A Study on development of realtime system for diagnosis of regional elasticity of myocardium and arterial wall using ultrasound

在这项研究中，我们开发了一种新的系统来精确测量心壁和动脉壁上的微小振动信号。通过这种方法，可以成功地检测到由10 mm的大幅度心跳引起的小幅度小于100微米的心壁小振动，并且在高达几百赫兹的频率范围内连续10次心跳的周期具有足够的重复性。所产生的微小振动不仅在时间域中分析，而且在频率域中分析。本文报道的初步实验证实，该方法为心脏疾病的声学诊断研究提供了潜力。另一方面，该系统也适用于局部脉搏波速度的测量，这是衡量主动脉壁几毫米范围内硬度的指标。在标准方法中，脉搏波速度(PWV)是由…的到达时间之差得到的更多的压力波从颈动脉传播到股动脉。在这种方法中，可测量的点仅限于主动脉位于皮肤表面附近，并且这些点之间的距离相当长，即数百毫米。然而，测量动脉壁表面的局部硬度对于早期诊断很重要。为了提高空间分辨率，需要测量频率高达50赫兹的脉搏波引起的振动。所开发的系统还适用于通过同时测量主动脉壁表面两个点的微小振动来测量局部PWV。该方法具有较高的空间分辨率，是评价局部硬度所必需的。通过硅管静态实验和动态实验的对比，证实了管壁的局部硬度(杨氏模数)也具有较高的空间分辨率。还对每个测量点的局部弹性(杨氏模数)进行了评估。因此，开发的系统也将是有效的局部评估的硬度在主动脉壁。较少

In this research, we have developed a new system to accurately measure small vibration signal on the heart wall and arterial 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 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. The resultant small vibration is analyzed not only in the time domain but also in the frequency domain. As confirmed by the preliminary experiments herein reported, the new method offers potential for research in acoustical diagnosis of heart disease.On the other hand, this system is also applicable to the measurement of local pulse wave velosity, which is an index of the hardness in the range of several millimeters on the aortic wall. In the standard method, the pulse wave velocity (PWV) is obtained from the difference in arrival time of … More pressure waves propagating from the carotid artery to the femoral artery. In this method, the measurable points are limited to those where the aorta exists near the skin surface and the distance between such points is considerable long, i. e., several hundred millimeters. It is important for early diagnosis, however, to measure the local hardness of the surface of the arterial wall. To increase the spatial resolution, it is necessary to measure vibrations due to pulse waves with frequency components up to about 50 Hz.The developed system is also applied to measurement of local PWV by simultaneously measuring small vibrations at two points on the surface of the aortic wall. By the developed method, high spatial resolution, which is necessary in the evaluation of local hardness, is attained. By comparing the static experiments and dynamic experiments using a silicon tube, it is confirmed that the local hardness (Young's modulus) of the vessel wall is also evaluated with high spatial resolution. The local elasticity (Young's modulus) is also evaluated for each measurement point. Thus, the developed system will be effective also for local evaluation of the hardness on the aortic wall. Less