A CT scan uses
X-rays to make detailed pictures of the spine and vertebrae.
test, you will lie on a table that is attached to the CT scanner, which is a
large doughnut-shaped machine. The CT scanner sends X-rays through the body.
Each rotation of the scanner takes a second and provides a picture of a thin
slice of the organ or area being studied. One part of the scanning machine can
tilt to follow the curve of your spine. 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 spine is done to:
Before the CT scan, tell your doctor
Arrange for someone to take you home in case you get a
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
doctor (radiologist). Other doctors also may review a CT scan.
may need to take off any jewelry. You will need to take off all or most of your
clothes, depending on which area is studied. You may be able to wear your
underwear for some scans. You will be given a gown to use during the
During the test, you will lie on a table that is attached to
the CT scanner.
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
scanning room. But the technologist will watch you through a window. You
will be able to talk to the technologist through a two-way intercom.
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.
A standard CT
scan may be done before the contrast material for a CT
myelogram is given. The dye is usually put in the space around your spinal cord. A sample of
the fluid from the spinal canal (cerebrospinal fluid) may be taken out
so other tests can be done on it.
If dye is
placed in your back, you will lie on your stomach or on your side on a table. The dye is usually put in your lower
back but may be put in at the base of your skull. The skin over the site may be
shaved. It will be cleaned. The area around the site may be
numbed with medicine.
The table may be tilted or you may be moved
into different positions so the dye moves to different areas of the
You need to lie very still so the dye stays in the right
place for clear pictures. Your pulse, breathing rate, and blood pressure may be
checked during the test.
In some cases, the dye can also be put in
a vein (IV) in your arm.
A CT scan with contrast material
usually takes 15 to 30 minutes. Drink lots of liquids for
24 hours after the scan to help flush the dye out of your body.
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 you get medicine to help you relax or if contrast material is used, you may have an IV 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.
If you have
dye put in your back, you may feel a sting or pinch when the needle is put
After a test in which the dye is put in your back, you will be
told to keep your head up and to not bend over or lie flat. This will help
prevent headaches and
The chance of a CT scan causing a problem is
A computed tomography (CT) scan uses
X-rays to make detailed pictures of the
spine and vertebrae in the neck (cervical spine),
upper back (thoracic spine), or lower back (lumbosacral spine).
results usually are ready for your doctor in 1 to 2 days.
Spinal bones (vertebrae) are
normal in shape, number, and alignment.
The discs and joints that support the spine
The spinal canal is normal in size and
contrast material is used, it flows evenly through the
spinal canal. No narrowing or blockage of the spinal canal is
None of the nerves leaving the spinal cord
are compressed or pinched. No growths or bulges are present.
Spinal bones (vertebrae) are missing,
damaged, or out of alignment.
One or more discs may be damaged. One or
herniated discs are found.
The flow of contrast material through the
spinal canal is restricted or blocked, indicating narrowing of the canal (spinal stenosis).
The vertebrae show signs of
arthritis or bone problems caused by
A condition that has been present from
birth (congenital condition) is present in the spine or the vertebrae.
spinal tumor is found.
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.
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:
June 5, 2013
Adam Husney, MD - Family Medicine
& Howard Schaff, MD - Diagnostic Radiology
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