Specialized Thermal Imaging

I thought I would post what David Valley of Mass Infrared and I have been discussing on the NACHI message board.

I figured I would post this and maybe some equestrian folks like Charlie B. could add to our observations.

There are a few interesting points that came out of this and I would like to share with those who do any kind of infrared service.

David forwarded me a radiometric scan of a horse he had encountered in the past so that I could manipulate it and offer an opinion of what I saw.

"Though I hate to attempt any analysis from one thermal imaging scan and without supporting information, it appears to me that we have some issues in the left front lateral digital extensor tendon.

Also the right posterior medial tarsal joint appears inflamed. The proximal medial area is warm also, but this area has considerable blood flow and retains heat even in normal conditions.

If injury is in advanced stages there is a possibility of bone spavin.

The two areas may be related as horses often adjust to injury where bilateral stress may occur.

I recommend that when doing equine scans, that a baseline scan be taken of the horse at rest from all directions to be used in comparison after the horse is exercised.
Attempt to eliminate all potential artifacts in preparation for the scans. The horse should be clean and dry with no topical application applied for any purpose.

David, Could you post the known symptoms and conditions at the time of your scan?"

David advised that the horse was diagnosed with  major arthritis to the legs.

I was thinking about this and took another look at the scans.

Osteoarthritis or degenerative joint disease is one of the leading causes of lameness in horses. So how does the infrared cameras see this condition? Sinovial fluid in the joint breaks down prior to the onset of arthritis. This fluid is what nourishes the joints components, not blood. Actually, blood (associated with inflammation of the joint) is what breaks down this fluid. So there is no source of heat to detect in degenerative joint disease, including bone spavin. The heat that we see with thermal imaging is associated with inflammation and stresses on the other components like tendons and ligaments. A horses joints must be able to lock and unlock so they can sleep standing up. Their inability to lock will increase strain on other leg components. Their inability to unlock will lead to lameness.

In this example, though we can detect inflammation around the joint, other equipment is required for a complete diagnosis.

Just like in home inspection, we can detect associated conditions that we cannot always diagnose the issue. An Example of this misinformation is mold detection. We do not detect the mold, rather the moisture associated with it.

I think that the most important point to consider is that any kind of testing that you perform with the infrared camera, you must work together in conjunction with experts on the subject you are scanning. I see all too often when I do a web search on equine thermal imaging (and other services), that owners of thermal imaging equipment lists services that they perform that appear way beyond their expertise. The shotgun approach of thermal imaging marketing!

Another important point in this example is the thermal tuning of the infrared scan. The first photograph is a raw scan. It is important to adjust focus, composition and distance. The rest can be done on your computer. This photograph was thermally tuned to the specific anomalies in the horse's legs. The palette used helps improve thermal patterns. Though we used a high resolution rainbow palette in the final product, the black-and-white or iron pallettes have better resolution for your initial scanning so you can identify the anomalies through the camera.

We see way too many "click and post" thermal scans around.

On the subject of liability, if a scan is not properly diagnosed through proper tuning you are in fact increasing your liability. I disagree with those that feel thermal imaging oversteps the bounds of home inspection and increases liability. If performed correctly, this is not the case.