Computed Tomography (CT) Scan of the Head and Face
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 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.
In some cases, a
dye called contrast material may be put in a vein (IV) in your arm or into the spinal canal. The dye makes structures and organs easier to see on the CT
pictures. The dye may be used to check blood flow and look for
tumors, areas of
inflammation, or nerve damage.
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
A CT scan of the head may be used to evaluate headaches.
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
Become very nervous in
small spaces. You need to lie still inside the CT scanner, so you may need a
medicine (sedative) to help you relax.
Arrange for someone to take you home in case you get a
medicine to help you relax (sedative) for the test.
Talk to your
doctor about any concerns you have regarding the need for
the test, its risks, or how it will be done. To help you understand the
importance of this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
A CT scan is usually done by a
radiology technologist. The pictures are usually read
radiologist, who writes the report. Other doctors also may review a CT scan.
may need to take off any jewelry, glasses, and hearing aids. Wear comfortable,
During the test, you will lie on a table
that is attached to the CT scanner.
Straps will hold your head still, but your face will not be covered.
The table slides into the round opening of the scanner, and the scanner
moves around your body. The table will move while the scanner takes pictures.
You may hear a click or buzz as the table and scanner move. It is very
important to lie still during the test.
During the test, you may
be alone in the scan room. But the technologist will watch you through a
window. You will be able to talk to the technologist through a two-way
The test will take about 30 to 60 minutes. Most of this time is spent getting ready for the scan. The actual scan only takes a few seconds.
How It Feels
The test will not cause pain.
The table you lie on may feel hard, and the room may be cool. It may be hard to
lie still during the test.
Some people feel nervous inside the CT
If a medicine to help you relax (sedative) or
dye (contrast material) is used, an IV is usually put in
your hand or arm. You may feel a quick sting or pinch when the IV is started.
The dye may make you feel warm and flushed and give you a metallic taste in
your mouth. Some people feel sick to their stomach or get a headache. Tell the
technologist or your doctor how you are feeling.
The chance of a CT scan causing a problem is
If you have
diabetes or take metformin (Glucophage), the dye may
cause problems. Your doctor will tell you when to stop taking metformin and
when to start taking it again after the test so you will not have
There is a small chance of developing cancer from having
some types of CT scans.1 The chance is higher in children, young
adults, and people who have many radiation tests. If you are
concerned about this risk, talk to your doctor about the amount of radiation
this test may give you or your child, and confirm that the test is
results usually are ready for your doctor in 1 to 2 days.
CT scan of the head and face
The brain and blood vessels
and bones of the skull and face are normal in size, shape, and
No foreign objects or growths
No bleeding or collections of
fluid are present.
A growth, such as a tumor, or
bleeding is present in or around the brain. Foreign objects, such as glass or
metal fragments, are present. The bones of the skull or face are broken
(fractured) or look abnormal. Nerves leading to or from the brain are damaged
A collection of fluid is
found, which may mean bleeding in or around the brain.
Children who need a CT scan may need special
instructions for the test. If the child is too young to hold still or is
afraid, the doctor may give the child a medicine (sedative) to
help him or her relax.
If your child is scheduled for a CT scan,
talk with your child's doctor about the need for the scan and the risk of
radiation exposure to your child.
CT scanners called spiral (helical) CT scanners and multi-slice (or
multi-detector) CT scanners are sometimes used for this test. They can find
atherosclerosis. These special CT scanners can:
Take better pictures of blood vessels and
Produce scans in less time.
Perfusion CT is a method to look at blood flow
in the brain. For this test, a dye (contrast material) is given intravenously (IV), and CT scans then follow the flow
of the dye through the brain. This type of CT scan can show damaged areas of
the brain. The scans also can show areas of the brain that are not getting any
CT results are often compared to positron emission
tomography (PET) results to help find cancer. Some new scanners do both scans
at the same time.
Einstein AJ, et al. (2007). Estimating risk of cancer
associated with radiation exposure from 64-slice computed tomography coronary
angiography. JAMA, 298(3): 317–323.
Other Works Consulted
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Pearce MS, et al. (2012). Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: A retrospective cohort study. Lancet, 380(9840): 499–505.
U.S. Food and Drug Administration (2008).
FDA preliminary public health notification: Possible malfunction of electronic
medical devices caused by computed tomography (CT) scanning. Available online:
How this information was developed to help you make better health decisions.