Magnetic resonance imaging (MRI) is a procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray without radiation. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, bones and organs. Other MRI systems include NMRI and fMRI.