A computed tomography (CT) scan uses X-rays to make detailed pictures of the spine and vertebrae in the neck (cervical spine), upper back (thoracic spine), or lower back (lumbosacral spine).

The spine is made of 33 bones, and most of the bones have discs that act as cushions in between the bones. The spinal cord is surrounded by the bones of the spine (vertebrae) and a sac holding cerebrospinal fluid (CSF).

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 (contrast material) may be put in a vein (IV) in your arm or into the spinal canal (intrathecally). The dye make structures and organs easier to see on the CT pictures. The dye may be used to check blood flow and to look for tumors, areas of inflammation, or nerve damage.

See CT images of the cervical spine.

Why It Is Done

A CT scan of the spine is done to:

• Look at the bones of the spine (vertebrae).
• Find problems of the spine, such as tumors, fractures, deformities, infection, or narrowing of the spinal canal (spinal stenosis).
• Find a herniated disc of the spine.
• Check to see if osteoporosis has caused compression fractures.
• Check on problems of the spine that have been present since birth (congenital).
• Look at problems seen during a standard X-ray test.
• Check how well spinal surgery or therapy is working for a spine problem.