Veil Carina, Muller Daniel, Walz Simon, Schule Johannes, Somers Peter, Tarin Cristina, Stenzl Arnulf, Sawodny Oliver
IEEE Trans Biomed Eng. 2023 Feb;70(2):650-658. doi: 10.1109/TBME.2022.3199468. Epub 2023 Jan 19.
Bladder cancer recurrence is an important issue after endoscopic urological surgeries. Additional sensor information such as electrical impedance measurements aim to support surgeons to ensure that the entirety of the tumor is removed. The foundation for differentiating lies in the altered sodium contents and cell structures within tumors that change their conductivity and permittivity. Mechanical deformations in the tissue expel fluid from the compressed area and pose a great difficulty, as they also lead to impedance changes. It is crucial to determine if this effect outweighs the alterations due to the tumorous tissue properties.
Impedance measurements under ongoing viscoelastic relaxation are taken on healthy and tumorous tissue samples from human bladders and breasts. A fluid model to account for extra- and intracellular fluid flow under compression is derived. It is based on the fluid content within the individual tissue compartments and their outflow via diffusion.
After an initial deformation, the tissue relaxes and the impedance increases. The proposed model accurately represents these effects and validates the link between fluid flow under mechanical deformation and its impact on tissue impedance. A method to compensate for these undesired effects of fluid flow is proposed and the measurements are assessed in terms of differentiability between tumorous and healthy tissue samples.
The electrical parameters are found to be promising for differentiation even under varying mechanical deformation, and the distinction is additionally improved by the proposed compensation approach.
Electrical impedance measurements show great potential to support urologist during endoscopic surgeries.
膀胱癌复发是泌尿外科内镜手术后的一个重要问题。诸如电阻抗测量等额外的传感器信息旨在辅助外科医生确保肿瘤被完整切除。区分的基础在于肿瘤内钠含量和细胞结构的改变，这些改变会使其电导率和电容率发生变化。组织中的机械变形会将液体从受压区域排出，这带来了很大困难，因为这也会导致阻抗变化。确定这种影响是否超过肿瘤组织特性引起的变化至关重要。
对取自人膀胱和乳房的健康及肿瘤组织样本进行粘弹性松弛过程中的阻抗测量。推导了一个用于解释压缩状态下细胞外和细胞内液流的流体模型。该模型基于各个组织隔室内的液体含量及其通过扩散的流出情况。
在初始变形后，组织松弛且阻抗增加。所提出的模型准确地体现了这些效应，并验证了机械变形下的液流与其对组织阻抗的影响之间的联系。提出了一种补偿液流这些不良影响的方法，并根据肿瘤组织样本和健康组织样本之间的可区分性对测量结果进行了评估。
发现即使在不同的机械变形情况下，电参数对于区分也很有前景，并且所提出的补偿方法进一步提高了区分效果。
电阻抗测量在内镜手术期间辅助泌尿外科医生方面显示出巨大潜力。
