How does an MRI scan work?
The MRI machine is a large, cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient.
The magnetic field, along with a radiofrequency, alters the hydrogen atoms' natural alignment in the body. Computers are then used to form a two-dimensional (2D) image 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 computed tomography (CT scans).
Another advance in MRI technology is the "open" MRI. Standard MRI units have a closed cylinder-shaped tunnel into which the patient is placed for the procedure. Open MRI units do not completely surround the patient, and some units may be open on all sides.
Open MRI units are particularly useful for procedures involving:
Children. Parents or other caregivers may stay with a child during the procedure to provide comfort and security.
Claustrophobia. Before the development of open MRI units, persons with severe claustrophobia often required a sedative medication prior to the procedure.
Very large or obese persons. Almost anyone can be accommodated in most open MRI units.