At the 2024 ACVIM Conference, David Byrne, MVB, MVetClinStud, MVetIntMed, MANZCVS, FHEA, DACVIM (LAIM), Senior Lecturer in Equine Medicine at Australia’s Murdoch University, delivered a presentation on electrical impedance tomography, a new imaging modality that has great potential in equine veterinary medicine.
What Is Electrical Impedance Tomography?
Electrical impedance tomography can reconstruct images of a specific region in the body based on the electrical conductivity of biologic tissue. The lungs are particularly conducive to using this noninvasive, real-time modality. It is radiation-free, portable, and well-tolerated as performed in sedated, standing horses.
Because air is a poor electrical conductor, it causes impedance at the end of inspiration in the lungs. Spacing 16-32 electrodes in pairs on a neoprene belt along the thorax enables imaging of the chest to detect intra-breath phenomenon; software then determines air in the chest as impedance per breath.
Applications for Electrical Impedance Tomography
Byrne said this technology can be used in multiple settings and for various syndromes:
- For anesthetized horses to help correct recumbency-induced atelectasis.
- To detect global flow changes in equine asthma, particularly to evaluate post-exercise respiratory function.
- To observe regional flow changes for bronchoconstriction and compare with changes from treatment, such as with albuterol.
- To examine foal ventilation and compare as right to left imbalances at birth improve over time to adult levels.
- To evaluate pulmonary edema due to left-sided cardiac overload.
- To evaluate for cardiac failure or pleuropneumonia.
Final Thoughts
While there’s currently no commercially available equine system or veterinary-specific software, electrical impedance tomography has important applications and should become more available in the future. According to Byrne, electrical impedance tomography does not interfere with other imaging technologies.
Related Reading
- Practical Field Cardiology for Horses
- Diagnosing Respiratory Ailments in Horses: Wash or Lavage?
- Positron Emission Tomography (PET): Not Just for Racehorses
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