Daimon Masao, Beppu Shintaro, Ishikura Fuminobu, Ueda Hiroaki, Kayano Hiroyuki, Kobayashi Haruka, Kashiwagi Yasushi, Yagura Sachiko, Hirata Kumiko, Yoshikawa Junichi
Department of Internal Medicine of Cardiology, Graduate School of Medicine, Osaka City University, Osaka.
J Cardiol. 2002 Jul;40(1):11-7.
Myocardial contrast echocardiography observes heterogeneous opacification between regions near and far from the transducer depending on the depth of the focus point. The efficacy of the multi-focus setting was investigated for the improvement of this heterogeneous opacification of the myocardium in myocardial contrast echocardiography.
Myocardial contrast echocardiography was performed in five closed-chest dogs using triggered (every fourth cardiac cycle) second harmonic technology (1.8/3.6 MHz) following intravenous injection of 0.1 ml of Optison. The short-axis view of the left ventricle was recorded and baseline subtracted video intensity (peak intensity) was calculated in the anterior, septal and posterior left ventricular walls to evaluate myocardial opacification. Three different single foci at near (2 cm), middle (4 cm), and far (6 cm) points were examined, as well as the multi-focus setting combining the near and far foci.
Using any single focus point, the peak intensities of segments far from the focus points were decreased and heterogeneous myocardial opacification was observed. Only the multi-focus setting demonstrated absence of differences in peak intensities between each segment with sufficient myocardial opacification of all segments.
The multi-focus setting may be advantageous for improving the heterogeneity of myocardial opacification in myocardial contrast echocardiography.
心肌对比超声心动图根据焦点深度观察换能器远近区域之间的不均匀显影。研究了多焦点设置在改善心肌对比超声心动图中心肌这种不均匀显影方面的效果。
对五只开胸犬进行心肌对比超声心动图检查，静脉注射0.1 ml欧乃影后，使用触发（每四个心动周期）二次谐波技术（1.8/3.6 MHz）。记录左心室短轴视图，并计算左心室前壁、室间隔和后壁的基线扣除视频强度（峰值强度）以评估心肌显影。检查了近（2 cm）、中（4 cm）、远（6 cm）三个不同的单焦点，以及结合近焦点和远焦点的多焦点设置。
使用任何单焦点时，远离焦点的节段的峰值强度降低，观察到心肌显影不均匀。只有多焦点设置显示各节段之间的峰值强度无差异，且所有节段心肌显影充分。
多焦点设置可能有利于改善心肌对比超声心动图中心肌显影的不均匀性。
