Computed tomography (CT) is a diagnostic tool that uses x-rays to obtain detailed cross-sectional images of the body. CT scans allow us to visualize disease that can be difficult to identify with other imaging techniques such as X-rays or ultrasound, and can even detect masses five times smaller than those seen on X-rays. Whereas traditional radiographs send X-rays through the pet’s body in one direction, during CT, X-rays cross through the body at all angles. The images that show up on the computer monitor help to identify structures that are normal or abnormal, such as brain tumor versus normal brain tissue. The computer typically images the height and width of the tissue, while newer machines can give a 3-D look.
How is a CT scan performed?
Once it has been determined that a patient needs a CT scan, a thorough evaluation of the patient is conducted by the clinicians. Your pet is then sedated or anesthetized as they must remain completely still for the procedure. The CT technician appropriately positions your pet on the CT imaging table and programs the CT computer for the desired type of study. The table on which your pet is laying then slowly advances through the CT gantry (which is the large donut shaped apparatus) while an x-ray tube and sensors rotate 360° at high speed around the patient. The images are then reconstructed on a computer console and are reviewed by a specialists.
Why would a CT scan be recommended?
Your veterinarian may recommend a CT scan because it is the preferred imaging modality for the following abnormalities:
- Long standing sinus and inner ear disease
- Spinal conditions such as calcified intervertebral disc disease
- To evaluate for spread of cancer (metastasis) in various tissues (i.e., lungs)
- Bone evaluation (especially complex fractures)
- Orthopedic conditions (i.e., elbow/shoulder conditions)
- Surgical planning for large organ (i.e., abdominal or chest cavity) tumor removal
- Investigation of suspected liver shunts (portosystemic shunts)
What you should expect for your pet during/after the CT scan?
As previously stated your pet needs to remain completely still for the procedure. Thus almost all CT scans are performed under heavy sedation or anesthesia. The anesthesia team uses a reversible sedation or the safest anesthetic agent available in order to minimize your pet’s anesthesia time. Your pet will be carefully monitored by the veterinary specialist and technicians both during and after the procedure until he/she is recovered. While the CT itself has no side effects, the effects of sedation or general anesthesia (i.e., “groggy” feeling) may last up to 12-24 hours following the procedure. You will be given complete instructions regarding at-home monitoring, caring and feeding at the time of your pet’s discharge.