Magnetic resonance imaging (MRI) is a medical technique that uses magnetic fields and radio waves to generate detailed images of the body. MRIs are a non-invasive option to help your doctor gain insight into your health. Healthcare professionals use an MRI to diagnose a variety of conditions that affect the body, including the brain, spinal cord, muscles, and ligaments. Because an MRI does not use radiation, it provides an ideal option for routine monitoring of conditions throughout the different stages of life including pregnancy.