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Magnetic Resonance Imaging Compatibility of the Polymer-based Cochlear Implant.

Kim JH, Min KS, An SK, Jeong JS, Jun SB, Cho MH, Son YD, Cho ZH, Kim SJ - Clin Exp Otorhinolaryngol (2012)

Bottom Line: In both devices, alignment magnets were removed for safety.In the 3.0 T images, the metal-based device on the left side generated the significant amount of artifacts.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.

View Article: PubMed Central - PubMed

Affiliation: School of Electrical Engineering and Computer Science, College of Engineering, Seoul National University, Seoul, Korea.

ABSTRACT

Objectives: 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.

Conclusion: 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.

No MeSH data available.


Related in: MedlinePlus

T1-weighted 3.0 T magnetic resonance images of the head: axial (A) and sagittal (B) plane views when the metal- and liquid crystal polymer-based cochlear implants are attached to the left and right side of the head, respectively.
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Figure 3: T1-weighted 3.0 T magnetic resonance images of the head: axial (A) and sagittal (B) plane views when the metal- and liquid crystal polymer-based cochlear implants are attached to the left and right side of the head, respectively.

Mentions: Fig. 3 shows T1-weighted 3.0 T MR images of the head with the metal-based implant attached to the left side of the head and the LCP-based implanted on the opposite side. Fig. 3A and 3B are the axial and sagittal images of the head, respectively. In Fig. 3A, brain imaging of the left side is obscured by artifacts. The diameter of the artifact caused by the metal-based cochlear implant was approximately 69 mm. Contrary to the metal implant, very mild artifacts were generated by the LCP-based device on the right side. A similar tendency was observed in the sagittal image of the head (Fig. 3B). There exist extremely small artifacts on the right side, while severe image distortion was generated on the left side by platinum coil and titanium packages. Therefore, if we use an fMRI to see the neuronal activity from the auditory brain cortex of the metal-based cochlear implant recipients, it will be impossible to monitor the ipsilateral temporal lobe that was applied to the primary auditory cortex. It should also be noted that the distorted area of the MRI images can be smaller compared to the images of the CI recipients, since the metal- and LCP-based cochlear implants were attached to the outside of the skin, and not fully implanted inside the skin.


Magnetic Resonance Imaging Compatibility of the Polymer-based Cochlear Implant.

Kim JH, Min KS, An SK, Jeong JS, Jun SB, Cho MH, Son YD, Cho ZH, Kim SJ - Clin Exp Otorhinolaryngol (2012)

T1-weighted 3.0 T magnetic resonance images of the head: axial (A) and sagittal (B) plane views when the metal- and liquid crystal polymer-based cochlear implants are attached to the left and right side of the head, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369977&req=5

Figure 3: T1-weighted 3.0 T magnetic resonance images of the head: axial (A) and sagittal (B) plane views when the metal- and liquid crystal polymer-based cochlear implants are attached to the left and right side of the head, respectively.
Mentions: Fig. 3 shows T1-weighted 3.0 T MR images of the head with the metal-based implant attached to the left side of the head and the LCP-based implanted on the opposite side. Fig. 3A and 3B are the axial and sagittal images of the head, respectively. In Fig. 3A, brain imaging of the left side is obscured by artifacts. The diameter of the artifact caused by the metal-based cochlear implant was approximately 69 mm. Contrary to the metal implant, very mild artifacts were generated by the LCP-based device on the right side. A similar tendency was observed in the sagittal image of the head (Fig. 3B). There exist extremely small artifacts on the right side, while severe image distortion was generated on the left side by platinum coil and titanium packages. Therefore, if we use an fMRI to see the neuronal activity from the auditory brain cortex of the metal-based cochlear implant recipients, it will be impossible to monitor the ipsilateral temporal lobe that was applied to the primary auditory cortex. It should also be noted that the distorted area of the MRI images can be smaller compared to the images of the CI recipients, since the metal- and LCP-based cochlear implants were attached to the outside of the skin, and not fully implanted inside the skin.

Bottom Line: In both devices, alignment magnets were removed for safety.In the 3.0 T images, the metal-based device on the left side generated the significant amount of artifacts.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.

View Article: PubMed Central - PubMed

Affiliation: School of Electrical Engineering and Computer Science, College of Engineering, Seoul National University, Seoul, Korea.

ABSTRACT

Objectives: 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.

Conclusion: 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.

No MeSH data available.


Related in: MedlinePlus