Computed tomography (CT or CAT scan) of the chest is a special noninvasive X-ray scan used to detect and diagnose health problems in the thorax (chest area). This scan can be used to evaluate symptoms such as shortness of breath, chest pain, unexplained cough, fever, and other chest symptoms. Chest CT can also help confirm the diagnosis of pneumonia, tumors, anatomic abnormalities, and other lung diseases.
Your doctor may recommend a chest CT if you have symptoms that could be caused by a lung disease or disorder. A chest CT may also be ordered to help evaluate an abnormality seen on a regular chest X-ray. Disorders of the lung typically fall into several categories:
- Infection – chest CT can detect pneumonia, tuberculosis, lung abscess, and other infections.
- Tumors – cancers of the lung can be detected by CT scan. This is especially important since CT scans can detect lung cancers at an early stage.
- Injury – chest CT can help evaluate the extent of damage due to chest trauma by evaluating the lungs, heart, blood vessels, ribs, sternum (breast plate), and spine.
- Lung-specific disease – Certain diseases specifically affect the lungs. Chest CT can help evaluate or diagnose bronchiectasis, cystic fibrosis, pleural disease, interstitial lung disease, and other disorders of the lungs.
Chest CT can help visualize problems in the middle of your chest cavity that includes organs and structures such as the heart, major blood vessels, esophagus, trachea, nerves, thoracic duct, thymus, and lymph nodes.
Chest CT is used to evaluate disease in the lungs when preparing for surgery or cancer treatment. The exam is also used to assess the response to lung cancer treatment.
- Chest CT scan is fast, noninvasive, and painless.
- Compared to traditional X-rays, chest CT provides much more information and detail.
- Urgent medical conditions, such as bleeding or lung injury, can be evaluated rapidly by chest CT. The speed of the test can help doctors make critical decisions that save lives.
- In a single scan, chest CT can evaluate bone, soft tissue, and blood vessels.
- Unlike MRI, if you have metal in your body (shrapnel, bullets, needles, etc.) or an implanted medical device, you can still have a chest CT since no magnets are used in the procedure.
- Chest CT can be performed in real time to make it easier for doctors to perform certain procedures, such as a lung biopsy.
- X-rays used in CT scans have no immediate side effects and do not remain in the body.
- Excessive radiation can increase the risk for cancer. However, the amount of radiation received from a chest CT alone is unlikely to cause cancer or increase cancer risk significantly.
- Pregnant women should be aware of the risk of radiation to the developing child. In some cases, doctors may recommend a different test instead of chest CT. For more details, please refer to the section What if I am pregnant? Can I still have a CT scan?
- The risk of negative side effects due to contrast are rare. Refer to the About Contrast section for more details about the risks of different types of contrast.
- The ACR states that current information suggests breastfeeding is safe after the use of intravenous contrast. Please discuss your breastfeeding options with your medical provider.
If you are, or think you are pregnant, be sure to notify your doctor or technologist before undergoing a CT scan. The amount of radiation received during a CT scan is unlikely to harm you or your baby. However, in general, CT scans are not recommended in pregnant women. In every case, the mother’s health must be considered as well. The benefit to the pregnant woman of having the CT scan to diagnose an illness may outweigh the small amount of risk to the baby from a low-dose CT scan.
The part of your body being scanned should also be considered. For example, brain CT exposes the unborn baby to little or no radiation. Even if the fetus is directly exposed to CT scan radiation (such as in CT scans of the abdomen or pelvis), the increased risk of developing cancer later in life is one in 1000. Some doctors may recommend another type of exam (ultrasound or MRI) to avoid exposing your baby to radiation.
The ACR states that current information suggests breastfeeding is safe after the use of intravenous contrast. Please discuss your breastfeeding options with your medical provider.
For more information on contrast, please see About CT Contrast.
- Chest CT is available at multiple ARA imaging centers and takes a total of approximately 30 minutes.
- You may be asked to change into a hospital gown for the procedure.
- Since metal can distort the CT images, all metal objects and jewelry should be removed prior to the exam. This may include hearing aids, removable dental prostheses, eyeglasses, piercings, hairpins, etc.
- The CT scanner is a large box shaped machine with a large hole in the middle.
- You’ll be placed on a moveable exam table which may have straps or bolsters to help keep your body from moving. You will need to remain as still as possible so the images will be clear.
- If your study requires intravenous (IV) contrast, your paramedic or technologist will place an IV line into your arm or hand to administer the contrast. IV placement may be uncomfortable and may cause bruising later. A saline solution drip may be used to help keep the IV line clear.
- Your study may require oral contrast (by mouth), which may has a chalky taste but is not unpleasant.
- The technologist will leave the CT scan room where you are and conduct the exam from a computer in a nearby room. You will be able to talk with the technologist at all times.
- The table will make a first quick pass through the scanner to set your body position. Next, the table will move through the scanner more slowly while the CT images are being taken. It may require several passes through the machine to complete the scan.
- You may hear slight buzzing, clicking, or rotating sounds during the scanning process.
- You may be asked to hold your breath during some parts of the scan. Breathing or any other movement can distort the images.
- When the scan is finished, you may be asked to wait a few minutes while the technologist checks the quality of the images. If needed, more images may be taken.
- Wear comfortable, loose fitting clothing. You may want to leave all jewelry, piercings and any other metal objects at home.
- If your exam requires contrast, you will be asked not to eat or drink for a few hours prior to the CT scan. In most cases, you will take all your medications as usual. Ask your health care provider for specific directions about your daily medications.
- Be sure to tell your health care provider, ARA scheduler, and ARA technologist about any illness or allergies you may have. Health care providers should know if you have asthma, multiple myeloma, heart, kidney, or thyroid issues, or if you have diabetes. Also, provide a list of your current medications.
- Inform your radiologist if you are pregnant. Although the risk of chest CT is very low for the unborn baby, your doctor may choose an alternate exam. Depending on the circumstances, both the physician and patient may decide it is necessary to go ahead with the CT scan. Also, pregnant women should not receive IV contrast unless the benefits clearly outweigh the risks. For more details, please refer to the section What if I am pregnant? Can I still have a CT scan?
- Head CT is fast and painless. If you feel like you might be anxious during the exam, tell your scheduler. ARA technologists and our clinical staff are experts at helping people through CT exams with minimum anxiety.
- You can return to your normal activities after the exam. Drinking plenty of water will help flush the contrast agent from your system.
A radiologist, a physician specifically trained to interpret radiological examinations, will analyze the images and send a signed report to the provider who referred you to ARA. The physician will then share the results with you.