One of the newest imaging modalities for use in horses is MRI or magnetic resonance imaging. Although common in human medicine, it has just become readily available for horses in the last several years. MRI has been used in many different areas but mostly difficult lameness cases, particularly cases involving the feet. The advantage of MRI over x-rays is that MRI shows all of the structures, including soft tissues and not just the bone as x-rays do. So for problems like caudal heel pain that affects the navicular area and surrounding structures, MRI is great.
With caudal heel pain that is called navicular disease, there are lots of other structures around the bone that may be causing the actual problem and these structures cannot be seen with an x-ray. For horses that have not responded to normal treatment for lameness, Dr's. Jake Hersman and Robert Cole at Animal Imaging in Irving, Texas, have had good success diagnosing these horses with MRI. MRI is helpful in other areas but is really helpful in the foot because ultrasound cannot see through bone or even through the hoof wall, so structures inside the hoof are difficult to examine. Also, MRI is helpful in finding very small changes in ligaments that are difficult to examine with ultrasound. MRI is also effective at diagnosing bone bruising, which no other modality can really determine. So if you have a horse with a lameness problem and regular treatment has not been effective, consider an MRI. Your equine veterinarian can help you find the closest MRI facility to your area.