He B, Zhang X, Lian J, Sasaki H, Wu D, Towle V L
Department of Bioengineering, University of Illinois at Chicago, 60607, USA.
Neuroimage. 2002 Jul;16(3 Pt 1):564-76. doi: 10.1006/nimg.2002.1127.
A boundary element method-based cortical potential imaging technique has been developed to directly link the scalp potentials with the cortical potentials with the aid of magnetic resonance images of the subjects. First, computer simulations were conducted to evaluate the new approach in a concentric three-sphere inhomogeneous head model. Second, the corresponding cortical potentials were estimated from the patients' preoperative scalp somatosensory evoked potentials (SEPs) based on the boundary element models constructed from subjects' magnetic resonance images and compared to the postoperative direct cortical potential recordings in the same patients. Simulation results demonstrated that the cortical potentials can be estimated from the scalp potentials using different scalp electrode configurations and are robust against measurement noise. The cortical imaging analysis of the preoperative scalp SEPs recorded from patients using the present approach showed high consistency in spatial pattern with the postoperative direct cortical potential recordings. Quantitative comparison between the estimated and the directly recorded subdural grid potentials resulted in reasonably high correlation coefficients in cases studied. Amplitude difference between the estimated and the recorded potentials was also observed as indexed by the relative error, and the possible underlying reasons are discussed. The present numerical and experimental results validate the boundary element method-based cortical potential imaging approach and demonstrate the feasibility of the new approach in noninvasive high-resolution imaging of brain electric activities from scalp potential measurement and magnetic resonance images.
一种基于边界元法的皮质电位成像技术已经被开发出来，借助受试者的磁共振图像将头皮电位与皮质电位直接联系起来。首先，在同心三球非均匀头部模型中进行计算机模拟，以评估这种新方法。其次，基于从受试者磁共振图像构建的边界元模型，从患者术前头皮体感诱发电位（SEP）中估计相应的皮质电位，并与同一患者术后的直接皮质电位记录进行比较。模拟结果表明，使用不同的头皮电极配置可以从头皮电位估计皮质电位，并且对测量噪声具有鲁棒性。使用本方法记录的患者术前头皮SEP的皮质成像分析显示，其空间模式与术后直接皮质电位记录具有高度一致性。在所研究的病例中，估计的硬膜下网格电位与直接记录的电位之间的定量比较产生了相当高的相关系数。还观察到估计电位与记录电位之间的幅度差异，以相对误差为指标，并讨论了可能的潜在原因。目前的数值和实验结果验证了基于边界元法的皮质电位成像方法，并证明了这种新方法在从头皮电位测量和磁共振图像进行无创高分辨率脑电活动成像方面的可行性。
