Shinozuka N, Yamakoshi Y, Okai T, Taketani Y
Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tokyo.
Nihon Sanka Fujinka Gakkai Zasshi. 1994 Jan;46(1):13-20.
Utilization of the fetal behavioral information in clinical medicine requires the development of an automated monitoring technique. As previously reported, the off-line signal processing of the low frequency Doppler signals by high accuracy displacement estimation made it possible to measure fetal breathing movements (FBM). However, there were several problems to solve before clinical application. We propose an advanced system that provides real-time calculation. The multi-channel pulsed doppler device was newly developed by modifying the Doppler ultrasound module of the cardiotocograph (CTG). A new signal processing algorithm was designed to produce real-time measurements. To improve the resolution, the backing module was attached to the probe. On-line signal processing produced a successful real-time and continuous calculation of displacement inside tissue. By means of an on-line 2/3 Hz high pass filter, the very low frequency noises and the artifacts derived from maternal respiration etc. were removed. The signal/noise ratio was obviously increased and the waves of fetal tissue movements due to FBM were easily recognized in real-time LCD outputs. Although there is a limitation in measuring accuracy as far as using modified CTG units, the results demonstrate that our system has commendable quality in FBM tracking.
在临床医学中利用胎儿行为信息需要开发一种自动监测技术。如先前报道，通过高精度位移估计对低频多普勒信号进行离线信号处理，使得测量胎儿呼吸运动（FBM）成为可能。然而，在临床应用之前有几个问题需要解决。我们提出了一种提供实时计算的先进系统。通过修改胎心宫缩图（CTG）的多普勒超声模块，新开发了多通道脉冲多普勒设备。设计了一种新的信号处理算法以进行实时测量。为了提高分辨率，在探头处附加了背衬模块。在线信号处理成功地对组织内的位移进行了实时连续计算。通过在线2/3 Hz高通滤波器，去除了极低频率噪声以及源自母体呼吸等的伪像。信噪比明显提高，并且在实时液晶显示器输出中可以很容易地识别出由FBM引起的胎儿组织运动波。尽管就使用改进的CTG设备而言，测量精度存在局限性，但结果表明我们的系统在FBM跟踪方面具有值得称赞的质量。
