For more information, visit http://www.nhlbi.nih.gov/health/health-topics/topics/cmri/

Other Names for Chest MRI

Chest MRI also may be called chest nuclear magnetic resonance.

Who Needs Chest MRI?

Your doctor may recommend chest MRI if he or she thinks you have a chest condition, such as:

• A tumor
• Problems in the blood vessels, such as an aneurysm (AN-u-rism) or blood clot
• Abnormal lymph nodes
• Another chest condition, such as a pleural disorder

Chest MRI also may be used to help explain the results of other tests, such as
chest x ray and chest CT scan.

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.

What To Expect Before Chest MRI

Your doctor or an MRI technician will ask you some questions before the test, such as:

• Are you pregnant or do you think you could be? Generally, you shouldn't have a chest MRI if you're pregnant, especially during the first trimester. Sometimes, though, an MRI is needed to help diagnose a serious condition that may harm you or your baby. If you're pregnant, discuss the risks and benefits of an MRI with your doctor.
• Have you had any surgery? If so, what kind?
• Do you use transdermal patches (patches that stick to the skin) to take any of your medicines? Some medicine patches contain aluminum and other metals. These metals can cause skin burns during an MRI. Examples of transdermal patches are nicotine and fentanyl (medicine used for pain) patches.
• Do you have any metal objects in your body, like metal screws or pins in a bone?
• Do you have any medical devices in your body, such as a pacemaker, an implantable cardioverter defibrillator, cochlear (inner-ear) implants, or brain aneurysm clips? The strong magnets in the MRI machine can damage these devices.

Your answers will help your doctor decide whether you should have chest MRI.

Items Not Allowed in the MRI Room

Your doctor or technician will ask you to not wear or bring metal, electronic, or magnetic objects into the MRI room. Examples include:

• Cell phones
• Hearing aids
• Credit cards
• Jewelry and watches
• Eyeglasses
• Pens
• Removable dental work
• Any other magnetic objects

MRI magnets can damage these objects, or the objects may interfere with the MRI machine.

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.

Contrast Dye

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.

What To Expect During Chest MRI

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.

How the Test Is Done

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.

A Patient Having a Chest MRI

The photo shows a patient lying on a sliding table outside of an MRI machine. The table will slide into the machine, and the patient will lie quietly while the machine takes pictures of the chest.

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 15 seconds at a time, while he or she takes pictures of the structures in your chest.

What To Expect After Chest MRI

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.

What Does Chest MRI Show?

The pictures from chest MRI may show a tumor, problems in the blood vessels (such as an aneurysm or blood clot), abnormal lymph nodes, or another chest condition (such as a pleural disorder).

What Are the Risks of Chest MRI?

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:

• Headache.
• Nausea (feeling sick to your stomach).
• Dizziness.
• Changes in taste.
• Allergic reactions, such as hives and itchy eyes. If you have an allergic reaction, your doctor can give you medicine to relieve your symptoms.

Rarely, contrast dye is harmful to people who have moderate to severe kidney disease.

Links to Other Information About Chest MRI

Non-NHLBI Resources

• Chest MRI (MedlinePlus)

Clinical Trials

• Children and Clinical Studies
• Clinical Trials (Health Topics)
• Current Research (ClinicalTrials.gov)
• NHLBI Clinical Trials
• NIH Clinical Research Trials and You (National Institutes of Health)
• ResearchMatch (funded by the National Institutes of Health)