中文摘要：

目的 采用血管内超声弹性成像技术评价斑块负荷（PB）与面积应变（AS）的关系。方法 对40只雄性纯种新西兰兔全程高脂饲料喂养。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检查,对每只动物选择两个等回声斑块,采集不少于3个心动周期的原位血管内超声图像,选择舒张末期连续2帧原位图像,构建血管内超声弹性图。测量并计算血管外弹力膜面积（EEMarea）、血管腔面积（Lumenarea）、斑块面积（PA）、PB、血管外弹力膜体积（EEMvolume）、血管腔体积（Lumenvolume）、斑块体积（PV）、斑块体积负荷（PVB）、斑块最大厚度（Tmax）、斑块最小厚度（Tmin）、斑块偏心指数（EI）、血管重构指数（RI）及AS。根据PB不同,将斑块分为低负荷斑块组（PB≤40%）和高负荷斑块组（PB〉40%）,并对两组间以上参数的差异、斑块形态学和力学参数的关系等进行统计学分析。结果两组的PA、PV、PB、PVB、Tmin、Tmax、Lumenarea、Lumenvolume、EI差异均有统计学意义（P均〈0.01）。经逐步多元线性回归分析,回归方程为：Y=-6.921＋10.430 X1＋12.207 X2（Y：AS;X1：EI;X2：PB;R2=0.272,P〈0.001）。在矫正偏心指数对AS的影响后,低负荷斑块组的AS明显小于高负荷斑块组（P=0.010）。结论 动脉粥样硬化斑块的负荷对斑块力学稳定性有影响。高负荷斑块较低负荷斑块更易受损。

英文摘要：

Objective To assess the relationship between plaque burden （PB） and area strain （AS） by intravascular ultrasonic elastography （IVUSE）. Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet. And the abdominal aorta endothelium was balloon-injured after 2 weeks. At the end of the 12th week, 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 elas- togram. Cross-sectional external elastic membrane area （EEMare）, lumen area （Lumen area）, plaque area （PA）, PB, external elastic membrane volume （EEMvolume）, lumen volume （Lumen volume）, plaque volume （PV）, plaque volume burden （PVB）, maximal plaque thickness （Tmax） and minimal plaque thickness （Tmin）, eccentric index （EI）, remodeling index （RI） and AS were measured and calculated, respectively. According to the PB, the plaques were divided into low PB group （PB≤40 % ） and high PB group （PB〉40%）. The differences of all above parameters between the two groups were compared, and the relationship between the plaque morphological and mechanical parameters were analyzed. Results PA, PV, PB, PVB, Tmin, Tmax, Lumenarea, Lumenvolume and EI were different between the 2 groups （all P〈0. 01）. On stepwise multiple regression analysis, the regression equation were built, Y=-6. 921＋10. 430X1 ＋12. 207X2 （Y： AS, XI： EI, X2： PB, R2 =0. 272, P〈0. 001）. After eliminating the effect of EI on the AS, the lower PB group had obviously smaller AS than higher PB group （P=0. 010）. Conchtsion The PB has effect on plaque mechanical stability. The plaques with higher burden are more vulnerable than those with lower burden.