由水分子扩散张量计算脑组织电导率张量的新方法

A New Method of Computing the ConductivityTensor of Brain Tissue Based on Water Diffusion Tensor

脑组织电导率在脑电/磁研究中是一个重要参数。为了获取脑组织电导率,本研究利用扩散张量成像(DTI)技术,从电化学角度出发,提出了基于Stokes-Einstein与Nernst-Einstein方程的计算脑组织电导率的一种新方法,以三个正交方向上的电导率作为不同脑组织的电导率张量特征值。在人体头部DTI数据上进行计算,并与不同脑组织(白质、灰质、脑脊液)的经验电脑率值进行了对比,发现扩散各向异性越严重的组织,其电导率张量特征值偏离经验值越远,进一步证明了在脑电/磁计算中要考虑脑组织电导率各向异性的必要性。所提出的方法,基于扩散张量,考虑脑液体中各种离子浓度等因素,为获取脑组织各向异性电导率分布提供了一种新的有效途径。

The conductivity of brain tissue is an important parameter in EEG/MEG research. A new method was proposed for getting these parameters from the view of electrochemistry based on diffusion tensor imaging （DTI） using Stokes-Einstein and Nernst-Einstein equations. The method was tested on DTI data of a human subject, and the result was compared to the experiential conductivity of different brain tissues （white matter, grey matter, CSF ）. It was showed that the more anisotropic the tissue was, the further the conductivity tensor eigenvalue of it deviated, illuminating the necessary of including anisotropic conductivity in EEG/MEG. This method was based on DTI data incorporating the factor of the concentration of the ions in brain liquid, and provided an effective approach of calculating anisotropic conductivity of brain tissue.