Magnetic resonance imaging (MRI) is a safe and painless test that produces clear cross-sectional or three-dimensional images of the body’s tissues, even through bone and other structures. Because of its safety and clarity, the MRI is a valuable tool that can aid in the diagnosis of a wide range of conditions.

The standard MRI usually requires no advance preparation, though some patients may need to adjust their medications if contrast medium (dye) will be used in the scan. The contrast medium helps increase the visibility of organs and tissues for a more detailed image. If a contrast medium is used, it is injected into the patient’s vein prior to the test.

An MRI  relies on a large magnetic field, therefore, certain people should avoid the test. These include patients with implanted pacemakers, implantable cardioverter defibrillators (ICDs), artificial joints or some of the older mechanical valves. Patients with some mechanical valves and coronary or other stents should consult with a cardiologist or cardiac surgeon to determine when they can undergo MRIs.

In all cases, patients should inform the physician or technician of any other metal objects present in their bodies. Also, pregnant women should generally avoid MRI because the risk to the developing fetus is unknown. However, there may be some instances when an MRI is warranted in high-risk pregnant patients.

An MRI may require up to an hour in a tight space. Patients who are nervous in small spaces may wish to ask their physician about receiving a sedative during the procedure. If patients receive a sedative, they may need someone to take them home from the test. Otherwise, patients are free to go about their daily activities, such as driving, after the test is completed.

The MRI is a valuable tool for physicians. Among other conditions, it can help detect or diagnose cardiovascular problems, including:

Depending on the results of the MRI, additional tests may be necessary.