Michelle White

Compatibility of the Cut Cochlear Electrode and Magnetic Resonance Imaging

Mentor: Richard Wiggins, MD

Department: Radiology and Imaging Sciences

A. Modern, FDA-approved cochlear implants (CIs) are MRI-conditional, under specific manufacturer guidelines. Increasingly, due to the potential to cause fibrous and bony obliteration of the scala tympani during removal of the intracochlear electrode, this is often cut and left behind while the internal receiver-stimulator is removed, facilitating an easier electrode replacement in the case that the CI fails or needs to be changed. Additionally, CI patients with a history of infection or cochlear trauma can incur ossification, making it difficult to remove the intracochlear electrode. Little is known on the effect of the electrode alone on MR imaging, and some CI manufacturers are unable to claim continued MRI-conditional status of their devices once the electrode has been cut. The objective of this study was to evaluate the cut CI electrode remaining in the cochlea and brain MR imaging compatibility arising from the electrode only. B. Three different patients with CI were imaged, all undergoing brain MRI after explantation of the internal receiver with the cut electrode left within the cochlea. C. Brain MR images of these patients before and after explantation were assessed for any significant artifact that hindered the evaluation of the surrounding skull base or brain parenchyma, with the images demonstrating no significant ferromagnetic artifact from the CI leads within the inner ear structures or surrounding parenchyma. D. As such, this study demonstrates that brain MRI is compatible with the cut electrode left within the cochlea, and does not limit the evaluation of the surrounding skull base or brain parenchyma.