A computed tomography (CT) scan uses X-rays to make pictures of the head and face.

During the test, you will lie on a table that is attached to the CT scanner, which is a large doughnut-shaped machine. Your head will be positioned inside the scanner. The CT scanner sends X-rays through the head. Each rotation of the scanner takes a second and provides a picture of a thin slice of the head and face. One part of the scanning machine can tilt to take pictures from different positions. All of the pictures are saved as a group on a computer. They also can be printed.

An iodine dye (contrast material) is often used to make structures and organs easier to see on the CT pictures. The dye may be used to check blood flow, find tumors, and look for other problems. Dye can be put in a vein (IV) in your arm. CT pictures may be taken before and after the dye is used.

A CT scan of the head can give some information about the eyes, facial bones, air-filled cavities (sinuses) within the bones around the nose, and the inner ear. If these areas are of concern, a specific CT scan of the area is usually done.

A CT scan of the head may be used to evaluate headaches. For more information, see:

Should I have imaging tests to evaluate my headaches?

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Why It Is Done

A CT scan of the head is done to:

• Find the cause of symptoms, such as confusion, paralysis, numbness, vision problems, vertigo, or headaches, that might mean a brain injury, a brain tumor, a ruptured aneurysm, or bleeding inside the head.
• Look for problems of the middle ear bones and the auditory nerve.
• Help plan for surgery.
• Find damage caused by a stroke and to help find the best treatment for the cause of a stroke.
• Find the cause of a loss of consciousness or a changing level of consciousness.
• Check on the success of treatment or surgery for a brain tumor.
• Provide guidance for a brain biopsy.

CT scans of the eyes, facial area, and sinuses may be done to:

• Look for problems of the eyes and the optic nerve. The test may find fractures of the bones around the eyes or foreign objects in the eye.
• Look for problems or diseases of the air-filled cavities in the bones around the nose (sinuses).
• Look for problems with the bones and joints of the jaw, face, and skull, such as temporomandibular disorder or Paget's disease.
• Find broken bones (fractures). See a CT scan of a cheekbone fracture.
• Look for foreign objects in the head and face.
• Plan for surgery to rebuild parts of the face that were damaged.