Demagnetization of Cochlear Implants and Temperature Changes in 3.0T MRI Environment

Abstract

Objective To investigate the level of demagnetization of the magnets and temperature changes in cochlear implants (Cis) in a 3.0 tesla (3.0T) MRI. Study Design Experimental. Subjects and Methods Demagnetization and remagnetization measurements were done on magnets for different types of CIs. Temperature of different body and electrode sides was measured in the MRI environment. Results Demagnetization of the magnets of the CI is dependent on the angle between the magnetic field of the CI magnet and the MRI. When this angle was greater than 80 degrees, relevant demagnetization occurred and sufficient remagnetization was not possible with the 3.0T MRI magnet. Maximum temperature rise was 0.5°C. Conclusions Patients carrying CIs with non-removable magnets should not enter a 3.0T MRI device in a routine clinical setup. Under special conditions (angle between the two magnets less than 80 degrees) imaging in a 3.0T MRI may be possible without harming the patient or the implant.