Dimensions of artefacts caused by cochlear and auditory brainstem implants in magnetic resonance imaging

Background: The aim of the study was to investigate the extent of MRI artefacts due to the magnet of selected auditory implants. Study design: Artefacts of the Synchrony cochlear implant at 1.5 T as well as at 3 T MRI devices were examined in cadavers and compared to the artefacts in MRI scans at 1.5 T of 17 patients implanted with CI (n = 12) and auditory brainstem implants (ABI) (n = 5). Results: None of the scanned implants showed any failure after MRI. After removal of the magnet, only a portion of the images in the direct neighbourhood of the implant, especially in the temporal and parietal lobe, contained artefacts. More anatomical substructures were visible without artefacts using the MedEl Synchrony device. Conclusion: Artefacts can be markedly reduced by rotating, self-aligning magnet. Removal of the magnet also results in reduction of artefacts.