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Introduction to Equine Thermography

As an equine thermographer, I tend to draw a bit of a crowd during an imaging session while people peek over my shoulder to get a look at the array of colours on my camera screen. Most people think equine thermography is a new modality in the equine industry, but it has been around since the early 70’s – used mainly as a screening tool at racetracks. However, when it came to the expensive yet basic cameras and the knowledge in how to correctly image and interpret those images, equine thermography was soon pushed aside by veterinarians.

Beginning stages of a bowed tendon, showing a break in the thermal pattern.

Beginning stages of a bowed tendon, showing a break in the thermal pattern.

So what is Equine Thermography?

Infra-red thermography is the science of acquisition and analysis of thermal information from non-invasive imaging equipment and software to detect minute differences in the horses thermal and neural condition. When an injury is in the acute stages of inflammation, thermal imaging works by detecting the heat generated from inflammation which allows direct visualization and measurement of areas of concern allowing thermographers to quickly and efficiently identify trauma in an injured animal.

How is Equine Thermography different from other diagnostic modalities?

The major difference between traditional diagnostics like ultrasound and thermal imaging is that one is anatomic and the other is physiologic.

  • An anatomic diagnostic modality will show a specific lesion or problem in anatomic structure. For example, an ultrasound will show the degree of damage in a tendon or ligament injury.
  • A physiologic modality such as thermal imaging cannot show a specific anatomic lesion, but down show a physiologic change in blood flow that helps localize a lesion and more easily shows changes over time. For example, showing whether the tendon or ligament injury is causing inflammation.

What makes Equine Thermography unique compared to the other modalities?

Thermography is the most effective preventative diagnostic modality due to its ability to identify asymmetrical thermal patterns of heat in the horse’s body indicative of inflammation.

Nerve impingement

Nerve impingement

Thermography has proven to detect damage to structures up to three weeks before a horse will show clinical signs of lameness. Before a structure, such as a tendon or ligament “breaks down” it goes through a degree of accumulative damage. This weakens the structure without the horse being active lame and while training with this micro damage they are much more susceptible to serious injury.  In fact, changes greater than 1C – 2C are considered significant.

Infra-red cameras have come a long way since the 70’s and the sensitivity of the camera for detecting temperature changes related to disease makes thermal imaging a valuable tool and it is just that, another valuable tool in the tool box of diagnostic modalities.

What should you look for in an Equine Thermographer?

When looking to hire an Equine Thermographer you should be asking the similar questions as you would when looking for a equine therapist:

  • How long have you been an Equine Thermographer?
  • What sort of training did you acquire to become an Equine Thermographer? Are you certified?
  • Do you belong to any professional associations?  The benefits of belonging to a professional association can include things like continuing education requirements, and thermographers carrying liability insurance, although these are not available everywhere yet.
  • What type of camera do you use? This is an important one as the two main companies that supply infra-red cameras are Fluke and Flir. These two companies offer a wide range of infra-red cameras available to the public. In order to have the quality of image required for veterinary diagnostics the camera your thermographer uses should have 320 x 240 IR resolution and at least a 60Hz which is the rate at which the image is captured. If the thermographer pulls out a cell phone or says they use an app to do their thermal imaging, they are wasting your time and money.
  • Do you have standardized patient preparation and imaging series? Standardization and patient preparation are crucial to successful equine imaging and the interpretation of the scan.
  • Are you willing to work with other professionals? Your horse can only benefit when you have a team of professionals working together. If the thermographer is hesitant to working with other professionals, be it a therapist or a veterinarian, you might want to keep searching.

What is required for successful??imaging and interpretation?

Standardization and correct patient preparation are crucial to accurate and successful imaging. The emphasis of environmental control when imaging is essential. Horses should be imaged indoors sheltered from the elements outside. Sunlight, wind, radiant heat from surrounding buildings, and sometimes even flooring in a barn can alter what the infra-red camera captures.

Soft tissue damage, vertebrae trauma, as well as the coxal tuber along the nearside of the horse.

Soft tissue damage, vertebrae trauma, as well as the coxal tuber along the nearside of the horse.

The patient should be clean, free of artifacts such as, moisture, dirt, liniments, blankets, bandages and has been indoors acclimatizing to their environment for a minimum of 45 minutes, tied to minimize movement, and minimal feed offered. Legally, thermographers cannot diagnose. Our job is to provide the horse owner and the veterinarian the opportunity to identify and focus on the exact area for further investigation. Interpretation must be done by a licensed veterinarian, preferably one that is experienced with equine thermography.

Equine Thermography is not about taking pretty pictures. It is a technical process that requires the technician to thoroughly understand the processes required and to apply them consistently for successful imaging. Having a clean, dry patient in an environment free of drafts, direct sunlight, or moisture, and a certified thermographer with an appropriate infra-red camera are fundamental to the success of your horses thermal imaging scan.