基于二维电学层析成像边缘效应的三维体积参数测量方法研究

Ubiquitous knowledge of bladder volume is of great interest to patients whose perception of bladder volume is impaired. Due to the increasing demand on clinical nursing, it is necessary to develop an extracorporeal and non-destructive measurement method to monitor the bladder volume automatically and continuously. In view of this application-driven demand, this study explores a non-destructive method to measure the 3D volumetric parameters of unary bladder based on the fringe effect of 2D electrical impedance tomography (EIT) imaging. Finite element simulation and in-vitro experiments will be conducted to validate the proposed method, as well as some in-vivo experiments for continuous monitoring of the bladder volume of trial subjects. Compared to the extraction of 2D spatial distribution information from the conventional 2D EIT imaging, the proposed method can provide the spatial distribution information of the bladder in the third dimension, and thus can give more accurate estimation about the bladder volume. Regarding the significant influences of the urine conductivity on the estimation accuracy of bladder volume as noticed by other researchers, a differential and relative measurement method, which is based on the differences of fringe effect between two separate EIT sensors, is combined with appropriate image processing techniques to lower the sensitivity of the volume estimation to the urine conductivity. This preliminary study paves the way for the development of a portable medical instrument to monitor the bladder volume continuously and non-destructively as desired.

膀胱体积的连续监测对于尿意缺失或排尿障碍患者具有重大的现实意义。近年来随着临床监护需求的提高，迫切需要研发一种可以自动连续监测患者膀胱体积的体外无损测量手段。本研究针对这一应用需求，利用二维电阻抗层析成像的边缘效应，探索一种可用于膀胱三维体积参数提取的无损测量方法，并进行了有限元仿真和离体模拟实验以及在体连续监测实验来验证该方法的可行性。相比以往基于二维层析成像的二维空间分布信息提取，本研究所采用方法可以提供膀胱在第三维上的的空间分布信息，从而可以给出更准确的膀胱体积估计。针对膀胱体积估计易受尿液电导率影响的问题，提出了利用双传感器感知到的边缘效应的差异进行差动和相对测量的方法，并结合图像处理方法进一步降低了体积估计对尿液电导率的敏感性。本项目中的仿真和实验研究为下一步便携式医疗器械的开发奠定了前期研究基础。

膀胱体积的连续监测对于尿意缺失或排尿障碍患者具有重大的现实意义。近年来随着临床监护需求的提高，迫切需要研发一种可以自动连续监测患者膀胱体积的体外无损测量手段。本研究针对这一应用需求，利用二维电阻抗层析成像的边缘效应，探索一种可用于膀胱三维体积监测的体外无损测量方法。从边缘效应对膀胱体积变化的灵敏度出发，优化了二维成像传感器阵列结构和激励测量模式，并进行了有限元仿真和离体模拟实验，获得了边缘效应特征值与膀胱体积的相关关系，显著降低了尿液电导率对测量的影响。研究基于深度学习和参数水平集的电学层析成像方法，提高了层析成像的空间分辨率，未来有望将这两种方法应用于膀胱体积监测。设计构建了两套电阻抗层析成像系统并通过离体实验验证了所提出方法的可行性和有效性。本项目中的仿真和实验研究为下一步医疗器械的开发奠定了前期研究基础，后期将与医院合作（已有一项临床转化合作项目获批，并对两项已授权的相关专利实施了许可）研发小型化便携式的膀胱体积监测系统，继续此课题内容的研究，加快促成膀胱体积监测的临床应用。