急性缺血条件下的动物脑部电阻抗特性变化规律的实验研究  

Experimental Study on the Changes of Electrical Impedance Characteristics of Animal Brain Under the Condition of Acute Ischemia

作　　者：周怡敏 陈真辉 史学涛 亢君君 付峰 ZHOU Yimin;CHEN Zhenhui;SHI Xuetao;KANG Junjun;FU Feng(Faculty of Biomedical Engineering,Air Force Medical University,Xi’an Shaanxi 710032,China;School of Basic Medical Sciences,Air Force Medical University,Xi’an Shaanxi 710032,China)

机构地区：[1]空军军医大学军事生物医学工程学系,陕西西安710032 [2]空军军医大学基础医学院,陕西西安710032

出　　处：《中国医疗设备》2019年第11期34-38,共5页China Medical Devices

基　　金：国家自然科学基金重点项目（51837011）;国家自然科学基金（61571445）;陕西省自然科学基金（2019JQ-706）;后勤科研重大项目（ALJ17J001）

摘　　要：目的研究缺血性脑损伤后脑组织电阻抗的频谱特性随时间的变化规律,为电阻抗成像(Electrical Impedance Tomography,EIT)技术在脑缺血性损伤监测方面的应用与优化提供生物物理与方法学支撑。方法采用两电极法在体测量脑缺血后大鼠脑部的电阻抗频谱,观察分析卒中后脑电阻抗频谱特性随时间的变化规律。结果大鼠脑组织电阻抗在缺血后前3 h快速上升,3 h时间节点的阻抗值达到阶段性的最高点,此后的变化相对平缓。频谱特性分析表明,缺血3 h时的最大阻抗相对变化率在79.4 kHz处,达48.7%。超微观形态学的观察结果显示,此时的星形胶质细胞终足水肿明显,与缺血后脑组织电阻抗升高变化相符。结论缺血后,脑组织电阻抗特性随测量时间与频率的变化会表现出不同的特性,通过测量频率的优选有望进一步提高EIT技术对脑缺血性损伤检测的灵敏度,而脑组织电阻抗随时间变化特性也有望为脑缺血性损伤的程度评价提供支撑,从而为EIT技术在超早期缺血性脑卒中的诊断和监测应用奠定基础。Objective To study the changes of electrical impedance spectra of brain tissue with time after ischemic brain injury,so as to provide biophysics and methodological support for the application and optimization of electrical impedance tomography(EIT)technology in the monitoring of cerebral ischemic injury.Methods The electrical impedance spectra of rat brain after cerebral ischemia were measured in vivo by two-electrode method.The changes of brain electrical impedance spectra with time after stroke were observed and analyzed.Results The electrical impedance of rat brain tissue increased rapidly within the first 3 hours after ischemia,and the impedance value reached the highest point at 3 hours after ischemia,and then the change was relatively smooth.The analysis of spectral characteristics showed that the maximum relative resistivity change at 3 h after ischemia was 48.7%,which was occurred at 79.4 kHz.The observation of ultrastructure of ischemia tissue at this stage showed that the end foot edema of astrocytes was obvious,which was consistent with the increase of electrical impedance of brain tissue after ischemia.Conclusion After ischemia,the electrical impedance characteristics of brain tissue will show different characteristics with the change of measuring time and frequency.The optimization of measuring frequency is expected to further improve the sensitivity of EIT technique in the detection of cerebral ischemic injury.The time-dependent electrical impedance of brain tissue is also expected to provide support for the evaluation of the degree of cerebral ischemic injury,which lays a foundation for the diagnosis and monitoring of ultra-early ischemic stroke by EIT imaging.

关 键 词：急性脑缺血 脑卒中 生物电阻抗测量 电阻抗成像 超微观形态学分析 

分 类 号：O441[理学—电磁学] R197.39[理学—物理]