Gracie Herring leads the way for Vet-IR in Australia and is one of our senior imaging consultants. She has build up a wealth of knowledge during her IR journey and below shares a helpful insight into the basic building blocks that should be considered when using IR imaging technology.
How veterinary infrared imaging should be used: The importance of accurate application for thermography to achieve reliable results to assist with veterinarian diagnosis, treatment and rehabilitation of equines.
The proper use of thermography when examining equine patients, or any animal patient for that matter, should be to ensure that similar clinical standards and principles used in the human medical sector be applied to veterinary infrared imaging. For this to happen it is necessary for the environment to be controlled and rigorous obedience to an imaging protocol be followed to eliminate errors or false readings.
When accurately applied, infrared imaging has numerous benefits and advantages to offer the veterinary industry. The technology can recognise dis’ease in the body at a much earlier stage than other common diagnostic tools, offering the horse owner and care team a way to monitor horses and implement preventative measures before lameness and poor performance peak.
“The validity of IR results depends on an accurate, reliable and standardised service.” – Sophie Gent Vet-IR Partner
Not all infrared cameras are suitable for veterinarian applications. The cameras that should be used are highly technical and need to be of a scientific standard, with a high enough accuracy and thermal sensitivity to detect minor temperature differentials. The quality of the image interpretation is only as good as the images that are captured, and a minimum resolution of 640 x 480-pixel arrays is required to obtain the superior image detail required to detect thermal irregularities.
Capturing of IR data
The imaging consultants (or thermographers) are responsible for taking the most precise images possible so that the interpreting vet has the best chance of achieving accurate and reliable information for analysis and reporting. Images must be taken at exactly 90 degrees and at a consistent distance to ensure accurate bilateral comparisons can be made. Data from opposing sides should be captured within a set time frame, thus minimising environmental factors.
Animals should be imaged both prior to exercise and after, where possible. This enables comparative studies to be run of previous and post-exercise, documenting the patient’s physiological response. This process provides invaluable data, helping to pinpoint and localise pathology.
Patient preparation and environment
Standardisation and correct patient preparation are most vital to minimize artefacts and maximize results. Clinical IR imaging must be done in a temperature consistent environment where the animal has had time to acclimatise to its surroundings. Artefacts such as moisture and sweat, dirt, bandages, and rugs, will affect the ability of the infrared camera to capture accurate skin temperature. Other such artefacts include long hair coats, feathers, rugs, and manes and tails may interfere with imaging, so it is important that this is tended to. Having a clean and dry patient in an environment free of drafts, direct sunlight, or moisture, are key to capturing accurate results.
Following proven protocols and standardisation means that IR imaging of animals is repeatable and reliable and essential to its continued acceptance as a valuable tool in veterinary diagnosis.
The analysis and interpretation of animal infrared (IR) data should be completed by a licensed veterinarian. However, not just any vet is able to review the data captured by the technician. Veterinary surgeons specifically trained in thermographic interpretation of the data are required.
“Interpreting thermography is far more complex than people think. It is not purely about “hot spots” but recognition of disruptions in homeostasis and anomalies in normal thermal patterns. As well as this it is important to have a rooted understanding of pathogenesis and pathophysiology as thermographic images will inevitably show something. Specialist experience and veterinary knowledge will be able to link the findings with clinical history and relevance to clinical presentation. Many services attempt to interpret without qualification and/or use an algorithm software to formulate a diagnosis. This results in questionable findings.
“Thermography without qualified veterinary interpretation is thermal art.” – The Equine Documentalist (Veterinary Infrared vs Thermal Art, 08/07/2020)
Clinical history and concerns
A history of the patient should be supplied. For equines, this must include the horse’s age, gender, breed, use, discipline, and current level of performance. Information of hoof function, current health problems and any previous injuries of the musculoskeletal system should also be included. Medical history is also required, including results of other veterinary examinations such as radiology, ultrasonography and palpation.
To conclude, accurately applied infrared imaging technology has many benefits and advantages to offer veterinarians and their clients, assisting owners and professionals detect injury, pain or dis’ease at a much earlier stage to help prevention in areas of equine lameness and poor performance, providing more comprehensive care for equines.
References and further reading:
Equine Documentalist. 2020. BLOG | The Equine Documentalist. Available online at: https://www.theequinedocumentalist.com/.
Equine Documentalist. 2020. Equine Thermography – Hot or not?. Available online at: https://www.theequinedocumentalist.com/post/equine-thermography-hot-or-not?
Imaging Techniques in Equine Lameness By Tracy A. Turner , DVM, MS, Turner Equine Sports Medicine and Surgery
Turner et al., 2001; Soroko et al., 2014