Current patterns and electrode types for single-source electrical impedance tomography of the thorax

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Electrical Engineering

Background:

• Electrical impedance tomography (EIT) is a non-invasive imaging technique.
• EIT reconstructs internal electrical properties from surface measurements.
• Thoracic EIT is used for imaging chest functions and conditions.

Purpose of the Study:

• To investigate the impact of current injection patterns on static thoracic EIT image quality.
• To evaluate the influence of measurement noise on EIT reconstruction.
• To determine optimal electrode configurations for improved EIT imaging.

Main Methods:

• Simulated EIT data using a computational phantom.
• Iterative image reconstruction algorithm.
• Analysis of reconstruction error and convergence rates under varying current patterns and signal-to-noise ratios (SNRs).

Main Results:

• Neighboring electrode placement for current source and sink significantly reduced mean squared reconstruction error by an order of magnitude.
• At 50 dB SNR, 60% of reconstructions converged with neighboring electrodes versus <10% for other patterns.
• Doubling the number of boundary electrodes reduced reconstruction error by nearly two orders of magnitude.
• "Compound electrodes" showed no practical improvement in image quality.

Conclusions:

• Neighboring current injection patterns are crucial for high-quality static thoracic EIT imaging.
• Increased electrode density substantially improves EIT reconstruction accuracy.
• The findings provide practical guidance for optimizing EIT hardware and protocols.