The influence of reference electrode in electrical impedance tomography
Zhimin Lin,
Weixiang Huang,
Zhijun Gao,
Lin Yang,
Yimin Li,
Yu Lu,
Meng Dai,
Feng Fu,
Ling Sang,
Zhanqi Zhao
Affiliations
Zhimin Lin
State Key Lab of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, The First Affiliated Hospital of Guangzhou Medical University, Department of Critical Care Medicine, Guangzhou, China
Weixiang Huang
State Key Lab of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, The First Affiliated Hospital of Guangzhou Medical University, Department of Critical Care Medicine, Guangzhou, China
Zhijun Gao
Department of Aerospace Medicine, Air Force Medical University, Xi'an, China
Lin Yang
Department of Aerospace Medicine, Air Force Medical University, Xi'an, China; Corresponding author.
Yimin Li
State Key Lab of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, The First Affiliated Hospital of Guangzhou Medical University, Department of Critical Care Medicine, Guangzhou, China
Yu Lu
Herz Medical, Suzhou, China
Meng Dai
Department of Biomedical Engineering, Air Force Medical University, Xi'an, China
Feng Fu
Department of Biomedical Engineering, Air Force Medical University, Xi'an, China
Ling Sang
State Key Lab of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, The First Affiliated Hospital of Guangzhou Medical University, Department of Critical Care Medicine, Guangzhou, China; Guangzhou Laboratory, Guangzhou, China; Corresponding author.
Zhanqi Zhao
Department of Biomedical Engineering, Air Force Medical University, Xi'an, China; Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
Background: Some electrical impedance tomography (EIT) devices equip reference electrodes. In practice, it is not uncommon to observe high contact impedance for the reference electrode. The influence of bad contact reference electrode on data quality is unknown. The study aimed to investigate the influence of reference electrode on EIT image reconstruction. Methods: Thirty lung healthy volunteers were prospectively examined with EIT. The subjects were spontaneously breathing in supine position. Three scenarios were constructed: 1. Normal measurement; 2. Reference electrode disconnected without recalibration; 3. Reference electrode disconnected, and the measurement restarted after recalibration of the system. EIT-based parameters measuring spatial and temporal ventilation distributions were calculated and compared. A so-call deviation score was calculated to assess the differences in EIT parameters between scenarios 2 and 1, between 3 and 1. Results: The absolute differences for all parameters were significantly higher than zero (p < 0.01 for all parameters and scenarios). Deviation score for scenario 2 was 4.5 ± 3.5. Four subjects had a deviation score of 0 in scenario 2 and five subjects had a score of 1. The deviation in scenario 3 was higher (6.1 ± 3.1). No subjects had a score of 0 and only two subjects had a score of 1. Conclusions: For EIT systems that equips with reference electrode, it is important to ensure the proper contact and functionality of the reference electrode. The EIT data quality would remain unchanged in only a small portion of subjects.
