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Computed Tomography (CT) Scan

What is it?

The CT or "CAT" scan is an X-ray test that shows bones and soft tissues. The abbreviation "CAT" stands for Computer Assisted Tomography. X-rays are taken and then interpreted by a powerful computer that makes them appear as "slices" through the body. Special software can combine these images into a three-dimensional view of the bones.

Why is it done?

The "slices" produced by a CT scan allow each section of the spine to be examined separately. The images show details of the bones that comprise the spine in great detail. A CT scan can show whether bone spurs are pushing against spinal nerve roots. It is often used when looking at spinal fractures or bones that have been damaged by infection or cancer. Some doctors have recently begun using CT scan technology on a limited basis to test for osteoporosis in the spine.

How is it done?

A CT scan is similar to having an MRI test. You will be asked to lie on a table that slides into a scanner. The scanner used for CT scans is essentially an X-ray tube that rotates in a circle. You will need to lie very still while the scanner takes many pictures. The procedure takes 30-60 minutes.

What are the limitations?

The CT scan does not show muscles or ligaments clearly. To make the nerves and soft tissues easier to see, this test is often combined with a myelogram.

What are the risks?

The CT scan uses X-rays. In large doses, radiation from the X-rays can increase the risk of cancer. The vast majority of patients who have a CT scan will never get enough radiation to worry about it causing cancer. Only patients who must have large numbers of X-rays or CT scans - hundreds over many years - need to be concerned. Children, and young adults who plan to have children, should be protected from radiation exposure to the testicles and ovaries because the radiation may damage the sperm and eggs. The person performing the CT scan will usually protect these areas for you by shielding them with a lead apron or lead blanket.

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