The Rainbow Equine Hospital is one of only three hospitals in the UK and the only equine hospital north of London to have the ability to conduct CT examinations. In horses CT scanning has become one of the most important tools we have for diagnosing a range of disorders of the equine limb and head.  CT has been part of the advanced diagnostic tools that Rainbow utilises to help provide the best and most accurate diagnosis for you and your horse for the past 7 years.  Recently we have installed a more advanced machine that allows us to take images of superior quality in much shorter time. The average CT scan actually takes only 30 seconds to complete.

WHAT IS IT?

CT works by taking a series of x-ray images at high speed circumferentially around the area of interest so giving us an image of such high quality anatomical detail that we can see very subtle changes in bone and soft tissue related to injury and disease.  The images can then be reconstructed so that we can look at the same piece of anatomy in different orientations (see the pictures below). With it we can see things that we have never been able to see before such as structures within the hoof. It is similar to slicing a loaf of bread and looking end on at the slices.

HOW IS IT DONE?

This depends on the region being scanned.

The head is a very important region that we commonly CT to diagnose tooth related disorders, the reason for sinus disease, brain related disorders and complex masses or fractures of the head. The Rainbow Equine Hospital has developed a technique that allows standing CT of the head thereby taking away the risk and cost associated with anesthesia. We can perform CT of the head very quickly and have instant results that are relayed to you and your veterinarian the same day as the scan.  Because the CT can be done under standing sedation, it reduces the cost and risk associated with anesthesia and means it can be done on an out patient basis.

DISTAL LIMB CT

One of the most common indications for CT is to examine in cross sectional detail the soft tissue and bone structures of the lower limb. It is essential that there is no movement during the CT and thus distal limb CT is performed under general anesthesia. Anesthesia is monitored throughout the course of the scan, by a veterinarian trained specifically in equine anesthesia.  A series of images are taken of the region of interest including a contrast enhanced series of images that is performed as described below.

The images are viewed during the examination by a recognized veterinary specialist and any areas of interest can be looked at more closely utilizing thinner cross sectional slices. In addition during the same anesthetic period, should lesions be seen, CT affords us the opportunity to treat areas of injury with various products. We use the CT to guide our needles directly into the affected site and so can be confident that any areas identified are treated accurately. Common disorders diagnosed and treated include Deep digital flexor tendon injuries, collateral ligament injuries, bone cysts, fractures of the limbs, keratomas and suspensory ligament injuries.

CONTRAST ENHANCEMENT

Every limb CT also undergoes a contrast enhanced CT scan. This entails injecting a contrast agent into an artery close to the site of interest through a pre-placed intra-arterial catheter. Contrast is injected simultaneously as a CT scan is taking place using a special pump. Areas of injury have a unique and distinctive blood supply that is then highlighted during the scan.  By looking at both the pre and post contrast enhanced CT we can distinguish those lesions that are active versus those that are more chronic and not active.

OTHER AREAS

We can also assess up to the proximal tibia and radius under CT guidance, helping us to assess the hock and carpus as well as suspected stress fractures of the upper fore and hind limbs.

CT is one of the most important advances in equine diagnostic imaging over the past 5 years enabling us to accurately diagnose previously undiagnosable conditions.  If your horse has an undiagnosed foot lameness, a tooth problem, a sinus problem or a suspected suspensroy ligament related injury then CT allows compete and accurate diagnosis and may allow lesion specific therapy of the injury. Please call us to discuss if this would be an appropriate next step in helping you to understand your horse’s problem.  What is more, the full cost of the scan and related expenses is covered under all insurance policies.