A chemical called contrast may be used to help improve the images. Some people can have an allergic reaction or develop
with contrast material.
However, these reactions are rare. Your doctor will review a list of possible complications of a CT scan with contrast.
A CT scan does use radiation. You and your doctor will weigh the harms and benefits of this test. A CT scan may not be advised if you are pregnant.
Be sure to discuss these risks with your doctor before the test.
Avoid eating or drinking anything for 4 hours before the test if contrast will be used.
Remove any metal objects, such as jewelry, hearing aids, or dentures.
Description of the Test
If contrast is needed, it will be injected into a vein.
You will be positioned on a special moving table. The table will move slowly through the CT scanner. You will need to stay still during the entire test. The technician may need to use a device to keep your head still. As the scanner takes pictures, you will hear humming and clicking. You will be able to talk to the technician through an intercom.
Brenner DJ. Should we be concerned about the rapid increase in CT usage?
Rev Environ Health.
Computed tomography (CT)—Head. Radiology Info.org—Radiological Society of North America website. Available at: ...(Click grey area to select URL) Updated June 8, 2016. Accessed February 15, 2018.
Positron emission tomography—computed tomograpy (PET/CT). Radiology Info.org—Radiological Society of North America website. Available at: ...(Click grey area to select URL) Updated January 23, 2017. Accessed February 15, 2018.
Last reviewed March 2018 by
EBSCO Medical Review Board
Rimas Lukas, MD Last Updated: 6/24/2013