Computed Tomography Scan

(Also called CT Scan)

Overview

What is a Computed Tomography Scan (CT Scan)?

In conventional x-rays, a beam of energy is aimed at the part of the body 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 regular x-ray, specific detail about internal organs and other structures is not available.

During a computed tomography scan (CT scan), the x-ray beam moves in a circle around the body. This allows for many different views of the same organ or structure, and provides much greater detail. The x-ray information is sent to a computer which interprets the x-ray data and displays it in 2-dimensional form on a monitor. While many images are taken during a CT scan, less radiation is received by the patient than during a single standard x-ray, in many cases.

CT scans may be done with or without contrast. "Contrast" refers to a substance taken by mouth or injected into an intravenous line that causes the particular organ or tissue being studied to be seen more clearly. If your physician schedules you for a CT scan of the heart or chest, you may need to be NPO (fasting, or nothing by mouth) for four hours prior to the procedure if contrast dye will be used. Your physician will provide specific instructions.

You will need to let your physician know if you have ever had a reaction to any contrast dye, or if you are allergic to iodine or seafood. If you are pregnant or think you may be pregnant, you should notify your physician. If you are claustrophobic or tend to become anxious easily, tell your physician ahead of time, as he/she may prescribe a mild sedative for you before the procedure to make you more comfortable. It will be necessary for you to remain still and quiet during the procedure, which may last 30 to 60 minutes.

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