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

我们之前开发了一种新的方法，即相位跟踪法，用于根据解调的超声信号的相位和幅度来精确跟踪心壁和动脉壁的运动，以确定对象的瞬时位置。使用这种方法，可以确定一次心跳期间壁厚的局部变化。我们现在已经开发了一种实时系统，用于连续测量动脉壁厚度的变化。该系统采用四片高速数字信号处理芯片，实时实现了初步开发的方法。将墙两侧的跟踪结果叠加在M(运动)模式图像上。可以成功地实时检测到小至几微米的动脉壁厚度的变化，具有良好的重复性。动脉壁的弹性是由血压得出的。在活体实验中，评估了一名年轻的健康受试者和一名年轻的吸烟者对给予硝酸甘油(NTG)后颈动脉壁厚度变化的快速反应。当厚度的变化与同时测量的压力相对应时，这些曲线也会因为使用NTG而发生变化。这在管理之后每隔35秒显示一次。这一新的实时系统通过评估心血管系统对NTG的快速反应，为早期动脉硬化的定量诊断提供了可能性。

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.