Digital cameras extend DVMs' diagnostic vision

What is the most important piece of equipment in your truck or clinic?

Use of digital cameras at shows, competitions, and other events can provide evidence of perfect gaits and motion or point out problems and deficiencies. The use of film review in all aspects of human sports development has greatly improved performances and similar gains can possibly be seen in equine sports.

Is it your X-ray machine or perhaps your ultrasound? Could it be your blood chemistry analyzer or simply your stethoscope or hoof tester?

While a case can be made for any of these, possibly the most important device in equine practice today may be the digital camera or digital video recorder.

Recent improvements to these devices have upgraded the quality, enhanced the usability and decreased the cost to a point where every trainer and equine veterinarian should have one.

In his paper, "Video analysis of gait in horses," Dr. Kevin Keegan, DVM, MS, writes that video cameras allow for an evaluation of equine athletic ability. The use of such cameras also enable veterinarians and trainers to monitor progress with training, to detect changes caused by trimming and shoeing and to measure lameness.

Keegan lists the two main benefits of digital camera use as "providing a medium for objective measurement and expanding the temporal resolution of the human eye (which is only about 0.1 sec)".

Simply stated, digital cameras and camcorders allow the viewer to see more, to save what was seen for later comparison and to dissect complex motion so that the human eye can process all of the available information. Given this capacity to capture and help utilize information, it may not be that much of a stretch to call a digital camera one of your most important pieces of equipment.

Nothing new

Cameras and film use have been solving problems in equine sports medicine for a long time.

In 1877 American photographer Eadweard Muybridge and French physiologist Etienne Jules Marey collaborated to do a series of studies on equine gait. Prior to this time, writes Dr. P. Rene van Weeren, professor of equine surgery at Utrecht University, "treatises on gait analysis had largely consisted of theoretical considerations while conclusions based on experimental data were scarce. This was largely due to the limitations of the human eye when observing the faster gaits."

Digital images can be taken and stored allowing veterinarians and owners to keep visual records of parameters that should be monitored. Hoof angles and shoeing concerns should be recorded. Healing wounds, tumor growth, gait changes, and nutritional improvements are only some of the aspects of horse care that lend themselves to digital record keeping.

A review of the prominent equine art of that period would show racing horses painted with front legs stretching out in front and with both hind legs pushing out behind. From our 21st century vantage point it seems silly that anyone would have thought that horses actually moved like that but we have been able to slow down horse gaits and have actually seen how they move. Without the benefit of cameras we would never know.

And it was Muybridge and Marey who finally documented that there are indeed times when all four limbs of a horse are off the ground at the same time (This was a point that had been argued reportedly since the time of the Egyptians).

By using 24 cameras in linear array, these early gait analysis pioneers uncovered previously unseen (and unsuspected) characteristics of the gaits of the horse. This array of cameras and some modification in their mechanics reduced exposure time to 1/6000 of a second. Whole new worlds of information were now available to owners, trainers and veterinarians.

New worlds

Similarly, the recent development of low cost, high quality digital camera and video equipment and the software to develop and store pictures and video are opening up new worlds to modern equine practitioners.

How often do you find yourself looking at a lame horse and asking the client if this horse always dragged his toes, or ever trotted with his tail cocked to the left or swung out the leg at the stifle on turns to the right? Most times there is no prior information and nothing to compare the current lameness to. Contrast this to major league baseball where a New York Yankee batter can call up a digital video, look at all the pitches he may have faced from a particular pitcher and watch himself swing at all those balls.

Digital cameras allow veterinarians to take pictures of radiographs, skin irritations, ocular conditions, wounds, tumors and other lesions. These digital images can then be quickly sent to any number of experts via e-mail. Detailed and timely responses can improve diagnosis and treatment of field cases.

Such a detailed look can help to point out subtle imperfections in movement and can show changes from past good performance as a means of pinpointing and correcting a problem.

Catching up

From golf swings to 3-point shots to deep sidelines passes, human athletes use digital film evaluation everyday. Equine sports medicine is just beginning to catch up.

Imagine if your clients had a video record of their horse's gaits when the animal was fine and moving normally. Comparison between the videos may help focus on specific areas of lameness and could help with diagnosis and treatment of the problem. Problems such as saddle-fit, rider imbalance and other training issues can be focused upon and perhaps helped by using digital video analysis as well.

Shoeing concerns

Digital cameras can be tremendously helpful in dealing with farriers and with shoeing concerns.

A simple lateral digital photo can be projected on the computer or television screen and measurements can be made of hoof length, angles and breakover points.

Digital video can provide information concerning loading and landing aspects of the foot and can show foot flight and leg motion.

