IEEE Trans Med Imaging. 2013 Nov;32(11):1997-2005. doi: 10.1109/TMI.2013.2269867. Epub 2013 Jun 21.
Electrical impedance tomography (EIT) is a noninvasive method to image conductivity distributions within a body. One promising application of EIT is to monitor ventilation in patients as a real-time bedside tool. Thus, it is essential that an EIT system reliably provide meaningful information, or alert clinicians when this is impossible. Because the reconstructed images are very sensitive to system instabilities (primarily from electrode connection variability and movement), EIT systems should continuously monitor and, if possible, correct for such errors. Motivated by this requirement, we describe a novel approach to quantitatively measure EIT data quality. Our goals are to define the requirements of a data quality metric, develop a metric q which meets these requirements, and an efficient way to calculate it. The developed metric q was validated using data from saline tank experiments and a retrospective clinical study. Additionally, we show that q may be used to compare the performance of EIT systems using phantom measurements. Results suggest that the calculated metric reflects well the quality of reconstructed EIT images for both phantom and clinical data. The proposed measure can thus be used for real-time assessment of EIT data quality and, hence, to indicate the reliability of any derived physiological information.
电阻抗断层成像（EIT）是一种用于对体内电导率分布进行成像的非侵入性方法。EIT 的一个很有前途的应用是作为一种实时床边工具来监测患者的通气情况。因此，EIT 系统能够可靠地提供有意义的信息，或者在不可能时向临床医生发出警报是至关重要的。由于重建图像对系统不稳定性非常敏感（主要来自电极连接的可变性和运动），EIT 系统应该持续监测，并在可能的情况下对这些错误进行纠正。出于这一要求，我们提出了一种定量测量 EIT 数据质量的新方法。我们的目标是定义数据质量指标的要求，开发一个满足这些要求的指标 q，并找到一种有效的计算方法。该开发的指标 q 通过盐水箱实验和回顾性临床研究的数据进行了验证。此外，我们还表明，q 可以用于通过体模测量来比较 EIT 系统的性能。结果表明，对于体模和临床数据，计算出的指标都很好地反映了重建 EIT 图像的质量。因此，该测量方法可用于实时评估 EIT 数据质量，并指示任何衍生生理信息的可靠性。
