|During the past several years I have written about some of the various lameness problems that frequently occur in our team roping horses. In those articles, I mentioned that in order to arrive at a diagnosis, it is necessary to perform a thorough clinical exam, which many times may include regional anesthesia, or blocking the leg, to determine exactly where the lameness is coming from.
It is also usually necessary to employ some type of diagnostic imaging to get a better idea of exactly what is causing the lameness. While radiographs, or x-rays, are the most commonly used form of diagnostic imaging, I am often asked about some of the other imaging systems that are available. These include computed radiography, nuclear scintigraphy, CT scans (computed tomography), MRI (magnetic resonance imaging), and ultrasonography. We will briefly look at these technologies so that we can better understand why our veterinarian suggests
their use to aid in a diagnosis.
Radiography is the most commonly used diagnostic imaging technique used by the equine practitioner. All of us have seen x-rays that our veterinarian has taken of our lame horse so we won’t spend a lot of time discussing this technique. Be aware that it is necessary to obtain the highest quality radiographs possible to arrive at a diagnosis of the cause of the lameness. Newer systems and equipment have provided the veterinarian with
very high-detail radiographs.
Computed radiography produces an image that is similar to the standard x-ray that all of us are used to seeing, but it does so by digitizing the image and storing it on a computer rather than using conventional x-ray film. This has the advantage of allowing for manipulation of the image by computer software to improve the image. There are several new systems that are available to the equine practitioner so more clinics and referral practices are now using this technology, even though it is very expensive.
Nuclear scintigraphy, or nuclear scanning, is a diagnostic imaging system that helps to identify the location of any inflamed tissue. It involves the injection of a radioactive substance into the bloodstream. This substance is concentrated in any inflamed tissue. It is then necessary to wait a prescribed period of time, and then scanning the horse with a gamma camera that detects radioactivity. This does not provide a diagnosis of what is causing the inflammation but it does isolate the affected area.
CT scanning involves taking a digitized radiographic image of a “slice” of an area of the body. Without going into the technical aspect of the system it gives more of a three-dimensional series of views of the area whereas a conventional radiograph limits to a two-dimensional views. One disadvantage of this technology is that a very long exposure time is involved so for CT scanning the horse needs to be anesthetized. The equipment is also very large and very expensive.
MRI, or magnetic resonance imaging, relies on magnetic fields to produce an image that is also three-dimensional. It is very useful for diagnosis of soft tissue lesions that are seen on radiographs. As is the case with CT scanning, this technology is very expensive, the equipment is very large, and the horse needs to be anesthetized for maximal image quality. For these reasons, very few facilities have the capabilities to perform CT scans or MRI imaging.
Most veterinarians have access to ultrasound machines as a diagnostic tool. As the name indicates, the image is produced by imaging reflected sound waves. While many of us have seen the veterinarian use ultrasound machines on the broodmares, the technology can also be used to produce diagnostic images, especially of soft tissues such as tendons and ligaments. This technology can be of value in assessing healing of lesions in tendon tissue.
As these cutting edge technologies become available to the equine practitioner it aids them in diagnosing the lamenesses that are sure to happen in our team roping horses. The more accurate the diagnosis of the problem, the easier it is to treat the problem. Good luck in keeping your horses sound.