Influence of head orientation and implantation site of a novel transcutaneous bone conduction implant on MRI metal artifact reduction sequence

Abstract

Purpose The use of magnetic resonance imaging (MRI) is often limited in patients with auditory implants because of the presence of metallic components and magnets. The aim of this study was to evaluate the clinical usefulness of a customized MRI sequence for metal artifact suppression in patients with BONEBRIDGETM BCI 602 implants (MED-EL, Innsbruck, Austria), the successor of the BCI 601 model. Methods Using our in-house developed and customized metal artifact reduction sequence (SEMAC-VAT WARP), MRI artifacts were evaluated qualitatively and quantitatively. MRI sequences were performed with and without artifact reduction on two whole head specimens with and without the BCI 602 implant. In addition, the influence of two different implantation sites (mastoid versus retrosigmoid) and head orientation on artifact presence was investigated. Results Artifact volume was reduced by more than the 50%. Results were comparable with those obtained with the BCI 601, showing no significant differences in the dimensions of artifacts caused by the implant. Conclusion SEMAC-VAT WARP was once more proved to be efficient at reducing metal artifacts on MR images. The dimensions of artifacts associated with the BCI 602 are not smaller than those caused by the BCI 601.

Magnetic Resonance Imaging Artifact Associated With Transcutaneous Bone Conduction Implants: Cholesteatoma and Vestibular Schwannoma Surveillance

“…Prior studies have had variable success in reducing artifact with the Bonebridge implant despite the smaller transducer design in the newest version of the implant (BCI 602). 12,13 Prior studies demonstrated improvement in imaging quality with the use of metal mitigation sequences and placement of the implant in the middle fossa region, however, non-EPI DWI sequences were not evaluated. 13,14 The notable artifact in this implant is partially attributable to the diametric (and MR imaging conditional) magnet, which is not removable.…”

“…To a certain extent, the surgical technique will vary across surgeons; however, it should be noted that given the large area of artifact and distortion, differences in patient anatomy and surgical technique would be unlikely to dramatically change the results of the study. Similarly, the level of the artifact was not assessed with different head positions; Talon et al 12 found that head position did not change the quality of the MRI image with Bonebridge, and given that the area of the artifact is large, similar findings may be true of the Osia device. Further work will be required to assess this.…”

“…While some studies have proposed metal artifact mitigation sequences that may improve MR imaging artifact associated with the Bonebridge implant, these improvements have been limited in clinical utility. [12][13][14] Furthermore, to the best of the authors' knowledge, the MR imaging artifact associated with the Osia implant has not yet been reported. As an increasing number of patients with a history of ipsilateral cholesteatoma or vestibular schwannoma are receiving transcutaneous bone conduction implants, understanding the limits of MR imaging surveillance secondary to the artifact is important.…”

“…Importantly, both these devices have larger metal components, and therefore larger MR imaging artifact regions when compared to cochlear implants. While some studies have proposed metal artifact mitigation sequences that may improve MR imaging artifact associated with the Bonebridge implant, these improvements have been limited in clinical utility 12‐14 . Furthermore, to the best of the authors' knowledge, the MR imaging artifact associated with the Osia implant has not yet been reported.…”

“…Despite these clinical advantages, transcutaneous bone conduction implants, encompassing magnets and metal components, are associated with magnetic resonance (MR) imaging artifact 11‐14 . The artifact and image distortion associated with both the magnet and metal components of these devices can obfuscate imaging of the temporal bone and head.…”