Magnetic Resonance Imaging

How does it work? MRI uses a powerful magnetic field along with radio waves (not X-rays) and a computer to produce highly detailed “slice-by-slice” pictures of virtually all internal structures of the body. The results enable physicians to examine parts of the body in minute detail and identify disease in ways that are not possible with other techniques. For example, MRI is one of the few imaging tools that can see through bone, making it an excellent tool for examining the brain and other soft tissue.

Patients must remain still during the imaging process. And because the scan takes place as the patient slides through a rather small tunnel in the machine, some people experience claustrophobia. In recent times, though, open MRI scanners have been developed for patients who are anxious or obese. Naturally, no metal objects such as pens, watches, jewelry, hairpins, and metal zippers as well as credit cards and other magnetically sensitive items are allowed into the examination room.

Risks: If a contrast fluid is used, there is a slight risk of allergic reaction, but the risk is less than that associated with the iodine-based substances commonly used with X-rays and CT scans. Otherwise, MRI poses no known risk to the patient. However, because of the effect of the strong magnetic field, patients with certain surgical implants or metal fragments from injuries may be unable to have an MRI. So if an MRI is recommended for you, be sure to tell your doctor and your MRI technologist if you have any of those things.

Benefits: MRI does not use potentially harmful radiation, and it is particularly good at detecting tissue abnormalities, especially those that may be obscured by bone.

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MRI