(Chest CT Scan, Thoracic CT Scan, CT of the Thorax)
Computed tomography (CT or CAT scan) is a noninvasive diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than standard x-rays.
In standard x-rays, a beam of energy is aimed at the body part being studied. A plate behind the body part captures the variations of the energy beam after it passes through skin, bone, muscle, and other tissue. While much information can be obtained from a standard x-ray, a lot of detail about internal organs and other structures is not available.
In computed tomography, the x-ray beam moves in a circle around the body. This allows many different views of the same organ or structure. The x-ray information is sent to a computer that interprets the x-ray data and displays it in a two-dimensional (2D) form on a monitor.
CT scans may be done with or without "contrast." Contrast refers to a substance taken by mouth or injected into an intravenous (IV) line that causes the particular organ or tissue under study to be seen more clearly. Contrast examinations may require you to fast for a certain period of time before the procedure. Your physician will notify you of this prior to the procedure.
CT scans of the chest can provide more detailed information about organs and structures inside the chest than standard x-rays of the chest, thus providing more information related to injuries and/or diseases of the chest (thoracic) organs.
CT scans of the chest may also be used to visualize placement of needles during biopsies of thoracic organs or tumors, or during aspiration (withdrawal) of fluid from the chest. CT scans of the chest are useful in monitoring tumors and other conditions of the chest before and after treatment.
Other related procedures that may be used to assess the heart include resting or exercise electrocardiogram (ECG or EKG), Holter monitor, signal-averaged ECG, cardiac catheterization, chest x-ray, echocardiogram, electrophysiological studies, magnetic resonance imaging (MRI) of the heart, myocardial perfusion scans, radionuclide angiography, and ultrafast CT scan. Please see these procedures for additional information.
The chest contains organs of the respiratory and cardiovascular systems, as well as the esophagus (hollow tube of muscle extending from below the tongue to the stomach). A CT scan of the chest may be performed to assess the chest and its organs for tumors and other lesions, injuries, intra-thoracic bleeding, infections, unexplained chest pain, obstructions, or other conditions, particularly when another type of examination, such as x-rays or physical examination, is not conclusive.
A CT scan of the chest may also be used to evaluate the effects of treatment of thoracic tumors. Another use of chest CT is to provide guidance for biopsies and/or aspiration of tissue from the chest.
There may be other reasons for your physician to recommend a CT scan of the chest.
You may want to ask your physician about the amount of radiation used during the CT procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous CT scans and other types of x-rays, so that you can inform your physician. Risks associated with radiation exposure may be related to the cumulative number of x-ray examinations and/or treatments over a long period of time.
If you are pregnant or suspect that you may be pregnant, you should notify your physician. Radiation exposure during pregnancy may lead to birth defects.
If contrast dye is used, there is a risk for allergic reaction to the dye. Patients who are allergic to or sensitive to medications should notify their physician. Studies show that eighty-five percent of the population will not experience an adverse reaction from iodinated contrast; however, you will need to let your physician know if you have ever had a reaction to any contrast dye, and/or any kidney problems. A reported seafood allergy is not considered to be a contraindication for iodinated contrast.
Patients with kidney failure or other kidney problems should notify their physician. In some cases, the contrast dye can cause kidney failure, especially if the person is taking Glucophage (a diabetic medication). The effects of kidney disease and contrast agents have attracted increased attention over the last decade, as patients with kidney disease are more prone to kidney damage after contrast exposure.
There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
Certain factors or conditions may interfere with the accuracy of a CT scan of the chest. These factors include, but are not limited to, the following:
A chest CT may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.
Generally, the chest CT follows this process:
While the CT procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.
If contrast dye was used during your procedure, you may be monitored for a period of time for any side effects or reactions to the contrast dye, such as itching, swelling, rash, or difficulty breathing.
If you notice any pain, redness, and/or swelling at the IV site after you return home following your procedure, you should notify your physician as this could indicate an infection or other type of reaction.
If you are given contrast by mouth, you may experience diarrhea after the procedure.
Otherwise, there is no special type of care required after a CT scan of the chest. You may resume your usual diet and activities unless your physician advises you differently.
Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.
The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. Please consult your physician with any questions or concerns you may have regarding your condition.
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American College of Chest Physicians
National Heart, Lung, and Blood Institute (NHLBI)
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Online Resources of Heart Center