Chest MRI (magnetic resonance imaging) is a safe, noninvasive test. "Noninvasive" means that no surgery is done and no instruments are inserted into your body. This test creates detailed pictures of the structures in your chest, such as your chest wall, heart, and blood vessels.
Chest MRI uses radio waves, magnets, and a computer to create these pictures. The test is used to:
As part of some chest MRIs, a substance called contrast dye is injected into a vein in your arm. This dye allows the MRI to take more detailed pictures of the structures in your chest.
Chest MRI has few risks. Unlike a CT scan or standard x ray, MRI doesn't use radiation or pose any risk of cancer. Rarely, the contrast dye used for some chest MRIs may cause an allergic reaction or worsen kidney function in people who have kidney disease.
Chest MRI also may be called chest nuclear magnetic resonance.
Your doctor may recommend chest MRI if he or she thinks you have a chest condition, such as:
Researchers are exploring ways to use chest MRI to study blood flow in the lungs. The test may help detect early signs of pulmonary hypertension (PH). PH is increased pressure in the pulmonary arteries. These arteries carry blood from your heart to your lungs to pick up oxygen.
Your doctor or an MRI technician will ask you some questions before the test, such as:
Your answers will help your doctor decide whether you should have chest MRI.
Your doctor or technician will ask you to not wear or bring metal, electronic, or magnetic objects into the MRI room. Examples include:
MRI magnets can damage these objects, or the objects may interfere with the MRI machine.
The MRI machine looks like a long, narrow tunnel. During the MRI, you lie on your back on a sliding table. The table passes through the scanner as it takes pictures of your chest. Newer machines are shorter and wider and don't completely surround you; others are open on all sides.
Tell your doctor if you're afraid of tight or closed spaces. He or she may give you medicine to help you relax, or find you a place that has an open MRI machine.
If you receive medicine to relax you, your doctor may ask you to stop eating about 6 hours before you take it. This medicine may make you tired, so you'll need someone to drive you home.
Your doctor may inject a substance called contrast dye into a vein in your arm before the MRI. You may feel some discomfort where the needle is inserted. You also may have a cool feeling as the dye is injected.
Contrast dye allows the MRI to take more detailed pictures of the structures in your chest. The dye used for chest MRIs doesn't contain iodine, so it won't create problems for people who are allergic to iodine. Rarely, people develop allergic symptoms from the dye, such as hives and itchy eyes. If this happens, your doctor can give you medicine to relieve your symptoms.
If you're breastfeeding, ask your doctor how long you need to wait after the test before you breastfeed. The contrast dye can be passed to your baby through your breast milk.
You may want to prepare for the test by pumping and saving milk for 24 to 48 hours in advance. You can bottle-feed your baby in the hours after the test.
Chest MRI usually is done at a hospital or at a special medical imaging facility. A radiologist or other doctor with special training in this type of test oversees the testing.
Chest MRI usually takes 45 to 90 minutes, depending on how many pictures are needed. The test may take less time with some newer MRI machines.
Chest MRI is painless and has few risks. During the test, you lie on your back on a sliding table as it passes through the MRI machine. A technician will control the machine from the next room. He or she will be able to see you through a glass window and talk to you through a speaker. Tell the technician if you have a hearing problem.
You'll hear loud humming, tapping, and buzzing noises from the MRI machine. You may be able to use earplugs or listen to music during the test.
Moving your body can cause the pictures to blur. The technician will ask you to remain very still during the test. If you can't lie still, you may be given medicine to help you relax. The technician also may ask you to hold your breath for 10 to
You usually can return to your normal routine right after chest MRI.
If you got medicine to help you relax during the test, your doctor will tell you when you can return to your normal routine. The medicine may make you tired, so you'll need someone to drive you home.
If contrast dye was used during the test, you may have a bruise where the dye was injected. If you're breastfeeding, the contrast dye can be passed to your baby through your breast milk. So, you'll need to bottle-feed your baby for a short time after the test.
Ask your doctor how long you need to wait before you breastfeed. You may want to prepare for the test by pumping and saving milk for 24 to 48 hours in advance.
The magnetic fields and radio waves used during chest MRI pose no risk.
Serious reactions to the contrast dye used for some MRI tests are very rare. However, side effects are possible and include the following:
Rarely, contrast dye is harmful to people who have moderate to severe kidney disease.
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