摘要
目的：探讨定量组织速度成像技术评价左心室急性心内膜下心肌缺血后局部心肌收缩舒张功能改变的价值。方法：经微导管向11只健康杂种犬左冠状动脉回旋支近端推注一定直径的血管栓塞微球，不开胸制备心内膜下心肌缺血模型。应用自制超声造影微气泡进行实时心肌超声造影（MCE），对节段室壁心肌造影强度时间曲线进行指数方程Y=A·（1-exp^-β·t）拟合。结果：冠状动脉内注射微球后，MCE发现28个节段左室壁心内膜下心肌血流灌注异常，标化后的A·β值明显降低（P〈0．05），对应的心外膜下心肌A·β标化值无明显变化（P〉0．05）。28个节段心肌室壁增厚率栓塞前后差异无统计学意义（P〉0．05），而心内膜下心肌缺血节段心肌长轴方向收缩期峰值运动速度和舒张早期峰值速度均明显减低（P〈0．05），等容舒张期速度曲线也由负向波为主转为正向波为主。结论：心肌长轴方向运动速度能够更加敏感、准确地发现急性心内膜下缺血导致的局部心肌收缩与舒张功能损伤改变和收缩后收缩现象。
Objective To explore the value of quantitative tissue velocity imaging （QTVI） in assessing regional myocardial systolic and diastolic functions in dogs with acute subendocardial ischemia. Methods Microsphere suspensions of 200 to 300 μm in diameter, with the amount of 3.5 ×10^4 microspheres, were injected into the proximal portion of left circumflex coronary artery in 11 closed-chest dogs via micro-catheters to induce subendocardial ischemia by embolization. Before and after embolization,2D echocardiography, QTVI and real time myocardial contrast echocardiography （MCE） by intravenous infusion of self-made microbubbles were performed separately. The regional myocardial contrast intensity versus time plots were fitted to an exponential function： Y = A· （1-exp^-β·t）, the product of A and β represented myocardial blood flow. Results MCE showed that subendocardial normalized A · β decreased severely （ P〈0. 05） in 28 left ventricular segments after embolization, including 6 basal and 9 middle segments of lateral wall,8 middle segments of posterior wall and 5 middle segments of inferior wall （IW）. However, subepicardial normalized A ·β did not decrease significantly. Although the systolic wall thickening did not change 5 minutes after embolization in these ischemia segments [（29 ±3）%vs （31± 5）%, P 〉0. 05], the subendocardial longitudinal peak systolic velocities and early-diastolic peak velocities recorded by QTVI declined significantly（ P 〈0.05）. Moreover, the subendocardial motion velocity curves during isovolumic relaxation predominantly showed positive waves, whereas they mainly showed negative waves before embolization. Conclusions Longitudinal peak systolic velocity, peak velocity during isovolumic relaxation and early-diastolic velocity are sensitive indices for the detection of subendocardial ischemia.
出处
《中华超声影像学杂志》
CSCD
2007年第8期706-710,共5页
Chinese Journal of Ultrasonography
关键词
超声检查
造影剂
心肌缺血
心室功能
左
组织速度成像
造影剂
Ultrasonography
Contrast media
Myocardial ischemia
Ventricular function, left
Tissue velocity imaging
