Magnet Removal and Reinsertion in a Cochlear Implant Recipient Undergoing Brain MRI

Abstract

Background: Recent advances in cochlear implants (CIs) and in magnetic resonance imaging (MRI) techniques have led to increasing numbers of implanted patients who have undergone brain MRIs for various reasons. This paper first describes the surgical procedure for removing the magnet before an MRI and its subsequent reinsertion immediately afterwards in a CI recipient. Method: After the administration of local anesthesia, the magnet was removed by a surgical incision made along the posterior margin of the receiver-stimulator. The flap was elevated and the capsule over the implant was incised. The magnet was removed, maintained under sterile conditions and reinserted immediately after the completion of the 1.5-Tesla MRI. Results: The patient was able to wear her device immediately after surgery. Large CI-associated artifacts were observed on the MRIs irrespective of sequences. The function of the device was not altered by either the MRI or the surgical procedure. Conclusion: The proposed surgical incision that follows the posterior margins of the receiver-stimulator allows the wearing of the device immediately after the surgical procedure. An MRI has limited diagnostic value for lesions located on the implanted side due to unavoidable artifacts, even after the magnet has been removed.

MRI Information for Commonly Used Otologic Implants: Review and Update

“…33,34 If the patient needs more than 1 MRI, the removed magnet can be replaced with a titanium plug and a new magnet can be placed when the patient has obtained all necessary MRIs. 33,34…”

Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study

“…While aspects of CI magnet movements with potential CI damage or harm to the patients during or after MR scans are discussed elsewhere [ 23 ], the present human cadaver study analyzed diagnostic usefulness, artifacts and image quality of acquired MR brain series after cochlear implantation before and after magnet removal using a 1.5T and a 3T MR scanner. A previous report documented that CI devices with internal magnet removal are safe for 1.5T MR systems [ 24 ]. If the patient needs more than one MR examination the explanted magnet can be replaced with a titanium spacer and a new magnet can be placed when the patient has obtained all necessary MRIs [ 24 , 25 , 26 ].…”

“…A previous report documented that CI devices with internal magnet removal are safe for 1.5T MR systems [ 24 ]. If the patient needs more than one MR examination the explanted magnet can be replaced with a titanium spacer and a new magnet can be placed when the patient has obtained all necessary MRIs [ 24 , 25 , 26 ].…”

Magnetic Resonance Imaging in a Neurofibromatosis Type 2 Patient with a Novel MRI-Compatible Auditory Brainstem Implant

“… 5 6 This often necessitated separate surgical intervention with magnet removal and replacement, which puts the device at high risk for damage or infection. 7 8 Recently there has been a push for securement with an external compression device for cochlear implants (CIs) that contain an internal magnet, alleviating the need for separate surgical procedure. Gubbels and McMenomey (2006) examined 16 cadaver heads with Nucleus 24 CI, in which they demonstrated that without proper securement 14 of the 16 had moderate to severe displacement of the magnetic device while undergoing MRI.…”