What is a computed tomography (CT) scan?

A computed tomography scan, also called a CT scan, is a special type of X-ray test. X-rays are taken from different angles and a computer puts the X-ray pictures together to create detailed views of the body. CT scans can show bone, muscle, fat, lymph nodes, organs, and blood vessels in detail.

A CT scan is done when your healthcare provider needs more detailed information than regular X-rays provide. CT scans are especially useful for seeing tumors and cysts. A CT scan may also be used by your provider to help guide other procedures, such as biopsies or placement of tubes.

During a CT scan, your body is exposed to a small amount of radiation. The amount of radiation you receive in a CT scan is less than you might receive in many other X-ray tests. Exposure to radiation is usually only dangerous if you are exposed to it often or in large amounts.

How is the CT scan done?

Before the test:

• Your healthcare provider will ask you to sign a consent form for the CT scan. The consent form will state the reason you are having the test, what happens during the test, and what you may expect afterward.
• Usually no preparation is necessary. However, in some cases your provider may have you prepare for the test by not eating for several hours before the test and taking medicine to help clean out your bowel.
• Remove any jewelry you are wearing.
• Tell your provider if you have had kidney problems or an allergy to chemicals, such as contrast dye. Contrast dye is used for some scans.
• Tell your provider if you are or think you may be pregnant.
• Tell your provider if you are afraid of enclosed spaces. Your provider may prescribe medicine to help you relax.
• You may have a needle inserted into a vein in your hand or arm. This will allow for medicine to be given into your blood system and to give you fluids.
• A solution of contrast dye may be injected into a vein, or you may be asked to drink the solution. This allows the scanner to show any abnormal areas as the dye passes through your body. The dye may cause you to feel warm, have a flushed face, headache, or a salty taste in the mouth. Rarely, it can cause nausea and vomiting.

During the test:

• Scans are painless, but you may get uncomfortable from lying in the scanner if the scan takes more than a few minutes. You can talk to the technologist at any time during the procedure.
• You will lie down on a movable table, which will slide you into a doughnut-like scanning machine.
• The scanner moves around you to change the angles of the X-rays.
• Inside the scanner, multiple X-ray beams are passed very quickly through your body at different angles.
• The images will be saved. Your healthcare provider will use a computer to look at the images.

After the test:

• You may stay in the hospital for a few hours or several days to recover, depending on your condition and your test results.
• While you are in the hospital, you will be checked often by nursing staff.
• Your provider will use your test results to make a plan for your care.
• Rarely some people have an allergic reaction to the dye. Most reactions happen right away, but it may happen several hours or days after the test.

How can I take care of myself when I go home?

• Follow activity restrictions, such as not driving or operating machinery, as recommended by your healthcare provider or pharmacist, especially if you are taking pain medicines or muscle relaxants.
• Unless your healthcare provider has told you to restrict fluids, if you were given dye, drink a lot of fluids after the procedure to help your body get rid of it.

Call emergency medical services or 911 if you have new or worsening:

• Throat swelling
• Trouble breathing

Call your healthcare provider if you have new or worsening:

• Itching
• Rash
• Sweating

What does the test result mean?

This test is only one part of a larger picture that includes your medical history and current health. Talk to your healthcare provider about your result and any follow up care you may need.

If your test results are not normal, ask your healthcare provider:

• If you need additional tests
• If you need treatment, and if so what your treatment plan choices are