Magnetic Resonance Imaging (MRI)

Equine MRIMagnetic Resonance Imaging (MRI) produces a radiofrequency pulse that affects the hydrogen atoms in the body. The computer detects how the hydrogen atoms are affected by the radiofrequency pulse, and generates a highly detailed image of bone and soft tissue. Although the technology has been present for some time in human medicine, the introduction of MRI to equine medicine and surgery is relatively new. Prior to the use of MRI in equine veterinary medicine, many soft tissue injuries, especially within the foot, were undiagnosed. Now, this technology allows horses to be successfully diagnosed, treated, and returned to athletic soundness.

MRI is best utilized when the problem can be narrowed down to a very specific region, for example the left front foot or right carpus. This is best accomplished by a detailed physical and lameness examination. The lameness examination may include temporary nerve blocks that help to localize the source of pain to a specific region. Once the pain is localized to a specific region, radiographs and ultrasound examinations are performed as needed. Pain can be caused by very small abnormalities in bones, tendons, or ligaments, and these abnormalities many of which are too small to be seen on radiographs or ultrasound. When radiographs or ultrasound are inconclusive but the area of pain is well defined, an MRI will often provide the necessary information.

Equine MRI scannerOur MRI unit requires that the horse be anesthetized for approximately 60-90 minutes. General anesthesia minimizes any movement that would blur the image and decrease the information obtained by the MRI scan. During anesthesia, each horse’s heart is monitored with an electrocardiogram (ECG). Breathing is assisted and arterial blood pressure is monitored for the duration of the MRI scan.

ntravenous fluids are administered and the horse is supported on a thick foam cushion to prevent any damage to muscle tissue. Following completion of the scan, the images are sent electronically to a board-certified veterinary radiologist specially trained in equine MRI interpretation. Results are typically available within 6-24 hours. Appropriate therapy for your horse’s specific problem can then be recommended and implemented.