PDF(Pubmed)
Abstract：
Cryogenic magnetoencephalography (MEG) enhances the presurgical assessment of refractory focal epilepsy (RFE). Optically pumped magnetometers (OPMs) are cryogen-free sensors that enable on-scalp MEG recordings. Here, we investigate the application of tri-axial OPMs [87Rb (Rb-OPM) and 4He gas (He-OPM)] for the detection of interictal epileptiform discharges (IEDs). IEDs were recorded simultaneously with 4 tri-axial Rb- and 4 tri-axial He-OPMs in a child with RFE. IEDs were identified visually, isolated from magnetic background noise using independent component analysis (ICA) and were studied following their optimal magnetic field orientation thanks to virtual sensors. Most IEDs (>1,000) were detectable by both He- and Rb-OPM recordings. IEDs were isolated by ICA and the resulting magnetic field oriented mostly tangential to the scalp in Rb-OPMs and radial in He-OPMs. Likely due to differences in sensor locations, the IED amplitude was higher with Rb-OPMs. This case study shows comparable ability of Rb-OPMs and He-OPMs to detect IEDs and the substantial benefits of triaxial OPMs to detect IEDs from different sensor locations. Tri-axial OPMs allow to maximize spatial brain sampling for IEDs detection with a limited number of sensors.
摘要：
低温脑磁图（MEG）可增强难治性局灶性癫痫（RFE）的术前评估。光泵浦磁力计（OPM）是无制冷剂传感器，可进行头皮MEG记录。这里,我们研究了三轴OPM[87Rb（Rb-OPM）和4He气体（He-OPM）]在发作间癫痫样放电（IED）检测中的应用。在一名RFE儿童中，IED与4个三轴Rb-和4个三轴He-OPM同时记录。简易爆炸装置被视觉识别，使用独立分量分析（ICA）与磁背景噪声隔离，并通过虚拟传感器按照其最佳磁场方向进行了研究。大多数IED(>1,000)可通过He-和Rb-OPM记录检测到。IED被ICA隔离，所产生的磁场在Rb-OPM中大部分与头皮相切，在He-OPM中大部分与头皮径向。可能由于传感器位置的差异，Rb-OPM的IED振幅更高。此案例研究显示Rb-OPM和He-OPM检测IED的能力相当，并且三轴OPM检测来自不同传感器位置的IED的实质性好处。三轴OPM允许利用有限数量的传感器来最大化用于IED检测的空间脑采样。
