Real Time 3D Contrast Echocardiography for Assessment of Perfusion Defects

心肌声学造影无创性评价心肌灌注缺损可能成为评价冠心病患者的一种有价值的工具。然而，由于标准成像平面的数量有限，二维超声心动图定量灌注不足心肌具有内在的局限性。实时三维超声心动图（RT 3D echo）是一种无需心电图或呼吸门控即可提供容积图像的新技术。本研究的目的是验证在急性冠状动脉闭塞的体内模型中使用RT 3D回波定量评估心肌灌注缺损。为此，20只绵羊在全身麻醉下接受了左前降支（n=14）或回旋支后分支（n=6）的急性结扎。在冠状动脉闭塞和左心房注射造影剂（perflenapent乳剂或Echogen？; 0.8-1 ml）。图像采集后，将伊文思蓝染料注射到闭塞的冠状动脉中，用于随后的灌注不足心肌的解剖识别。在安乐死后直接测量整个左心室（LV）和灌注不足心肌区域的质量。采用基于Silicon Graphics工作站和定制软件的交互式辅助手动描记技术，根据RT 3D回波图像进行LV质量和灌注缺损质量的盲法离线计算。LV总质量范围为68 - 141 g（平均值+/-SD：92+/-24）。灌注缺损的质量范围为0 - 43 g（平均值+/-SD：16+/-9）或总LV质量的0 - 36%（平均值+/-SD：18+/-9%）。左室总质量的RT 3D回波估计与解剖测量值密切相关（r=0.91; y=-2.54 +1.04x; SEE= 11.9 g）。灌注不足心肌质量的RT 3D回波计算也与解剖测量结果密切相关，无论是绝对值（r=0.96; y= 2.01+0.87x; SEE= 2.2g）还是百分比（r=0.96; y= 0.11+1.02x; SEE= 2.8%）。因此，在急性冠状动脉闭塞的动物模型中，心肌造影剂显影的RT 3D回波准确预测灌注不足心肌的量。因此，这项技术可能是有用的定量评估心肌灌注缺损的冠状动脉疾病患者。- 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