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EIT images of ventilation: what contributes to the resistivity changes?
Jie Zhang1, Robert P Patterson
1Biomedical Engineering Institute, University of Minnesota, Minneapolis, MN 55455, USA. zhang132@umn.edu
Physiological Measurement
|March 31, 2005
Summary
Electrical impedance tomography (EIT) monitoring of lungs is affected by chest expansion and organ movement. These factors introduce artifacts and alter resistivity measurements, requiring careful consideration in EIT data analysis for accurate pulmonary ventilation and edema assessment.
Area of Science:
- Medical Imaging
- Biomedical Engineering
- Physiology
Background:
- Electrical impedance tomography (EIT) is a valuable tool for monitoring pulmonary ventilation and edema.
- Accurate interpretation of EIT images requires understanding factors influencing resistivity changes.
Purpose of the Study:
- To investigate factors contributing to lung resistivity changes in EIT images.
- To quantify the impact of chest expansion and tissue/organ movement on EIT data.
Main Methods:
- Utilized three-dimensional (3D) finite difference human models as virtual phantoms.
- Simulated chest expansion and tissue/organ movement to analyze resistivity variations.
Main Results:
- Chest expansion caused artifacts in EIT images, ranging from -2% to 31% of image magnitude.
- Averaged resistivity changes in lung regions due to chest expansion were 0.65% to 18.31%.
- Tissue/organ movement, including heart displacement, led to increased resistivity in lung and anterior regions.
Conclusions:
- Chest expansion and tissue/organ movement are significant contributors to lung resistivity changes in EIT.
- These movements introduce artifacts and alter measurements, necessitating their consideration in EIT data analysis.
- Accurate EIT analysis for pulmonary monitoring must account for physiological motion artifacts.