Diagnostic imaging is an essential tool when generating a treatment plan for equine injuries and determining prognosis, which can lead to improved welfare for horses. Practitioners can use computed tomography (CT) to pinpoint pathology after a thorough physical and lameness examination, or if portable imaging modalities such as radiographs were not useful for making an accurate diagnosis. Historically, horses had to be anesthetized for CT scans. However, newer technology allows horses to remain standing, making it safer for animals and easier for veterinarians to use.

“CT can provide veterinarians with an increased understanding of normal and pathological findings,” said Nicolas Ernst, DVM, Dipl. ACVS, professor in the Department of Veterinary Population Medicine at the University of Minnesota’s College of Veterinary Medicine, in St. Paul, during his presentation at the 2023 World Equestrian Veterinary Association Congress, held Nov. 8-11, in Santiago, Chile. “It can also help us understand potential treatments for tendon, ligament, bone, and joint injuries.”

Advantages of Standing CT for Horses

Previous CT models, which required the horse to be anesthetized, were less accessible and more challenging to use due to the risks associated with anesthetizing a horse and the staff required to do so, said Ernst. However, some standing CT models allow the horse to stand in a natural position, negating the need for anesthesia and reducing the staff required to complete the imaging process. The standing position is also more comfortable for the horse, making it easier for them to remain stationary during the imaging process.

“This system has high spatial resolution, and three-dimensional reconstruction makes it possible for us to overcome super-imposition (which is common with radiographs),” said Ernst. “The standing CT can obtain an image of the desired area within one minute, and the entire process from start to finish can be completed in about 15 minutes.” This allows for a more patient-friendly experience, which horses generally tolerate well, he added.

When to Use CT in Horses

Practitioners often use CT when radiographs or ultrasound fail to help them diagnose the source of a lameness, those methods lead to an incomplete diagnosis, or the diagnosis does not match the findings on the lameness examination. They can also employ this imaging modality in emergency situations and commonly to gain more information about skull injuries.

“CT provides a complete evaluation of the area of concern, which helps veterinarians provide an accurate diagnosis and prognosis to owners,” said Ernst. For example, CT might reveal that a pathology that once seemed treatable will not resolve with treatment, and retirement is the best option.

Due to the multiple views the CT provides, a surgeon can use this modality to better visualize the area, injury, or problem before anesthetizing the horse and beginning the procedure, added Ernst.

Take-Home Message

Standing CT provides equine veterinarians a more accessible way to obtain high-quality images for developing an accurate diagnosis and treatment plan. However, before using CT, veterinarians should always be sure to complete a comprehensive lameness examination, have specific knowledge of the animal’s anatomy, and localize the area that needs to be evaluated, said Ernst. This approach allows veterinarians to examine patients’ head, neck, and limbs in a way that is more horse-friendly due to the standing position and ease of use, making it more accessible to veterinarians serving a wider variety of horses.