Magnetic Resonance Imaging (MRI) uses radio wave energy and a strong magnetic field, rather than X-rays, to take clear and detailed pictures of organs, soft tissues, bone and virtually all other internal body structures.
What can a cardiovascular MRI tell my doctor?
Cardiac MRI is used to diagnose and evaluate a number of diseases and conditions, including:
- Damage caused by a heart attack
- Heart failure
- Heart valve problems
- Congenital heart defects
- Pericarditis (a condition in which the membrane, or sac, around your heart is inflamed)
- Cardiac tumors
It can also be used to:
- Evaluate heart muscle thickness and function and heart size.
- Assess if heart function may be improved by bypass surgery or angioplasty.
- Evaluate structures around the heart, such as the aorta, pulmonary arteries and pericardium (membrane around the heart).
How do I prepare for my exam?
Guidelines about eating and drinking before an MRI exam vary. For some types of exams, you will be asked to fast for 3 hours.
Patients may be required to receive an injection of contrast material. Some conditions, such as severe kidney disease may prohibit the use of contrast material. Women should inform their physician if there is any possibility that they are pregnant.
If you are claustrophobic or anxious, you may want to ask your physician for a prescription for a mild sedative to take in advance of your exam.
Jewelry and other accessories should be left at home before the MRI scan because they can interfere with the magnetic field of the MRI unit.
It is important for us to know if you have any metal in your body before your MRI scan is performed. The MRI uses a very strong magnet that may create movement of certain metal objects in your body.
In most cases, an MRI exam is safe for patients for metal implants, except for a few types. Patients with the following implants cannot be scanned and should not enter an MRI scanning area unless explicitly instructed to do so by a radiologist or technologist who is aware of the presence of any of the following:
- Pacemaker or Automatic Implantable Cardioverter Defibrillator (AICD).
- Some types of metal coils placed within blood vessels.
- Any implanted mechanical or electrical device (i.e. cochlear or stapes ear implant, magnetic dentures, spinal stimulator, etc.).
- Some types of brain aneurysm clips.
Knowing the make and model of the implanted device is helpful.
How is the test performed?
Patients will change into a gown and remove all metallic objects. Electrodes will be attached to the chest to monitor heart rhythm. Once you are lying down on an imaging table, an imaging coil will be secured over your chest.
If a contrast material will be used in the MRI exam, a nurse or tech will insert an IV line into a vein in your arm. A saline solution may be used to prevent blockage of the IV line until the contrast material is injected.
Once that is set up, you will then be moved into the MRI scanner. Your healthcare providers will make you as comfortable in the scanner as possible.
For the most part, patients will lie quietly while the scan is taking place. You may be asked to hold your breath for a few seconds when pictures are taken of your heart. You will know when images are being recorded because you will hear tapping or thumping sounds when the coils that generate the radiofrequency pulses are activated.
The entire examination is usually completed within one to three hours once imaging has started.
Are there risks?
A cardiac MRI test is safe. Patients are not exposed to radiation and side effects are rare.
How will I find out the results?
A cardiologist will review your test and provide a report to your physician.