An MRI is a very useful tool for helping your doctors see images of the inside of your body, including tissue that can't be seen on a conventional x-ray.

Before your exam, it's very important to fill out the safety screening form carefully. MRI is safe and painless. But metal in the scanner can cause serious safety problems or reduce the quality of the images.

Your health care team needs to know about any metal in your body, even a small shard of metal from an accident. Fillings, bridges, and other dental work typically do not pose a problem. But other metal that has been put into your body might prevent you from having an MRI. That includes some pacemakers, clips for treating aneurysms, and other devices with metal in them.

A nurse may review your health history before your exam. You may be given medications or contrast dye or have blood drawn. Be sure to tell the nurse if you're pregnant, have an allergy to contrast dye, or have kidney or liver problems. You may not wear clothing with snaps or zippers in the scanner. You will be asked to wear a gown. Do not wear any jewelry or bring anything metal into the scanner, including a hearing aid.

An MRI machine uses a powerful magnet to make images of your body. Unlike a CT scan, it does not use x-rays or other radiation. You will be given earplugs. The scanner makes a loud noise when it's operating.

A device called a coil may be put on or around the area to be scanned to help capture the images. You will also be given a squeeze ball to hold. You can use this to signal the technologist any time you need something. The MRI is controlled from a nearby room. You will be closely observed throughout the procedure.

A series of scans are taken with a brief pause between each. You may hear different noises as different scans are taken. It's normal for the noise to be very loud. You need to remain still when the scan is being taken.

People are typically in the scanner from 30 to 50 minutes, depending on the images to be taken. A complex examination can take longer. If you are concerned about being in the scanner for this length of time, talk to your physician and the technologist. They can help you with some tips for staying comfortable.

If you need to be removed from the scanner, this can be done very quickly. The ends of the scanner are always open.

After your exam, the images will be reviewed by your radiologist. He or she will send a report to the health care provider who ordered the test. Ask your health care provider any questions you have about your MRI.