A CT scan uses X-rays to make detailed pictures of the spine and vertebrae.
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 blood flow and look for tumors, areas of inflammation, or nerve damage.
A CT scan of the spine is done to:
Before the CT scan, tell your doctor if you:
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?).
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.
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 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 spine.
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 scanner.
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 in.
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 seizures.
The chance of a CT scan causing a problem is small.
The radiologist may discuss the CT scan with you right after the test. 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, indicating narrowing of the canal (spinal stenosis).
A condition that has been present from birth (congenital condition) is present in the spine or the vertebrae.
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.
|Primary Medical Reviewer||Adam Husney, MD - Family Medicine|
|Specialist Medical Reviewer||Howard Schaff, MD - Diagnostic Radiology|
|Last Revised||June 13, 2011|
Last Revised: June 13, 2011
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