A magnetic resonance imaging, or MRI, scan produces clear images of the shoulder by using strong magnets, radio frequency pulses and a computer, explains RadiologyInfo. During the test, a patient lies still on a movable table and slides into the center of a cylinder-shaped MRI machine.
MRI does not use ionizing radiation like traditional X-ray examinations or computed tomography scans, notes RadiologyInfo. Radio waves change the alignment of hydrogen atoms naturally present in the body without triggering chemical changes in the tissues. The hydrogen atoms produce varying levels of energy as they resume their normal alignment. The MRI machine monitors the energy and produces an image of the scanned tissues.
MRI machines typically generate a powerful magnetic field by sending an electric current through wire coils, states RadiologyInfo. Other coils in the unit produce signals by sending and receiving radio waves. The wire coils detect these signals, and then a computer in a different room processes the imaging information and creates images that each display a small section of the body.
Compared to X-ray, ultrasound and CT tests, an MRI scan is often a better method to differentiate abnormal tissues from normal tissues, RadiologyInfo explains. This noninvasive medical test can diagnose a wide variety of conditions, especially muscle and bone abnormalities. It also helps identify if a patient needs surgery for a shoulder injury.