Key Points

• A chest CT scan is a painless, noninvasive test that creates precise images of the structures in your chest, such as your lungs.
• A chest CT scan is a type of x ray, but a CT scan’s pictures show more details than the pictures from a standard chest x ray. Like other x-ray tests, chest CT scans use a form of energy called ionizing radiation. This energy helps create pictures of the inside of your chest.
• A CT scanner is a large machine with a tunnel-like hole in the center. During a chest CT scan, you lie on a table as it moves small distances at a time through the hole.
• The chest CT scanning machine takes many pictures, called slices, of the lungs and the inside of the chest. Sometimes, a special substance (called contrast dye) is injected into a vein in your arm. This substance highlights areas in your chest, which helps create clearer images.
• People who have symptoms of lung problems, such as a chest pain or trouble breathing, may need chest CT scans.
• The scan helps find the cause of the symptoms. It looks for problems such as tumors, excess fluid around the lungs, and pulmonary embolism (a blood clot in the lungs). The scan also can check for other conditions, such as tuberculosis, emphysema, and pneumonia.
• Wear loose-fitting, comfortable clothing for the chest CT scan. You’ll be asked to remove jewelry, eyeglasses, and metal objects that might interfere with the test. Let your doctor know if you’re pregnant, have other medical conditions are taking any medicines, or have any allergies.
• Contrast dye may be used as part of the chest CT scan. If you’re breast-feeding, ask your doctor how long you should wait after the test before you breast-feed. The contrast dye can be passed to your baby through your milk. You may want to prepare for the scan by pumping and saving milk for 24 to 48 hours in advance. You can bottle-feed your baby in the hours after the scan.
• A chest CT scan takes about 30 minutes, which includes preparation time. The scan itself doesn’t hurt, but you may feel anxious if you get nervous in tight or closed spaces. Your doctor may give you medicine to help you relax.
• You usually can return to your normal routine right after a chest CT scan. If contrast dye was used, your doctor may give you special instructions, such as drinking plenty of liquids to flush out the substance.
• A chest CT scan provides detailed pictures of the size, shape, and position of your lungs and other structures in your chest. A CT scan can show whether you have a lung problem or other condition.
• Chest CT scans have few risks. Because the test uses radiation, there may be a slight risk of cancer. However, the amount used is about the same as the amount you’re naturally exposed to over 3 years. Rarely, people have allergic reactions to the contrast dye that sometimes used. If this happens, your doctor will give you medicine to relieve the symptoms.