Magnetic resonance imaging (MRI) can produce images of the inner structures of the body, including a horse’s hoof. This provides a new and more effective way to view those structures and is becoming a valuable tool for diagnosing lameness conditions.

Diagnosing problems within the foot has often been a challenge, since the hoof capsule makes it difficult to image internal structures via ultrasound and radiographs are not always conclusive. A growing number of university clinics and private veterinary practices are now utilizing MRI technology.

Human MRI machines are “closed” systems — utilizing high-field magnets and large cylinders in which the patient lies. Some of these are also used for horses. This requires that the horse be lying down, under general anesthesia, so its legs can be put into the cylinder. In the past few years, there have been a growing number of “open” MRI machines, using smaller, low-field magnets that don’t require the horse to be lying down. These machines utilize sensors placed in collars that can be put around the foot or limb of a standing horse that is merely sedated.

Sarah Sampson, DVM, has been doing research on foot problems at Washington State University in Pullman, Wash., for the last 6 years, using a high-field magnet system. This particular MRI has been available for live horses since 1997, and was the first one used with horses.

New Views Inside The Hoof

“Previous to having MRI available for horses, the only way we could look at the living horse’s…