基于DTI的脑白质电导率张量计算模型比较研究

Comparative Study on Conductivity Tensor Calculation Models of Cerebral White Matter Based on DTI

目的研究脑白质电导率与水分子扩散系数之间的关系,解决脑白质各向异性电导率张量计算模型存在的问题。方法从电化学角度出发,引入结构系数,推导脑白质电导率与水分子扩散系数之间的关系;以实验得到的扩散张量数据为基础,计算了线性关系模型、体积约束模型和电化学模型的脑白质电导率张量值,并对计算结果进行了分析和比较。结果证明了白质电导率与水分子扩散系数之间的线性关系。以线性关系模型为基础,比较了上述三种模型计算结果的相对误差,发现计算结果有较大的差异。结论线性关系模型和电化学模型的计算结果相对可信。由于电化学模型只考虑了主要离子的影响,致使计算电导率存在误差。本文通过引入结构系数,提高了电化学模型计算电导率张量的精度。

Objective To solve the problems of computational model of anisotropic conductivity of cerebral white matter by studying the relationship between cerebral white matter conductivity and diffusion coefficient of water molecules. Methods From the aspect of electrochemistry,the structural coefficient was introduced,the relationship between cerebral white matter conductivity and diffusion coefficient of water molecules was deduced. Based on the diffusion tensor data obtained from the experiments,the cerebral white matter conductivity tensor values calculated from linear relationship model,volume constraint model and electrochemistry model were presented. The results from these three models were compared and analyzed. Results The linear relationship between anisotropic conductivity of white matter and diffusion coefficient of water molecules was proved.Based on the linear relationship model,the relatively errors of the computational results of each model were compared. There was significant difference in the computational results from three models. Conclusion The calculation results of anisotropic conductivity tensor of linear relationship model and electrochemistry model are relative reliable. Since the electrochemical model only considers the impact of major ions,there are some errors for conductivity calculation. The accuracy of the calculation of anisotropic conductivity tensor was improved by electrochemistry model.