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Equine Thermal Imaging

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Thermal imaging finds its niche in diagnosing mystery lamenesses, scanning horses at pre-purchase evaluations, aiding farriers with hoof pathology and imbalances, addressing common saddle-fitting problems, and providing both baselines and serial documentation of equine health and lameness. A case-based approach to the technology provides evidence of its vast uses and tremendous sensitivity in equine medicine, and numerous publications evaluate the technology in equine, bovine, and small animal fields.

Technological advances

As with most technologies, (from radiographs to ultrasounds and MRI) thermography cameras have greatly improved. Gone are the days when bulky cameras were wheeled around on carts, and the images were so grainy and poor that all detail was lost. Today’s thermal imagers are roughly the size of a hand-held radar gun or SLR camera. Many are able to record digital images alongside the thermal images, and some also record video for real-time imaging (excellent for teaching, or for research such as equine treadmill projects).

As the technology has significantly improved, the cost has also greatly decreased, meaning that thermal cameras are more affordable additions to today’s veterinary practices. That said, there are very important caveats to successful patient scanning and image interpretation.

Skill and experience crucial

When evaluating individual patients and case studies, it is imperative to remember that the images are only as good as the technician’s skill in obtaining them, as well as the standardization of patient and environmental preparation. Equally necessary for a positive outcome is the veterinarian’s experience in evaluating the images. Only when these conditions are met can the most successful interpretation be made.

The historical failure of thermal imaging in the equine industry was due to a lack of understanding of how and where to prepare and place the horse, and how to read the images once they were obtained. As interest in this technology grows, it will continue to come under fire as less skilled and untrained technicians and veterinarians attempt to add it to their businesses without a complete understanding of its proper implementation.

Thermal imaging is safe, cost effective for the client and practitioner, quick to perform, and reliable in experienced hands. These advantages will aid thermography’s broad acceptance, as skilled practitioners recognize these inherent benefits and seek to use the tool correctly.

Thermal imaging is a physiologic modality

Diagnostic imaging modalities may be divided into anatomic and physiologic. Thermal imaging is a physiologic imaging modality; therefore, it detects changes in blood flow and metabolism, but cannot necessarily tell you which exact anatomic structure is affected. The camera converts infrared waves into an image visible to the human eye. Another physiologic imaging modality is nuclear scintigraphy, which requires a hospital stay and injection of a radioactive isotope.

Anatomic imaging modalities, meanwhile, include traditional radiographs, ultrasound, Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). These modalities pinpoint the structures affected with pathology, but only give a static image of disease processes.

Thermal imaging detects surface heat directly correlated to circulation, or a lack thereof. Therefore, anything that requires a tool to identify inflammation, reduced circulation, potential nerve damage, or serial patterning, could be evaluated with thermography.

Case studies

• Lady is a ten-year-old Thoroughbred mare. Thermal imaging was used as a general screening tool to help her owner decide if she should continue with more expensive diagnostics and treatments to address the horse’s lameness, or if retirement was a more appropriate choice. Lady had been used as a racehorse, then retired to work as a children’s lesson horse and low hunter. She always took a long time to warm up, had a history of a club foot and badly rotated limb, and was more recently treated for a suspected suspensory ligament injury. Her owner requested a scan to determine if there were other issues that would prevent the horse from returning to full soundness, or whether she would require ongoing care that the owner might not be able to provide. A full horse scan was provided, and numerous problems were noted on thermal images.

Lady’s images showed focal hotspots in her spine consistent with spinal arthritis (perpendicular patterning suggestive of Over-riding Spinous Processes), or dorsal spinous ligament inflammation and paraspinal muscle inflammation, with possible saddle-fit issues. These areas would require further diagnostics to evaluate, but may explain her slow warm-up and crooked gait. Lady also showed decreased circulation in the right front foot (the club foot), bilateral tarsitis (inflammation in both hocks) and increased heat in both hind feet. These findings suggest that even after healing from her current injury, Lady will require ongoing maintenance to be performance sound. While the owner will ultimately have to decide what she wants to invest emotionally and financially in the patient, there is simply no other modality available that would so quickly and inexpensively provide this whole-horse information for the owner.

• Another patient was presented due to lethargy and toe-stabbing. In this case, thermal imaging demonstrated general muscle inflammation, a specific area of muscle trauma, and an area identified as a sole bruise. The attending veterinarian treated the horse before seeing the imaging report, and later confirmed all findings documented by thermal imaging in the horse’s interpretation. Subsequently, all horses in the barn have undergone baseline thermal imaging scans.

The above cases are real horses presented in daily practice. There are literally thousands of other case examples. The safe, quick, whole-horse imaging obtained with the thermography camera provides valuable information for both veterinarians and farriers, and can help clients with emotional and financial decision-making regarding the welfare and continued performance of their horses. These cases help demonstrate the extreme versatility of this imaging modality when used with proper training and interpreted by skilled practitioners.

To learn more about equine thermal imaging, visit equineir.com or ieinfrared.com.

Performance horses benefit

Most racehorses and upper level show horses are financial commodities, not pets. When their performance decreases, their value may also drop. Having a quick and effective diagnostic evaluation tool, e.g. thermal imaging, is imperative to keeping these horses sound and performing to their maximum potential.

Performance horses present with many different lesions on thermal imaging scans – from tendon and ligament tears (confirmed with anatomic imaging), to bone inflammation, muscle inflammation or atrophy, splints, and other performance limiting injuries.

Monitoring healing

Another good use of thermal imaging is serial imaging of a lesion to monitor healing. While ultrasound is also useful for soft-tissue evaluation, the cost and small examination area involved can limit its use. Thermal imaging can quickly monitor healing of both soft tissue and bony lesions through serial analysis of heat signature. While palpation may suggest a splint lesion is “cold” and the horse is ready to go back to work, thermal imaging can provide a more sensitive evaluation.

Finally, hoof imbalances, bruises, abscesses, shoeing problems, laminitis, navicular syndrome, thin soles and more, will create thermal patterns indicative of disease.

Dr. Joanna Robson is the owner of Inspiritus Equine, Inc. (inspiritusequine.com), an integrative equine veterinary practice in Napa, California. She is a sought-after national and international lecturer and clinician on topics such as equine thermography, veterinary acupuncture and chiropractic, and saddle-fitting. She is co-founder of the HIPPOH Foundation (HippohFoundation.org), which unites like-minded equine professionals for the health and welfare of the performance horse.