Assessment of the high resolution micro-gradiometer for its clinical application

我们已经开发了12通道显微梯度仪来检测来自各种生物组织的磁场，这是传统的脑磁仪无法检测到的。利用该装置，我们首次记录了电刺激人体正中神经所诱发的体感诱发皮质场。诱发磁场比常规脑磁图仪检测到的磁场大10倍左右。该系统还能清晰地检测到周围神经传导电流所产生的磁场，这是常规系统所不能检测到的。虽然该系统的S/氮比与常规系统相当，但我们证实，由于传感器线圈与生物组织之间的距离较短，该系统具有探测较小磁场变化和较高空间分辨率的潜力。

We have developed the 12-ch micro-gradiometer to detect the magnetic field derived from various biological tissues which would not be able to be detected by a conventional magnetoencephalograph. Using this device, we first recorded the somatosensory evoked cortical field induced by the electrical stimulation on the median nerve of a human subject. The evoked magnetic field was about 10 time larger than that detected by the conventional magnetoencephalograph. The magnetic field induced by the peripheral nerve conduction current was also clearly detected by this system, which could not be possible for the conventional system. Although this system's S/N ratio was comparable as those of the conventional system, we comfirmed that this system has a potential to detect smaller magnetic field change with the higher spatial resolution due to the short distance between the sensor coil and the biological tissues.