"Magnetic Resonance Imaging (MRI) is a diagnostic procedure that uses a combination of a large magnet, radio frequencies 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, to assess blood flow, to detect tumor and diagnose many forms of cancer, to evaluate infections, and to assess injuries to bones and joints.

MRI can be performed on an outpatient basis, or as part of inpatient care. The MRI machine is a large, cylindrical (tube-shaped) machine that creates a strong magnetic field around you. This magnetic field, along with a radio frequency, alters the hydrogen atoms' natural alignment in your body. Computers are then used to form 2-dimensional images of a body structure or organ based on the activity of the hydrogen atoms. Cross-sectional views can be obtained to reveal further details. MRI does not use radiation, as do x-rays or CT scans."

https://www.chifranciscan.org/health-care-services/diagnostic-imaging-radiology-services/tests-and-procedures/magnetic-resonance-imaging--mri-.html