"Development of system for diagnosis of early-stage arteriosclerosis using ultrasound"

在这项研究中，我们开发了一种新的方法来测量局部脉搏波速度，这是一个指数的硬度范围内的几毫米的主动脉壁。在标准方法中，根据从颈动脉传播到股动脉的压力波的到达时间差获得脉搏波速度（PWV）。在该方法中，可测量点限于主动脉存在于皮肤表面附近的那些点，并且这些点之间的距离相当长，即，几百毫米然而，测量动脉壁表面的局部硬度对于早期诊断是重要的。为了提高空间分辨率，需要测量频率成分高达约50 Hz的脉搏波引起的振动，因此，我们开发了一种新的系统，该系统基于超声多普勒效应从皮肤表面无创地测量心脏壁或主动脉壁上的微小振动信号。 关于我们 通过该系统，振幅为10 - 20的小振动在1 kHz的频率范围内，连续检测了10 mm大振幅的100 μ m左右的心搏运动。本研究还发展了一种通过同时测量管壁表面两点的微小振动来获得局部PWV的新方法。主动脉壁通过所开发的方法，高的空间分辨率，这是必要的局部硬度的评价，是实现。通过比较静态实验和动态实验，使用硅管，它被证实，血管壁的局部硬度（杨氏模量）也具有高的空间分辨率进行评估。通过应用所开发的系统和方法在体内实验，振动波的PWV之间的两个点之间的主动脉壁，即使是主动脉瓣附近。两点之间的距离大约是几毫米。还针对每个测量点评估局部弹性（杨氏模量）。因此，所开发的系统将是有效的主动脉壁上的硬度的局部评价。少

In this research, we have developed a new method to measure local pulse wave velocity, 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 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.Therefore, we have developed a new system to noninvasively measure small vibration signals on the heart wall or the aortic wall from the surface of the skin based on the ultrasonic Doppler effect. … More By this system, small vibrations with amplitudes of 10 - 100 mum on the motion due to heart beat with the large amplitude of 10 mm are successfully detected in the frequency range up to 1 kHz continuously for more than ten beat periods from the chest.This research also developed a new method for obtaining local PWV by simultaneously measuring small vibrations at two points on the surface of the tube wall and 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.By applying the developed system and the method to in vivo experiments, the PWV of the vibration wave transmitted between the two points on the aortic wall is obtained even for the aortic wall near the aortic valve. The distance between the two points is about several millimeters. The local elasticity (Young's modulus) is also evaluated for each measurement point. Thus, the developed system will be effective for local evaluation of the hardness on the aortic wall. Less