基于CT图像修正的人体呼吸过程中肺部电阻抗成像的研究

发布时间：2018-06-02 21:01

本文选题：EIT + 水平集分割　；参考：《天津大学》2012年硕士论文

【摘要】：电阻抗断层成像(EIT)是通过按顺序的在相邻电极间注入电流,对其他非注入电流的电极之间的电压进行记录,并使用一定图像重建算法将其转化成肺部横断面电阻率分布图。EIT具有对人体无损伤、成像快、成本低、设备体积小等的特点,可实现连续监控。迄今为止的大量的研究表明,肺部区域吸入空气量同阻抗变化有紧密联系。于是怎样获得准确的肺部电阻抗变化同呼吸的关系成为了现今研究的重点。本研究使用CT修正的人体胸腔模型,对肺部呼吸期间的电阻抗的变化原因进行了多方面的研究。对CT图像进行图像分割和处理,得到可以用于实验研究的仿真模型。在图像分割过程中主要通过水平集分割方法进行图像分割;辅助中值滤波、形态学滤波等手段对结果进行处理;最后通过图像叠加的方法生成模型图像。本文在水平集分割的基础之上总结出可用于自动的分割部分胸腔器官的方法,能够相对简化模型生成的过程。而后,利用有限差分法对生成的模型进行计算,通过对胸腔模型上的电极加入激励电流,对其他非激励电极上电压的测定,得到胸腔模型的电阻抗成像结果。最后,利用在不同呼吸状况下的两套胸腔模型(分别位于吸气终止时刻和呼气终止时刻)以及在实际测量中所得的实验结果进行分析,证明了胸部尺寸扩大、电极位置变化以及组织、器官的位移能够对电阻抗成像产生一定的影响。本研究利用CT修正的人体胸腔模型,对肺部呼吸期间的电阻抗的变化原因进行了多方面的研究,对电阻抗成像技术在临床上的应用提供了理论的依据。
[Abstract]:Electrical impedance tomography (EITs) is the recording of voltages between other non-implanted electrodes by injecting currents between adjacent electrodes sequentially. A certain image reconstruction algorithm is used to transform it into a lung cross section resistivity distribution map. EIT has the characteristics of no damage to human body, fast imaging, low cost and small equipment volume, which can realize continuous monitoring. A large number of studies have shown that the volume of inhaled air in the lung area is closely related to the change of impedance. Therefore, how to obtain accurate relationship between lung electrical impedance change and respiration has become the focus of current research. In this study, CT modified human chest model was used to study the causes of electrical impedance during lung respiration. The CT image is segmented and processed, and the simulation model can be used for experimental research. In the process of image segmentation, the method of horizontal set segmentation is used to segment the image; the auxiliary median filter and morphological filter are used to process the result; finally, the model image is generated by the method of image superposition. Based on the level set segmentation, this paper summarizes the method of automatic segmentation of thoracic organs, which can simplify the process of model generation. Then the generated model is calculated by finite difference method. The electrical impedance imaging results of the thoracic model are obtained by adding the excitation current to the electrode and measuring the voltage on the other non-excited electrodes. Finally, two sets of thoracic models (at inspiratory termination time and expiratory termination time) and the experimental results obtained in actual measurements were used to prove the enlargement of chest size. The change of electrode position and the displacement of tissues and organs can influence the electrical impedance imaging. In this study, CT modified human chest model was used to study the causes of the changes of electrical impedance during lung respiration, which provided a theoretical basis for the clinical application of electrical impedance imaging.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R310

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