Magnetic Resonance Imaging in a Neurofibromatosis Type 2 Patient with a Novel MRI-Compatible Auditory Brainstem Implant

Abstract

Auditory brainstem implantation has become a key technique for the rehabilitation of hearing in patients with neurofibromatosis type 2. The nature of this devastating genetic disease requires ongoing MRI for the patient's lifespan. Today, most auditory brainstem implants require removal of the magnet that connects the internal device to the external speech processor to undergo imaging as their disease progresses. Patients have the option of having a short procedure to have the magnet taken out and replaced each time, or alternately using a headband to secure the processor over the receiver coil of the internal device. Novel magnet technology has led to the development of a freely rotating magnet that can be used inside the magnetic field of an MRI scanner without losing magnet strength and without being displaced from the body of the device. We report one of the first patients implanted with a Med-El Synchrony ABI in the United States who subsequently underwent successful imaging with MRI 1.5 tesla to follow for other existing schwannomas.

Keywords: auditory brainstem implant; magnetic resonance imaging; neurofibromatosis type 2.

Fig. 1

MRI with a Med-El Synchrony auditory brainstem implant (ABI) demonstrates clear and quality images of the contralateral homogenously enhancing cerebellopontine mass. The ABI creates moderate metallic artifact distortion that limits evaluation of the ipsilateral cerebral and cerebellar hemispheres. (A) Axial view sequence from inferior to superior (left to right). (B) Coronal view sequence from anterior to posterior (left to right).