The external components of the HiResolution™ Bionics Ear System are MR Unsafe and must be removed before entering a room containing an MRI scanner.
The implant components of the HiRes™ Ultra 3D cochlear implant are MR conditional.
The HiRes Ultra 3D cochlear implants have a specifically designed magnet that allows safe MRI scanning with the magnet in place, without angular restrictions of the head, and without surgical removal of the magnet or a bandaging protocol.
Do not allow patients with a HiRes cochlear implant to be in the area of an MRI scanner unless the following conditions have been met:
Testing has demonstrated that the HiRes Ultra 3D cochlear implant is MR Conditional. Unilateral and bilateral recipients with this device with magnet in place can be safely scanned in a horizontal closed bore quadrature coil MR system meeting the following conditions:
MRI Field Strength
|Maximum Spatial Field Gradient||20 T/m||20 T/m|
|RMS Gradient Field||34.4 T/s||34.4 T/s|
|Peak Slew Rate||200 T/m/s||200 T/m/s|
Maximum Whole Body Averaged SAR
|2.0 W/kg||2.0 W/kg|
|Maximum Head Averaged SAR||3.2 W/kg||2.6 W/kg|
When tested under scan conditions defined above, the HiRes Ultra 3D cochlear implant produced a maximum temperature rise of <3˚C after 15 minutes of continuous scanning.
Note: During the scan, patients might perceive auditory sensations. Adequate counseling of the patient is advised prior to performing the MRI. The likelihood and intensity of the auditory sensations can be reduced by selecting sequences with a lower Specific Absorption Rate (SAR) and slower gradient slew rates.
The largest artifact at 3.0T is > 15 cm when imaged under spin echo and gradient echo sequences. Smaller artifacts are possible if using different scanning parameters or a non-magnetic plug.
Note: For cases that would clinically benefit from reduced device artifact (for example, some head or neck scans), the internal magnet is surgically removed and possibly replaced with a Temporary Non-Magnetic Plug before the recipient undergoes an MRI procedure. The HiRes Ultra 3D cochlear implant can withstand 5 replacement cycles.
For additional information regarding the use of an MRI scanner with a HiRes Ultra 3D Cochlear Implant, please contact Advanced Bionics Technical Support at firstname.lastname@example.org.