MRI Scan

A Patient's Guide to MRI Scans of the Spine

What it is: The MRI scan is a fairly new test that does not use radiation. By using magnetic and radio waves, the MRI creates computer-generated images. The MRI is able to cut through multiple layers of the spine and show abnormalities of soft tissues, such as nerves and ligaments. The MRI is probably the most commonly used test for looking at the spine.

What the test shows: The MRI shows the spine in very clear detail. The test gives information about the bones, ligaments, muscles, and discs. The test also can be used to show early degeneration of the disc, such as the loss of water in the nucleus pulposus - the earliest stage of disc degeneration. The test can be used to show facet joint arthritis, spinal stenosis (narrowing of spinal canal), or a herniated disc (protrusion or rupture of the intervertebral disc). The test is useful for any condition where the anatomy of the spine and its soft tissue contents need to be seen clearly.

What the test does not show: There is not much the MRI does not show. However, X-rays are still best when fine detail about bones is needed. For problems that are related to fractures or bone destruction from infection or tumor, many spine specialists still rely on the CAT scan.

How the test is done: During an MRI scan, you will be asked to lie on a table that slides into a machine with a large, round tunnel. The machine's scanner then takes many pictures that are watched and monitored by a technician. The MRI scanner is noisy. You may be offered headphones to listen to music while the scan is taking place. The scanner is also pretty cramped; the tunnel that you lie in does bother some patients who are extremely claustrophobic. You may be given a mild sedative if you are claustrophobic to make the experience more tolerable. There are also some newer MRI machines called Open MRI Scanners that might be more comfortable for patients who experience claustrophobia. The procedure takes 30-60 minutes.

What risks the test has: The test uses magnetic waves; however, there appears to be no known risks associated with exposure to the waves. There are problems if you have any metal objects in your body that could be attracted to the strong magnetic field. For example, if you have some type of metal clip that was used for a previous surgery, you will want to inform the technician. You may also have X-rays taken of your skull before the test to make sure that there are no metal fragments in your eyes or brain that could move when the magnet is turned on.

What the test costs: A MRI scan of the spine usually has two costs associated with the test. The first cost is the fee for actually doing the test. This is called the "technical fee". The second cost is the fee of having a specialist, such as a radiologist, read and interpret the test. This is called the "professional fee". You may get two bills for this test: one from the hospital or clinic where you had the MRI scan done, and one from the specialist who read the test.

Copyright © 2003 DePuy Acromed.

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