Compensating Electrode Errors Due to Electrode Detachment in Electrical Impedance Tomography

Abstract

Electrical impedance tomography (EIT) shows a great promise for monitoring pul- monary and cardiovascular functions non-invasively. However, there are some challenges to bring EIT from the laboratory to daily clinical use in intensive care unit (ICU). One of the main challenges is the measurement errors caused by poor contact or de- tachment of electrodes due to the dynamics of en- vironment and human body. Such errors create large image artifacts and may even lead to misleading re- sults. Thus, there is a need for unsupervised failing electrode identification and electrode error compen- sation. We developed a novel formulation to compen- sate for such errors caused by failing electrodes and to eliminate image artifacts in real-time. We tested the error correction algorithms with measurements acquired on a cylindrical tank filled with a conduc- tive saline solution. A test object was placed at differ- ent positions inside the tank using a robotic system. For each position, several combinations of discon- nected electrodes were tested. The developed algo- rithm - evaluated by comparing the known test object with the reconstructed images - reduced image arti- facts caused by failing electrodes and thus improved the robustness of EIT measurements. The results also demonstrated that the proposed failing electrode compensation strategy was effective up to 6 discon- nected electrodes for a 32-electrode EIT system. The proposed strategy can help to use EIT as a practical and robust bedside imaging technique for ventilation monitoring.