Institut de Génie Biomédical, Ecole Polytechnique de Montréal, Montréal, QC H3C3A7, Canada.
IEEE Trans Biomed Eng. 2010 Sep;57(9):2257-66. doi: 10.1109/TBME.2010.2052618. Epub 2010 Jun 14.
Assessing the performance of electrical impedance tomography (EIT) systems usually requires a phantom for validation, calibration, or comparison purposes. This paper describes a resistive mesh phantom to assess the performance of EIT systems while taking into account cabling stray effects similar to in vivo conditions. This phantom is built with 340 precision resistors on a printed circuit board representing a 2-D circular homogeneous medium. It also integrates equivalent electrical models of the Ag/AgCl electrode impedances. The parameters of the electrode models were fitted from impedance curves measured with an impedance analyzer. The technique used to build the phantom is general and applicable to phantoms of arbitrary shape and conductivity distribution. We describe three performance indicators that can be measured with our phantom for every measurement of an EIT data frame: SNR, accuracy, and modeling accuracy. These performance indicators were evaluated on our EIT system under different frame rates and applied current intensities. The performance indicators are dependent on frame rate, operating frequency, applied current intensity, measurement strategy, and intermodulation distortion when performing simultaneous measurements at several frequencies. These parameter values should, therefore, always be specified when reporting performance indicators to better appreciate their significance.
评估电阻抗断层成像（EIT）系统的性能通常需要使用体模进行验证、校准或比较。本文介绍了一种电阻网格体模，可在考虑类似于体内条件的电缆杂散效应的情况下评估 EIT 系统的性能。该体模由印刷电路板上的 340 个精密电阻组成，代表一个 2D 圆形均匀介质。它还集成了 Ag/AgCl 电极阻抗的等效电模型。电极模型的参数是通过阻抗分析仪测量的阻抗曲线拟合得到的。所使用的构建体模的技术是通用的，适用于任意形状和电导率分布的体模。我们描述了可以使用我们的体模测量的三个性能指标，用于每个 EIT 数据帧的测量：信噪比、准确性和建模准确性。在不同的帧率和应用电流强度下，我们在自己的 EIT 系统上评估了这些性能指标。性能指标取决于帧率、工作频率、应用电流强度、测量策略以及在多个频率同时进行测量时的互调失真。因此，在报告性能指标时，应始终指定这些参数值，以便更好地理解其意义。
