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Diagnosing Migraines and Headaches With a CT Scan

Computed axial tomography (CT scan) uses X-rays and computers to produce images of cross-sections of the body. This can aid in the diagnosis of headaches and their causes.

Why Is a CT Scan Used to Evaluate Migraines and Headaches?

A CT scan of the head may be recommended if you are getting daily or almost daily headaches.

A CT scan can help your doctor rule out other causes of headaches, such as:

  • Brain tumor
  • Abscess (an infection of the brain)
  • Hydrocephalus (the abnormal buildup of cerebrospinal fluid in the brain)
  • Sinus blockage
  • Injuries
  • Aneurysm or bleeding in the brain

A CT scan is not able to diagnose migraines.

Is a CT Scan Uncomfortable or Dangerous?

The test is painless. You'll be asked to lie on the scanning table during the test. You may be injected with contrast material to increase what the doctors are able to see.

Be sure to inform the doctor or nurse if you've had an allergic reaction to contrast material in the past. These agents contain iodine, which can cause an allergic reaction in some people.

The CT scanner uses X-rays. The amount of radiation you receive is kept to a minimum. However, if you are, or think you may be pregnant, inform the doctor, as X-rays can be harmful to a developing baby. It is recommended that children have a CT scan done at a facility that accommodates children so that the lowest possible dose of radiation can be used.


How Should I Prepare for a CT Scan?

  • Do not eat anything 4-hours before your CT scan.
  • Continue taking your medications as usual  after checking with your doctor to be sure it is safe to receive contrast.
  • Allow at least one hour for your CT scan. Most scans take from 15 to 60 minutes.
  • Consult your doctor if you have questions.

What Happens Before a CT Scan?

  • You may be given a sedating drug that will make you feel relaxed and drowsy.
  • You may be asked to change into a hospital gown, because snaps and zippers in street clothes can interfere with the scan. You also may be asked to remove your watch, rings, or jewelry. It's a good idea to leave your valuables, including jewelry, at home.

What Happens During the CT Scan?

  • A contrast material may be injected intravenously (into your vein) so the radiologist can see the body structures on the CT image. After the contrast agent is injected, you may feel flushed, or you may have a metallic taste in your mouth. These are common reactions. If you experience shortness of breath or any unusual symptoms, tell the technologist.
  • The technologist will help you lie in the correct position on the examining table. The table will then automatically move into place for imaging. It is very important that you lie as still as possible during the entire procedure. Movement could blur the images.
  • You may be asked to hold your breath briefly at intervals when the X-ray images are taken.

What Happens After the CT Scan?

Generally, you can resume your usual activities and normal diet immediately after a CT scan.


WebMD Medical Reference

Reviewed by David T. Derrer, MD on July 31, 2014

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