Compensation for large thorax excursions in EIT imaging.

Area of Science:

• Medical Imaging
• Physiological Measurement
• Pulmonary Medicine

Background:

• Electrical impedance tomography (EIT) is increasingly used for lung ventilation monitoring in spontaneously breathing patients with asthma, cystic fibrosis (CF), and chronic obstructive pulmonary disease (COPD).
• Deep inspirations during lung function testing cause significant thorax excursions, leading to artifacts in EIT-reconstructed images.
• These artifacts can hinder accurate diagnosis and monitoring of respiratory diseases.

Purpose of the Study:

• To introduce and evaluate a novel approach for compensating image artifacts in EIT caused by thorax excursion.
• To improve the quality of EIT images for spontaneously breathing patients undergoing lung function tests.
• To assess the potential of EIT as a supplemental tool for pulmonary diagnostics.

Main Methods:

• A new method was developed to compensate for image artifacts by modifying measured voltages based on boundary voltage changes induced by thorax excursion.
• The technique was validated using a simulation study on a homogeneous model.
• Applicability was demonstrated on human subjects using a motion-tracking system.

Main Results:

• The simulation study confirmed that modifying measured voltages can reduce the impact of thorax excursion on reconstructed EIT images.
• The method effectively reduced artifacts and improved image quality in human subjects.
• The computational effort required for artifact compensation was not substantially increased, allowing for real-time application.

Conclusions:

• The proposed EIT artifact compensation technique is effective in improving image quality for spontaneously breathing patients.
• This approach enhances the suitability of EIT for real-time lung ventilation imaging.
• The technique holds promise for establishing EIT as a valuable supplemental tool in lung function testing for diagnosing and monitoring respiratory diseases like COPD and CF.