Visualization of coronary arteriole plexus image by contrast echocardiography

心肌超声造影（MCE）提供了有用的信息，如血流速度极低的毛细血管水平心肌灌注。低机械指数（MI）模式实现了实时灌注成像，而高机械指数模式则需要间歇成像。本研究的目的是观察心脏小动脉水平的灌注情况。方法：对开胸犬进行检查。在0.075mg/min的时间内，采用Sequoia 512 （SIEMENS）的相干对比成像技术，以各种力学指数（0.1-0.6）进行短轴视图实时MCE成像。注射YM454。采用Free-scan （3D- tec）磁传感器进行三维重建。结果：低心肌梗死（0.1 ~ 0.2）时混浊均匀，随着心肌梗死的增加，混浊逐渐变粗，最后逐渐消失。在MI 0.3 ~ 0.4时观察到小圆点和亮线。徒手扫描获得MCE在mi0.3处的三维重建，如图所示，显示了细小的冠状动脉复合体。结论：相对高的心肌梗死指数（0.3 ~ 0.4）提供了小动脉水平的灌注图像，血流速度可能较高。这些图像可能为利用MCE研究微循环提供新的信息。

Myocardial contrast echocardiography (MCE) provided useful information, such as myocardial perfusion at capillary level in which blood flow speed was extremely low. Low mechanical index (MI) realized real-time perfusion imaging, On the other hand, intermittent imaging was necessary at high MI mode. The aim of this study was to visualize the perfusion at arteriole level of heart.Methods : Open chest dogs were examined. The real-time MCE in the short axis view was performed using coherent contrast imaging with various mechanical index (0.1-0.6) by Sequoia 512 (SIEMENS) during 0.075mg/min. of YM454 infusion. 3D reconstruction was performed by Free-scan (3D-Tec) with the magnetic sensor.Result : Homogeneous opacification was obtained at low MI (0.1-0.2) and according to increase of MI, opacification became coarse and finally faded away. Small dots and bright lines was observed at MI 0.3-0.4. 3-D reconstruction of MCE at MI 0.3 was obtained by free-hand scanning as shown in a figure which shown the fine coronary arteriole complex.Conclusion : Relative high MI (0.3-0.4) provides the perfusion images at arteriole level in which blood flow speed might be high. And those images might provide a new information about microcirculation using MCE.