Magnetic resonance imaging (MRI) is a noninvasive medical test that helps physicians diagnose and treat medical conditions.
Figure A shows the heart’s position in the body and the location and angle of the MRI images shown in figure C. Figure B is a MRI angiogram, which is sometimes used instead of a standard angiogram. Figure C shows MRI pictures of a normal left ventricle (left image), a left ventricle damaged from a heart attack (middle image), and a left ventricle that isn’t getting enough blood from the coronary arteries (right image).
MR imaging uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. The images can then be examined on a computer monitor, transmitted electronically, printed or copied to a CD. MRI does not use ionizing radiation (x-rays).
Detailed MR images allow physicians to better evaluate various parts of the body and determine the presence of certain diseases that may not be assessed adequately with other imaging methods such as x-ray, ultrasound or computed tomography (also called CT or CAT scanning).
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| Cardiac MRI unit. Credit: Philips |
Cardiac MRI uses a computer to create images of your heart as it’s beating, producing both still and moving pictures of your heart and major blood vessels. Doctors use cardiac MRI to get images of the beating heart and to look at the structure and function of the heart. These images can help them decide how best to treat patients with heart problems.
Cardiac MRI is a common test for diagnosing and evaluating a number of diseases and conditions, including:
- Coronary artery disease
- Damage caused by a heart attack
- Heart failure
- Heart valves problems
- Congenital heart defects
- Pericardial disease (a disease that affects the tissues around the heart)
- Cardiac tumors
Cardiac MRI images can help explain results from other tests, such as X-ray and CT scans. Cardiac MRI is sometimes used to avoid the need for other tests that use radiation (such as X-rays), invasive procedures, and dyes containing iodine (these dyes may be harmful to people who have kidney problems).
Sometimes during cardiac MRI, a special dye is injected into a vein to help highlight the heart or blood vessels on the images. Unlike the case with X-rays, the special dyes used for MRI don’t contain iodine, so they don’t present a risk to people who are allergic to iodine or have kidney problems.