MRI and the HiRes 90K Implant

What is Magnetic Resonance Imaging?
Magnetic resonance imaging (MRI) is a technique for taking remarkably clear and detailed pictures of internal organs and tissues using radio waves and a strong magnetic field.

When might a person be referred for an MRI?
MRI is the most sensitive exam for brain tumors, strokes, and certain chronic disorders of the nervous system such as multiple sclerosis. In addition, MRI might be recommended as a means of documenting disease of the cardiovascular system, pituitary gland, eye or inner ear.

Is the cochlear implant safe with MRI?
Only after the magnet has been removed. As referrals for MRI are increasing, it is comforting to know that your implant is safe with this imaging technique. But you must be sure to have the magnet removed first.

The United States Food and Drug Administration (FDA) cleared the HiResolution® Bionic Ear System's HiRes 90K® implant for Magnetic Resonance Imaging (MRI) at 0.3 Tesla and 1.5 Tesla with the internal magnet removed.

The magnetic and electrical properties of an MRI machine can potentially cause harm to a patient with a cochlear implant and damage the device. Therefore a patient with a cochlear implant should not be near an MRI machine, whether or not in use, unless the following conditions have been met:

• Internal magnet has been removed

• External processor and headpiece have been removed

A cochlear implant recipient should always consult with their implant surgeon before any imaging is performed, regardless of the imaging technique.

If an MRI is needed, what are the steps required to remove the magnet of the
cochlear implant?
Removing the magnet is a quick and easy procedure typically performed under local anesthesia. Your surgeon will shave a small area of hair directly over the implant. A small incision will be made exposing the implant. The magnet is gently removed and replaced with a sterilized insert. The incision is then closed. You may experience some swelling and slight discomfort following the procedure.

Will I be able to wear my processor after the magnet is removed?
Once the incision has healed, you will be able to wear your processor. You should check with your implant center before resuming device use.

Your audiologist will assist you in coupling the headpiece to the implant. Typically, a small hair clip is attached to the headpiece that holds the headpiece in place over the implant.

Can the magnet be replaced after an MRI?
Yes, your surgeon can replace the magnet after an MRI is completed, provided that further MRI evaluations are not anticipated. Under local anesthesia, your surgeon will shave the hair over the implant and make a small incision. The sterilized insert is removed and replaced with a new sterilized magnet ordered from Advanced Bionics.

If necessary, can the HiResolution® Bionic Ear System’s HiRes 90K® be implanted without the magnet?
Yes, your surgeon can elect to remove the magnet from the HiRes 90K before the device is implanted. In this case, the surgeon will order the sterilized insert with the device and replace the magnet with the sterilized insert at the time of surgery.

What recommendations should be provided to the radiologist/technician when an MRI is ordered for a cochlear implant recipient?
Your implant center can provide the MRI technician or radiologist with the HiResolution® Bionic Ear System’s HiRes 90K® package insert. Further instructions are provided when the implant center orders the sterilized insert or replacement magnet from Advanced Bionics that can be forwarded to the MRI technician as well.

Is an MRI safe with other implanted devices?
The magnetic field is used for MRI will pull on any ferrous metal object implanted in the body, including a prosthetic hip, heart pacemaker (or artificial heart valve), any metal plates, pins, screws, or surgical staples. Even tattoos and permanent eyeliner may also create a problem. If there is any uncertainty, the radiologist or technician will request an x-ray to identify any metal objects before the patient has an MRI.

Are other imaging techniques available? How is MRI different?
There are many imaging techniques used today including x-rays, computed tomography (CT ) scans, positron emission tomography (PET) scans, and ultrasound. MRI requires specialized equipment and expertise and allows evaluation of some body structures that may not be as visible with other imaging methods. Your medical team will discuss these options with you and determine which technique is optimal for your healthcare needs.

What do we need to do if we want to replace the magnet after the MRI?
Provided additional MRI are not anticipated, the center can order a sterilized "replacement magnet" CI-1412 from Advanced Bionics' Customer Service. The replacement magnet will come with a surgical insert title "MRI for HiRes 90k® implant" which provides detailed surgical instructions.

The Insert Dummy and Replacement Magnets are ordered SEPARATELY.

Can we implant the HiRes 90K without the magnet to begin with?
Yes, order the Insert Dummy with the device. The surgical insert titled "MRI for HiRes 90K implant" that accompanies the insert dummy includes detailed surgical instructions for removing the magnet prior to implantation.

What specific recommendations can we provide the MRI technician?
The HiRes 90K implant is FDA approved for PRI testing at 0.3 Tesla and 1.5 Tesla with the magnet removed. The external hardware must also be removed before the patient enters the MRI testing room/suite. The center can provide the technician with the "MRI for HiRes 90K implant" surgical insert that accompanies the insert dummy or replacement magnet.