Alternate Names: Chest CT; CT scan - lungs; CT scan - chest

How Performed: You are asked to lie flat on a narrow table that is then guided into the CT scanner. The scanner emits X-rays from a complete circle around you. Each "slice" of X-rays lasts a few seconds, then the table is advanced into the scanner a slight amount, and a new "slice" of X-rays is taken. The complete scan often lasts between 1/2 and 1 hour.

A contrast-medium (dye) may be inserted into a vein to help define blood vessels and certain tissues. During the test, it is very important to remain still. If you are restless or traumatized, you may be given a sedative. The technologist operating the computer may indicate when it is necessary to control breathing. A sound system is built into the machine to allow for communication during the test.

How To Prepare: Fasting for 4 to 6 hours may be recommended if contrast dye is to be used or if sedation is anticipated. You will wear a hospital gown during the procedure. You must sign a consent form before the procedure.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How It Feels: If a dye is needed to increase the contrast between different tissues or organs, it is administered by injection into a vein. The injection may sting, and the injection site may be tender to the touch for several minutes. After the injection, there may be a warm or flushed feeling for a few seconds.

The X-rays are painless, and the test is only mildly uncomfortable. Some people experience claustrophobia or anxiety when placed within the scanner. If you usually becomes anxious when in an enclosed area, inform the technician before the test.

Risks: CT scans and other X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to reproduce the image. During pregnancy, a thoracic CT scan is not recommended unless the benefits outweigh the risk of radiation exposure to the fetus. CT scans provide low levels of radiation.

The most common dye used is iodine-based. A person who is allergic to iodine may experience nausea, sneezing, vomiting, itching, or hives. In people who are sensitive to iodine, the dye may occasionally cause anaphylaxis (life-threatening allergic response) or toxic effects to the kidneys.

Why Performed: Thoracic CT may be recommended when there is a need for examination of the structures inside the chest. It is noninvasive and poses less risk than invasive procedures (such as angiography or exploratory surgery).

Common indications for thoracic CT include:

• when there is a chest injury
• when tumor or mass (aggregation of cells) is suspected
• to determine the size, shape, and position of internal organs
• to look for bleeding or fluid collections in the lungs or other areas

Normal Values: No abnormalities of organ size and position. No abnormal growths or fluid collections.

Abnormal Results: Thoracic CT may show many disorders of the heart, lungs, or chest area, including:

• enlarged lymph nodes (lymphadenopathy)
• abnormalities of the structure or position of the heart, lungs, or blood vessels
• bronchiectasis
• tumors, nodules, or cysts within the chest
• the stage of some lung tumors or esophageal cancer
• aortic aneurysm (thoracic)
• pleural effusion
• pneumonia
• accumulations of blood or fluid

• alcoholic cardiomyopathy
• asbestosis
• atrial myxoma; left
• atrial myxoma; right
• cardiac tamponade
• coarctation of the aorta
• dilated cardiomyopathy
• echinococcus
• heart failure
• histoplasmosis
• hypertensive heart disease
• idiopathic cardiomyopathy
• infective endocarditis
• ischemic cardiomyopathy
• left-sided heart failure
• mesothelioma (malignant)
• metastatic cancer to the lung
• mitral regurgitation; acute
• mitral regurgitation; chronic
• mitral valve prolapse
• pericarditis; bacterial
• pericarditis; constrictive
• pericarditis; post-MI
• peripartum cardiomyopathy
• pulmonary edema
• restrictive cardiomyopathy
• senile cardiac amyloid
• SVC obstruction

Cost:

Special Considerations: The benefits of a CT scan usually far outweigh the risks of the X-rays. A CT scan is one of the best ways of "looking" at soft tissues such as the heart and lungs.