Computed Tomography Scan of the Head and Neck
A body scanner delivers x-rays to the head and neck area at many different angles. A computer then compiles this information to construct highly detailed, cross-sectional images of internal structures. In some cases, a contrast dye may be injected to better define tissues and blood vessels on the images. Cranial CT scan is used to detect abnormalities outside of the skull.
Purpose of the Cranial CT Scan
- To detect inflammation, tumors and other masses, and other abnormalities in the head and neck region, including the mouth, tongue, salivary glands, throat (pharynx), sinuses, nasal cavities, vocal cords (larynx), and ear
- To investigate the cause of hearing loss, detect bone or soft tissue damage in the ear, confirm abnormalities of the cochlea (a cone-shaped tube in the inner ear), and identify candidates for a cochlear implant
- To determine the extent of head or neck tumors before treatment for cancer, and to monitor the area for recurrence after cancer therapy
- To detect bleeding, brain injury and skull fracture in patients with a head injury
- To locate bleeding in the brain caused by a ruptured or leaking aneurysm in a patient with a sudden severe headache
- To locate a blood clot or bleeding in the brain in a patient who exhibits symptoms of a stroke (especially with a new technique called Perfusion CT)
- To detect enlarged brain cavities (ventricles) in patients with hydrocephalus
- To detect diseases and malformations of the skull
- To assess the pituitary gland, pineal gland, and sinuses
- To help determine the cause of headaches, unexplained weakness, or a change in mental status
Who Performs Cranial CT Scan
- A radiologist and/or a trained technician
Special Concerns about Cranial CT Scan
- CT scans are not usually done during pregnancy because exposure to ionizing radiation may harm the fetus.
- People who experience claustrophobia may find it difficult to undergo a CT scan, which takes place in a narrow, tunnel-like structure.
- People with allergies to iodine or shellfish may experience an allergic reaction to the iodine-based contrast material.
Before the Cranial CT Scan
- Inform your doctor if you have an allergy to iodine or shellfish. You may be given a combined antihistamine-steroid preparation to reduce the risk of an allergic reaction.
- Tell your doctor about any recent illnesses or other medical conditions, including a history of heart disease, asthma, diabetes, kidney disease or thyroid problems.
- Tell your doctor if you suffer from claustrophobia. He or she may prescribe a sedative that can help you tolerate the procedure.
- If a contrast dye is to be used, drink large amounts of fluids on the day before the test to prevent dehydration. Do not eat or drink anything for 1 to 2 hours before the test. (Fasting is unnecessary before noncontrast CT scans.)
- Remove any hair clips, jewelry, dentures, glasses, and other metal objects from your head and neck.
- If a contrast dye is to be administered, an intravenous (IV) needle or catheter is inserted into a vein in your arm immediately before the test begins.
- Tell your doctor if you are pregnant or may be pregnant.
What You Experience during Cranial CT Scan
- You will lie on your back on a narrow table, and your head and neck are advanced into the CT scanner. Your head is immobilized but your face is left uncovered.
- The scanner takes pictures at different intervals and varying levels over your head and neck area, so you will feel the table move during the test. The resulting images are displayed on a viewing monitor and recorded on x-ray film.
- You must remain still because any movement can distort the image on the scan.
- A contrast dye may be administered through the IV line in your arm to help define blood vessels and various tissues. (Upon injection of the dye, you may experience a brief flushing sensation and a metallic taste in the mouth.)
- The test usually takes 30 minutes to 1 hour. However, if a contrast dye is used, the procedure time may be longer because scans are taken before and after the dye is administered.
Risks and Complications of Cranial CT Scan
- Although radiation exposure is minimal, you will receive a higher dose of radiation than during standard x-ray procedures.
- Some people may experience an allergic reaction to the iodine-based contrast dye, which can cause symptoms such as nausea, sneezing, vomiting, hives, and occasionally a life-threatening response called anaphylactic shock. Emergency medications and equipment are kept readily available.
After the Cranial CT Scan
- If contrast dye was used, you are encouraged to drink clear fluids to avoid dehydration and help flush the dye out of your system.
- You may leave the testing facility and resume your normal diet and activities.
- Blood may collect and clot under the skin (hematoma) at the dye injection site; this is harmless and will resolve on its own. For a large hematoma that causes swelling and discomfort, apply ice initially; after 24 hours, use warm, moist compresses to help dissolve the clotted blood.
- Delayed allergic reactions to the contrast dye, such as hives, rash, or itching, may appear 2 to 6 hours after the procedure. If this occurs, your doctor will prescribe antihistamines or steroids to ease your discomfort.
Cranial CT Scan Results
- A radiologist will examine the CT images for evidence of any abnormality.
- If a definitive diagnosis can be made, appropriate treatment will be initiated, depending on the specific problem.
- In some cases, additional tests, such as fine needle aspiration of a head or neck mass, laryngoscopy, or thyroid ultrasound, may be needed to establish a diagnosis and determine the extent of the problem.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media