이식형 의료기기로 인한 MRI영상의 인공음영 축소를 위한 외부 코일 시스템 설계 = A Method for Reducing Artifact of MR Image due to the Implantable Hearing Aid

다국어 초록 (Multilingual Abstract)

Recently, several implantable medical devices have a power receiving module from outside the body, such as a cochlear implant which are frequently used to treat the hearing impaired patients. Most of implantable medical devices are adopted magnet pairs to couple between internal and external devices for the enhancement of power transmission. Usually, the internal device which containing a magnet in the center of receiving coil is implanted under the skin of the temporal bone.
In case of MRI scanning to a patient who has such implant, the static magnetic fields of the MRI might be interfered by the fields of the implanted magnet in the skin. From the reasons above, the image from MRI is degraded by large area of artifact, so that diagnostics are almost impossible in deteriorated region.
In this paper, we propose an external coil that can compensate the magnetic fields due to the internal coupling magnet. By applying the optimum current in the external coil, it can produce optimum cancellation magnetic field for these interferences. And finally, the effectiveness of the proposed coil by using MRI and finite element analysis is verified.

목차 (Table of Contents)

• 목 차
• Ⅰ. 서 론 1
• Ⅱ. 이식형 의료기기 5
• 2.1 MRI 내 이식형 보청기의 문제점 9
• 2.1.1 MRI 영상의 인공음영 12
• 2.1.2 MRI 촬영을 위한 영구자석 제거수술 14
• Ⅲ. 제안한 외부 코일의 설계 16
• 3.1 정상 전류에 의한 자기장 16
• 3.2 제안한 외부 코일의 설계와 특성 20
• Ⅳ. 실험 및 고찰 25
• 4.1 제안한 외부 코일의 유한요소해석 25
• 4.1.1 유한요소해석을 위한 모델링 25
• 4.1.2 제안한 코일의 디자인에 따른 인공음영의 변화 28
• 4.1.3 제안한 코일의 전류에 따른 인공음영의 변화 30
• 4.1.4 실제 MRI 내 인공음영의 변화 32
• Ⅴ. 결 론 35
• 참 고 문 헌 38
• 영 문 초 록 45