脑磁图在癫痫手术前定位的重要意义

The role of magnetoencephalography in presurgical focus localization in epilepsy

癫痫患者术前定位的“金标准”仍是颅内电极记录,尤其是立体脑电图(Stereoencephalography,SEEG),但其缺点是有创性及空间分辨力低。1982年脑磁图(Magnetoencephalography,MEG)开始用于癫痫病的临床。MEG不受颅骨和头皮的影响,时间和空间分辨力高,可用于确定癫痫源区(Epiletogensis zone,EZ)和发作起始区(Seizure onset zone,SOZ)的部位。MEG和磁共振成像(Megnetic resonens imaging,MRI)融合后称为磁源成像(Magnetic source imaging,MSI),目前已成为术前定位的重要方法。近20年有很多MRI后处理方法更增加了MEG的应用价值。就定位的敏感性而言,MEG不如SEEG,但优于头皮VEEG、MRI、PET及SPECT。此外MEG尚可以帮助颅内电极的安置及改善手术前计划。MEG的缺点是价格昂贵,对辐射位电源不敏感,对大脑内侧深部起源的定位有一定困难。目前设备的更新及后处理算法的改进,有望逐步克服这些缺点。

Intracranial electrographic recording,especially stereoencephalography(SEEG),remains the gold standard for preoperative localization in epilepsy patients.However,this method is invasive and has low spatial resolution.In 1982,magnetoencephalography(MEG)began to be used in epilepsy clinics.MEG is not affected by the skull and scalp,can provide signals with high temporal and spatial resolution,and can be used to determine the epiletogensis zone(EZ)and the seizure onset zone(SOZ).Magnetic source imaging(MSI)is a method that superimposes the MEG data on a magnetic resonance image(MRI)and has become a major tool for presurgical localization.The applicability of MEG data has been largely improved by the development of many post-MRI processing methods in the last 20 years.In terms of the sensitivity of localization,MEG is superior to VEEG,MRI,PET and SPECT,despite inferiority to SEEG.MEG can also assist in the intracranial placement of electrodes and improve preoperative planning.Limitations of MEG include high cost,insensitivity to radiation source,and difficulty in locating deep EZ in the medial regions of the brain.These limitations could be overcome by new generations of equipment and improvement of algorithmics.