Magnetic resonance imaging, or MRI, uses magnets, radio waves and computers to see detailed images of the internal structures of the body. This technology can be used to diagnose trauma, strokes, problems with the aorta and problems with soft tissues. There are two main types of MRI machines ― open and closed. They both have a top over the patient. The main difference is in their size and how much the machine surrounds the patient. A closed machine has a smaller and more narrow tube and provides the best images.
An open MRI machine is open on three sides, making it more comfortable for the patient. However the images produced by the open MRI may not be as good since the magnet is not traveling around the whole body. A closed machine is the preferred type of MRI by physicians because of its more accurate pictures. However due to the fact that the top of the machine is just inches above a patient’s face and the patient is encircled by the machine, it can be uncomfortable for many patients and create feelings of claustrophobia.
In addition, a closed MRI machine can only be used to scan patients that weigh less than three hundred pounds. With an open MRI, the magnets do not circle around the patient’s body so its imaging capabilities are more limited. Open machines can accommodate patients that weigh up to four hundred and fifty pounds.
With advances in technology there are now also MRI’s that allow the patient to sit or stand in the machine so that the physician can see the effects of weight bearing on the body. For example, a patient’s pain or pressure may subside as the patient lies down in an open or closed MRI but may be better detected when he or she is sitting or standing.