Thermal Imaging

I promised to share some of the thermal images of P that we had taken, so this is for just that.  I apologize in advance for the mediocre quality, I was in a fight with the scanner - and apparently lost.  Such is life.

I've had several conversations with my vet about the merits (and pitfalls) of thermal imaging as a diagnostic tool, so I was really interested to see first hand what sort of information she was able to gleam for the pictures as well as how the photo shoot (for lack of a better term) would go.

If you'll recall, the day that we took the Thermals of P, we went on a nice trail ride then turned the beast out and let her play with a new herdmate who was just being introduced.

Vet was adamant that Pia had at least 30 minutes to relax in pasture before we took images because even a low key trail ride that doesn't warrant a sweat causes a pretty serious change in blood flow to muscles and whatnot.  I picked up early on how critical it is for the subject to be as clean and dry as possible.

Dry I could arrange for, but please recall that yak-mare looks something like this at the moment:

There's only so much a 2 minute curry can accomplish when fighting against 9 months of pasture time...

The reason why "clean and dry" is essential is because unlike thermal images of... oh say... a baby's bottom, the furry coat on horses does a fantastic job of insulating them and masking true variations in blood flow.  On top of that, any change in hair pattern, cowlick, matted bit of sweat or damp spot reflects the heat slightly differently and will result in an irregularity in the image.

This is why it's critical (IMHO) to be in front of the real live horse when reviewing thermal pics.

Vet has expressed her frustration at being sent sets of images remotely to examine and then expected to try and guess which cold (or hot) spots are due to blood flow, and which ones are manure stains from an afternoon nap...  It's hard.

So I was grateful to be present when she took pics of P and was able to explain her methodology to me.  First, an image:

As you can well imagine, these images are of P's shapely bottom, and then a bird's eye view of her spine (head away from us).  You can also see my creepy (apparently warm) eyeballs glowing in the top shot...

The scale on the right shows you what the colors mean as well as the range of temperatures that the camera is reading.  What's cool about this is that you can basically control the sensitivity of the camera to the point that if you see a "hot spot" on a leg, you can "zoom" in by stretching the color scale out over a smaller degree range.  The top pic had a range of 49 degrees to 90 degrees, where as the spine picture ranges only from 66 to 84. Essentially this provides more detail in the temperature variations.

When you find an interesting spot you can set the range to just a few degrees and get a much sharper picture of what's going on...  (based on blood flow).  You can literally tell if the heat in your horse's tendon is a strain, or just a concussion from whacking their leg on the fence...

That is pretty bad ass in my opinion and would be a really handy piece of information to have before whipping out the checkbook for ultrasounds... plus it's just cool to see.

What these couple pictures of P show is that our fantastic Vet isn't making anything up.  P's "hammies" are tight in her butt (a side effect of her compensation for tight shoulders) and she has a hot "cross" on her back that is basically her spine and a stripe across her shoulders.  This isn't the best picture we have to illustrate that, but it's the best one I have a copy of :)...

What's even cooler is I was able to look at comparable images from other horse's in order to see how much cooler their spines/withers are and see how P's body is unique. 

Here's one more example of the thermals:

Top picture is a side shot of her wither/shoulder (the purple blob at the top is a piece of mane) and the bottom picture are her front toes.  I don't know if you remember but it looked like P had blown an abscess that day (she hadn't been sore) but we couldn't quite tell if it was an abscess or part of the blister that her (mean, nasty, awful) boots gave her.  You can see the flaming white hot spot on her pastern from the boot (I felt so guilty), and just below you can see a different heat pattern in her hoof which pointed toward abscess.

just as a side - we did then "zoom in" on that foot and get a more detailed shot which literally showed where the abscess had been in more detail.  Vet said that she considered this image a very "general, almost fuzzy" image that she would always follow up on.  Once again.. how cool to think "gosh, does my horse have an abscess?" then be able to take a thermal image and see the compressed heat and know for certain that an abscess was the answer... so interesting.

I definitely came away from the process with more understanding of how careful you have to be when taking pictures.  Directional sunlight is enough to warp the results, as is pretty much any sort of recent activity, mud, water, or sweat.  But, I feel like taken with enough consideration, the thermal images are a great additional tool for a vet to have in their tool box.  Certainly provides an interesting bit of information...

P wasn't so sure though.  She thought the camera was definitely a snack....