Zappasodi F, Tecchio F, Pizzella V, Cassetta E, Romano G V, Filligoi G, Rossini P M
Istituto di Elettronica dello Stato Solido, C.N.R., Roma, Italy.
Brain Res. 2001 Nov 2;917(2):167-73. doi: 10.1016/s0006-8993(01)02901-8.
MagnetoEncephaloGraphy (MEG) is proposed as a non-invasive technique to detect the physiological activity of fetal brain, due to its ability to record brain activity without direct contact with the head and the transparency of magnetic signals in passing through extracerebral fetal layers and the mother's abdomen. Healthy women with uncomplicated pregnancies and fetuses in breech presentation were examined; gestational ages at time of study ranged between 36 and 40 weeks. In order to evaluate fetal well-being, ultrasound and cardiotocographic data were assessed a few days before and after MEG recording sessions. The participating women were placed in a semi-reclining position in a magnetically shielded room; here the presentation of the fetus and precise region of the mother's abdomen corresponding to the fetal head were determined by ultrasound investigation in order to place the MEG detecting system as near as possible to the fetal brain. MEG recordings were performed by means of a 28-channel neuromagnetic system. Every MEG recording session was performed during the acoustic stimulation of fetuses, in order to detect the cerebral events evoked by peripheral stimuli. The auditory stimuli were delivered from a plastic tube placed on mother's abdomen, near the fetal head, and consisted of a 300 ms 103 dB pure tone at 500 and 1000 Hz, presented at a 0.4 c/s repetition rate. In six cases following accurate digital subtraction of maternal and fetal electrocardiographic (EKG) signals we remained with a stimulus-related response peaking at about 250 ms; this was considered to originate from the fetal brain. In favour of this in three cases a clear dipolar distribution was evident at the peak of brain response centered on the fetal head and consistent with a brain generator. Despite several technical problems requiring solution before a possible routine clinical application, MEG has been found to be suitable for the non-invasive exploration of the fetal brain.
磁脑图（MEG）被提议作为一种检测胎儿大脑生理活动的非侵入性技术，因为它能够在不直接接触头部的情况下记录大脑活动，并且磁信号在穿过胎儿脑外各层和母亲腹部时具有透明性。对妊娠情况简单且胎儿为臀位的健康女性进行了检查；研究时的孕周在36至40周之间。为了评估胎儿健康状况，在MEG记录 sessions 前后几天对超声和胎心监护数据进行了评估。参与研究的女性被安置在磁屏蔽室内的半卧位；在此通过超声检查确定胎儿的胎位以及母亲腹部对应胎儿头部的精确区域，以便将MEG检测系统尽可能靠近胎儿大脑放置。通过28通道神经磁系统进行MEG记录。每次MEG记录 session 都在对胎儿进行声刺激期间进行，以便检测由外周刺激诱发的大脑事件。听觉刺激通过放置在母亲腹部靠近胎儿头部的塑料管传递，由频率为500和1000赫兹、时长300毫秒、强度103分贝的纯音组成，以0.4次/秒的重复率呈现。在6例中，经过精确数字减法去除母体和胎儿心电图（EKG）信号后，我们得到了一个在约250毫秒达到峰值的与刺激相关的反应；这被认为源自胎儿大脑。在其中3例中，支持这一观点的是，在以胎儿头部为中心的大脑反应峰值处明显呈现出清晰的偶极分布，且与脑电发生器一致。尽管在可能的常规临床应用之前还存在几个需要解决的技术问题，但已发现MEG适用于胎儿大脑的非侵入性探测。
