Typically, magnetic resonance imaging (MRI) is an outpatient test performed at a hospital or clinic. Patients should closely follow their physician’s recommendations in preparing for the test. Usually, patients will be allowed to eat without restrictions and to take their usual medications. Once at the facility, patients may be asked to change into a gown or to wear clothing without fasteners, such as a sweatshirt and sweatpants.

It is important for the patient to remove all personal metal objects (e.g., jewelry, watches, hairpins, digital devices) prior to the test. Patients may want to leave these objects at home. Additionally, there should be no metal objects inside the room in which the MRI is being performed.

Certain types of implanted medical devices rule out the use of MRI.  These objects generally include (but are not limited to):

• Pacemakers
• Implantable cardioverter defibrillators (ICDs)
• Artificial hips, knees and other joints (in some cases)
• Inner ear (cochlear) implants
• Titanium implants in the mouth
• Aneurysm clip of the brain
• Neuromuscular stimulators
• Implanted drug infusion pump, such as a spinal pump or implantable insulin pump

MRI may be allowed with some types of medical devices, such as artificial joints and certain types of stents and heart valves. Sometimes a specified period of time must have elapsed. Such patients should inform the physician and get clearance before an MRI. If patients suspect that they have a metal device or fragment (such as from an injury) inside their body, an MRI might not be an option.

Sometimes MRI involves injection of a contrast medium (dye) into a vein in the arm or hand shortly before the procedure. This dye can increase the clarity of the images by making the body’s tissues more responsive to the machine’s magnetic and radio waves.