CT Scan of the Head: About This Test

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What is it?

A CT (computed tomography) scan uses X-rays to make detailed pictures of your body and the structures inside your body. A CT scan of the head can give your doctor information about your eyes, the bones of your face and nose, your inner ear, and your brain.

During the test, you will lie on a table that is attached to the CT scanner. The CT scanner is a large doughnut-shaped machine.

Why is this test done?

A CT scan of the head can help find the cause of symptoms that may mean you have a brain injury or bleeding inside your head. It can also find a tumor and damage caused by a stroke. And it can help find the best treatment for the cause of a stroke.

How do you prepare for the test?

In general, there's nothing you have to do before this test, unless your doctor tells you to.

Tell your doctor if you get nervous in tight spaces. You may get a medicine to help you relax. If you think you'll get this medicine, be sure you have someone to take you home.

How is the test done?

Before the test

  • You may have to take off jewelry.
  • You will take off all or most of your clothes and change into a gown. If you do leave some clothes on, make sure you take everything out of your pockets.
  • You may have contrast material (dye) put into your arm through a tube called an IV.

During the test

  • You will lie on a table that is attached to the CT scanner.
  • The table slides into the round opening of the scanner. The table will move during the scan. The scanner moves within the doughnut-shaped casing around your body.
  • You will be asked to hold still during the scan. You may be asked to hold your breath for short periods.
  • You may be alone in the scanning room. But a technologist will watch you through a window and talk with you during the test.

How long does the test take?

The test will take about 30 to 60 minutes. Most of this time is spent getting ready for the scan. The actual test only takes a few minutes.

How does having a CT scan of the head and face feel?

The test will not cause pain, but some people feel nervous inside the CT scanner.

If a medicine to help you relax (sedative) or dye is used, you may feel a quick sting or pinch when the IV is started. The dye may make you feel warm and flushed and give you a metallic taste in your mouth. Some people feel sick to their stomach or get a headache. Tell the technologist or your doctor how you are feeling.

What are the risks of the test?

The chance of a CT scan causing a problem is small.

  • There is a chance of an allergic reaction to the contrast material.
  • If you breastfeed and are concerned about whether the contrast material used in this test is safe, talk to your doctor. Most experts believe that very little dye passes into breast milk and even less is passed on to the baby. But if you are concerned, you can stop breastfeeding for up to 24 hours after the test. During this time, you can give your baby breast milk that you stored before the test. Don't use the breast milk you pump in the 24 hours after the test. Throw it out.
  • There is a risk of damage to cells or tissue from being exposed to radiation, including the small amounts used in CTs, X-rays, and other medical tests. Over time, exposure to radiation may cause cancer and other health problems. But in most cases, the risk of getting cancer from being exposed to small amounts of radiation is low. It is not a reason to avoid these tests for most people.

What happens after the test?

  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.
  • If dye was used, drink plenty of fluids for 24 hours after the test, unless your doctor tells you not to.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.