A CT (computed tomography) scan is a type of specialized X-ray that can show cross-sectional images of a specific area of the body. In a CT scan, the machine circles the body and sends the images to a computer, where they are viewed by a technician.
Each picture is viewed as a cross section (like a piece of sliced bread) of the body to provide doctors with alternate views of your body. An abdominal CT scan helps doctors see the organs, vessels, and bones in the abdominal cavity.
A CT scan is also referred to as a CAT scan. 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 the specifics through a physical examination.
Some of the reasons your doctor may want you to undergo an abdominal CT scan include:
- abdominal pain
- palpable abdominal mass
- 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
- blood clots
Your doctor will probably ask you to fast for two to four hours before the scan. You may be asked to stop certain medications prior to your test. You may want to wear loose, comfortable clothing because you will be required to lie down on the table. You may also be given a hospital gown to wear. You’ll be instructed to remove any jewelry and other unnecessary items from your body.
Depending on the reason you’re getting your CT scan, you may need to drink a large glass of oral contrast, a liquid that contains barium and has a chalky taste and texture. Barium is a chemical that helps doctors better see the lining of your organs.
You’ll usually wait between 60 and 90 minutes after drinking the contrast for it to distribute into the bowels.
Before going into your CT scan, tell your doctor if you have any of the following conditions:
- allergy to oral contrast (barium)
- diabetes (fasting may lower blood sugar levels)
An abdominal CT scan is 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 contrast dye can be put through your veins (it is critically important to convey any dye allergies to your doctor, and to the X-ray staff). This contrast helps the machine get better images of your blood vessels and organs. You may also have to swallow a barium shake.
The technician may require you to lie in a specific position during the test. They may use pillows or straps to make sure that 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 will 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 ensure they are clear enough for your doctor to read correctly.
A typical abdominal CT scan takes between 10 and 30 minutes to complete.
An abdominal CT is a relatively safe procedure, but there are risks. You’ll be exposed to ionizing radiation during the test. This amount of radiation is higher than the amount with an X-ray. As a result, an abdominal CT scan slightly increases your risk for cancer. A 2009 study found that of the 72 million CT scans done in 2007, it was suspected that 29,000 led to cancer. This is a relatively small risk.
Since exposure to radiation during pregnancy may increase the risk of birth defects, it’s important to tell your doctor if you are or may be pregnant. As a precaution, your doctor may recommend another imaging test instead, such as an MRI or an ultrasound.
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 can increase the risk of kidney failure if you're dehydrated or have a pre-existing kidney problem.
Since children are more sensitive to radiation exposure, your child's doctor may order a CT scan as a last resort, and only if other tests cannot confirm a diagnosis.
After the test, you can typically go about your day. Side effects of barium contrast can include abdominal cramping, diarrhea, nausea, vomiting, or constipation. If these symptoms become severe you should contract your doctor right away. Fewer than 3 out of 100 people will experience other symptoms such as immediate rash, itching, retching, coughing and dizziness. People with a history of asthma or allergies are at higher risk for these reactions.
Results for an abdominal CT scan typically take a day to process. Your doctor will schedule a follow-up appointment to discuss your results and how to proceed, depending on what was found.