CT scan is a type of imaging test. It uses X-rays and computer technology to make images or slices of the body. A CT scan can make detailed pictures of any part of the body, including the bones, muscles, fat, organs, and blood vessels. They are more detailed than regular X-rays.
In a CT scan, an X-ray beam moves in a circle around your body. This allows many different views of the same part of the body. The X-ray information is sent to a computer that interprets the X-ray data and displays it on a monitor.
During some tests you receive a contrast dye that can be given orally or through a vein. This will make parts of your body show up better in the image.
CT scans of the liver and biliary tract can provide more detailed information about the liver, gallbladder, and related structures than regular X-rays of the belly. CT scans can give healthcare providers more information related to injuries or diseases of the liver, gallbladder, and biliary tract.
A CT scan of the liver and biliary tract may be used to check the liver or gallbladder and their related structures for:
- Tumors or other lesions
- Abscesses (collections of pus)
- Unexplained belly pain
- Other health problems
A CT scan may be done when another type of exam, such as an X-ray, physical exam, or ultrasound, is not conclusive.
CT scans of the liver and biliary tract may also be used to guide needles during biopsies of the liver. A biopsy involves removing a small piece of tissue so it can be examined in the lab.
It can also be done to help remove fluid from the area of the liver or biliary tract. CT scans of the liver are useful in the diagnosis of certain types of jaundice. Jaundice is the yellowing of the skin and eyes that’s caused by certain liver problems.
There may be other reasons for your healthcare provider to recommend a CT scan of the liver and biliary tract.
You may want to ask your healthcare provider about the amount of radiation used during the CT scan. He or she can also explain your personal risks.
If you are pregnant or think you could be, tell your healthcare provider. Radiation exposure during pregnancy may lead to birth defects.
If contrast dye is used, there is a risk for allergic reaction to the dye. If you are allergic to or sensitive to medicines, contrast, or iodine, tell your healthcare provider.
People taking the diabetes medicine metformin should alert their healthcare provider before having IV contrast. It can cause a rare condition called metabolic acidosis. If you take metformin, you will be asked to stop taking it 24 hours before and for 48 hours after your CT scan. A blood test may be needed before you can start taking metformin again.
People with kidney failure or other kidney problems should notify their healthcare provider. In some cases, the contrast dye can cause kidney failure, and people with kidney disease are more prone to kidney damage after contrast exposure.
There may be other risks depending on your specific medical problems. Be sure to discuss any concerns with your healthcare provider before the procedure.
Certain things can make a CT scan of the liver and biliary tract less accurate. These include:
- Metallic objects within the abdomen, such as surgical clips
- Presence of barium in the intestines from a recent barium study
- Previous procedure using oral or IV contrast within a certain period of time
- Your healthcare provider will explain the procedure to you and give you a chance to ask any questions.
- If your CT scan involves the use of contrast dye, you will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if anything is not clear.
- Tell the technologist if you have ever had a reaction to any contrast dye, or if you are allergic to iodine.
- Generally, there is no fasting (not eating) requirement prior to a CT scan, unless a contrast dye is to be used. Your healthcare provider will give you special instructions ahead of time if contrast is to be used and you won’t be able to eat or drink.
- Tell your healthcare provider of all medications, vitamins, herbs, and supplements that you are taking.
- Tell the technologist if you are pregnant or think you could be.
- Tell the technologist if you have any body piercings on your chest or abdomen.
- Based on your medical condition, your healthcare provider may request other preparations.
You may have a CT scan as an outpatient or as part of your stay in a hospital. Procedures may vary depending on your condition.
Generally, a CT scan of the liver and biliary tract follows this process:
- You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
- If you are asked to remove clothing, you will be given a gown to wear.
- If you are to have a scan done with contrast, an IV line will be started in your hand or arm for injection of the contrast dye. For oral contrast, you will be given a liquid contrast to drink.
- You will lie on a narrow scan table that slides into a large, circular opening of the ring-shaped scanning machine. Pillows and straps may be used to help prevent movement during the scan.
- The technologist will be in another room where the scanner controls are located. However, you will be able to see the technologist through a window at all times. Speakers inside the scanner will allow the technologist to talk to you and hear you. You will have a call button so that you can let the technologist know if you have any problems during the scan. The technologist will be watching you at all times and will be in constant communication.
- As the scanner begins to rotate around you, X-rays will pass through your body for short amounts of time. You will hear clicking and whirring sounds, which are normal.
- The X-rays absorbed by the body’s tissues will be detected by the scanner and transmitted to the computer. The computer will transform the information into an image to be interpreted by the radiologist.
- It will be important that you stay very still during the scan. You may be asked to hold your breath for a short time at various times during the scan.
- If contrast dye is used, you will be removed from the scanner after the first set of scans has been completed. A second set of scans will be taken after the contrast dye has been given.
- If contrast dye is used, you may feel some effects when the dye is injected into the IV line. These effects include a warm flushing sensation, a salty or metallic taste in the mouth, a brief headache, and/or nausea. These effects usually only last for a few moments.
- You should tell the technologist if you have any sweating, numbness, trouble breathing, or heart palpitations.
- When the procedure has been completed, you will be removed from the scanner.
- If an IV line was inserted, it will be removed.
- You may be asked to wait for a short period of time while the radiologist examines the scans to make sure they are clear.
While the CT scan itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly if you’ve recently been injured or had surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.
If contrast dye was used, you may be watched for a period of time for any side effects or reactions to the contrast dye. These include itching, swelling, rash, or trouble breathing. Tell the radiologist or your healthcare provider right away if you notice any of these symptoms.
Tell your healthcare provider if you notice any pain, redness, or swelling at the IV site after you go home. These could be signs of infection or other type of reaction.
Otherwise you don't need any special care after a CT scan of the liver and biliary tract. You may go back to your usual diet and activities unless your healthcare provider tells you differently.
Your healthcare provider may give you other instructions, depending on your situation.
Before you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- What results to expect and what they mean
- The risks and benefits of the test or procedure
- What the possible side effects or complications are
- When and where you are to have the test or procedure
- Who will do the test or procedure and what that person’s qualifications are
- What would happen if you did not have the test or procedure
- Any alternative tests or procedures to think about
- When and how will you get the results
- Who to call after the test or procedure if you have questions or problems
- How much will you have to pay for the test or procedure
January 16, 2018
ACR–SAR–SPR Practice Parameter for the Performance of Computed Tomography (CT) Enterography. American College of Radiology
Grossman, Neil, MD,Kolbus, Karin, RN, DNP,, COHN-S