Rapid Cardiac Output Monitoring Using 3D Electrical Impedance Tomography Based on a Region-Focused Current Injection Protocol

Z. X. Zhu¹, X. Y. Zhao¹, Z. T. Yuan¹, H. T. Fu¹, J. T. Sun¹, L. J. Xu¹

¹School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China

^*Email: jiangtao_sun@buaa.edu.cn

ABSTRACT

Cardiac output (CO), as a key indicator of cardiac pumping function and tissue perfusion, requires real-time, accurate, and noninvasive monitoring in clinical practice. Electrical impedance tomography (EIT), as an emerging noninvasive imaging technique, shows great promise for this purpose. However, conventional two-dimensional EIT methods suffer from insufficient accuracy and are prone to interference from pulmonary signals, thus failing to meet the requirements for high-precision monitoring. In this study, we propose a cardiac output monitoring method based on three-dimensional (3D) electrical impedance tomography combined with a region-focused current injection strategy. By optimizing the electrode array configuration and adopting a “maximum current density (Max J)” protocol, the sensitivity within the cardiac region is significantly enhanced, while interference from adjacent tissues such as the lungs is effectively reduced. Moreover, to meet the demands of real-time imaging, a 3D reconstruction algorithm based on total variation (TV) regularization and linear approximation is developed, which confines iterative updates exclusively to the region of interest, thereby substantially reducing the computational dimensionality and increasing reconstruction speed. Finally, experiments using three-dimensional thoracic phantoms under both complex and non-complex backgrounds are conducted. Experiments with 3D thoracic phantoms show that the reconstructed cardiac volumes closely match true values, with maximum relative errors below 17%. This approach meets clinical qualitative assessment needs and provides a novel solution for continuous and noninvasive cardiac function monitoring.

Keywords: 3D EIT, CO monitoring, Region-focused current injection, Rapid reconstruction

Industrial Application: Medical Devices, Biomedical Engineering