Clinical Application of Magnetophysiology : Spatiotemporal Integration of Magnetoencephalography and Functional Magnetic Resonance Imaging

在这项研究中，脑磁图(MEG)和功能磁共振成像(FMRI)已被应用于基础和临床脑地形图。这两种技术都是最近发展起来的无创磁生理学工具。结果总结如下：舌头、手指、手、四肢和泌尿生殖器官的体感诱发电场表明，大脑初级体感皮质的体位组织。手部、舌头和嘴唇运动以及手部感觉刺激的功能磁共振成像也表明了负责每种活动的特定区域。这些数据被整合到基于MRI的解剖图像、静脉造影和表面解剖扫描中。在胶质瘤病例中，我们通过术中清醒状态下的皮质刺激来验证这些感觉-运动皮质的功能定位。听觉和视觉诱发磁场被应用于各种类型的颅内结构病变患者。在一定的异常条件下，我们发现诱发反应中主要成分的峰潜伏期延迟。部分患者去除病变后反应潜伏期恢复正常，脑磁图空间分辨率和时间分辨率分别为毫米级和毫秒级。脑磁图对于在空间和时间上定位点源特别有用。另一方面，功能磁共振成像适合于在一定的时间长度内对空间扩展区域的脑活动进行定位，通常为几十秒量级。对于了解人脑功能，这两种技术是相辅相成的；两种技术的结合对临床应用尤其重要。

In this study, magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) have been applied to basic and clinical brain mapping. Both techniques have been recently developed as non-invasive magnetophysiological tools.Results are summarized as follows.Somatosensory evoked field for tongue, digit, hand, low extremities, and urogenital organs indicated somatotopic organization of the primary somatosensory cortex of the brain. fMRI for hand, tongue and lip movement as well as hand sensory stimuli also indicated a certain area responsible for each activity. These data were integrated on MRI-based anatomical images, venography and surface anatomical scan. In cases of glioma, we verified these functional localization of sensori-motor cortices by intraoperative cortical stimulation under the awake condition.Auditory and visually evoked magnetic fields were applied for patients with various types of intracranial structural lesions. In a certain abnormal conditions, we found delay of peak latency of major components in evoked responses. In some patients, latency of the responses normalized after removal of lesions.Spatial and temporal resolution of MEG are millimeter and millisecond order respectively. MEG is especially useful to localize pin-point sources spatially and temporally. On the other hand, fMRI is suitable to localize brain activity of spatially extended area and within a certain length of time, of usually a few ten seconds order. For understanding human brain function, both techniques are complementary ; integration of the two techniques will be important especially for clinical application.