Research on the developmental changes of central nervous system in the fetus using magnetocardiography and magnetoencephalography

心磁图和脑磁图研究胎儿中枢神经系统发育变化

基本信息

批准号：
12671061
负责人：
HORIGOME Hitoshi
金额：
$ 2.11万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

To assess the functional development of fetal central nervous system, we first analyzed heart rate variability in the fetus based on the data set of RR intervals obtained by fetal megnetocardiography (fMCG), fMCG was recorded in uncomplicated fetuses with the gestational age of 20-40 weeks, and power spectral analysis was applied to calculate the power of the low frequency band (LF), high frequency band (HF) and LF/HF ratio. Consequently, it was demonstrated that the power of LF (sympathetic activity) increases significantly with the gestational age although that of HF (parasympathetic activity) remained unchanged during the period. The LF/HF ratio also increases in proportion with the gestational age, indicating sympathetic dominance in later gestation. Thus, .fMCG is recognized as useful methodology to evaluate fetal autonomic nervous system or fetal well-being, as the detection rate of R waves and the time resolution are very high.Then, we attempted to measure auditory evoked magnet … More ic fields of the fetal - brain. The detection of fetal megnetoencephalogram (fMEG) has been considered very hard because the magnitude of fMEG signals is much weaker than that of fMlCG, almost at the level of units of 10^<-14> Tesla, and because signal averaging technique is difficult to apply due to non-cyclic nature of the signals. To improve the success, rate of recording fMEG, we refined the sensors of the SQUID system and realized spatial resolution of <10 fT/√<Hz>. fMEG was recorded over the site of fetal skull on maternal abdomen under stimulation with acoustic pulses (frequency, 0.5 or 1KHz ; magnitude, 70-100 dB ; width, 50 msec) with a stimulus frequency of 0.5 Hz for 8 min. The signals obtained were averaged triggered by the acoustic pulse. With this methodology, a peak of MEG signal was detected at 120 msec after the pulse in neonates immediately after birth, and two peaks were detected at 120 and 220 msec after the pulse in infants. However, no apparent fMEG peaks were determined for fetuses even in full term. We concluded that further improvement of sensitivity of the SQUID system, auditory stimulation and recording methods, and post processing of the'data would be required to assess the functional development or maturation of the fetal brain using fMEG. Less

为了评估胎儿中枢神经系统的功能发育，我们首先根据胎儿心磁图（fMCG）获得的RR间期数据集分析胎儿的心率变异性，fMCG记录于胎龄20-40岁的无并发症胎儿周，并应用功率谱分析计算了测试的低频段（LF）、高频段（HF）的功率以及LF/HF比值。 LF（交感神经活动）随着孕龄的增加而显着增加，尽管 HF（副交感神经活动）在此期间保持不变，LF/HF 比率也随着孕龄的增加而成比例增加，表明交感神经在妊娠后期占主导地位。 fMCG 被认为是评估胎儿自主神经系统或胎儿健康的有用方法，因为 R 波的检测率和时间分辨率非常高。然后，我们尝试测量听觉诱发磁体……更多胎儿脑磁图（fMEG）的检测一直被认为非常困难，因为fMEG信号的幅度比fMlCG弱得多，几乎在10^<-14>特斯拉单位的水平，由于信号的非循环性质，信号平均技术很难应用，为了提高记录fMEG的成功率，我们改进了SQUID系统的传感器，实现了<10的空间分辨率。 fT/√<Hz> 在声脉冲（频率，0.5 或 1KHz；幅度，70-100 dB；宽度，50 毫秒）刺激下，刺激频率为 0.5 Hz，记录母体腹部胎儿颅骨部位的 fMEG。所获得的信号由声脉冲触发平均，在新生儿的脉冲后 120 毫秒处检测到 MEG 信号峰值。出生时，在婴儿脉搏后 120 和 220 毫秒处检测到两个峰值，但即使足月胎儿也没有确定明显的 fMEG 峰值，我们得出的结论是 SQUID 系统、听觉刺激和记录方法的灵敏度进一步提高。，并且需要对数据进行后处理，以使用 fMEG Less 评估胎儿大脑的功能发育或成熟。