A type of x-ray examination that uses a CT scanner to obtain multiple images of the spinal column, that can be changed by the computer after they have been acquired into three-dimensional images if needed. These detailed images may be examined on a computer or printed out like x-rays.
- Detect (or rule out) spinal damage in patients with injuries.
- Evaluate the spine before and after surgery.
- Detect various types of tumour in the vertebral column.
- Examine a narrowing spinal canal, a vertebral fracture, an infection, or degenerative disease such as arthritis.
- Find if spinal pain is related to a herniated intervertebral disk.
- Detect risks of osteoporosis.
- Guide procedures like a biopsy or abscess removal.
- Clothing: wear comfortable, loose-fitting clothing on your way to the imaging center. There, you will be given a hospital gown to put on. Any metal object must be removed before exam (jewellery, eyeglasses, dentures, hairpins, etc.).
- Fast: you may be asked not to eat or drink anything for several hours beforehand, especially if you are to receive contrast material which may be a drink be given an injection which in some cases is required to improve the image .
- Allergies: tell the physician or technologist if you have allergic reactions, especially to iodine which is often present in contrast material. Any history of heart disease, asthma, diabetes or thyroid problems also.
- Anxiety: if your infant or young child is to have spinal CT, there are measures that can be taken to ensure that the test will go smoothly and will not be a cause of anxiety for either the child or parent.
- Pregnancy: a woman of reproductive age should inform her physician or the technologist if there is any possibility that she is pregnant.
The CT scanner is a large unit with a hole, or tunnel, running directly through its center. The technologists helps the patient to lies on a table that can be moved up or down and that slides into and out of the center of the tunnel. The technologist then goes to an adjoining room watching through a window and/or by video camera throughout the procedure. An intercom system allows communication with the technologist.
In CT scanning, a source of x-rays and a set of electronic x-ray detectors rotate around the patient. The detectors absorb the x-rays that have passed through the patient and measure the amount of radiation. The information collected by the detectors is sent to a computer system that processes it and reconstructs two-dimensional cross-sectional images (the “slices”) of the body part. A single slice is recorded in only a few seconds. Modern spiral CT units produce high-quality images in a short time, for example the spinal column in just minutes.
CT scanning is carried out with the patient lying on his or her back. The technologist will make sure that you are properly positioned, and may use pillows to help you maintain a correct posture during the study. If indicated, a contrast material will be injected into an arm vein during the procedure so as to sharpen the images of various tissues. A scan of the lower spine may also be done after injecting contrast material into the spinal canal surrounding the spinal cord during a lumbar puncture. This will help to detect tumors or locate areas of inflammation or nerve compression. Initially the table will move rapidly through the scanner to determine the correct starting position. Further scans then are made as the table moves more slowly through the tunnel in the scanner.
CT scanning is painless, apart from a needle stick if an intravenous injection is needed. Discomfort comes mainly from having to lie still on the table for some time. Injection of contrast material may cause a slight burning feeling in the arm, a metallic taste, and warm flushing of the entire body. These all are normal reactions and usually end within a few seconds. Patients who have a hard time remaining still or who are claustrophobic may find CT to be stressful. The same may be the case for those who have chronic pain. If you are one of these patients, the technologist may give you a mild sedative to help get you through the exam.