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.
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A CT scan of the head is done
CT scans of the eyes, facial area, and sinuses may be done
Before the CT scan, tell your doctor
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?).
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.
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
A computed tomography (CT) scan uses
X-rays to make detailed pictures of structures inside the body.
results usually are ready for your doctor in 1 to 2 days.
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.
aneurysm is present.
The openings in the brain
(ventricles) through which
cerebrospinal fluid flows into the spine are enlarged.
An area of the brain shows swelling (edema) or other
changes that may mean a
sinuses are filled with fluid or have a thick
The following may stop you from
having the test or may change the test results:
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.
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: http://www.fda.gov/cdrh/safety/071408-ctscanning.html.
June 13, 2011
Adam Husney, MD - Family Medicine
& Howard Schaff, MD - Diagnostic Radiology
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