Traditionally, magnetic resonance imaging (MRI) was contraindicated for patients with cochlear implants (CIs), due to concern about device displacement, overheating of the device or tissues, or direct damage to the device electrode. In addition, image artifact from the device magnet gave poor imaging information in the cranial and upper cervical spine region. Today, MRI is increasingly required in patients who have undergone cochlear implantation, and CI design and MRI protocols have therefore changed to allow implanted patients to safely enter the MRI field, in some cases without removal of the CI internal magnet.
We present a patient with bilateral CIs who required MRI to investigate new neurological symptoms. Despite tight head bandaging applied according to our protocol, MRI at 1.5 T led to bilateral skin reactions and displacement of the magnet on the left. Both magnets were subsequently removed to allow the skin reactions to settle and for further imaging without artifact. The functioning of the patient's implants was not affected.
The final decision to recommend that a patient with a CI undergoes MRI, with or without removal of the internal magnet, requires close cooperation between the CI team, the physician requiring the scan, and the radiology team involved in the patient's care. The case study we present highlights the need for patients to be fully informed of the risks involved.