A 3D Reconstruction Algorithm for Real-time Simultaneous Multi-Source EIT Imaging for Lung Function Monitoring

Abstract

Monitoring regional pulmonary ventilation and pulsatile perfusion changes in a 3D region of interest (ROI) of the lung is a promising application for electrical impedance tomography (EIT). This paper describes a 3D analytical reconstruction algorithm that was embedded in a prototype EIT system to enable a real-time image reconstruction at nearly 20 frames per second for monitoring impedance changes in the chest in real-time. The derivation and results of the 3D analytical forward solution and inverse solution and details of the real-time reconstruction algorithm are given. The algorithm and EIT system are validated with simulated data, in-vitro phantoms, and finally shown to be capable of imaging ventilation and pulsatile perfusion in human subjects. The human subject data was obtained using a high-precision, high-speed and simultaneous multiple current source (SMS-EIT) developed by GE Research. Data was collected using four rows of 8 electrodes for a healthy adult male subject and 2 rows of 16 electrodes for six healthy human female subjects, with one row placed above the breasts and a second row placed at the infra-mammary fold. Each of the female subjects performed a breathing maneuver with a volumetric incentive spirometer, and the volume of air inhaled was calculated from the EIT images. Pulsatile perfusion images were computed from this data, and regional lung filling was also analyzed.

Fast absolute 3D CGO-based electrical impedance tomography on experimental tank data

“…Applications of EIT began with geophysical exploration over a century ago (Keller andFrischknecht 1966, Allaud andMartin 1977) and have since expanded into several fields including the transport of fluids and gases (Eggleston et al 1989, Kaipio and Somersalo 2004, Wang 2015, and biomedical imaging (Swanson 1976, Henderson and Webster 1978, Barber and Brown 1984, Holder 2005, Frerichs et al 2017, de Castro Martins et al 2019, Kao et al 2020, Adler and Holder 2021. Systems for monitoring lung function in real-time are now commercially available and clinical trials are in progress to determine the extent to which some of these systems might be used to guide mechanical ventilation (The PLUG group 2022, Brochard 2022, Timpel 2022.…”

“…It was demonstrated in Goble (1990), Blue (1997), Holder (2005), Kao et al (2020) that it is possible to make electrical impedance tomography (EIT) Systems that produce both 3D static and dynamic images of the interior of the chest showing heart and lung regions, as well as changes in those regions due to ventilation and perfusion. These systems used linearized and iterative methods.…”

Fast Absolute 3D CGO-Based Electrical Impedance Tomography on Experimental Tank Data

“…Applications of EIT began with geophysical exploration over a century ago [4,44] and have since expanded into several fields including the transport of fluids and gases [26,40,80], and biomedical imaging [2,7,20,29,35,36,42,70]. Systems for monitoring lung function in real-time are now commercially available and clinical trials are in progress to determine the extent to which some of these systems might be used to guide mechanical ventilation [12,73,75].…”

“…It was demonstrated in [10,32,36,42] that it is possible to make electrical impedance tomography (EIT) Systems that produce both 3D static and dynamic images of the interior of the chest showing heart and lung regions, as well as changes in those regions due to ventilation and perfusion. These systems used linearized and iterative methods.…”