应用实时心肌造影超声心动图对心肌灌注的定量评价

Quantitative assessment of myocardium perfusion using real-time myocardial contrast echocardiography

目的 确定实时心肌灌注显像技术定量评价左心室各节段心肌灌注的可行性。方法 应用实时显像技术对 10条麻醉犬采集左室乳头肌中段短轴观图像。机械指数 (MI)分别调至 0 .1,0 .2和 0 .4,帧速设为 2 0Hz,Optison分别以 0 .1,0 .2和 0 .5ml/min的速度静脉滴注。在 2～ 3次多普勒诱导微泡破裂后立即记录 150帧实时图像。用肉眼和定量两种方法评价左室 6节段的心肌浊化程度 (前间隔、后间隔、下壁、后壁、侧壁和前壁 )。以心肌信号强度对应实时图像制作曲线并拟合指数函数Y =A (1-e- βt)。结果 采用低MI(MI为 0 .1或 0 .2 )并以 0 .2或 0 .5ml/min的速度静脉滴注Optison的方法 ,实时显像技术可以获得充分的心肌浊化和清晰的左室心内膜轮廓 ,并能同时显示心肌增厚率和室壁运动。结论实时心肌灌注显像技术不仅能够定量评价心肌灌注 。

ObjectiveTo determine the possibility of r eal-time perfusion imaging in the quantitative evaluation of myocardial perfusion in various segments of left ventricle. MethodsImages of ten anesthetized dogs were obtained at the mid-papillary muscle short-axis view with a real-time imaging system. Mechanical index (MI) was adjusted to 0.1 , 0.2 and 0.4 respectively, and frame rate was set at 20 Hz. Optison was infused intravenously at a rate of 0.1 , 0.2 and 0.5 ml/min, respectively. Images were recorded for 150 real-time frames commencing immediately after a couple of Doppler bursts. Myocardial opacification was assessed both visually and quantitatively for six segments of left ventricle (antero- and infero-septum, inferior, posterior, lateral and anterior wall). Myocardial signal intensity versus real-time frame curves were made and fitted to an exponential function: Y=A(1-e -βt ). ResultsUsing low MI (MI= 0.1 or 0.2 ) and with continuously infusion of Optison at a rate of 0.2 or 0.5 ml/min, real-time imaging resulted in sufficient myocardial opacification and left ventricular endocardial border definition, and displayed myocardial thickening and wall motion simultaneously. ConclusionsReal-time imaging has a potential in the quantitative assessment of myocardial perfusion, and allows simultaneous assessment of perfusion and myocardial function.