"Development of a method for evaluation of myocardium based on noninvasive measurement and nonstationary spectrum analysis of small vibration on heart wall"

为了基于心肌声学特征的心脏病无创诊断，我们开发了一种准确跟踪心壁运动的新方法。通过这种方法，可以成功地检测到由振幅为10毫米的大心跳引起的小振幅小于10毫米的心壁速度信号，并且在长达几百赫兹的频率范围内具有足够的再现性，连续周期约为10次心跳。在本研究中，将该方法应用于沿超声束在左室壁上预设的多个点，从而同时获得这些点上速度的空间（深度）分布。心壁的运动分为以下两部分：心壁的平行全局运动和心肌收缩/舒张期间穿过左室壁各深度心肌层增厚的变化。后一个分量被叠加在M（运动）模式图像上，使用颜色代码将收缩映射为红色，扩展映射为蓝色。通过初步的人体研究，验证了本文提出的方法的原理，并确定了心肌增厚和/或变薄产生的成分的频带。这种新方法为心肌局部运动（即心室壁各深度心肌层功能）的无创性声学诊断提供了研究潜力。

For the noninvasive diagnosis of heart disease based on the acoustic characteristics of the heart muscle, we have developed a new method for accurately tracking the movement of the heart wall. By this method, a velocity signal of the heart wall with a small amplitude of less than 10 mum on the motion resulting from a heartbeat with large amplitude of 10 mm can be successfully detected with sufficient reproducibility in the frequency range up to several hundred Hertz continuously for periods of about ten heartbeats.In this research, the method is applied to multiple points preset in the left ventricular (LV) wall along the ultrasonic beam so that the spatial (depth) distributions of the velocity at these points are simultaneously obtained. The motion of the heart wall is divided into the following two components : parallel global motion of the heart wall and the change in myocardial layr thickening at each depth across the LV wall during myocardial contraction/relaxation. The latter component is superimposed on the M (motion) -mode image using a color code to map contraction as red and expansion as blue. By preliminary human studies, the principle of the method proposed in this paper is verified and the frequency band of the components generated by thickening and/or thinning in the myocardium is identified. This new approach offers potential for research on noninvasive acoustical diagnosis of myocardial local motility, that is, the myocardial layr function at each depth in the ventricular wall.