How is the CT spine scan procedure performed?

In a CT spine scan, several x-ray beams pass through the spine at various angles. Special sensors measure the amount of radiation absorbed by different tissues within the spine, including lesions and tumours.

In order to undergo a CT spine scan, your general physician must write you a letter of referral stating why he or she believes a CT spine scan is necessary in your situation. A CT spine scan will take place in either a hospital or in an outpatient radiology center.

During a CT spine scan, the patient lies still on a table. The table is rolled into the center of the CT scanner. For the first few scans, the table will move rapidly through the scanner so that the technologists can determine the best starting position. Once this position has been determined, the next few scans are made as the table moves more slowly through the tunnel in the scanner. The CT scanner revolves around the patient and emits and records x-ray beams. The different areas of the spine absorb different amounts of x-ray. A special computer program then forms graphical cross-sections, or “tomograms,” based on these x-ray absorption differences.

The CT images represent the density of different tissues. Bone and other dense tissues appear white, while the spinal cord and other less dense tissues appear in shades of gray. The spinal canal, which encloses the cerebrospinal fluid, comes up dark gray.

Once the patient enters the scanner, the technologist may turn on special lights to ensure the patient is positioned properly for the CT spine scan. The patient should lie on his or her back for the duration of the CT spine scan. Though the technologist will not actually be in the room with the patient, an intercom within the scanner allows the patient and technologist to communicate throughout the procedure. The technologist will tell the patient when and how to breathe, as breath can disrupt the CT image.

The duration of the CT spine scan depends on the number of images needed to get the information the doctor requires. Typically, a CT spine scan session takes anywhere from 5 to 30 minutes, though most of this is set up and preparation time. The actual CT spine imaging takes a very short time. At the conclusion of the CT spine scan, the technologist will look over the images to ensure sufficient images have been created to provide the radiologist with the necessary information. If more images are necessary, the technologist will ask the patient to stay for further scanning.