During the 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 for blood flow and look for tumors, areas of inflammation, or nerve damage.
Why It Is Done
A CT scan of the spine is done to:
- Look at the bones of the spine (vertebrae).
- Find problems of the spine, such as tumors, fractures, deformities, infection, or narrowing of the spinal canal (spinal stenosis).
- Find a herniated disc of the spine.
- Check to see if osteoporosis has caused compression fractures.
- Check on problems of the spine that have been present since birth (congenital).
- Look at problems seen during a standard X-ray test.
- Check how well spinal surgery or therapy is working for a spine problem.
How To Prepare
In general, there's nothing you have to do before this test, unless your doctor tells you to.
Tell your doctor if you get nervous in tight spaces. You may get a medicine to help you relax. If you think you'll get this medicine, be sure you have someone to take you home.
How It Is Done
You 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 test.
You may have contrast material (dye) put into your arm through a tube called an IV.
During the test, you will lie on a table that is attached to the CT scanner.
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 scanning room. But a technologist will watch you through a window and talk with you during the test.
How long the test takes
The test will take about 30 to 60 minutes. Most of this time is spent getting ready for the scan. The actual test only takes a few minutes.
How It Feels
The test will not cause pain, but some people feel nervous inside the CT scanner.
If a medicine to help you relax (sedative) or dye is used, 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 small.
- There is a chance of an allergic reaction to the contrast material.
- If you breastfeed and are concerned about whether the contrast material used in this test is safe, talk to your doctor. Most experts believe that very little dye passes into breast milk and even less is passed on to the baby. But if you are concerned, you can stop breastfeeding for up to 24 hours after the test. During this time, you can give your baby breast milk that you stored before the test. Don't use the breast milk you pump in the 24 hours after the test. Throw it out.
- There is a small chance of an infection at the needle site on your spine or bleeding into the space around the spinal cord.
- There is a risk of damage to cells or tissue from being exposed to radiation, including the small amounts used in CTs, X-rays, and other medical tests. Over time, exposure to radiation may cause cancer and other health problems. But in most cases, the risk of getting cancer from being exposed to small amounts of radiation is low. It is not a reason to avoid these tests for most people.
Complete 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 are normal.
The spinal canal is normal in size and shape.
If contrast material is used, it flows evenly through the spinal canal. No narrowing or blockage of the spinal canal is present.
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 more herniated discs are found.
The flow of contrast material through the spinal canal is restricted or blocked, which may mean narrowing of the canal (spinal stenosis).
A condition that has been present from birth (congenital) is present in the spine or the vertebrae.
Current as of: April 5, 2022
Author: Healthwise Staff
Adam Husney MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
Howard Schaff MD - Diagnostic Radiology