Pinpointing the underlying cause of subtle neurologic signs, abnormal head positions, and obscure lamenesses frequently requires the use of advanced imaging techniques. One such procedure is myelography, which involves injecting a dye into the cerebrospinal fluid within the spinal cord and performing radiography (X rays) to identify cord lesions that might explain the horse’s clinical signs.

Equine veterinarians from Sweden and the United States have taken the traditional myelogram a step further, showing that imaging horses’ necks with computed tomography (CT)—a technology that historically has had limited use in horses–instead of radiography is both possible and beneficial, even in large horses.

Mads Kristoffersen, DVM, CertES (Orth), Dipl. ECVS, of the Evidensia Equine Hospital, in Helsingborg, Sweden, presented a study on the procedure at the 2016 American Association of Equine Practitioners Convention, held Dec. 3-7 in Orlando, Florida.

Veterinary use of CT has escalated over the past few years, but equine practitioners have been limited in their use of the technology because many conventional CT units cannot accommodate horses’ large bodies. Even their extremities are sometimes too big to fit in the unit.

However, a custom-designed equine CT table and a commercial Big Bore scanner make imaging neck lesions in horses a very real possibility, said Kristoffersen.

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Kristoffersen shared data from his study of CT examination results from 91 horses, including 72 that had CT myelograms rather than traditional myelograms. Here are key points he described:

  • CT can be successfully performed in large adult horses, including Warmbloods weighing up to 714 kilograms (1,574 pounds);
  • Even the uppermost areas of the vertebrae in the thoracic (chest) area can be imaged via the CT used in the study;
  • Common diagnoses included osteoarthritis of the joints between individual vertebrae (articular processes), soft tissue lesions (such as hematomas, degenerated cervical discs, and joint distension), vertebral bone fragments and fractures, and spinal cord impingement and compression (wobbler syndrome); and
  • Images were obtained in approximately one hour, and there were no complications following any procedure.

“More than half of the described lesions occurred quite low in the neck region, behind the fifth vertebrae, which is a large anatomic region to image,” he said.

While acknowledging that further studies need to be conducted in this field, Kristoffersen said, “CT can be performed in large adult horses and has great potential to not only diagnose cervical lesions but also guide treatment options.”