TY - JOUR
T1 - Reduction of artifact of metallic implant in magnetic resonance imaging by coating of diamagnetic material
AU - Gao, Yanhui
AU - Muramatsu, Kazuhiro
AU - Kushibe, Atsumichi
AU - Yamazaki, Keita
AU - Chiba, Akihiko
AU - Yamamoto, Tom
PY - 2009/10
Y1 - 2009/10
N2 - Metallic implants composed of paramagnetic materials, such as stainless steel (SUS), Ti, Co-Cr-Mo alloy, etc., are widely used as artificial hip joints or aneurysm clips. When the metallic implant is placed in a uniform magnetic field of a magnetic resonance scanner, a magnetic disturbance is created due to its magnetization. This magnetic disturbance distorts the image of the metallic implant and body tissues in the magnetic resonance imaging (MRI). In order to overcome this problem, a method of coating the metallic implant with diamagnetic material has been proposed as the magnetic disturbance created by the metallic implant can be removed by the cancellation of the respective magnetizations of the paramagnetic and diamagnetic materials. But the optimal thickness of the diamagnetic coating has been obtained only for a sphere model by mathematical modeling. In this paper, the effects of a straight cylindrical hip joint model and an aneurysm clip model on the magnetic disturbance are investigated by using the magnetic field analysis of the finite element method (FEM). First, the magnetic disturbances generated by the two models made of paramagnetic material are calculated and compared with measured results. Moreover, the associations of susceptibilities Xpar and Xdia of the paramagnetic and diamagnetic materials and the optimal thicknesses of the diamagnetic coating when the magnetic disturbances can be reduced for the two models are shown.
AB - Metallic implants composed of paramagnetic materials, such as stainless steel (SUS), Ti, Co-Cr-Mo alloy, etc., are widely used as artificial hip joints or aneurysm clips. When the metallic implant is placed in a uniform magnetic field of a magnetic resonance scanner, a magnetic disturbance is created due to its magnetization. This magnetic disturbance distorts the image of the metallic implant and body tissues in the magnetic resonance imaging (MRI). In order to overcome this problem, a method of coating the metallic implant with diamagnetic material has been proposed as the magnetic disturbance created by the metallic implant can be removed by the cancellation of the respective magnetizations of the paramagnetic and diamagnetic materials. But the optimal thickness of the diamagnetic coating has been obtained only for a sphere model by mathematical modeling. In this paper, the effects of a straight cylindrical hip joint model and an aneurysm clip model on the magnetic disturbance are investigated by using the magnetic field analysis of the finite element method (FEM). First, the magnetic disturbances generated by the two models made of paramagnetic material are calculated and compared with measured results. Moreover, the associations of susceptibilities Xpar and Xdia of the paramagnetic and diamagnetic materials and the optimal thicknesses of the diamagnetic coating when the magnetic disturbances can be reduced for the two models are shown.
KW - Diamagnetic material
KW - Index Terms-Artifact
KW - Magnetic field analysis
KW - Metallic implant
KW - MRI
KW - Paramagnetic material
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U2 - 10.1109/TMAG.2009.2025774
DO - 10.1109/TMAG.2009.2025774
M3 - Article
AN - SCOPUS:70350581151
SN - 0018-9464
VL - 45
SP - 4837
EP - 4840
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 10
M1 - 5257229
ER -