Health Library

CT Scan of the Chest

What is a CT scan of the chest?

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. This will make parts of your body show up better in the image.

CT scans of the chest can provide more detailed information about organs and structures inside the chest than standard X-rays of the chest. They can give more information about injuries or diseases of the chest organs.

Why might I need a CT scan of the chest?

The chest contains organs of the respiratory and cardiovascular systems, as well as the esophagus. This is the hollow tube of muscle extending from below the tongue to the stomach. A CT scan of the chest may be done to check the chest and its organs for:

  • Tumors and other lesions
  • Injuries
  • Intrathoracic bleeding
  • Infections
  • Unexplained chest pain
  • Blockages
  • Other health problems

A CT scan may be done when another type of exam, such as an X-ray or physical exam, is not conclusive.

CT scans of the chest may also be used to guide needles during biopsies of thoracic organs or tumors. A biopsy is when a small piece of tissue is removed so it can be examined in the lab. They can also be done to help remove a sample of fluid from the chest. CT scans of the chest are useful in keeping an eye on tumors and other conditions of the chest before and after treatment.

There may be other reasons for your health care provider to recommend a CT scan of the chest.

What are the risks of a CT scan of the chest?

You may want to ask your health care provider about the amount of radiation used during the CT scan. He or she can discuss the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure. Tell your health care provider about previous CT scans and other types of X-rays. Your risks of radiation exposure may be related to the total number of X-ray exams or treatments over a long period of time.

If you are pregnant or suspect that you may be pregnant, tell your health care 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. Tell your health care provider if you have ever had a reaction to any contrast dye, or if you’ve had any kidney problems.

People with kidney failure or other kidney problems should tell their health care provider. In some cases, the contrast dye can cause kidney failure, especially if the patient has underlying kidney problems or is dehydrated. Patients taking the diabetes medicine metformin or Glucophage with contrast are at risk for developing metabolic acidosis. This is a condition where the person has an unsafe change in blood pH. People with kidney disease are more prone to kidney damage after contrast exposure.

There may be other risks depending on your specific medical condition. Discuss any concerns with your health care provider before the procedure.

Certain things may make a CT scan of the chest less accurate. These include:

  • Metallic objects within the chest, such as surgical clips or a pacemaker
  • Body piercing on the chest
  • Barium in the esophagus from a recent barium study

How do I get ready for a CT scan of the chest?

  • Your health care provider will explain the chest CT procedure to you and give you a chance to ask any questions that you might have.
  • If your procedure involves the use of contrast dye, you may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.
  • Tell the technologist if you have ever had a reaction to any contrast dye, or if you are allergic to iodine. If you take metformin, you will be asked to stop taking the medicine for at least 48 hours after your injection. 
  • Usually, there is no fasting requirement prior to a CT scan, unless a contrast dye is going to be used. You will be given special instructions ahead of time if contrast is to be used and if you won’t be able to eat or drink.
  • Tell the technologist if you are pregnant or think you may be pregnant.
  • Tell the technologist if you have any body piercings on your chest and/or abdomen.
  • Dress in clothes that give access to the area or that can easily be taken off.
  • Follow all other instructions your health care provider gives you to get ready.

What happens during a CT scan of the chest?

You may have a chest CT scan as an outpatient or as part of your stay in a hospital. Procedures may vary depending on your condition and your hospital’s practices.

Generally the chest CT scan follows this process:

  1. You will be asked to remove any clothing, jewelry, or other objects that may get in the way of the procedure.
  2. If you are asked to remove clothing, you will be given a gown to wear.
  3. If you need to have a procedure done with contrast, an IV line will be started in the hand or arm for injection of the contrast dye. For oral contrast, you will be given a liquid contrast preparation to drink.
  4. You will lie on your back with your arms above your head on a scan table. The table slides into a large, circular opening of the scanning machine. Pillows and straps may be used to prevent movement during the procedure.
  5. The technologist will be in another room where the scanner controls are located. However, you will be to see the technologist through a window. Speakers inside the scanner will enable the technologist to communicate with and hear you. You will have a call button so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication.
  6. As the scanner begins to rotate around you, X-rays will pass through the body for short amounts of time. You will hear clicking sounds, which are normal.
  7. 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.
  8. It will be important that you stay very still during the procedure. You may be asked to hold your breath at various times during the procedure.
  9. If contrast dye is used for your procedure, 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 administered.
  10. If contrast dye is used for your procedure, you may feel some effects when the dye is injected into the IV line. These effects include a flushing sensation, a salty or metallic taste in the mouth, a brief headache, or nausea and/or vomiting. These effects usually last for a few moments.
  11. You should tell the technologist if you feel any breathing difficulties, sweating, numbness, or heart palpitations.
  12. When the procedure has been completed, you will be removed from the scanner.
  13. If an IV line was inserted for contrast administration, it will be removed.
  14. 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 in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after a CT scan of the chest?

If contrast dye was used during your procedure, 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 your health care provider if you notice any pain, redness, or swelling at the IV site after you return home. These could be signs of an infection or other type of reaction.

If you are given contrast by mouth, you may have diarrhea or constipation after the procedure.

Otherwise you don't need any special care after a CT scan of the chest. You may go back to your usual diet and activities unless your health care provider advises you differently.

Your health care provider may give you other instructions, depending on your situation.

Next steps

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
  • The risks and benefits of the test or procedure
  • When and where you are to have the test or procedure and who will do it
  • When and how will you get the results
  • How much will you have to pay for the test or procedure