MRI Safety Information
Testing has demonstrated that the HiRes 90K™ cochlear implant family is MR Conditional. Unilateral and bilateral recipients with this device can be safely scanned in an MR system meeting the following conditions:
- Horizontal closed bore scanners with a static magnetic field of 1.5T (magnet in place or removed)
- Maximum MR system reported, whole body averaged specific absorption rate (SAR) of ≤ 1.7 W/kg at 1.5T for quadrature transmit RF body coils
- Maximum MR system reported, head averaged SAR of ≤ 1.0 W/kg at 1.5T for quadrature transmit RF head coils
- RMS gradient field of 30 T/s and peak gradient field of 150 T/s
- Maximum spatial field gradient of 2.5 T/m at 1.5T with the magnet in place and 2.5 T/m at 1.5T with the magnet removed.
When tested under the scan conditions defined above with patient's head in the center of the MR scanner, the HiRes 90K Advantage implant produced a maximum temperature rise of <2.4°C after 15 minutes of continuous scanning when using a body coil and whole body averaged SAR of 1.7 W/kg.
In MRI testing of unilateral recipient conditions, the image artifact caused by the device extends from the HiRes 90K Advantage implant:
- Approximately 6 cm in a 1.5T MRI with the temporary non-magnetic plug in place using a gradient echo pulse sequence
- Approximately 11.5 cm in a 1.5T MRI with the magnet in place using a gradient echo pulse sequence.
These artifacts may result in a loss of diagnostic information in the implant vicinity.