Computed tomography is an imaging test that uses X-rays and a computer to make detailed
images of the body. A CT scan shows details of the bones, muscles, fat, and organs.
CT scans are more detailed than standard X-rays.
In standard X-rays, a beam of
energy is aimed at the body part being studied. A plate behind the body part captures
the variations of the energy beam after it passes through skin, bone, muscle, and
tissue. While healthcare providers can get much information from a standard X-ray,
doesn’t give a lot of detail about internal organs and other structures.
In a CT scan, an X-ray beam moves
in a circle around the body. This allows many different views of the same organ or
structure. The X-ray information is sent to a computer that interprets the X-ray data
and displays it in a 2-D form on a monitor.
CT scans may be done with or
without contrast. Contrast refers to a substance taken by mouth or injected into an
(intravenous) line that causes the particular organ or tissue under study to show
more clearly on the scan.
CT scans of the spine can provide
more detailed information about the bones of the spine (vertebrae), the disks between
the vertebrae, and other spinal structures and tissues than standard X-rays of the
spine. CT scans can give healthcare providers more information related to injuries
diseases of the spine.
A CT scan of the spine may be used
to check the spine for:
- A herniated disk
- Tumors or other lesions
- Structural problems, such as spina bifida. This is a problem
with the spine a person is born with (congenital)
- Blood vessel problems
A CT scan may be done when another type of exam, such as an X-ray, MRI, or physical
exam, doesn’t give enough information.
A CT of the spine may also be used to assess the effects of treatment of the spine,
such as surgery or other therapy.
There may be other reasons for your healthcare provider to recommend a CT scan of
You may want to ask your healthcare
provider about the amount of radiation used during the CT scan and the risks related
your particular situation. Radiation from CT scans varies, but it may be up to 100
greater than a normal chest X-ray. It’s a good idea to keep a record of your radiation
exposure, such as previous CT scans and other types of X-rays, so that you can tell
provider. Risks linked to radiation exposure may be related to the number of X-ray
or treatments over a long period.
Tell your provider if you’re
pregnant or think you may be. Radiation exposure during pregnancy may lead to birth
defects. If you need to have a CT of the spine, special precautions will be taken
reduce the radiation exposure to the fetus.
If you’re breastfeeding, talk with
your provider about delaying breastfeeding after getting contrast. There are conflicting
recommendations on this topic.
If contrast dye is used, there is a
risk for allergic reaction to the dye. Tell your provider if you’re allergic to or
sensitive to medicines, contrast, or iodine. Most people won’t have any problems from
contrast dye. But tell your provider if you’ve ever had a reaction to any contrast
Having a seafood allergy won’t stop you from getting contrast.
Tell your provider if you have any
kidney problems. In some cases, the contrast dye can cause kidney failure. People
kidney disease are more likely to have kidney damage after contrast exposure.
There may be other risks depending
on your specific health condition. Talk about any concerns with your provider before
- The CT technologist will explain the
test and you can ask questions.
- If your CT scan involves the use of
contrast dye, you’ll be asked to sign a consent form that gives permission to do the
scan . Read the form carefully and ask questions if anything is unclear.
- Tell the technologist if you’ve ever
had a reaction to any contrast dye or if you’re allergic to iodine.
- You don’t usually need to fast before
a CT scan, unless a contrast dye is to be used. Your healthcare provider will give
you special instructions ahead of time if contrast is to be used and you need to
- Tell your provider about all
prescription and over-the-counter medicines, vitamins, herbs, and supplements you’re
- Tell your provider about any recent illnesses or other health
conditions you have, such as heart disease, kidney disease, asthma, diabetes, or
thyroid problems. These can increase the risk for problems.
- Tell the technologist if you’re
pregnant or think you may be.
- Tell the technologist if you have any
body piercings on your chest or stomach.
- If you’re claustrophobic, talk about
taking medicine before the test with your provider.
- Your provider may have other
instructions on how to get ready.
CT scans can be done on an outpatient basis or as part of your hospital stay. Steps
may vary depending on your condition and your healthcare provider’s practices.
Generally, a CT scan of the spine follows this process:
- You’ll be asked to remove any
clothing, jewelry, or other objects that may interfere with the test, such as
eyeglasses, hairpins, dentures, and possibly hearing aids.
- If you’re asked to remove clothing,
you’ll be given a gown to wear.
- If you’re to have a scan done with
contrast, a healthcare professional will start an IV (intravenous) line in your hand
or arm for injection of the contrast dye.
- You’ll lie on a narrow table that
slides into a large, circular opening of the ring-shaped scanning machine. Pillows
and straps may be used to help keep you still during the scan.
- The technologist will be in another
room where the scanner controls are located. But you’ll be in constant sight of the
technologist through a window. Speakers inside the scanner will allow the
technologist to talk with you and hear you. You’ll have a call button so that you
let the technologist know if you have any problems during the scan. The technologist
will be watching you at all times and will be in constant communication.
- The scanner will start to rotate
around you and X-rays will pass through your body for short amounts of time. You’ll
hear clicking and whirring sounds, which are normal.
- The X-rays absorbed by the body’s tissues will be detected by the scanner and transmitted
to the computer. The computer will transform the information into an image to be interpreted
by the radiologist.
- It will be important for you to stay very still during the scan. You may be asked
to hold your breath for a short time at various times during the scan.
- If contrast dye is used, you’ll be
removed from the scanner after the first set of scans has been completed. A second
set of scans will be taken after the contrast dye has been given.
- If contrast dye is used, you may feel some effects when the dye is injected into the
IV line. These effects include a warm flushing sensation, a salty or metallic taste
in the mouth, a brief headache, or nausea. These effects usually only last for a few
- Tell the technologist if you feel any breathing difficulties, sweating, numbness,
or heart palpitations.
- When the test has been completed,
you’ll be removed from the scanner.
- If an IV line was inserted, it will be removed.
- You may be asked to wait for a short time while the radiologist examines the scans
to make sure they are clear.
While the CT test itself causes no pain, having to lie still for the length of the
test might be uncomfortable, particularly if you’ve recently been injured or had surgery.
The technologist will use all possible comfort measures and complete the test as quickly
as possible to minimize any discomfort or pain.
If contrast dye was used, you may be watched for a period for any side effects or
reactions to the contrast dye, such as itching, swelling, rash, or trouble breathing.
Tell the radiologist or your healthcare provider right away if you notice any of these
If you notice any pain, redness, or
swelling at the IV site after you go home, tell your provider as this could be a sign
infection or other type of reaction.
Otherwise, there is no special type
of care needed after a CT scan of the spine. You may go back to your usual diet and
activities unless your provider tells you differently.
Your provider may give you other
instructions after the test, depending on your situation.
Before you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or
- What results to expect and what they mean
- The risks and benefits of the test or procedure
- What the possible side effects or complications are
- When and where you are to have the
test or procedure
- Who will do the test or procedure and what that person’s qualifications are
- What would happen if you did not have
the test or procedure
- Any alternative tests or procedures to think about
- When and how you will get the
- Who to call after the test or procedure if you have questions or problems
- How much :you will have to pay for the
test or procedure