Electrical Impedance Tomography (EIT) for Lung Monitoring image
PROJECT

Electrical Impedance Tomography (EIT) for Lung Monitoring

Electrical Impedance Tomography (EIT) for Lung Monitoring

Electrical Impedance Tomography (EIT) is an imaging technology that uses the electrical properties within an anatomic structure derived from measurements made on the structure’s surface. EIT is a non-invasive, non-ionizing, real-time, functional imaging technique with no harmful side effects. EIT is suitable for patients of any age and can be performed continuously at the bedside without sedation. EIT can generate images of lung ventilation, perfusion, and V/Q ratio maps in real time – breath to breath and beat to beat.

GE Research collaborated with academic partners to develop a novel, simultaneous multi-source EIT. We refer to this as SMS-EIT. GE has built prototype SMS-EIT systems with 32 independent channels. Each channel consists of individual current source and voltage measurement circuits for driving and measuring signals  operating at 10 kHz operating frequency. Data is acquired at about 20 frames per second with 16-bit accuracy. 

While other EIT commercial systems exist, they use an inferior approach and multiplex a single (or bipolar) current source about their electrode array. A single source approach affords significantly less capability to detect small inhomogeneities than an SMS-EIT systems in which the number of current sources is equal to the number of skin electrodes. GE’s SMS-EIT design provides higher signal-to-noise ratio and greater sensitivity to image pulmonary perfusion in addition to ventilation.

 

Project Impact

Non-invasive real-time lung monitoring and assessment is an unmet need for the many high acuity care conditions: 

  • Differentiate pneumothorax and hemothorax and track its progression for combat casualty care
  • Monitor lung function for ventilated patients during aeromedical evacuation
  • Enable successful weaning with continuous lung function monitoring following ventilator disconnect
  • Monitor lung function and therapy response for premature neonates and pediatric patients

Lung function assessment with EIT presents a radiation free alternative for pediatric and neonate patients. EIT can be implemented as a small, battery-operated and portable device to bring continuous lung assessment to the point of injury for civilian or military trauma applications.

Publications

  1. Pigatto A.V., Kao T-J, Mueller J. L. Mueller, Baker C. D., DeBoer E. M. Kupfer O., Electrical impedance tomography detects changes in ventilation after airway clearance in spinal muscular atrophy type I, Respiratory Physiology & Neurobiology 2021 (pending).
  2. T.-J. Kao, B. Amm, D. Isaacson, J. Newell, G. Saulnier, J. L. Mueller, A 3D Reconstruction Algorithm for Real-time Simultaneous Multi-Source EIT Imaging for Lung Function Monitoring, bioRxiv 2020.05.29.124222; doi: https://doi.org/10.1101/2020.05.29.124222.
  3. Boverman G, Kao TJ, Wang X, Ashe JM, Davenport DM, Amm BC. Detection of small bleeds in the brain with electrical impedance tomography. Physiological Measurement 2016;37(6):727-750. doi:10.1088/0967-3334/37/6/727.
  4. Amm B, Kao TJ, Newell J, D. Isaacson, G. J. Saulnier, D. Shoudy, G. Boverman, R. Sahni, M. Weindler, D. Chong, D. DiBardino, D. Davenport, J. Ashe. Comparison of impedance measurements near the skin of newborns and adults. Physiological Measurement 2016;37(6):938-950. doi:10.1088/0967-3334/37/6/938.
  5. G. Boverman, D. Isaacson, J. C. Newell, G. J. Saulnier, T. J. Kao, B.C. Amm, X. Wang, D. M. Davenport, D. H. Chong, R. Sahni, and J. M. Ashe "Efficient Simultaneous Reconstruction of Time-Varying Images and Electrode Contact Impedances in Electrical Impedance Tomography," in IEEE Transactions on Biomedical Engineering, vol. 64, no. 4, pp. 795-806, April 2017, doi: 10.1109/TBME.2016.2578646.
  6. P. A. Muller, T. Li, D. Isaacson, J. C. Newell, G. J. Saulnier, T. J. Kao, J. Ashe, “Estimating a regional ventilation-perfusion index,” Physiological Measurement, June 2015, 36(6):1283-95. doi: 10.1088/0967-3334/36/6/1283. Epub 2015 May 26.
  7. X. Chen, T. J. Kao, J. M. Ashe, G. Boverman, J. E. Sabatini, D. M. Davenport, “Multi-channel electrical impedance tomography for regional tissue hydration monitoring,” Physiological Measurement, June 2014, 35(6):1137-47. doi: 10.1088/0967-3334/35/6/1137. Epub 2014 May 20.
  8. T. Li, D. Isaacson, J. C. Newell, G. J. Saulnier, “Adaptive techniques in electrical impedance tomography reconstruction,” Physiological Measurement, June 2014, 35(6):1111-24. doi: 10.1088/0967-3334/35/6/1111. Epub 2014 May 20.
  9. P. A. Muller, D. Isaacson, J. C. Newell, G. J. Saulnier, “Calderón’s method on an elliptical domain,” Physiological Measurement, June 2013, 34(6):609-22. doi: 10.1088/0967-3334/34/6/609. Epub 2013 May 29.
  10. T. Li, T. J. Kao, D. Isaacson, J. C. Newell, G. J. Saulnier, “Adaptive Kaczmarz method for image reconstruction in electrical impedance tomography,” Physiological Measurement, June 2013, 34(6):595-608. doi: 10.1088/0967-3334/34/6/595. Epub 2013 May 29.

