Research on the relationship between area strain and eccentric index of atherosclerotic plaques by intravascular ultrasonic elastography

Abstract

Objective To assess the relationships between area strain (AS) and eccentric index (EI) of atherosclerotic plaques as seen by intravascular ultrasonic elastography (IVUSE), and to reveal the effect of EI on the plaques stability. Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet; the abdominal aorta endothelium was balloon-injured after 2 weeks; at the end of week 12, 2 plaques with moderate echo from each rabbit were chosen for in situ imaging, and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram. Results The eccentric plaques showed significantly greater area stain (AS) than the centripetal plaques [4.77(2.92, 8.01)% vs 3.27(2.15, 4.82)%, P=0.029] with smaller plaque area and plaque burden (P<0.05). The plaque AS was positively correlated with EI (r=0.392, P=0.003). The eccentric plaques showed significantly greater AS in the shoulder than in body [4.98(3.17, 8.48)% vs 4.64(2.51, 5.92)%, P=0.008]. Conclusions The EI is one of influential factors on plaque AS.Eccentric plaques may be more vulnerable than centripetal plaques, especially in the shoulder of eccentric plaques which have greater AS than their body. Key words: Intravascular ultrasound elastography; Atherosclerotic plaque; Eccentric index; Area strain