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Magnetic Resonance Imaging
(MRI)
Definition:
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Dr. White in front of the cardiac
MRI scanner
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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 uses the 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
How to prepare:
- If you are not claustrophobic (fear of
closed spaces):
- You will not require any sedation.
- Eat as usual.
- Take your medications as usual.
- If you are claustrophobic:
- You may ask your doctor to schedule
your MRI with sedation (a medication to help you relax).
- If you
take a sedative, you may not eat any solid food for six hours prior
to receiving your sedative to avoid nausea. You may have clear liquids
(apple juice, jello, black coffee or tea, water) up to two hours
prior to your medication time.
- You may take your regular medications
unless your doctor advises against it.
- For your safety, bring a companion
to drive you home.
- Take your regular medication with
sips of water
- If you do not require sedation, do
not request it.
- 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 (for example, the Zenith AAA Endovascular
Graft)
- Wear a shirt or blouse that can be easily
removed. Women should wear a bra that can be easily removed prior to
the examination. You may wear metal-free pants, such as sweatpants with
elastic bands, during the test. A gown will be provided. Leave these
items at home, if possible:
- metal zippers
- snaps
- watches
- wallets with bank or credit cards with
magnetic strips
What to expect:
- An MRI technologist will prepare you for
your scan.
- You will change into a hospital gown.
- The technologist will place small sticky,
electrode patches on your chest and back. Men may expect to have their
chest partially shaved to help the electrodes stick. The electrodes
are attached to an electrocardiograph (ECG) monitor, which charts your
heart’s electrical activity during the test.
- Most likely, an intravenous (IV) line
will be inserted into a vein in your arm for non-iodine based contrast
(dye) administration.
- The MRI scanner unit is a long tube that
scans the body as you lie on a platform bed. It is fully lit and ventilated,
and open at both ends. An intercom system allows you to talk to the
scanner operators during the test. You will lie on your back on the
scanner bed, with your head and legs elevated for comfort. During the
exam, you will be asked to lie as still as possible. The technologist
will ask you to hold your breath periodically for short periods in order
to reduce blurring of the images from breathing motion.
- During scanning, you may hear loud banging
noises, which can be muffled with headphones or earplugs you will receive
before scanning begins.
The MRI scan takes about 30 to 75 minutes,
depending on the extent of the imaging needed.
After the procedure:
- If you received sedation:
- The MRI nurse will give you instructions
on when you can eat, drink and return to normal activities.
- A companion should drive you home.
- If you did not receive sedation, you may
resume your usual activities and normal diet immediately.
- Your physician will discuss the results
of your test with you.
Please ask your doctor if you have any questions
about the MRI. To schedule an appointment, you or your doctor may contact:
800/223-2273, extension 57050.
Find
a Cleveland Clinic Heart Center doctor who performs this procedure
Click
here to learn more about Diagnostic Radiology: Cardiovascular Imaging
- MRI/CT
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