Real-time 2D and 3D electrical impedance tomography and applications

Abstract

Electrical impedance tomography (EIT) is a non-invasive and non-ionizing real-time bedside imaging modality for functional pulmonary imaging. The EIT systems produce images of impedance distributions within the body by injecting electric currents and measuring voltages on electrodes applied to the skin. Regional EIT images of ventilation and pulsatile perfusion have the potential to provide information about the lung structure and function of patients with pulmonary diseases. The Adaptive Current Tomograph 5 (ACT5) system is a novel EIT system that can provide 2D and 3D EIT measurements from ventilation and pulsatile perfusion sequences, and simultaneously monitor heart activity by measuring and recording the electrocardiogram (ECG) at all active electrodes while measuring EIT data. This dissertation describes all the components present in the software side of the ACT5 system, which include 2D and 3D EIT reconstruction algorithms, digital filters, a graphical user interface, and the EIT reconstructions on healthy controls and patients with cardiac and pulmonary diseases. To evaluate the potential of EIT on reconstructing pulmonary ventilation and pulsatile perfusion images, EIT reconstructions were performed from data collected on premature babies and patients with cystic fibrosis, acute respiratory distress syndrome, pulmonary vein stenosis, and healthy control subjects. The EIT reconstructions from patients show different ventilation and perfusion distributions when compared to healthy subjects. Lung regions affected by cardiopulmonary diseases can also be identified in the EIT reconstructions.