Often your diagnosis starts with an X-ray of your back. In conventional radiography, a beam of low-dose radiation is passed through your body to produce two-dimensional images of your spine. Muscles, ligaments and other soft tissue don't show up.
CT, or computerized tomography, is an X-ray technique that produces cross-sectional images, or slices, through a computer to provide a three-dimensional view inside your body. Some CT scans require use of a contrast agent, or dye, to highlight a particular area. Some patients may experience an allergic reaction to the dye, but that's not common.
MRI, magnetic resonance imaging, uses a magnetic field to make hydrogen protons emit radiofrequency signals that are processed into images whose detail reflects their water content. It's not an X-ray procedure.