多通道电阻抗方法胃动力测量机制研究  

Mechanistic Study of Multichannel Impedance Method for Gastric Motility Measurement

作　　者：赵舒[1] 沙洪[1] 任超世[1] 

机构地区：[1]中国医学科学院生物医学工程研究所,天津300192

出　　处：《中国生物医学工程学报》2014年第2期129-138,共10页Chinese Journal of Biomedical Engineering

基　　金：国家自然科学基金(81301288)

摘　　要：建立多通道电阻抗信号与胃收缩传导过程的关系,明确生物电阻抗方法检测胃动力的测量机制。应用COMSOL软件建立圆柱容积导体模型,模拟胃环行肌收缩传导过程,进行电磁场正问题仿真计算,获取边界测量电压波形。设计专用实验装置,制作了不同电导率的三层琼脂模型,模拟胃部和胃收缩扰动,完成盐水槽动态模拟实验。仿真研究结果表明,轴向和径向激励模式下,边界测量电压波形清晰显示了胃收缩发生的部位及传导过程,相邻通道间存在明显的相位差。模拟实验结果中,对于电导率为1.35 S/m的被测琼脂模型,轴向激励模式各测量通道出现双波谷的时间差约为9 s;径向激励模式各测量通道出现双波谷的时间差约为6 s,与各测量通道的电极安放位置和间距正好相对应。胃内容物为高电导率和低电导率情况下,边界电压波形的变化趋势相同,方向相反。参数δ,珚U和Umax/Umin定量评价结果表明,靠近激励电极的测量通道,电压敏感性和均值较高。多个通道测量的电阻抗信号,能够有效地反映胃内容物电导率的变化、胃不同部位的收缩、以及胃运动传导的时相关系。The aim of this work is to investigate the relationship between multichannel electrical bio-impedance signals and propagation of gastric peristalsis wave, and obtain the measurement mechanism of the electrical impedance method for gastric motility. A cylindrical volume conductor model was built using COMSOL software. The contraction of gastric circular muscle and its propagation were simulated in this model. The voltage measured from boundary of the region was obtained by solving the forward problem of electromagnetic field. An experimental device including mechanical drive unit and three-layer agar models with different conductivity was made to simulate the stomach and its contraction, and the dynamic test was performed in a salt water tank. Under the axial and radial direction current excitation pattern, the waveform of boundary voltage shows the position of circular muscle contraction and the process of peristalsis propagation. The phase difference between voltage waveform of adjacent channel exists. In experiment result, the phase differences respectively are 9 s and 6 s under axial and radial direction current excitation pattern for the agar model with conductivity of 1.35 S/m. It is correlated with the position and spacing of the measurement electrodes. The boundary voltage variations follow the same trends but in opposite direction when the electrical conductivity of gastric content is higher or lower than that of the background. The voltage sensitivity and mean value of the channels close to excitation electrodes are relatively high when using parameter δ,U and Umax/Umin for quantitative evaluation. The muhichannel electrical bio-impedance signals can reflect the conductivity changes of gastric content, the contracts in different region and the peristaltic wave propagation time effectively.

关 键 词：生物电阻抗 胃动力 多通道测量 胃收缩传导 

分 类 号：R318[医药卫生—生物医学工程]