A spine MRI uses powerful magnets and radio waves to photograph the structures that make up the spine, the spinal cord, and the spaces between the vertebrae through which the nerves travel. After plain x-rays of the spine, MRI is the next least-invasive imaging test for neck or back pain and radiating arm and leg pain.

Unlike conventional x-rays and computed tomography (CT) imaging, which make use of potentially harmful radiation to generate images, an MRI is based on the magnetic properties of atoms in the patient's body. A powerful magnet generates a magnetic field roughly 10,000 times stronger than that of the Earth. A small percentage of hydrogen atoms within the body align with this field. Radio wave pulses are broadcast toward the hydrogen atoms in tissues of interest, returning a signal. The subtle differing characteristics of that signal from different tissues enable MRI to differentiate between various organs, and to potentially provide contrast between benign and malignant tissue. MRI is excellent at showing degenerative changes, such as arthritis, which may narrow the spaces through which the spinal nerves travel. In addition, MRI can determine disease of the spinal discs between vertebral levels that may be bulging and compress either the spinal cord or a nerve. For more information, please visit UCLA Radiology.