MR compatibility of Med EL cochlear implants: clinical testing at 1.0 T.

Abstract

Our aim was to evaluate the MR compatibility of Med EL cochlear implants by performing in vitro and in vivo tests. All experiments were done on a 1.0 T machine. Potential movement of the cochlear electrode relative to a scale was recorded. Potential dislodgment of the magnetic receiver coil was evaluated with the coil fixed to the retroauricular skin of a volunteer. Temperature changes were measured with temperature sensors fixed to the electrode, performing standard MR sequences. In 11 patients, MRI of the brain was performed 1 day before explantation of the devices using standard MR sequences. Testing of the auditory abilities was done before and after the examination. All explanted devices were assessed for function. There was no detectable movement of the electrode or the receiver coil nor any temperature change. There were no adverse events for the patients. All 11 explanted cochlear implants retained their function. Med EL cochlear implants are not a firm contraindication for MRI.