Safe magnetic resonance scanning of patients with metallic middle ear implants.
OBJECTIVE
To determine the MR scanning risk to patients with otologic implants.


METHODS
We used a repeated-measures study with an additional control measure to assess two aspects of risk; (i) movement of the device in the magnetic field, and (ii) absorption of energy leading to local heating. We used an ex vivo test method that met with international standards. We measured the effects in a Philips Intera Achieva 3 Tesla (T) MR scanner using a Sense Head 8 channel RF coil.


METHODS
University-based magnetic resonance research facility.


METHODS
Heating or displacement of the stapedectomy pistons.


RESULTS
No evidence of displacement or heating was found.


CONCLUSIONS
Complying with the ex vivo standard testing protocols, the Schuknecht and McGee wire pistons (device product numbers 140106 and 140108, respectively) were found to be safe in a 3 T MR scanner. These conclusions can be extrapolated to the in vivo case.
Wild
D C
DC
ENT Department, Queens Medical Centre, Nottingham, UK. dcwilde@rcsed.ac.uk
Head
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K
Hall
D A
DA
D004427:Ear Diseases / Q000175:diagnosis*; D004869:Equipment Safety; D006361:Heating; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects*; D008670:Metals; D009998:Ossicular Prosthesis; D011474:Prosthesis Design; D011475:Prosthesis Failure
D008670:Metals