Magnetic Resonance Imaging Artifact Associated With the Oticon Medical Sentio Ti Transcutaneous Bone Conduction Hearing Implant.

OBJECTIVE

To evaluate magnetic resonance (MR) imaging artifact and image distortion associated with the Oticon Medical Sentio Ti bone conduction implant (BCI) and identify optimized imaging techniques.

STUDY

DESIGN

Cadaveric study.

INTERVENTION: One cadaveric head specimen was unilaterally implanted with Sentio Ti BCI according to the manufacturer's instructions.

MAIN OUTCOME MEASURES: Imaging was performed with a Siemens 1.5 Tesla MR machine on XA60 software before and after implantation. Imaging was performed with both standard and metal mitigation techniques. Image scoring (diagnostic vs. nondiagnostic) and qualitative assessment of anatomic subsites were performed by 2 experienced neuroradiologists.

RESULTS

Image distortion and artifact were noted in all postimplant sequences. For all sequences, imaging of the ipsilateral middle ear, mastoid, and internal auditory canal (IAC) was nondiagnostic. The axial T1 turbo spin echo high bandwidth sequence had the best artifact reduction; however, the ipsilateral temporal bone remained nondiagnostic. Notably, nonecho planar diffusion-weighted imaging (non-EPI DWI) was nondiagnostic for both the ipsilateral temporal bone and the contralateral IAC and middle ear.

CONCLUSIONS

After implantation of the Sentio Ti BCI, imaging of the ipsilateral temporal bone is rendered nondiagnostic on all MR sequences due to artifact despite the use of metal mitigation techniques. Importantly, the non-EPI DWI HASTE sequence, which is used for cholesteatoma surveillance, is nondiagnostic for all ipsilateral and most contralateral temporal bone subsites, making cholesteatoma surveillance challenging with an implant in place. This finding is critical for clinical decision-making, as rehabilitation of conductive hearing loss in the setting of chronic otitis media is among the most common indications for use of a BCI.