A head CT scan uses x-rays and special computers to make images of the inside of the head.
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Reasons for Test
A CT scan is done to look at the skull, brain, jaw, sinuses, and facial bones. It will look for signs of injuries, tumors, infections, or other diseases.
A head CT may be done when a person has:
Problems are rare, but all procedures have some risk. The doctor will go over some problems that may happen.
A contrast material may be used to get the best images. It could cause an allergic reaction or kidney problems in some people. This is not common.
A CT also uses radiation. Radiation doses may build up in the body over time. This can raise the risk of some cancers or thyroid problems. The risk is higher in children and women who are pregnant.
What to Expect
Prior to Test
Before the test:
- Do not eat or drink anything for 4 hours before a test using contrast material.
- Remove any metal objects, such as jewelry, hearing aids, or dentures.
Description of the Test
Any contrast that is used will be injected into a vein.
You will be positioned on a special moving table. A device may be used to keep your head still. The table will move slowly through the CT scanner. You will need to stay still during the entire test. The scanner will hum and click as it takes pictures.
If you had contrast, you may be asked to drink extra fluid. This will flush the contrast from the body.
How Long Will It Take?
About 10 minutes
Will It Hurt?
You may feel flushed if you are given contrast. You may also feel nauseated and notice a salty or metallic taste in your mouth.
A radiologist will look at the images. Your doctor will get the results and share them with you.
Call Your Doctor
Call the doctor if any of the following occur after having a test that uses contrast:
- Swollen, itchy eyes
- Tightness of throat
- Problems breathing
If you think you are having an emergency, call for medical help right away.
American Cancer Society
Radiological Society of North America
Canadian Association of Radiologists
Canadian Radiation Protection Association
Computed tomography (CT)—Head. Radiology Info.org—Radiological Society of North America website. Available at: http://www.radiologyinfo.org/en/info.cfm?pg=headct. Updated June 22, 2018. Accessed April 6, 2020.
Positron emission tomography—computed tomograpy (PET/CT). Radiology Info.org—Radiological Society of North America website. Available at: http://www.radiologyinfo.org/en/info.cfm?pg=PET. Updated August 1, 2019. Accessed April 6, 2020.
Last reviewed February 2020 by EBSCO Medical Review Board Rimas Lukas, MD Last Updated: 4/6/2020