Simultanous Measurement of Velocity Signals at Multiple Points in the Heart Wall for Noninvasive Evaluation of Left Ventricular Inner Pressure and Elastic Modulus

通过相位跟踪方法发现，心肌运动表现出高达100赫兹的频率分量。为了同时测量左心室(LV)表面多个点的快速和微小速度信号，本研究对常规超声诊断设备进行了改进，允许实时任意选择扇形扫描仪的10条扫描线进行分析。考虑到心壁速度的最大值和距胸部表面的最大深度，为了避免混叠，超声脉冲的传播方向应谨慎地确定为10个，这远远少于常规组织多普勒成像(TDI)所采用的数目。应用该系统，对三名健康志愿者同时测量了心壁约240个点的速度信号。在舒张末前后短短35ms的时间内，心壁的速度信号在空间上发生变化。在系统…的末尾在室间隔(IVS)底部附近的子波中，慢脉搏持续约30ms，正好在第二心音的辐射时间之前。然后，就在主动脉瓣关闭的时候，出现了一个陡峭的脉搏。底部的陡峭脉冲比顶点的脉冲快几毫秒。通过对每个小波的傅里叶变换，清晰地显示了陡峭脉冲分量的相位空间分布。将该测量方法应用于两例主动脉瓣狭窄(AS)患者，可在射血期直接检测到与心音杂音相对应的不规则振动信号。在传统的TDI中，只显示由于心跳而引起的大的缓慢运动，而不能显示这些快速和微小的速度分量。此外，在本研究中，首次从沿10条扫描线的多个点同时测量的每个速度信号中检测到相位分量。这种测量和分析方法为心功能不全的新诊断技术提供了可能性。较少

Myocardial motion exhibits frequency components of up to 100 Hertz as found by a phased tracking method. To simultaneously measure the rapid and minute velocity signals at multiple points along the surface of the left ventricle (LV), in this study, conventional ultrasonic diagnosis equipment was modified to allow 10 scan lines from a sector scanner to be arbitrarily selected in real time for analysis. By considering the maximum value of the velocity in the heart wall and the maximum depth from the chest surface, the number of transmission directions of the ultrasonic pulses should be carefully confirmed to be 10 to avoid aliasing, which is much less than the number employed in conventional tissue Doppler imaging (TDI). By applying the system, the velocity signals at about 240 points in the heart walls were simultaneously measured for three healthy volunteers. During a short period of 35 ms around end-diastole, the velocity signals varied spatially in the heart wall. At the end of systo … More le, in the wavelets near the base of the interventricular septum (IVS), the slow pulse continued for about 30 ms just before the radiation timing of the second heart sound. Then, a steep pulse occurred just at the timing of the closure of the aortic valve. The steep pulse at the base preceded that at the apex by several milliseconds. By Fourier transforming each wavelet, the spatial distribution of the phase of the steep pulsive components were clearly displayed. By applying the measurement method to two patients with aortic stenosis (AS) , irregular vibration signals, which correspond to the murmur of the heart sound, could be directly detected during ejection period. In conventional TDI, only the large slow movements due to the heartbeat are displayed, while these rapid and minute velocity components cannot be displayed. In this study, moreover, the phase components were detected for the first time from each of the velocity signals simultaneously measured at multiple points along the 10 scan lines. This measurement and method of analysis offer potential for new diagnostic techniques in cardiac dysfunction. Less