
Search for specific topic by selecting first letters:

Thoracic CT

Definition

Thoracic CT is a computed tomography scan of the chest and upper abdomen.

How the test is performed

You will be asked to lie on a narrow table (gantry) that slides into the center of the scanner. Depending on what is being scanned, you may lie on the stomach, back, or side. If contrast media (dye) is to be given, an IV (intravenous needle or tube) will be placed in a small vein of your hand or arm.

As with standard photography, if you move while the CT image is being taken, it will blur. Because of this, the operator of the scanner will tell you when to hold your breath and not move.

As the exam takes place, the gantry will advance small intervals through the scanner. Modern spiral scanners can perform the examination in one continuous motion of the gantry. Generally, complete scans will only take a few minutes. However, additional contrast-enhanced or higher-resolution scans will add to the scan time. The newest multi-detector scanners can image the entire body, head-to-toe, in under 30 seconds.

How to prepare for the test

The health care provider may advise you to avoid eating or drinking for 4 - 6 hours prior to the scan, if contrast dye is to be used.

The CT scanner has a weight limit to prevent damage to the mechanized gantry. Have the health care provider contact the scanner operator if you weigh more than 300 pounds.

Metal interferes with the x-rays, so you may be asked to remove jewelry and wear a hospital gown during the study.

How the test will feel

The x-rays are painless. The primary discomfort may be from the need to lie still on the table.

If intravenous contrast dye is given, you may feel a slight burning sensation in the injected arm, 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.

Why the test is 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 a tumor or mass (clump 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

What abnormal results mean

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

Additional conditions under which the test may be performed:

What the risks are

CT scans and other x-rays are regulated to provide the minimum amount of radiation exposure needed to produce 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, vomiting, sneezing, itching, or hives, and occasionally anaphylaxis (life-threatening allergic response ). In people with kidney problems, the dye may have toxic effects on the kidneys.

Special considerations

The benefits of a CT scan usually far outweigh the risks. A CT scan is one of the best ways of looking at soft tissues such as the heart and lungs.