The Computer Assisted Tomography scan is often referred to as a CT or CAT scan to show fine details of bone. This scan is a series of fine slices of x-rays that are interpreted by a powerful computer that makes them appear as "slices" through the body. Software combines these images into a three-dimensional view of the bones, allowing each section of the spine to be separately examined. We can order slices to as small as 1mm cuts for fine reconstruction. The CT scan provides incredible detail of the bones, allowing visualization of bone spurs, fractures, damage to bone from infection or cancer, and healing status of fusion. This test does not show muscles, nerve roots, or ligaments clearly. In some cases this test is combined with a myelogram to see nerves and soft tissues more clearly. In a myelogram, dye is injected into the spinal sac to outline nerves.