What’s it for?
Cardiac magnetic resonance imaging, or cardiac MRI is a test that produces high-quality still and moving pictures of the heart and great vessels. MRI uses large magnets and radio-frequency waves to produce pictures of the body’s internal structures; no x-ray exposure is involved. MRI acquires information about the heart as it is beating; creating moving images of the heart throughout its pumping cycle.
Your doctor may use an MRI to evaluate:
- The anatomy and function of the structures of the chest: heart, great vessels and pericardium.
- Presence of disease: ischemic heart disease, thoracic aortic disease, pericardial disease, right ventricular abnormalities, cardiac tumors, valve disease, heart muscle disease (cardiomyopathy), pulmonary artery disease and complex congenital heart disease.
Who should avoid an MRI?
The MRI uses powerful magnets to create its images. For your safety, anyone undergoing a scan should be free of certain metallic or magnetic items. Inform the MRI staff if you have any metallic implants or any metal under the skin. Most metallic implants, such as sternal wires and mediastinal clips used for heart surgery, pose no problem. However, some conditions may make an MRI inadvisable.
Tell your doctor if you have any of the following conditions:
- Implanted pacemaker or defibrillator
- Cerebral aneurysm clip (metal clip in a blood vessel in the brain)
- Pregnancy
- Implanted insulin pump, narcotic pump or implanted nerve stimulators (TENS) for back pain
- Metal in the eye or eye socket
- Cochlear (ear) implant for hearing impairment
- Some stents – while most stents are safe, some stents may not be.
How it’s done
A cardiac MRI is performed in a specially designed room. The MRI equipment itself consists of a large machine that creates a strong magnetic field. Because of this magnetic field, patients with pacemakers or other metal articles in their body cannot have MRIs.
During an MRI, you lay on a table which then moves within the magnetic field. Radio waves are used to create pictures of your heart and other tissues. These pictures are then examined by your doctor for any abnormalities.
A cardiac MRI is a totally noninvasive test. No x-ray exposure is involved.
The MRI scan takes about 30 to 75 minutes, depending on the extent of the imaging needed.