MedlinePlus Medical Encyclopedia: Cranial CT scan

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Cranial CT scan

Contents of this page:
Alternative names Definition How the test is performed How to prepare for the test How the test will feel	Why the test is performed What abnormal results mean What the risks are Special considerations

Alternative names

Head CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses

Definition Return to top

A cranial CT scan involves computed tomography of the head, including the skull, brain, orbits (eyes), and sinuses.

How the test is performed Return to top

A head CT will produce an image from the upper neck to the top of the head. If the patient cannot keep his/her head still, immobilization may be necessary. All jewelry, glasses, dentures, and other metal should be removed from the head and neck to prevent artifacts.

A contrast dye may be injected into a vein to further evaluate a mass. (The mass becomes brighter with contrast dye if it has a lot of blood vessels). Contrast dye is also used to produce an image of the blood vessels of the head and brain.

The total amount of time in the CT scanner is usually a few minutes.

How to prepare for the test Return to top

Generally, there is no preparation necessary.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

infant test or procedure preparation (birth to 1 year)
toddler test or procedure preparation (1 to 3 years)
preschooler test or procedure preparation (3 to 6 years)
schoolage test or procedure preparation (6 to 12 years)
adolescent test or procedure preparation (12 to 18 years)

How the test will feel Return to top

As with any intravenous iodinated contrast injection, there may be a slight temporary burning sensation in the arm, metallic taste in the mouth, or whole body warmth. This is a normal occurrence and will subside in a few seconds.

Otherwise, the CT scan is painless.

Why the test is performed Return to top

A CT scan is recommended to help:

evaluate acute cranial-facial trauma
determine acute stroke
evaluate suspected subarachnoid or intracranial hemorrhage
evaluate headache
evaluate loss of sensory or motor function
determine if there abnormal development of the head and neck

CT scans are also used to view the facial bones, jaw, and sinus cavities.

What abnormal results mean Return to top

There may be signs of:

trauma
bleeding (for example, chronic subdural hematoma or intracranial hemorrhage)
stroke
masses or tumors
abnormal sinus drainage
sensorineural hearing loss
malformed bone or other tissues
brain abscess
cerebral atrophy (loss of brain tissue)
brain tissue swelling
hydrocephalus (fluid collecting in the skull)

Additional conditions under which the test may be performed:

What the risks are Return to top

Iodine is the usual contrast dye. Some patients are allergic to iodine and may experience a reaction that may include hives, itching, nausea, breathing difficulty, or other symptoms.

As with any x-ray examination, radiation is potentially harmful. Consult your health care provider about the risks if multiple CT scans are needed over a period of time.

Special considerations Return to top

A CT scan can decrease or eliminate the need for invasive procedures to diagnose problems in the skull. This is one of the safest means of studying the head and neck.

Update Date: 4/22/2003

Updated by: Benjamin Taragin, M.D., Department of Radiology, Columbia Presbyterian Medical Center, New York, NY. Review Provided by VeriMed Healthcare Network.

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