Chest CT
A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen.
How the Test is Performed
The test is done in the following way:
- You'll likely be asked to change into a hospital gown.
- You'll lie on a narrow table that slides into the center of the scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you.
x-ray
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray waves through the body. The images...
ImageRead Article Now Book Mark Article - You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short period of time.
The complete scan takes 30 seconds to a few minutes.
Certain CT scans require a special dye, called contrast, to be delivered into the body before the test starts. Contrast highlights specific areas inside the body and creates a clearer image. If your health care provider requests a CT scan with intravenous contrast, you will be given it through a vein (IV) in your arm or hand. A blood test to measure your kidney function may be done before the test. This test is to make sure your kidneys are healthy enough to filter the contrast.
CT scans
A computed tomography (CT) scan is an imaging method that uses x-rays to create pictures of cross-sections of the body. Related tests include:Abdomin...
IV
Intravenous means "within a vein. " Most often it refers to giving medicines or fluids through a needle or tube inserted into a vein. This allows th...
Read Article Now Book Mark ArticleYou may be given medicine to help you relax during the test.
How to Prepare for the Test
Tell your provider if you are pregnant. Chest CT scans are generally avoided during pregnancy, and special precautions are taken if they are needed.
Some people have allergies to IV contrast and may need to take medicine before their test to safely receive this substance.
If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.
If you weigh more than 300 pounds (lb) or 136 kilograms (kg), have your provider contact the scanner operator before the exam. CT scanners have an upper weight limit of 450 lb (204 kg). Some newer scanners can accommodate up to 680 lb (308 kg). Because it is hard for x-rays to pass through metal, you will be asked to remove jewelry.
How the Test will Feel
Some people may have discomfort from lying on the hard table.
Contrast given through an IV may cause a slight burning sensation, a metallic taste in the mouth, and a warm flushing of the body. These sensations are normal and usually go away within a few seconds.
There is no recovery time, unless you were given medicine to relax. After a CT scan, you can go back to your normal diet, activity, and medicines.
Why the Test is Performed
A CT scan quickly creates detailed pictures of the body. The test may be used to get a better view of the structures inside the chest. A CT scan is one of the best ways of looking at soft tissues such as the heart and lungs.
A chest CT may be done:
- After a chest injury
- When a tumor or mass (clump of cells) is suspected, including a solitary pulmonary nodule seen on a chest x-ray
Tumor
A tumor is an abnormal growth of body tissue. Tumors can be cancerous (malignant) or noncancerous (benign).
Read Article Now Book Mark ArticleSolitary pulmonary nodule
A solitary pulmonary nodule is a round or oval spot (lesion) in the lung that is seen with a chest x-ray or CT scan.
ImageRead Article Now Book Mark Article - To determine the size, shape, and position of organs in the chest and upper abdomen
- To look for bleeding or fluid collections in the lungs or other areas
- To look for infection or inflammation in the chest
- To look for blood clots in the lungs
- To look for scarring in the lungs
- To look for emphysema
Emphysema
Chronic obstructive pulmonary disease (COPD) is a common lung disease. Having COPD makes it hard to breathe. There are two main forms of COPD:Chroni...
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What Abnormal Results Mean
A chest CT may show many disorders of the heart, lungs, mediastinum, or chest area, including:
- A tear in the wall, an abnormal widening or ballooning, or narrowing of the aorta, the major artery carrying blood out of the heart
Tear in the wall
Aortic dissection is a serious condition in which there is a tear in the wall of the major artery carrying blood out of the heart (aorta). As the te...
ImageRead Article Now Book Mark ArticleAbnormal widening or ballooning
An aneurysm is an abnormal widening or ballooning of a portion of an artery due to weakness in the wall of the blood vessel. A thoracic aortic aneury...
ImageRead Article Now Book Mark ArticleNarrowing
The aorta is a larger artery that carries blood from the heart to the vessels that supply the rest of the body with blood. If part of the aorta is n...
ImageRead Article Now Book Mark Article - Other abnormal changes of the major blood vessels in the lungs or chest such as blood clots (pulmonary embolism)
Pulmonary embolism
A pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.
ImageRead Article Now Book Mark Article - Buildup of blood or fluid around the heart
Blood or fluid around the heart
Cardiac tamponade is pressure on the heart that occurs when blood or fluid builds up in the space between the heart muscle and the outer covering sac...
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Lung cancer or cancer that has spread to the lungs from elsewhere in the body
Cancer that has spread to the lungs
Lung metastases are cancerous tumors that start somewhere else in the body and spread to the lungs.
ImageRead Article Now Book Mark Article - Collection of fluid around the lungs (pleural effusion)
Pleural effusion
A pleural effusion is a buildup of fluid between the layers of tissue that line the lungs and chest cavity.
ImageRead Article Now Book Mark Article - Damage to, and widening of the large airways of the lungs (bronchiectasis)
Bronchiectasis
Bronchiectasis is a disease in which the large airways in the lungs are damaged. This causes the airways to become permanently wider. Bronchiectasis...
ImageRead Article Now Book Mark Article - Enlarged lymph nodes
- Lung disorders in which lung tissues become inflamed and then damaged (interstitial lung disease)
Interstitial lung disease
Interstitial lung disease (ILD) is a group of lung disorders in which the lung tissues become inflamed and then damaged.
ImageRead Article Now Book Mark Article - Pneumonia
- Esophageal cancer
Esophageal cancer
Esophageal cancer is cancer that starts in the esophagus. This is the tube through which food moves from the mouth to the stomach.
ImageRead Article Now Book Mark Article - Lymphoma in the chest
- Tumors, nodules, or cysts in the chest
Risks
CT scans and other x-rays are strictly monitored and regulated to make sure they use the least amount of radiation. CT scans use low levels of ionizing radiation, which has the potential to cause cancer and other defects. However, the risk from any one scan is small. The risk increases as many more scans are done.
The most common type of contrast given into a vein contains iodine. If a person with an iodine allergy is given this type of contrast, nausea, sneezing, vomiting, itching, or hives may occur. In rare cases, the dye can cause a life-threatening allergic response called anaphylaxis. If you have any trouble breathing during the test, you should notify the scanner operator immediately. Scanners come with an intercom and speakers, so the operator can hear you at all times.
Anaphylaxis
Anaphylaxis is a life-threatening type of allergic reaction.
In people with kidney problems, the dye may have harmful effects on the kidneys. In these situations, special steps may be taken to make the contrast dye safer to use.
In spite of its risks, a CT scan may still be done if the benefits greatly outweigh the risks. For example, it can be more risky to not have the exam if your provider thinks you might have cancer.
Reviewed By
Allen J. Blaivas, DO, Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant Professor, Rutgers New Jersey Medical School, East Orange, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Jokerst CE, Gotway MB. Thoracic radiology: noninvasive diagnostic imaging. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 20.
Nair A, Barnett JL, Semple TR. Current status of thoracic imaging. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 1.
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