Introduction: 
The approval process for MRI safety of implants includes physical observations and the experimental evaluation in artificial settings to simulate the in vivo effect. This contains the observation of temperature changes and artificial current generation by the magnetic field. From these findings the safety of an implant and its effect on the patient can be estimated.
MRI safety is based on in vivo evaluation of adverse events after the approval process but actual analysis of the effect on different tissues is not followed.
The effect of MRI scanning in cochlear implantees on residual hearing as the correlate of hair cell function is so far unknown, therefore the aim of the present study was to observe the effect of 3T MRI on the residual hearing of cochlea implantees.
Material and Methods: 
In this prospective study we performed a 3 T MRI T2 2D MS Drive sequence in 8 cochlea implanted ears.  Before and after the MRI scan a bone conduction pure tone audiogram (BC PTA) was performed. All cochlea implantees had a pre-scanning threshold of low frequency residual hearing between 20 dB and 65 dB.
Results: 
Low frequency mean residual hearing was not affected by 3 T T2 2D MS Drive sequence. We observed a pre scanning threshold at 250 Hz of 42.9 (SD 3.9) dB and for 500 Hz 57.1 (SD 6.4) dB. Post scanning BC PTA was for 250 Hz 42.1 (SD 3.9) dB and for 500 Hz 57.1 (SD 5.7) dB. 
Conclusion: 
3 T MRI scanning has no significant functional effect on hair cells in cochlea implantees in low frequencies with a T2 2D MS Drive sequence. 


Prospective evaluation of 3 T MRI effect on residual hearing function of cochlea implantees

It is with great pleasure and enthusiasm, that on behalf of the Cochlear Implant centers of the Radboud UMC in Nijmegen and Erasmus MC Sophia Children’s Hospital in Rotterdam to invite you to attend the 16th European Symposium on Pediatric Cochlear Implantation to Rotterdam, the Netherlands in 2023.

Yours sincerely, on behalf of the CI Centers at Radboud UMC and Erasmus MC,