By John Gilpatrick
When a veterinarian wants a closer look at an animal’s particular organ, muscle, bone, or other internal body part, he or she may order a CT scan.
While it’s similar to a traditional X-ray, a computed tomography scan obtains images of slices of a patient, meaning they can go very small and later reconstruct the slices into three-dimensional models of the affected area, according to Dr. Wilfried Mai, an associate professor of veterinary radiology at the University of Pennsylvania School of Veterinary Medicine.
“This provides excellent detail of the internal anatomy and much more information than a simple radiograph,” Mai says.
A CT scan for pets is nearly identical to those done in humans, Mai says. The equipment, including the machine, is mostly the same, and the only difference in procedure is that most pets require anesthetization in order to keep them completely still throughout the procedure.
Why Do Pets Need CT scans?
The models assembled following a CT scan are ideal when it comes to understanding apparent anomalies in the body and planning for various surgeries, Mai says.
“When a patient has a tumor, and the surgeon needs to know its precise location and its relationship to neighboring structures, a CT scan will help plan and facilitate the surgical approach and minimize surgery time,” he adds. “This is especially important for liver tumors and pulmonary tumors, for example.”
A CT scan may also be conducted on an animal’s lungs. This helps veterinarians identify or rule out metastasis (or spreading) of various cancers that are known to be present elsewhere in the body. To this end, CT scans are vital tools for understanding the extent of canine and feline cancers and planning for treatment, Mai says.
Cancers aren’t the only reason to have a CT scan, however. The evaluation of nasal disease in dogs and cats with chronic nasal discharge is the most common reason, according to Dr. John Hathcock, professor and chief of the radiology and anesthesia section at Auburn University’s College of Veterinary Medicine.
CT scans also help veterinarians understand orthopedic abnormalities (like elbow dysplasia) and plan for corrective procedures, Mai says. Dentists order them to examine tooth decay and abscesses. And in cases of poly-trauma—where multiple organs and systems are damaged—CT scans enable doctors to obtain a firmer grasp on the severity and complexity of the various injuries, facilitating smarter and more strategic treatment.
Notably, CT scans are not ideal for neurology patients. “Brain and spinal cord diseases, with some exceptions, are not nicely diagnosed by CT scans,” Mai says. “An MRI performs a lot better for these cases.”
How are CT Scans Conducted?
Hathcock says CT scans are generally done at large hospitals, including university teaching hospitals, due to the need for skilled technicians and expensive equipment. If a university teaching hospital is not close by, CT scans also are performed at most specialty hospitals.
“Patients are usually held off food the night before the exam is to be conducted,” he says. Upon arriving at the facility the next day, blood work is taken, and the patient is prepped for anesthetization.
Once the animal is under, she is positioned by a veterinary technologist. Then, the technologist and anesthesiologist step into a separate room to run the scan. There is a large window through which everyone can monitor the animal and her vitals. Every scan only takes about 30 seconds, Mai says, and between each, the anesthesiologist steps into the room with the animal to check on her. The entire procedure—from going under to waking up—takes about 45 minutes.
In some cases, the scan may be conducted twice—once normally and once with an injection of iodine. Mai says this allows the radiologist to observe an abnormal intake of iodine, which might indicate inflammation or tumors.
A report is generated immediately following the exam, and in most cases, it’s in the hands of the referring veterinarian hours later.
Are There Any Side Effects to a CT Scan?
None. While Mai says that humans who have many CT scans over the course of their lives may develop an increased risk for radiation-induced cancers, repeat scans for dogs and cats are rare. Additionally, their respective life spans aren’t long enough to be affected in this way.
However, as with any procedure that requires anesthesia, Hathcock says the patient should be monitored for a short period of time for any ill effects.
How Much Do CT Scans for Pets Cost?
The cost of a CT scan for pets depends on the complexity of the scan and the study, Mai says. Scans that require the injection of iodine, for instance, could run up to $1,000 for the entire procedure. Costs may also vary by veterinarian and geographic location. In New York City, the total cost—including consultation, examination, blood work, anesthesia, hospitalization, and the scan itself—can range from $1,500 to $2,500.