Magnetic resonance imaging (MRI) is a radiological study that obtains images with magnets and radio waves. Unlike X-rays and CT scans, MRI uses no radiation. There are three types of MRI machines: closed, open and standing. Closed and open are most commonly used.
Closed MRIs are the oldest type of MRI machines. During the procedure, the patient lies down on a table, which slides into a large tube. The patient is asked to lie very still during the test. The procedure usually lasts about 30-45 minutes.
Open MRI is built in a "C" shape configuration. The patient can slide in and out on the side and never be fully enclosed in the machine. Apart from these differences, the technique is performed in the same way as the closed MRI.
Doctors usually use closed MRIs as a first choice. However, if the patient is too large for a closed machine, an open MRI is an option. Claustrophobic patients can also benefit from the use of an open MRI.
Early open MRI machines were not able to produce the same quality scans as closed MRIs. However, newer technology has been developed so that images produced by open MRIs are comparable to closed MRI films.
Patients who have pacemakers or aneurysm clips should not have MRIs. If you have a metal implant, speak with your physician or the radiological staff before having an MRI performed.