Traditional MRIs require patients to endure loud noises in a tightly enclosed tunnel. Because not everyone can tolerate such conditions, open MRIs were developed for people who have claustrophobia or otherwise cannot comfortably be scanned using a regular MRI machine, according to the National Institute of Biomedical Imaging and Bioengineering.
MRI stands for magnetic resonance imaging, and both types create detailed 3D images without harmful radiation. While one may still feel enclosed from above and below in an open MRI machine, the sides of the patient's body remain unconfined. The NIBIB reports that the open setup is less likely to trigger claustrophobia and can better accommodate a larger body.