Because of the magnet and the contrast agent, there are some risks associated with having an MRI exam. However, most people can successfully complete the exam with minimal risk once they are medically screened and fully informed. Check out the International MR Safety Central Web Site for more information on MRI risks and safety issues.
Because the magnet attracts certain metals, it can exert a strong force on some metallic objects brought within the scan room, which could possibly harm you. In order to prevent such an event from happening, you will be asked to fill out and sign a metal screening form before you can go into the magnet room. Persons with cardiac pacemakers, metal prostheses (an artificial device replacing a body part) or magnetic clips in their heads from previous surgery will not be examined. Also excluded are persons who may have metallic particles in their eyes. All metals (such as jewelry, pens, watch, pager) should be removed from your body before you enter the magnet room (most sites will have lockers to store your personal items). Most surgical staples and clips are now made with metal that will not be affected by the magnet, but it is a good idea to note any on your screening form. Regular dental work or fillings are fine.
There is no detailed study available on the effects of MRI or the contrast agent during pregnancy. Because the risks to a fetus are unknown, pregnant women should not participate. In order to participate in MRI, you should have avoided becoming pregnant from the first day of your most recent menstrual period. You should avoid becoming pregnant for at least 2 days after your contrast enhanced MRI scan. You should not participate in the study if you think there is a possibility that you might become pregnant during that time.
If you have minor claustrophobia (fear of enclosed spaces) or anxiety, you may want to get a prescription for a mild sedative from your doctor to provide short-term relief from minor anxieties. If you are extremely claustrophobic, MRI may not be for you. For pictures of what the magnet looks like, click here.
While there are no significant risks from the MRI studies to be performed, your participation may mean some discomfort for you. In particular, you may be bothered by feelings of claustrophobia and by the noise levels during the study. During imaging, you will hear a tapping sound that is loud enough to be annoying without ear plugs. You will be given ear plugs that decrease the level of this sound. If you are prone to claustrophobia (fear of enclosed spaces) please tell the investigator during your pre-scan interview. You must also be able to stay completely still, except for normal breathing, for the duration of the exam.
A contrast agent is used in most breast MRI exams. This requires that a small IV needle or tube be placed in your hand or arm. The insertion may cause some discomfort; you may experience some bruising and there is a very small chance of irritation or infection. At injection, you may feel a coolness from or awareness of the contrast agent--this is normal.
Few experience side effects from the contrast agent, which can include mild headache, nausea and local pain. Rarely (less than 1% of the time) low blood pressure and lightheadedness occurs. This can be treated immediately with intravenous fluids. Very rarely (less than one in one thousand), patients are allergic to the contrast agent. These effects are most commonly hives and itchy eyes, but more severe reactions have been seen which result in shortness of breath.
Breast MRI is still experimental and the results can be difficult to interpret. Cancerous tissues are likely to become very bright on MRI images after contrast injection. Some normal and non-cancerous breast tissue can also become very bright (such as a fibroadenoma). Such false positive results may cause some anxiety for you. The investigator or radiologist can provide information about the results in light of what research has shown us about interpreting breast MRI. The MRI exam does not replace appropriate breast self-examination, physical examination of the breast by a qualified professional, screening and diagnostic mammography or, when indicated by your doctor, fine needle aspiration or biopsy.
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