My journey in thermology began in humans and before I became a vet. I trained as a thermologist for a chiropractor who routinely used thermography for breast health at his clinic.
After qualifying in veterinary medicine, I had an opportunity to learn to interpret veterinary thermal images and become a veterinary thermologist. I jumped at the chance, already knowing what a great technology this is.
Thermography is a rapidly evolving, non-invasive diagnostic tool in veterinary medicine, which compliments other imaging modalities such as ultrasound and radiography. It can help to provide a pathway of clinical investigation that may not otherwise have been considered. Thermography looks at the constant infrared radiation emissions coming from the body surface (at the level of the first 5mm of skin). The resulting image is essentially a map of superficial circulation and the heat that blood flow is creating or not creating (if there is reduced vascular supply). So we are provided with an immediate assessment of inflammatory, vascular and soft-tissue related conditions.
Interpretation is based upon differences in emissivity on contralateral sides of the animal. A normal animal will have symmetrical vascular supply on each side of the body. Thermal asymmetries manifest as temperature differentials which can then be clinically correlated by physical examination or other imaging protocols. It is extremely valuable in localising those low-grade musculoskeletal dysfunctions and evaluation of poor performance cases. It can also dynamically show changes in resting physiology compared to after exercise and can be used to monitor response to therapy as well as baseline health status.
Interpretation of thermography images is largely based on pattern recognition, but there is a lot more to it than simply looking for “hot-spots”. An understanding of the physiology of circulation as it relates to temperature regulation of the body, inflammatory processes, and the autonomic nervous system is required. Painful areas may appear hyperthermic or hypothermic depending on the underlying cause. Acute injuries will generally appear as focal regions of hyperthermia. Chronic conditions and some neurological disease can however manifest as diffuse or focal regions of hypothermia due to the effects of the sympathetic nervous system on vascular constriction. Over the years, repeat patterns have become evident to me. For example a particular group of repeatable thermal abnormalities are observed in cases of sacroiliac disease in horses.
As with every imaging technology, there are limitations associated with thermography. Strict protocols are required with to regard ambient temperature in the imaging environment and background interference from sunlight and other animals/people. Animals should have time to acclimatise to the imaging environment and short hair is preferred to reduce the risk of false negative results. However, I do recall a case of shoulder OCD in a young and very hairy St. Bernard which was nicely detected by the camera! Clip lines observed on horses also provide an extra challenge in that they create large temperature differentials that affect interpretation of the physiological thermal pattern.
A successful thermal study is also reliant on the experience of the thermologists who strictly follows imaging protocols with respect to anatomical region, framing of views etc. If contralateral images are not directly comparable, then false positive or false negative interpretations can result. Studies must also be repeatable in cases of monitoring recovery and response to therapy.
I hope that this has been a useful insight for any professional thinking of diving into thermology. I am very grateful to have been introduced to this technology as I have learned so much and it has greatly enhanced my own veterinary practice with the various cases I have referred for thermal imaging.
I have been very lucky to work with the team behind Vet-IR for ten years now and I’m very excited for what the future holds for IR technology.
If you would like more information about thermology interpretation or training then contact Vet-IR via our contact form.