Real Time 3D Contrast Echocardiography for Assessment of Perfusion Defects

心肌声学造影剂超声心动图对血流灌注缺陷的无创性评估在评价冠心病患者方面可能是一种有价值的工具。然而，由于标准成像平面数目的限制，二维超声心动图定量欠灌注心肌有其固有的局限性。实时三维超声心动图(RT3D ECHO)是一种无需心电或呼吸门控即可提供容积图像的新技术。本研究的目的是在急性冠状动脉闭塞的活体模型中验证使用RT3D ECHO定量评估心肌灌注缺陷。为此，20只绵羊在全身麻醉下急性结扎左前降支(n=14)或旋支后支(n=6)。在冠状动脉闭塞和左房注射造影剂(全氟乳剂或Echogen？，0.8-1ml)后，获得RT3D回声图像。图像采集完成后，将伊文思蓝染料注入闭塞的冠状动脉，用于随后对欠灌注心肌的解剖识别。在安乐死后，直接测量整个左心室(LV)的质量和心肌灌注不足区域的质量。采用基于Silicon Graphics工作站和定制软件的交互式辅助手动跟踪技术，从RT3D回波图像中盲离线计算左室质量和灌注缺损区质量。左心室总质量68~141g，平均+/-SD：92+/-24。灌注缺损区的质量范围为0~43g(平均+/-SD：16+/-9)或0~36%(平均+/-SD：18+/-9%)。总LV质量的RT3D回声估计与解剖测量高度相关(r=0.91；y=-2.54+1.04x；SEE=11.9g)。在绝对(r=0.96；y=2.01+0.87x；SEE=2.2g)和百分比(r=0.96；y=0.11+1.02x；SEE=2.8%)方面，RT3D心肌质量的RT3D回声计算与解剖测量也有很强的相关性。因此，在急性冠脉闭塞的动物模型中，具有心肌造影剂的RT3D回声可以准确地预测心肌灌注不足的数量。因此，这项技术可能有助于定量评估冠心病患者的心肌灌注缺陷。三维超声心动图；心肌灌注；冠脉循环

Non-invasive assessment of perfusion defects with myocardial contrast echocardiography can potentially be a valuable tool in the evaluation of patients with coronary artery disease. However, quantification of under-perfused myocardium with two-dimensional echocardiography has intrinsic limitations due to the restricted number of standard imaging planes. Real-time three-dimensional echocardiography (RT3D echo) is a novel technique that provides volumetric images without ECG or respiratory gating. The aim of this study was to validate the use of RT3D echo for the quantitative assessment of myocardial perfusion defects in an in vivo model of acute coronary occlusion. To this end, 20 sheep underwent acute ligation of the left anterior descending (n=14) or the posterior branch of the circumflex (n=6) artery under general anesthesia. RT3D echo images were obtained after coronary occlusion and left atrial injection of a contrast agent (perflenapent emulsion or Echogen?; 0.8-1 ml). After image acquisition, Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of under-perfused myocardium. The mass of the entire left ventricle (LV) and of the under-perfused myocardial region were directly measured following euthanasia. Blinded off-line calculation of LV mass and perfusion defect mass from RT3D echo images were performed using an interactive aided manual tracing technique based on a Silicon Graphics workstation with customized software. Total LV mass ranged from 68 to 141 g (mean+/-SD: 92+/-24). The mass of the perfusion defect ranged from 0 to 43 g (mean+/-SD: 16+/-9) or 0 to 36% of total LV mass (mean+/-SD: 18+/-9%). RT3D echo estimation of total LV mass strongly correlated with the anatomic measurement (r=0.91; y=- 2.54+1.04x; SEE= 11.9 g). RT3D echo calculation of the mass of under- perfused myocardium also strongly correlated with the anatomic measurement, both in absolute (r=0.96; y= 2.01+0.87x; SEE= 2.2g) and percent (r=0.96; y= 0.11+1.02x; SEE= 2.8%) terms. Thus, RT3D echo with myocardial contrast opacification accurately predicts the amount of under-perfused myocardium in an animal model of acute coronary occlusion. This technique may therefore be useful for the quantitative assessment of myocardial perfusion defects in patients with coronary artery disease. - three-dimensional echocardiography; myocardial perfusion; coronary circulation