- herniated discs (the most common cause of back pain)
- birth defects of the cervical spine in children
- tumors that may have originated in the spine or elsewhere in the body
- broken bones
A cervical spine CT (computed tomography) scan is a medical procedure that combines specialized X-ray equipment with computer imaging to create a visual model of your cervical spine. This is the portion of the spine that runs through the neck.
Your doctor may order this test if you have been in a recent accident or are suffering from neck pain. The exam can help more accurately diagnose potential injuries to that area of your spinal column.
The test may also be called a neck CT scan.
The most common reason for a spinal CT scan is to check for injuries after an accident. However, your doctor may also order the test to investigate:
It can also provide important information if you have certain bone diseases, such as arthritis or osteoporosis, by measuring your bone density. This can help your doctor determine the severity of your condition and identify any weakened areas that should be protected from fractures.
If your doctor is doing a biopsy (tissue removal) or removing fluid from an infected area in your cervical spine, he or she may use a CT scan of your neck as a guide during the procedure.
A CT scan of the neck may be done along with other tests, such as MRI scans or X-rays.
A regular X-ray directs a small amount of radiation into your body. Bones and soft tissue absorb radiation differently, so they show up in different colors on the X-ray film. Bones appear white, while your soft tissues and organs are grey. Any black area on your X-ray is air.
A CT scan functions in a similar way, but instead of one flat image, many X-rays are taken in a spiral. This provides more detail and accuracy.
Once you are inside the scanner, multiple X-ray beams move around your upper torso and neck in a circular motion, while electronic X-ray detectors measure the radiation your body absorbs.
A computer interprets that information to create separate images, or “slices.” These can then be combined to create a three-dimensional model of your cervical spine.
Although it sounds complicated, a CT scan only takes about 10 to 20 minutes.
In some cases, you will need to have an injection of contrast dye. This will help your doctor to clearly see certain areas of interest in your body. If your test requires dye, you will be given it through an intravenous (IV) line or through an injection near your spinal cord. A nurse or doctor will inject the dye before the test begins.
Once you are ready, you will lie—usually on your back—on an examination table that slides into a tunnel at the center of the CT scanner. Then, the table will move slowly through the scanner while the X-ray beams record images.
Any movement you make while inside the scanner can affect the CT images. You will need to stay still during the exam so that the images will be as clear as possible. A pillow and straps will sometimes be used to help you stay in place.
If you know you that have a hard time staying still or if you are claustrophobic, you may want to ask your doctor for a sedative. However, this is not usually necessary because the exam is brief.
While the scan itself is painless, you may notice some odd sensations—such as warmth in your body or a metallic taste in your mouth—immediately after receiving the contrast dye. That should fade within a few moments.
If your exam involves the use of contrast dye, you will need to make certain preparations beforehand. Be sure to tell your doctor if you have allergies or if you are diabetic. In rare cases, people have an allergic reaction to the dye. It can also cause a negative reaction if you take certain drugs to treat diabetes.
You should not eat or drink for four to six hours before your scan if you are receiving contrast dye.
It is generally recommended that CT scans not be performed during pregnancy unless the benefits of the scan out weight the risks. If you are pregnant, you will need clearance from your doctor before having this exam.
You will need to take off any metal objects—such as jewelry, piercings, or eyeglasses—and any hearing aids or removable dental work. These may affect your CT scan.
Some machines have a weight limit; so make sure to let your doctor know if you weigh more than 300 pounds.
As with any procedure involving exposure to radiation, there is a very slight risk of cancer from a CT scan. However, the exposure from any single scan is very low.
You should discuss your concerns with your doctor, particularly if you are pregnant. Overall, the benefits of diagnosing a serious cervical spine problem generally outweigh any risk from the radiation exposure.
Most patients have no issues with the contrast dye. For those who are allergic to the iodine that is commonly used in the dye, side effects may include nausea, vomiting, or hives. Reactions more serious than that are extremely rare.
After the test, you can change back into your regular clothes and go about your day right away. If you needed contrast dye for your test, you may want to drink a lot of water. This will flush the chemicals from your body.
Results from your CT scan may be available within 48 hours. Your doctor will review the images and determine how to proceed. Depending on your results, he or she may order additional imaging scans, blood tests, or other diagnostic measures to help get an accurate diagnosis.