中文摘要：

目的采用血管内超声弹性成像（IVUSE）技术评价斑块的偏心指数（EI）与面积应变（AS）的关系，从力学角度揭示动脉粥样硬化斑块偏心性对斑块稳定性的影响。方法40只雄性纯种新西兰兔全程高脂饲料喂养12周。第2周末行腹主动脉球囊拉伤术。第12周末行腹主动脉血管内超声（IVUS）检查，每只动物选择两个等回声斑块（相距不小于1cm），采集不少于3个心动周期的原位IVUs图像，选择舒张末期连续两帧原位图像构建IVUS弹性图。结果偏心斑块（EI〉0.5）的斑块面积、斑块负荷、斑块体积负荷和斑块最小厚度明显小于向心斑块（EI〈0.5）（P〈0．05），但AS显著高于向心斑块[4．77（2．92，8．01）％对3．27（2．15，4．82）％，P=0．029]。斑块的偏心指数与斑块的面积应变呈中度正相关（r=0．392，P=0．003）。偏心斑块肩部的AS明显高于其体部[4．98（3．17，8．48）％对4．64（2．51，5．92）%，P=0．0081。结论动脉粥样硬化斑块的偏心性对斑块的力学稳定性有影响。偏心斑块较向心斑块力学稳定性差，这一特点尤其体现在偏心斑块的肩部。

英文摘要：

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-iniured 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.