大脑脉动血流电导率孔隙导电模型仿真

Simulation on Pore Conductivity Model of Cerebral Pulsating Blood Flow Conductivity

脑血液电导率是脑阻抗成像和脑疾病评估的重要参数。为了研究脑部脉动血液电导率变化机理,该文基于Maxwell-Fricke原理建立血液红细胞绝缘孔隙导电模型,以血流动力学参数为指标,研究血流电导率与红细胞绝缘孔隙几何参数之间的数值关系。在此基础上构建具有孔隙导电结构的高分辨率大脑Willis环模型,利用耦合非线性微分方程计算脑动脉血流动力学参数的时空分布,模拟非均匀电导率血液的等效体积电导率。结果表明,与不考虑孔隙取向的定常血流模型电导率相比,一个心动周期内孔隙导电模型的电导率峰值增大27.6%,其余时刻增大约12%,增大比例与心脏泵血时期密切相关。仿真结果与真实脉动血液电导率具有较好的一致性,使用该文所提出的模型能够准确预测不同血液流变条件下的在体血流电导率。

Cerebral blood conductivity is an important parameter for brain impedance imaging and brain disease assessment.In order to study the change mechanism of brain blood pulsating conductivity,a model of erythrocyte insulation pore conductivity was established based on Maxwell-Fricke principle.Using hemodynamic parameters as reference indicators,the numerical relationship between blood flow conductivity and geometric parameters of erythrocyte insulation pores was analyzed.Then,a high-resolution model of circle of Willis with porous conductive structure was constructed,the coupled nonlinear differential equations were used to calculate the temporal and spatial distribution of cerebral artery hemodynamic parameters,and the equivalent volume conductivity of non-uniform conductivity blood was simulated.Compared with the steady blood flow model without considering the pore orientation,the peak conductivity of the pore conductivity model increases by 27.6% in one cardiac cycle and 12% at the rest of the time,which is closely related to the heart pumping period.The simulation results are in good agreement with the real pulsating blood conductivity,which proves that the model proposed in this paper can accurately predict the in vivo blood conductivity under different hemorheological conditions.