Learning objectives
MR examinations in patient with hearing implants is feasible in most cases ("MR conditional")
We present a standardized algorithm for safe and feasible MR examinations in patients with hearing implants.
Background
MR examinations in patient with hearing implants is feasible in most cases ("MR conditional").
However,
they can cause major artifacts which can hamper clinical diagnosis markedly.
Furthermore,
there is a certain risk of magnet dislocation.
A rare complication might be damage or warming of the implant.
Due to these reasons there are various vendor-dependant restrictions and limitations for a safe use of hearing implants during MR examinations.
Nonetheless,
several of patients with hearing implants may need further MR examinations.
Findings and procedure details
We performed a thorough literature research and gathered all relevant aspects and restrictions regarding MR safety of hearing implants from the four leading vendors Med-El,
Cochlear,
Advanced Bionics,
and Oticon.
We then summarized these restrictions and filtered the "least commom denominator" and integrated them to an standard procedure algorithm applicable to the majority of all available hearing implants.
We present a standardized and save algorithm for feasible MR examinations in patients with hearing implants:
Before MR appointment
MR examination at least 6 months after implantation...
Conclusion
The diagnostic advantages of a 3T MR machine may not compensate the increased efforts and risks of magnet dislocation or demagnetization as compared to using a 1.5T machine.
Several hearing implants are not permitted for use in 3T machines,
and in some implant types the surgical magnet removal before examination is mandatory.
Therefore,
we present a simple and standardized algorith which allows for safe and feasible MR examination of the great majority of patients with hearing implants.
References
Med-El medical procedures guidelines
Cochlear MRI safety guidelines
Oticon MRI exam instructions
Advanced Bionics MRI safety information