The influence of reference electrode in electrical impedance tomography

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Physiology

Background:

• Electrical impedance tomography (EIT) devices often include reference electrodes.
• High contact impedance for reference electrodes is a practical challenge.
• The impact of poor reference electrode contact on EIT data quality is not well understood.

Purpose of the Study:

• To investigate the influence of the reference electrode on EIT image reconstruction.
• To assess the impact of reference electrode connectivity on EIT data quality.

Main Methods:

• Thirty healthy volunteers underwent EIT measurements during spontaneous breathing.
• Three scenarios were tested: normal measurement, reference electrode disconnected without recalibration, and disconnected with recalibration.
• EIT parameters for spatial and temporal ventilation were calculated and compared using a deviation score.

Main Results:

• Significant differences in EIT parameters were observed when the reference electrode was disconnected (p < 0.01).
• The average deviation score was 4.5 ± 3.5 without recalibration and 6.1 ± 3.1 with recalibration.
• Only a small subset of subjects (4/30 without recalibration, 2/30 with recalibration) showed minimal deviation.

Conclusions:

• Proper contact and functionality of the reference electrode are crucial for EIT systems.
• EIT data quality is significantly affected by reference electrode status in most individuals.
• Maintaining reference electrode integrity is essential for reliable EIT image reconstruction.