Medical Content Created by the Faculty of the
Harvard Medical School
CT scans are pictures taken by a specialized x-ray machine. The machine circles your body and scans an area from every angle within that circle. The machine measures how much the x-ray beams change as they pass through your body. It then relays that information to a computer, which generates a collection of black-and-white pictures, each showing a slightly different "slice" or cross-section of your internal structures. A CT scan of the back may view one or more of the three areas of the spine: the cervical spine (neck), thoracic spine (middle back), and lumbar spine (lower back).
Doctors can use a CT scan of the spine to examine the vertebrae in the spine for fractures, arthritis, or pinching of the nerves or spinal cord (spinal stenosis). Occasionally, doctors x-ray the pelvis to help diagnose the cause of back pain.
A CT scan of the spine can be combined with a test called a "myelogram" (discussed separately) to give a clear view of the spinal cord and places where the vertebral bones might be pinching it.