Clinical Application of Functional Brain Cortical Mapping Using Magnetoencephalography and Electroencephalography

我们开发了一个MRI连接的全头脑磁图（MEG）系统作为一种无创的功能脑映射工具。用头盔型66导脑磁图系统对20例健康人、80例颅内结构病变患者和4例顽固性癫痫患者进行了全脑神经磁场测量，首先测量了体感诱发场（SEF）、听觉诱发场（AEF）和视觉诱发场（VEF）。我们使用多偶极子模型定位了上述大脑活动的发生器，每个受试者的头部都有一个最适合的球体。最后，将偶极子叠加在三维MRI上。正中神经和胫神经刺激的SEF定位对侧中央沟。声调的AEF定位于双侧上级颞平面。VEF定位于刺激半视野对侧距状裂。源的位置是准确的责任皮层表面上，标准偏差为2-4毫米，无论是否有结构性病变。第二，在癫痫患者，发作间期癫痫放电测量MEG和EEG的手段。这些偶极模式在中线上相互重叠。双偶极模型估计双侧新皮质、单侧新皮质和对侧近中颞叶结构或双侧近中颞叶结构中的“尖峰”或“波”偶极。另2例仅在单侧半球出现单一偶极型，这些棘波或波偶极估计在一个叶内。整个头部脑磁图系统是有用的，以本地化多灶性癫痫放电，以及评估信号传播之间的双边semiles.In总结，MEG本地化的皮质功能非侵入性，具有非常高的空间分辨率证实了我们的MRI连接系统。该技术适用于常规和血管内神经外科手术，以及立体定向放射外科手术。

We developed a MRI-linked whole head magnetoencephalography (MEG) system as a tool of non-invasive functional brain mapping. In 20 healthy subjects, 80 patients with intracranial structural lesions and 4 patients with intractable seizures, neuromagnetic fields were measured over the entire head, using a helmet shaped 66 channel MEG system.First, we measured somatosensory evoked field (SEF), auditory evoked field (AEF), and visually evoked field (VEF). We localized generators of above brain activities, using a multiple dipole model with a best-fitting sphere for each subject's head. Finally, the dipoles were superimposed on 3-D MRI.SEF for median and tibial nerve stimuli localized the contralateral central sulcus. AEF for tones localized bilateral superior temporal planes. VEF localized calcarine fissure contralateral to the stimulated half visual field. Positions of the sources were precisely on the responsible cortical surface, with standard deviation of 2-4 mm, either with or without structural lesions.Second, in patients with epilepsy, interictal epileptic discharges were measured by means of both MEG and EEG.We observed two dipole patterns bilaterally in two cases. These dipolar patterns overlap each other across the midline. A two dipole model estimated "spike" or "wave" dipoles in bilateral neocortices, unilateral neocortex and contralateral mesial temporal structure, or bilateral mesial temporal structures. In the other 2 cases, single dipole pattern appeared on unilateral hemisphere only ; these spike or wave hipoles were estimated within one lobe. The whole head MEG system is useful to localize multifocal epileptic discharges, as well as to evaluate signal propagation between bilateral hemispheres.In summary, MEG localized cortical function non-invasively, with exceptionally high spatial resolution confirmed by our MRI-linked system. This technique was useful for conventional and intravascular neurosurgery, as well as for stereotaxic radiosurgery.