In just a few decades, the use of magnetic resonance imaging (MRI) scanners has grown tremendously. Doctors may order MRI scans to help diagnose multiple sclerosis, brain tumors, torn ligaments, tendonitis, cancer and strokes, to name just a few.

Magnetic resonance imaging (MRI) is a noninvasive way to take pictures of the body.An MRI scan is the best way to see inside the human body without cutting it open.

Unlike x-rays and computed tomographic (CT) scans, which use radiation, MRI uses powerful magnets and radio waves. The MRI scanner contains the magnet. The magnetic field produced by an MRI is about 10 thousand times greater than the earth's.

The magnetic field forces hydrogen atoms in the body to line up in a certain way (similar to how the needle on a compass moves when you hold it near a magnet). When radio waves are sent toward the lined-up hydrogen atoms, they bounce back, and a computer records the signal. Different types of tissues send back different signals.

Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images.

You may not be able to have an MRI if you have any of the following metallic objects in your body:
    Brain aneurysm clips
    Certain artificial heart valves
    Inner ear (cochlear) implants
    Recently placed artificial joints
    Some older types of vascular stents