After an exciting day of cross country at the Rolex Kentucky Three-Day Event on April 27, horse owners and enthusiasts gathered to hear top equine veterinarians from Rood and Riddle Equine Hospital speak on health issues pertaining to the sport horse. Among the speakers was Scott Hopper, DVM, MS, Dipl. ACVS, a surgeon, who provided a very informative overview of how a veterinarian goes about diagnosing a lame horse. He said a veterinarian will use a combination of methods–including a review of the horse’s history, a physical exam, gait evaluation, flexion tests, diagnostic anesthesia, radiography, ultrasound, and scintigraphy–to isolate and diagnose the specific cause(s) of a lameness. The goal of a lameness exam is to provide a definitive diagnosis to the owner so a treatment plan can be developed to return the horse to exercise as soon as possible.

Hopper went into detail about Rood and Riddle’s use of computed radiography, which uses a computer to extract data from an X ray, then convert it into a digital signal. This digital signal can be manipulated to correct exposure or enlarge the image. He said that computed radiography has been a great asset, one which the veterinarians at Rood and Riddle use in about 90% of lameness cases. He showed several examples of injuries using both traditional radiography and computed radiography. Several of the digital radiographs allowed veterinarians to diagnose an obscure injury that did not show up on a traditional radiograph.

In addition, Hopper pointed out that this method minimizes the number of retakes and allows veterinarians to save an image to CD or email it to other veterinarians for another opinion.
Another diagnostic method Hopper finds useful is nuclear scintigraphy, or the bone scan. When performing a bone scan, the veterinarian first injects technetium into a vein, then waits two to four hours. The technetium binds to areas where there is increased bone metabolic activity (site of an injury), and emits gamma radiation, producing an image that shows a “hot spot,” or a darker area.

Scintigraphy can be used to detect stress fractures, bone remodeling associated with a stressed or pulled tendon or ligament attachment, neoplasms (abnormal growth of tissue), or sacroiliac injuries. Veterinarians must be aware of factors that could produce a false hot spot, such as decreased blood flow due to a low temperature or motion from the horse during the scan. Hopper likes to use scintigraphy primarily for cases that have an unblockable multiple limb lameness or if he suspects a fracture