Risks

Because MRI uses powerful magnets, the presence of metal in your body can be a safety hazard if attracted to the magnet. Even if not attracted to the magnet, metal objects can distort the MRI image. Before having an MRI, you'll likely complete a questionnaire that includes whether you have metal or electronic devices in your body.

Unless the device you have is certified as MRI safe, you might not be able to have an MRI. Devices include:

• Metallic joint prostheses
• Artificial heart valves
• An implantable heart defibrillator
• Implanted drug infusion pumps
• Implanted nerve stimulators
• A pacemaker
• Metal clips
• Metal pins, screws, plates, stents or surgical staples
• Cochlear implants
• A bullet, shrapnel or any other type of metal fragment
• Intrauterine device

If you have tattoos or permanent makeup, ask your doctor whether they might affect your MRI. Some of the darker inks contain metal.

Before you schedule an MRI, tell your doctor if you think you're pregnant. The effects of magnetic fields on fetuses aren't well understood. Your doctor might recommend an alternative exam or postponing the MRI. Also tell your doctor if you're breast-feeding, especially if you're to receive contrast material during the procedure.

It's also important to discuss kidney or liver problems with your doctor and the technologist, because problems with these organs might limit the use of injected contrast agents during your scan.