These digital photos can be saved and used at the next shoeing to compare growth, wear, and other dynamic aspects of the horse's foot.

Farriers may be able to stay more consistent with their trimming of some feet if they are provided with a video record of the horse in question. This non-subjective record of what the foot looked like and what its measurements were would be a great help to the farrier. More correct, more consistent shoeing could therefore be developed.

Documentation, I.D.

Practitioners in the field can use digital cameras to document cases of trauma and to produce extremely accurate records for the identification of horses.

Video use during a prepurchase examination can help practitioners document any irregularities for both medical and legal reasons.

Insurance companies also like video records of problems.

Skin conditions, ocular lesions and tumors are especially well suited to monitoring via digital photography since progression and changes in size can be easily recorded. A good photograph of a squamous cell carcinoma near the canthas of an eye can be used for diagnosis, treatment and as a means of monitoring recovery. Digital cameras allow the user to send photographs via the Internet to virtually anywhere. The equine practitioner can therefore use a digital camera to take pictures of a lesion and then to send those photos to an expert for evaluation.

This method of information exchange greatly speeds up the current process of sending hard-copy medical records to local experts and it greatly expands the number of experts that can be used for second opinions.

Radiography

Radiography can be handled as digital information as well. The newer digital radiology systems will simply let the practitioner send the entire X-ray, but for veterinarians using standard radiograph systems, a digital picture of an X-ray must be taken. Good quality radiographs are needed first, but then a simple digital photo taken of such a radiograph on a light box can be immediately sent for consultation. Thus, digital cameras can improve both the speed and accuracy of diagnosis.

Clearer picture

The complexities of equine gait are made much clearer through the use of slow motion video.

The distance that a foot travels and the manner in which the hoof strikes the ground are much easier to appreciate in slow motion. Jaye Perry, a farrier in Georgia, feels that digital video is an extremely useful tool.

"With this modality," says Perry, "The human eye can see what it cannot in live action, thus pinpointing details missed which may result in musculoskeletal injury to the horse over the horse's career. By seeing these small details in digital review, it helps train your brain to look for the minute distinctions."

Rehab

Rehabilitation is another area that lends itself well to the use of digital photography.

Small subtle changes in a horse or a human that is undergoing a rehabilitative process can be signs of enormous progress.

By measuring stride length on a computer screen you might find that a rehab horse's right hind foot is tracking up by 1.5 inches toward where it should be. This small change might well be unnoticed by the eye of the average horse owners who might then get frustrated because of the lack of progress with the rehabilitation program.

If these owners had seen that his hind end was indeed moving somewhat better, then they might have been more hopeful about his progress and would have been more likely to continue following the prescribed exercise program.

Which to buy

But even if you are sold on the idea of what a digital camera or recorder can do for your practice, you still have to buy one.

There are thousands of different cameras currently available ranging in price from $100 to $1,000.

Many come with more "bells and whistles" than others, but much of the difference between cameras has to do with pixels. Pixels are the individual spots of information (color and detail) that are stored in an image. Pixels translate into resolution. The more pixels that your camera is able to capture, the larger and higher the resolution of your photos.

Most veterinary cameras have a resolution of 2.1 to 3.4 megapixels but are available in the 5 to 6 pixel range. It is generally recommended to purchase the maximum number of pixels that you can afford.

Some cameras come with zoom options. Digital cameras use memory cards in place of film. Images are taken and stored in the memory in the individual card. This card is then removed and placed into a computer so that the card's information can be downloaded into regular files.

A card of 16-MB (megabytes) would provide enough memory to store one uncompressed image and up to 17 compressed ones. Digital images are either compressed or uncompressed which refers to the computer's method of storing pixels. Uncompressed images are sharper and clearer. When files (pictures) are compressed, the computer attempts to drop out or remove some pixels in each photo. This allows the computer to more quickly send or store that information.

Compressed images, however, must have the missing pixels "filled in" before the photo can be restored to accurate size and sometimes mistakes can be made at this point.

Memory cards of much greater storage potential can be purchased for your camera and they will allow the user to take and store many more photos without having to download the card so quickly.

Second set of eyes

Digital cameras allow trainers and veterinarians to see what our eyes are too slow to see and that can sometimes be very surprising.

Digital cameras used with treadmills will likely yield the next new important information of interest to equine practitioners. An old saying states that one will miss more things by not looking for them rather than by not knowing about them.

Digital cameras are providing veterinarians with a means of obtaining information that would not have been available in any other way.

The things that will be learned about how a horse moves could influence the way we trim and shoe, train, jump or perform in any discipline. Digital cameras and digital video truly are a new way of looking at things.