脑卒中病灶对多频EIT边界电压谱特性的影响研究

Impacts of stroke lesions on characteristics of boundary voltage spectra of multi-frequency electrical impedance tomography

目的:量化评估脑卒中病灶对多频电阻抗断层成像(electrical impedance tomography,EIT)边界电压谱的影响。方法:在构建具有真实人头阻抗频谱分布的三维人头模型的基础上,仿真计算3个区(额区、颞区和枕区)、3个位置(距颅脑中心远、中、近)、3种不同体积(脑体积的5%、2.5%和0.5%)和2种类型(缺血和出血)共54种脑卒中病灶引起的多频EIT边界电压谱,定量分析脑卒中发生前后的多频EIT边界电压谱变化,并对比分析缺血性和出血性脑卒中病灶对应的多频EIT边界电压谱特征。结果:缺血性脑卒中引起的多频EIT边界电压变化在10 Hz~100 kHz频段内差异最大,虚部差异最大值约为8%,而出血性脑卒中引起的多频EIT边界电压变化在200 kHz~1 MHz频段内差异最大,实部差异最大值可达1.7%。缺血性脑卒中对应的多频EIT边界电压在低频段(10 Hz~<1 kHz)变化最明显,实部变化最大值约为0.4%,虚部变化最大值约为0.5%;出血性脑卒中对应的多频EIT边界电压在高频段(100 kHz~1 MHz)变化较大,实部变化最大值约为0.6%,虚部变化最大值约为1.5%。结论:脑卒中病灶可引起多频EIT边界电压谱发生特异性改变,该研究为未来多频EIT检测脑卒中研究奠定了良好的数据基础。

Objective To quantitatively evaluate the impacts of stroke lesions on the characteristics of multi-frequency EIT(MFEIT)boundary voltage spectra.Methods Based on the three-dimensional human head model with realistic impedance spectra distribution simulations of stroke lesions with different positions(frontal area,temporal area and occipital area),different volumes(5%,2.5%and 0.5%of brain volume)and different types(ischemia and hemorrhage)were performed to calculate MFEIT boundary voltage spectra.Then,the changes of MFEIT boundary voltage spectra before and after the occurrence of stroke were quantitatively analyzed.Also,the MFEIT boundary voltage spectra corresponding to ischemic and hemorrhagic stroke lesions were compared.Results There was the largest difference in the change of MFEIT boundary voltage caused by ischemic stroke lesion within 10 Hz-100 kHz(the maximum difference of the imaginary part reached 8%),while the obvious change of MFEIT boundary voltage caused by hemorrhagic stroke occurred within 200 kHz-1 MHz(the maximum difference of real part was up to 1.7%).The MFEIT boundary voltage corresponding to ischemic stroke varied most obviously in the low frequency band(10 Hz-<1 kHz),such as 0.4%for the real part change and 0.5%for the imaginary part change,while the MFEIT boundary voltage corresponding to hemorrhagic stroke changed greatly in the high frequency range(100 kHz-1 MHz),such as 0.6%for the real part change and 1.5%for the imaginary part change.Conclusion Stroke lesions can cause specific changes in the boundary voltage spectra of MFEIT,which further proves the feasibility using MFEIT to detect stroke.[Chinese Medical Equipment Journal,2022,43(3):1-7]