Research and Development of System for Continuous Measurement of Transient Response of Arterial Wall to Administration of Nitroglycerine

我们以前开发了一种新的方法，相位跟踪方法，用于准确地跟踪心脏壁和动脉壁的运动的基础上的相位和幅度的解调超声信号，以确定一个对象的瞬时位置。利用这种方法，可以确定在一次心跳期间壁厚度的局部变化。我们现在已经开发了一个实时系统，用于连续测量动脉壁厚度的变化。在该系统中，四个高速数字信号处理芯片用于实现真实的时间初步开发的方法。墙壁两侧的跟踪结果叠加在M（运动）模式图像上。可以成功地以良好的再现性在真实的时间内检测小至几微米的动脉壁厚度的变化。动脉壁的弹性来自血压。在体内实验中，评价了年轻健康受试者和年轻吸烟者的颈动脉壁厚度变化对硝酸甘油（NTG）给药的快速反应。当将厚度的变化相对于同时测量的压力作图时，这种曲线也由于NTG的施用而改变。给药后每35秒显示一次。这种新的实时系统提供了潜在的定量诊断早期动脉硬化的心血管系统NTG的快速反应的评价。

We previously developed a new method, the phased tracking method, for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated ultrasonic signals to determine the instantaneous position of an object. With this method, the local change in wall thickness during one heartbeat can be determined. We have now developed a real-time system for continuously measuring the change in thickness of the arterial wall. In this system, four high-speed digital signal processing chips are employed for realizing the initially developed method in real time. The tracking results for both sides of the wall are superimposed on the M (motion)-mode image. The change in thickness of the arterial wall as small as several micrometers can be successfully detected in real time with good reproducibility. The elasticity of the arterial wall is derived from the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the administration of nitroglycerine (NTG) is evaluated for a young healthy subject and a young smoker. When the change in thickness is plotted against the simultaneously measured pressure, such curves also change due to the administration of NTG. This is shown every 35 seconds after the administration. This new real-time system offers potential for quantitative diagnosis of early-stage arteriosclerosis by evaluation of the rapid response of the cardiovascular system to NTG.