Alternate Names: Head CT; CT scan - skull; CT scan - head

How Performed: Remove all jewelry, dentures, glasses, or other metal from your head and neck. You lie face up on a movable table called a gantry, and your head is positioned inside the CT scanner. During the test, you must remain still.

Your head is immobilized and your face is left uncovered. X-rays are passed through the head in sections, or slices. A contrast-media (dye) may be injected into a vein to help define certain tissues. Each exposure takes a few seconds and the machine will make an audible hum. The table will move slightly (1/4 to 1/2 inch) between each scan to align for the next cross-section image. A sound system is built into the machine to allow for communication between the technician and you during the test.

The total amount of time in the CT scanner is 1/2 to 1 hour.

How To Prepare: Usually any preparations are done just prior to the scan, such as removal of jewelry and the injection of a contrast dye. There is no restriction of food or fluids. You must sign a consent form.

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 experience, 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 It Feels: If a dye is needed, there will be the small amount of pain when the needle is inserted, and shortly thereafter. Other than that, the CT is painless.

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

There may be some concern regarding X-rays. There is no direct link between an X-ray and any disease or condition; however, radiation is potentially harmful. Consult your health care provider about the risks if multiple CT scans are needed over a period of time.

Why Performed: A CT scan is recommended over other tests to determine:

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

Normal Values: Intracranial structures are symmetrical and have a specific density, position, size, and shape. Bone appears white, brain matter appears gray, and cerebral fluid appears black.

Abnormal Results: There may be signs of:

• trauma
• bleeding (for example, chronic subdural hematoma, subarachnoid 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)
• cerebral edema (brain tissue swelling)
• hydrocephalus (fluid collecting in the skull)

• acoustic neuroma
• acoustic trauma
• acromegaly
• acute (subacute) subdural hematoma
• amyotrophic lateral sclerosis
• arteriovenous malformation (cerebral)
• benign positional vertigo
• cancer of the throat
• central pontine myelinolysis
• cerebral aneurysm
• Cushing’s syndrome
• deep intracerebral hemorrhage
• delirium
• dementia
• dementia due to metabolic causes
• drug-induced tremor
• encephalitis
• epilepsy
• essential tremor
• extradural hemorrhage
• familial tremor
• general paresis
• generalized tonic-clonic seizure
• hemorrhagic stroke
• hepatic encephalopathy
• Huntington’s disease
• hypertensive intracerebral hemorrhage
• hypopituitarism
• intracerebral hemorrhage
• juvenile angiofibroma
• labyrinthitis
• lobar intracerebral hemorrhage
• Ludwig’s angina
• mastoiditis
• melanoma of the eye
• Meniere’s disease
• meningitis
• metastatic brain tumor
• multi-infarct dementia
• multiple endocrine neoplasia (MEN) I
• neurosyphilis
• normal pressure hydrocephalus (NPH)
• occupational hearing loss
• optic glioma
• orbital cellulitis
• otitis media; chronic
• otosclerosis
• partial (focal) seizure
• partial complex seizure
• petit mal seizure
• pituitary tumor
• primary brain tumor
• primary lymphoma of the brain
• prolactinoma
• retinoblastoma
• Reye’s syndrome
• schizophrenia
• senile dementia/Alzheimer’s type
• acute sinusitis
• stroke secondary to atherosclerosis
• stroke secondary to cardiogenic embolism
• stroke secondary to FMD
• stroke secondary to syphilis
• subarachnoid hemorrhage
• syphilitic aseptic meningitis
• temporal lobe seizure
• toxoplasmosis
• transient ischemic attack (TIA)
• Wilson’s disease

Cost:

Special Considerations: 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.