Magnetic Resonance Imaging Compatibility of the Polymer-based Cochlear Implant.
OBJECTIVE
In this study, we compared the magnetic resonance (MR) image artifacts caused by a conventional metal-based cochlear implant and a newly developed liquid crystal polymer (LCP)-based device.


METHODS
The metal-based cochlear implant system (Nurobiosys Co.) was attached to side of the head of a subject and the LCP-based device was attached to opposite side. In both devices, alignment magnets were removed for safety. Magnetic resonance imaging (MRI) was performed on a widely used 3.0 T and an ultra-high 7.0 T MRI machine. 3.0 and 7.0 T MR images were acquired using T1- and T2(*)-weighted gradient echo sequences, respectively.


RESULTS
In the 3.0 T images, the metal-based device on the left side generated the significant amount of artifacts. The MR images in the proximity of the metal package were obscured by the artifacts in both axial and sagittal views. On the other hand, the MR images near the LCP-based device were relatively free from the artifacts and clearly showed the brain structures. 7.0 T MR images showed the more severe distortion in the both sides but the metal-based cochlear implant system caused a much larger obscure area than the LCP-based system.


CONCLUSIONS
The novel LCP-based cochlear implant provides a good MRI compatibility beyond present-day cochlear implants. Thus, MR images can be obtained from the subjects even with the implanted LCP-based neural prosthetic systems providing useful diagnostic information. Furthermore, it will be also useful for functional MRI studies of the auditory perception mechanism after cochlear implantations as well as for positron emission tomography-MRI hybrid imaging.
School of Electrical Engineering and Computer Science, College of Engineering, Seoul National University, Seoul, Korea.
Jin Ho
JH
Kim
Kyou Sik
KS
Min
Soon Kwan
SK
An
Joon Soo
JS
Jeong
Sang Beom
SB
Jun
Min Hyoung
MH
Cho
Young-Don
YD
Son
Zang-Hee
ZH
Cho
Sung June
SJ
Kim