A three-dimensional ultrasonographic quantitative analysis of non-ulcerated carotid plaque morphology in symptomatic and asymptomatic carotid stenosis

Abstract

Background and purpose Studies evaluating the association between carotid plaque composition and occurrence of ischemic cerebrovascular disease reveal inconsistent results. This study correlates the carotid echomorphology with the degree of stenosis in symptomatic and asymptomatic patients. Methods We included consecutive patients with hemispheric stroke or asymptomatic carotid artery stenosis assessed with 2D ultrasound. The echomorphology was assessed with mean gray value (MGV) of the three-dimensional (3D) volume. We used the free-hand approach for 3D image and volume acquisition. Analyses of the stored carotid plaque volumes were carried out offline using the Virtual Organ Computer-aided Analysis (VOCAL™) program. Results We studied 110 symptomatic and 104 asymptomatic atherosclerotic carotid plaques. MGV was lower in symptomatic carotid plaques causing <70% stenosis compared to plaques causing ≥70% stenosis (25.95 ± 7.40 vs. 32.16 ± 11.35, p = 0.002). There was no difference in MGV between plaques producing <60% and those with ≥60% in asymptomatic patients (32.08 ± 8.36 vs. 31.46 ± 9.25, p = 0.724). There were significant differences in MGV between symptomatic and asymptomatic plaques causing <60 or <70% stenosis; MGV was lower in symptomatic patients. Conclusions Lower plaque echogenicity is observed in symptomatic than in asymptomatic patients with moderate degree of carotid stenosis, indicating that it is a significant factor for the production of cerebral ischemia. Our method could be useful in assessing the risk of cerebral ischemia and the response of carotid artery atherosclerosis to medical therapies.