MRI (magnetic resonance imaging) is a diagnostic procedure that uses a combination of a large magnet, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. An MRI is often used to examine the heart, brain, liver, pancreas, male and female reproductive organs, and other soft tissues. It can assess blood flow, detect tumors and diagnose many forms of cancer, evaluate infections, and assess injuries to bones and joints.