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Computed tomography (CT or CAT) scan
Computed tomography is a specialized imaging technique that uses X-rays collected from many different angles around the body to generate detailed cross-sectional images as well as detailed three-dimensional images of the body's internal structures and organs, including the aorta.
The procedure is painless and requires the patient to lie as still as possible on a table that is guided into a machine that resembles an enormous doughnut. Called a gantry, it directs small doses of electromagnetic radiation toward the body from various angles. Because different tissues of the body absorb varying amounts of radiation, a computer can analyze the radiation transmitted through the body to reconstruct the images of the internal structures and organs.
Sometimes a contrast medium, akin to a dye, is injected into a vein to help depict blood flow during a CT scan. If contrast medium is used, patients typically fast for a few hours before the procedure. The contrast medium may, on occasion, cause an allergic reaction. The most common reaction is hives or a feeling of itchiness. In people with asthma, the allergic reaction may manifest as an asthma attack. In very rare instances, a patient may experience swelling in the throat or other areas of the body. If you experience hives, itchiness, or swelling in your throat during or after your CT scan, immediately tell the technologist or doctor.
Chest and abdominal CT scans involve exposure to a dose of radiation that typically exceeds the average background dose of radiation we're experience in daily living. For most patients, however, the benefits far outweigh the minor risks associated with exposure to this level of radiation. However, pregnant women may prefer to postpone getting a CT scan until after they've delivered or choose alternative testing procedures. Individuals with pacemakers or internal cardioverter defibrillators who have been advised to avoid MRIs can safely have a CT scan.
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