Friday, December 12, 2008

HEADS UP: MRIs and CIs- NY Times Article

Posted to the Pediatric Cochlear Implant Circle by a Mom

Hazards: Scanners Can Damage Hearing Implants

Published: December 8, 2008
People who have cochlear implants should avoid newer models of M.R.I. machines, which can damage their hearing devices irreparably, researchers say.

Demagnetization of cochlear implants and temperature changes in 3.0T MRI environment (Otolaryngology — Head and Neck Surgery)The machines in question are known as 3T scanners and are much more powerful than early versions. The problem is they can demagnetize an important component of the implants. The study, led by Dr. Omid Majdani of Vanderbilt University, appears in the December issue of Otolaryngology — Head and Neck Surgery.

Unlike other hearing aids, which can be easily removed, cochlear implants are put in surgically. They are used by more than 100,000 people, and as 3T scans become more common, the issue is likely to become more important, the researcher said.

Magnets are used in the implants to allow them to be connected through the skin to a processor. They are also used in magnetic resonance imaging, as the name implies.

For the study, researchers placed a variety of implant magnets in an M.R.I. in different positions and for different lengths of time. They found that demagnetization was common at some angles. To their surprise, they also found that they were unable to fully remagnetize them by changing their position in the scanner.

More Articles in Health » A version of this article appeared in print on December 9, 2008, on page D6 of the New York edition.

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