A CT (computed tomography) scan, also called a CAT scan, is a type of specialized X-ray. The scan can show cross-sectional images of a specific area of the body.
With a CT scan, the machine circles the body and sends the images to a computer, where they’re viewed by a technician.
An abdominal CT scan helps your doctor see the organs, blood vessels, and bones in your abdominal cavity. The multiple images provided give your doctor many different views of your body.
Keep reading to learn why your doctor may order an abdominal CT scan, how to prepare for your procedure, and any possible risks and complications.
Abdominal CT scans are used when a doctor suspects that something might be wrong in the abdominal area but can’t find enough information through a physical exam or lab tests.
Some of the reasons your doctor may want you to have an abdominal CT scan include:
- abdominal pain
- a mass in your abdomen that you can feel
- kidney stones (to check for size and location of the stones)
- unexplained weight loss
- infections, such as appendicitis
- to check for intestinal obstruction
- inflammation of the intestines, such as Crohn’s disease
- injuries following trauma
- recent cancer diagnosis
You may have heard of other imaging exams and wonder why your doctor chose a CT scan over other options.
Your doctor may choose a CT scan over an MRI (magnetic resonance imaging) scan because a CT scan is faster than an MRI. Plus, if you’re uncomfortable in small spaces, a CT scan would likely be a better choice.
An MRI requires you to be inside an enclosed space while loud noises occur all around you. In addition, an MRI is more expensive than a CT scan.
Your doctor may choose a CT scan over an X-ray because it provides more detail than an X-ray does. A CT scanner moves around your body and takes pictures from many different angles. An X-ray takes pictures from one angle only.
Your doctor will probably ask you to fast (not eat) for two to four hours before the scan. You may be asked to stop taking certain medications before your test.
You may want to wear loose, comfortable clothing because you’ll need to lie down on a procedure table. You may also be given a hospital gown to wear. You’ll be instructed to remove items such as:
- jewelry, including body piercings
- hair clips
- hearing aids
- bras with metal underwire
Depending on the reason why you’re getting a CT scan, you may need to drink a large glass of oral contrast. This is a liquid that contains either barium or a substance called Gastrografin (diatrizoate meglumine and diatrizoate sodium liquid).
Barium and Gastrografin are both chemicals that help doctors get better images of your stomach and bowels. Barium has a chalky taste and texture. You’ll likely wait between 60 and 90 minutes after drinking the contrast for it to move through your body.
Before going into your CT scan, tell your doctor if you:
- are allergic to barium, iodine, or any kind of contrast dye (be sure to tell your doctor and the X-ray staff)
- have diabetes (fasting may lower blood sugar levels)
- are pregnant
About contrast and allergies
In addition to barium, your doctor may want you to have intravenous (IV) contrast dye to highlight blood vessels, organs, and other structures. This will likely be an iodine-based dye.
If you have an iodine allergy or have had a reaction to IV contrast dye in the past, you can still have a CT scan with IV contrast. This is because modern IV contrast dye is less likely to cause a reaction than older versions of iodine-based contrast dyes.
Also, if you have iodine sensitivity, your healthcare provider can premedicate you with steroids to reduce the risk of a reaction.
All the same, be sure to tell your doctor and the technician about any contrast allergies you have.
A typical abdominal CT scan takes from 10 to 30 minutes. It’s performed in a hospital’s radiology department or a clinic that specializes in diagnostic procedures.
- Once you’re dressed in your hospital gown, a CT technician will have you lie down on the procedure table. Depending on the reason for your scan, you may be hooked up to an IV so that contrast dye can be put into your veins. You’ll probably feel a warm sensation throughout your body when the dye is infused into your veins.
- The technician may require you to lie in a specific position during the test. They may use pillows or straps to make sure you stay in the right position long enough to get a good quality image. You may also have to hold your breath briefly during parts of the scan.
- Using a remote control from a separate room, the technician will move the table into the CT machine, which looks like a giant doughnut made of plastic and metal. You’ll most likely go through the machine several times.
- After a round of scans, you may be required to wait while the technician reviews the images to make sure they’re clear enough for your doctor to read.
The side effects of an abdominal CT scan are most often caused by a reaction to any contrast used. In most cases, they’re mild. However, if they become more severe, you should call your doctor right away.
Side effects of barium contrast can include:
Side effects of iodine contrast can include:
If you’re given either type of contrast and have severe symptoms, call your doctor or go to the emergency room right away. These symptoms include:
An abdominal CT is a relatively safe procedure, but there are risks. This is especially true for children, who are more sensitive to radiation exposure than adults. Your child’s doctor may order a CT scan only as a last resort, and only if other tests cannot confirm a diagnosis.
Risks of an abdominal CT scan include the following:
You may develop a skin rash or itchiness if you’re allergic to the oral contrast. A life-threatening allergic reaction can also happen, but this is rare.
Tell your doctor about any sensitivities to medications or any kidney problems you have. IV contrast raises the risk of kidney failure if you’re dehydrated or have a preexisting kidney problem.
Because exposure to radiation during pregnancy increases the risk of birth defects, it’s important to tell your doctor if you are or might be pregnant. As a precaution, your doctor may suggest another imaging test instead, such as an MRI or an ultrasound.
Slightly increased risk of cancer
You’ll be exposed to radiation during the test. The amount of radiation is higher than the amount used with an X-ray. As a result, an abdominal CT scan slightly increases your risk of cancer.
However, keep in mind that the U.S. Food and Drug Administration (FDA) estimates that any one person’s risk of cancer from a CT scan is much lower than their risk of getting cancer naturally.
After your abdominal CT scan, you can likely return to your regular daily activities.
Results for an abdominal CT scan typically take one day to process. Your doctor will schedule a follow-up appointment to discuss your results. If your results are abnormal, it could be for several reasons. The test could have found problems, such as:
- kidney problems like kidney stones or infection
- liver problems like alcohol-related liver disease
- Crohn’s disease
- abdominal aortic aneurysm
- cancer, such as in the colon or pancreas
With an abnormal result, your doctor will likely schedule you for more testing to find out more about the problem. When they have all the information they need, your doctor will discuss your treatment options with you. Together, you can create a plan to manage or treat your condition.