the CAP area showing the lowest density (CAPALD) using radiological tools available in daily clinical practice, and to compare CAPALD values between symptomatic and asymptomatic carotids.We retrospectively screened preoperative CTA scans of 206 consecutive adult patients undergoing CEA for symptomatic or asymptomatic stenosis. CAPALD values were compared between symptomatic and asymptomatic carotids. Asymptomatic carotids included arteries contralateral to the symptomatic CEA artery, and asymptomatic stenotic arteries undergoing CEA and their contralateral arteries. Carotids were excluded when there was <30% stenosis, or when CAP could not be identified or CAPALD could not be measured.In total, 95 symptomatic and 112 asymptomatic carotids (derived from 174 patients) were analyzed. In multivariate analysis, symptomatic arteries showed more severe stenosis (median 70% vs. 67%, p = 0.0228) and lower CAPALD values (median 17 vs. 25 HU, p = 0.049), whereas degree of stenosis and CAPALD values were not correlated (rho = -0.02, p = 0.77). HU values of <25 were more frequent in symptomatic than asymptomatic carotids (68% vs. 47%, p = 0.0022).On CTA, symptomatic carotids are associated with CAP areas with low densities. CTA analysis of CAP may be interesting to help identify vulnerable plaques at risk for future stroke, especially in patients lacking strict indications for CEA based on the current guidelines.