Impact of Cochlear Implant With Diametric Magnet on Imaging Access, Safety, and Clinical Care

Review safety and effectiveness of magnetic resonance imaging (MRI) of patients implanted with a cochlear implant (CI) containing a diametric magnet housed within the undersurface of the device.

Retrospective chart review with additional review of MRI at a tertiary-care children's hospital.

Seven patients with mean age of 8.4 years (range = 1.3-19 years) with a diametric magnet in situ during MRI. The intervention comprised one or more sessions of 1.5 T or 3.0 T MRI without a head wrap. The main outcome measures were the occurrence of magnet-related complications including discomfort and magnet displacement, use of anesthesia or sedation, and clinical usefulness of MRI studies.

Seven CI recipients underwent 17 episodes of 1.5 or 3.0 T MRI with an in situ diametric magnet. Thirteen of 17 (76%) MRI sessions were completed in awake patients. No patients had device-related discomfort. No magnet-related complications occurred. Thirteen of 14 (93%) brain studies were clinically useful despite artifacts.

The diametric magnet enabled MRI with magnet in situ without the discomfort or magnet displacement associated with removable axial magnets. The reduction in MRI magnet-related complications occurred because torque is not directed perpendicular and outward from the plane of the magnet, and the magnet is securely contained within its housing. The design of this device increased access and reduced the need for sedation or anesthesia.

4 Laryngoscope, 131:E952-E956, 2021.