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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.

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Last Updated: October 1, 2010