Computed Tomography (CT) Scan

What is a CT scan?

CT” stands for computed tomography (tuh-MOG-ruff-ee). CT uses x-rays and a computer to make a picture of sections of the body. The picture is called a scan. A CT scan shows the body’s organs in greater detail and more clearly than regular x-rays.

What is a CTA scan?

CTA” stands for computed tomography angiography (AN-jee-OG-ruff-ee). A CTA scan gives a view of specific blood vessels (arteries and veins). CTA is often included in a CT exam.

Why are CT and CTA used?

CT and CTA help find problems in your body and how far disease has spread. They also help show the effects of treatment and how your body is responding to treatment. CT and CTA scanning can study many parts of the body, such as the brain, neck, chest, abdomen, pelvis, spine, arms, and legs.

How do I prepare for the test?

This section gives you some general guidelines to prepare for your test. Your doctor, nurse, or testing center will give you more detailed instructions.



Ask your doctor or testing center for instructions. If you have diabetes, ask your doctor about taking your routine medicine.


Your testing center will give you instructions. If your doctor or testing center tells you to take your routine medicine, take it only with a small sip of water. You may be asked to take a liquid preparation and a bowel preparation before you come to the testing center.

What to bring

When you come for your test, please bring:

  • A prescription slip or requisition from your doctor
  • Insurance forms, referrals, or both
  • A list of your medicines, including any special Glucophage instructions, over-the- counter drugs, and herbal drugs
  • A list of allergies to food, latex, or medicine


Tell the doctor or technologist if you’ve ever had an allergic reaction to a contrast enhancing agent, iodine, or shellfish, or if you have asthma.

CT and CTA scanning exposes you to some radiation. If you are pregnant or think you might be, or if you are breast-feeding, tell the doctor and technologist before your test.

What happens during the test?

You will put on a hospital gown and remove all metal objects that might interfere with the scan. If a contrast enhancing agent is used, you’ll receive it in one of the following ways:

  • By drinking it
  • By an enema (inserted through the rectum)
  • By an intravenous (IV) line in your arm


The IV enhancing agent may give you a brief sensation that moves up your arm. You also may get a warm, flushed feeling; a taste of salt or metal in your mouth; or nausea for a few minutes. This is normal, but you should tell the technologist about these or other reactions.

You may also experience nausea, shortness of breath, itchiness, or sneezing. If any of these occur, tell the doctor or technologist right away.

The CT scanner has a very large ring, like a donut standing upright. A narrow table moves through the center hole.

The technologist will help you onto the table and then will go into a room behind a large window. The staff will watch you carefully through the window. You’ll be able to talk to the staff through an intercom. You will be asked to hold your breath for a short time during the CT scan. You will hear whirring sounds and the table will move during the exam.

CT and CTA scanning usually takes less than 30 minutes. Some tests are shorter or longer, based on the number of areas tested and the equipment used. If an enhancing agent is used, the test will take longer.

What happens after the test?

When your scan is over, the technologist will help you off the table. If you had a change in diet before the scan, you may resume your normal diet. If you received an enhancing agent, you should drink plenty of fluids to flush it out of your body. If you cannot drink, you will be given fluids by IV. If you have diarrhea that lasts for longer than a day, call your doctor.

How do I get my test results?

A doctor who is a radiologist will study your scans and report the results to your doctor. Your doctor will discuss the results with you. Talk with your doctor or testing center about how to get your test results.

My test appointment

Date: ____________ Time: ____________
Place: _______________________________
Phone number: _______________________
Special instructions: ___________________

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