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Magnetic Resonance Imaging (MRI) scans, which use high-powered magnets to obtain detailed images of the inside of the human body, are an important diagnostic tool for an array of disorders. However, for patients with implanted medical devices containing metal components, MRI scans need to be conducted with extreme caution, if they are to be done at all, because the powerful magnet may forcefully dislodge these devices.
A less-severe and less-recognized adverse event was recently...
Magnetic Resonance Imaging (MRI) scans, which use high-powered magnets to obtain detailed images of the inside of the human body, are an important diagnostic tool for an array of disorders. However, for patients with implanted medical devices containing metal components, MRI scans need to be conducted with extreme caution, if they are to be done at all, because the powerful magnet may forcefully dislodge these devices.
A less-severe and less-recognized adverse event was recently highlighted by the Food and Drug Administration (FDA). On March 5, 2009, the FDA sent a public health warning to patients and doctors that transdermal drug patches containing metal may overheat during a MRI scan, causing skin burns.
Transdermal patches offer several advantages to patients, including less-frequent dosing, steady release of the drug into blood stream, and circumventing drug digestion by the liver, potentially allowing lower doses of the drug to be administered. There are about 60 transdermal patches on the market, the FDA estimates, and about one-third contain metal. However, the metal is not always visible and not all metal-containing patches contain a warning about removing the patch prior to a MRI scan on their packaging. The FDA is in the process of reviewing all transdermal patches and requiring all metal-containing ones to carry such a warning on the patches themselves. Patients who use a transdermal patch can take several precautions:
- Discuss with the doctor who prescribed the patch whether to remove it in the event of an MRI scan, and, if so, whether the same patch may be put back in place afterward or if a new patch should be used.
- If a doctor suggests an MRI scan, tell him/her that you use a transdermal patch.
- Notify the MRI facility that you use a transdermal patch when you first schedule the scan.
- When you go for the MRI scan, notify the staff that you are wearing a transdermal patch and follow the plan developed with your prescribing doctor.