Conferences

  1. T.-J. Kao, B. Amm, J. Ashe, D. Davenport, Pulmonary Ventilation and Pulsatile Perfusion Imaging on Premature Neonates using Simultaneous Multi-Source EIT, In Conf. Proc. IEEE Eng. Med. Biol. Soc., 2020.
  2. T-J Kao, D. Davenport. “Lung Function Monitoring Using EIT for Mechanically Ventilated Aeromedical Evacuation Patients” Military Health System Research Symposium (MHSRS) 2019 presentation, August 21st, 2019.
  3. J. Ashe, T.-J. Kao, G. Boverman, B. Amm, D. Isaacson, J. Newell, G. Saulnier, D. Chong, R. Sahni, A Ventilation-Perfusion Index for Continuous Monitoring in the Critical Care Setting, Military Health System Research Symposium (MHSRS) 2019 presentation, August, 2016.
  4. Sahni R, Kao T-J, Weindler M, Chong D, DiBardino D, Newell J, Amm B, Boverman G, Shoudy D, Sabatini J, Saulnier G, Isaacson D, Davenport D, Ashe J.  Use of electrical impedance tomography to evaluate effects of continuous positive airway pressure on lung ventilation and perfusion related impedance changes in preterm infants. In Pediatric Academic Society 2016 Meeting, April 30-May 03, 2016, Baltimore MD, USA, 2016.
  5. Sahni R, Kao T-J, Weindler M, Chong D, DiBardino D, Newell J, Amm B, Boverman G, Shoudy D, Saulnier G, Isaacson D, Davenport D, Sabatini J, Ashe J. Regional ventilation distribution using simultaneous multi-source EIT imaging in healthy newborns lying in different body positions. In Pediatric Academic Society 2016 Meeting, April 30-May 03, 2016, Baltimore MD, USA, 2016.
  6. D. DiBardino, T.-J. Kao, D. Chong, J. Newell, B. Amm, G. Boverman, D. Shoudy, G. Saulnier, D. Isaacson, D. Davenport, J. Ashe, “Rapid Shallow Breathing Index Calculated by Electrical Impedance Tomography: a Case Report before and after Extubation,” in American Thoracic Society Annual Meeting, San Francisco, 2016.
  7. D. DiBardino, T.-J. Kao, D. Chong, J. Newell, B. Amm, G. Boverman, D. Shoudy, G. Saulnier, D. Isaacson, D. Davenport, J. Ashe, “Measuring Tidal Volume with Electrical Impedance Tomography,” in American Thoracic Society Annual Meeting, San Francisco, 2016.
  8. T-J. Kao, B. Amm, X. Wang, G. Boverman, D. Shoudy, J. Sabatini, J. Ashe, J. Newell, G. Saulnier, D. Isaacson, D. Davenport, “Real-time 3D electrical impedance imaging for ventilation and perfusion of the lung in lateral decubitus position,” In Conf. Proc. IEEE Eng. Med. Biol. Soc., pages 1135-1138, 2014.
  9. B. Amm, T-J. Kao, X. Wang, G. Boverman, D. Shoudy, J. Sabatini, J. Ashe, J. Newell, G. Saulnier, D. Isaacson, D. Davenport, “Real-time 3D electrical impedance imaging for ventilation monitoring of the lung: Pilot study,” In Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, pages 6064{6067, 2014., 2014:6064-7. doi: 10.1109/EMBC.2014.6945012.
  10. T-J. Kao, J. Ashe, B. Amm, G. Boverman, J. Sabatini, D. Shoudy, J. Chen, D. Isaacson, J. Newell, G. Saulnier, D. Davenport, “Regional 3D VQ Index using EIT on a Healthy Human,” In 16th International Conference on Biomedical Applications of Electrical Impedance Tomography, EIT 2015, Proceedings, Neuchatel, Switzerland, 2015.
  11. G. Boverman, T-J. Kao, J. Ashe, B. Amm, D. Davenport, “EIT of the Human Body with Optimal Current Patterns and Contact Impedance,” Journal of Physics: Conference Series EIT 2014.
  12. J. Ashe, D. Shoudy, G. Boverman, J. Sabatini, T-J. Kao, B. Amm, “A High Precision Parallel Current Drive Experimental EIT System,” Journal of Physics: Conference Series EIT 2014.
  13. X. Chen, T-J. Kao, J. Ashe, G. Boverman, J. Sabatini, D. Davenport, “Multi-channel EIT for layer-based hydration monitoring,” Journal of Physics: Conference Series EIT 2014.
  14. T. Li, D. Isaacson, J. C. Newell, G. J. Saulnier, “Studies of an Adaptive Kaczmarz Method for Electrical Impedance Imaging,” Journal of Physics: Conference Series 434 012075, EIT 2013.
Acknowledgment/Disclaimer: This research was supported by Grant 1R01HL 109854 from the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
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