"Research on noninvasive and quantitative measurement of small vibration in myocardium for early stage diagnosis of heart diseases"

在本研究中，我们开发了一种新的系统，以准确地测量心脏壁上的小振动信号。通过这种方法，在由具有10 mm的大幅度的心跳引起的运动中具有小于100 μ m的小幅度的心壁的小振动可以在高达几百赫兹的频率范围内连续地以足够的再现性成功地检测到大约十次心跳的周期。由此产生的小振动不仅在时域中，而且在频域中进行了分析。本文将该方法应用于左心室壁沿着超声束预设的多个点，同时获得了这些点处速度的空间（深度）分布。心脏壁的运动分为以下两个部分：心脏壁的平行整体运动和心肌收缩/舒张期间LV壁各深度处心肌层增厚的变化。后一个分量使用颜色cude叠加在M（运动）模式图像上，以将收缩映射为红色，将膨胀映射为蓝色。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/或变薄所产生的成分的频带。这种新的方法为无创性声学诊断心肌局部运动，即心室壁各深度心肌层功能的研究提供了可能。

In this research, we have developed a new system to accurately measure small vibration signal on the heart wall. By this method, small vibrations of the heart wall with small amplitudes less than 100 mum on the motion resulting from a heartbeat with large amplitude of 10mm can be successfully detected with suflicient reproducibility in the frequency range up to several hundred Hertz continuously for periods of about ten heartbeats. The resultant small vibration is analyzed not only in the time domain but also in the frequency domain. As confirmed by the experiments herein reported, the new method offers pontential for research in acoustical diagnosis of heart diseases.In this research, the method is applied to multiple points preset in the left ventricular (LV) wall along the ultrasonic beam so that the spetial (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 cude 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.