Equine Magnetic Resonance Imaging
Equine Magnetic Resonance Imaging (MRI or MR) has recently been added to the broad array of imaging modalities now available at the VMTH to aid in the diagnostic evaluation of horses with lameness problems or orthopedic injuries involving the lower limbs. As in humans, MRI is particularly well suited for imaging tendon and ligament injuries in horses and can now be used in concert with ultrasound and contrast CT to identify conditions that could not previously be diagnosed ante mortem. Our MRI system relies on a large horseshoe-shaped "open" low-field magnet to create images of distal limb structures in standing, sedated horses. These images can be displayed in the saggital, transverse, and frontal planes. Additional sequences with the slices positioned to focus on areas of special interest, such as the distal impar or collateral ligaments, may be obtained during examination of the foot.
While MRI can provide important diagnostic information, particularly regarding injuries to soft tissue structures, it has a small imaging window and is, therefore, not useful as a screening tool for lameness that has not been accurately localized using nerve or joint blocks or other imaging techniques. Referring veterinarians will, therefore, be asked to review details of the diagnostic workup and the results of other imaging studies with a faculty clinician in one of the Surgery and Lameness services before an MRI examination will be scheduled. Because scan times may extend to 2 to 3 hours, the patient must be sufficiently healthy to tolerate several hours of sedation and not be so lame that it will be unable to bare weight or remain still during the procedure. If you have a patient that could potentially benefit from this new and exciting diagnostic imaging modality, you can schedule appointments through one of the Equine Surgery and Lameness services.