• Title, Summary, Keyword: 강자성 인공물

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Assessment of Magnetic Resonance Image Quality For Ferromagnetic Artifact Generation: Comparison with 1.5T and 3.0T. (강자성 인공물 발생에 대한 자기공명영상 질 평가: 1.5T와 3.0T 비교)

  • Goo, Eun-Hoe
    • Journal of the Korean Society of Radiology
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    • v.12 no.2
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    • pp.193-199
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    • 2018
  • In this research, 15 patients were diagnosed with 1.5T and 3.0T MRI instruments (Philips, Medical System, Achieva) to minize Ferromagnetic artifact and find the optimized Tesla. Based on the theory that the 3.0T, when compared to 1.5T, show relatively high signal-to-ratio(SNR), Scan time can be shortened or adjust the image resolution. However, when using the 3.0T MRI instruments, various artifact due to the magnetic field difference can degrade the diagnostic information. For the analysis condition, area of interest is set at the background of the T1, T2 sagittal image followed by evaluation of L3, L4, L5 SNR, length of 3 parts with Ferromagnetic artifact, and Histogram. The validity evaluation was performed by using the independent t test. As a result, for the SNR evaluation, mere difference in value was observed for L3 between 1.5T and 3.0T, while big differences were observed for both L4, and L5(p<0.05). Shorter length was observed for the 1.5T when observing 3 parts with Ferromagnetic artifact, thus we can conclude that 3.0T can provide more information on about peripheral tissue diagnostic information(p<0.05). Finally, 1.5T showed higher counts values for the Histogram evaluation(p<0.05). As a result, when we have compared the 1.5T and 3.0T with SNR, length of Ferromagnetic artifact, Histogram, we believe that using a Low Tesla for Spine MRI test can achieve the optimal image information for patients with disk operation like PLIF, etc. in the past.

Metal Artifact Caused by Magnetic Field Strength and Sequence on T1WI-MRI (자기공명영상에서 자장세기와 시퀀스에 따른 아티팩트 변화)

  • Ko, Seong-Jin
    • The Journal of the Korea Contents Association
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    • v.10 no.9
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    • pp.302-308
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    • 2010
  • In MRI, the Ferromagnetic artifact is generated by the metalization within in which the before inspection removal is impossible and the distortion of an image is brought. The distortion measure according to the steel for each sequence of T1 image and magnetic field intensity are analyzed and minimized method is looked into. We used SIEMENS 1.5T and 3.0T MRI for experiment equipment. First, it places within the Phantom making a metalization(Ti+Al, Stainless, Nitinol) on 1.5T, 3.0T MRI and the T1 weighted image for each Sequence is acquired. The distortion of an image and about adjacent portion change of the metal material were compared through the obtained image, we analyzed. In all metalizations, a distortion was generated and a distortion was few in particularly, and Titanium-Aluminium alloy. And the extent of a distortion was worse image in the Turbo spin Echo. The use of the Titanium-Aluminium alloy the inserted in an internal material of the metalization is recommend. and, equipment of 1.5T the patient inserting a metal in an internal is used in an inspection than equipment of 3.0T. Also, the sequence is suitable when it obtains the optimum T1 weighted image of an impersonate to use the Turbo spin Echo.

DENTAL TREATMENT IN A PATIENT WITH ATYPICAL TERATOID RHABDOIDAL TUMOR UNDER GENERAL ANESTHESIA (비정형 유기형/간상 종양(Atypical teratoid rhabdoidal tumor) 환자의 전신마취 하 치과치료)

  • Kim, Hyuntae;Song, Ji-Soo;Hyun, Hong-Keun;Kim, Young-Jae;Kim, Jung-Wook;Jang, Ki-Taeg;Lee, Sang-Hoon;Shin, Teo Jeon
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.15 no.1
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    • pp.74-78
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    • 2019
  • Atypical teratoid rhabdoidal tumor(AT/RT) is a rare and fast-growing tumor usually diagnosed in childhood. Routine magnetic resonance imaging(MRI) assessment of AT/RT patients is done to detect metastatic tumors and recurrent lesions. The purpose of this case report is to present a case about caries treatment of a 3-year-8-month old female patient with AT/RT under general anesthesia. A 3-year-8-month old patient with AT/RT visited Seoul National University Dental Hospital for caries treatment. At the first dental visit, she was receiving chemotherapy. Multiple caries were observed from clinical and radiographic examination. The dental procedure was successfully performed under general anesthesia. Patients with brain tumor may take routine MRI to detect metastatic tumors and recurrent lesions. Dentists should take into consideration of possible dislodgement of restoration by ferromagnetic properties and artifact formation on MRI image. Ready-made zirconia crowns can be a good restoration option for such patients.

Analysis of Magnetic Flux Leakage based Local Damage Detection Sensitivity According to Thickness of Steel Plate (누설자속 기반 강판 두께별 국부 손상 진단 감도 분석)

  • Kim, Ju-Won;Yu, Byoungjoon;Park, Sehwan;Park, Seunghee
    • Journal of Korean Society of Disaster and Security
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    • v.11 no.2
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    • pp.53-60
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    • 2018
  • To diagnosis the local damages of the steel plates, magnetic flux leakage (MFL) method that is known as a adaptable non-destructive evaluation (NDE) method for continuum ferromagnetic members was applied in this study. To analysis the sensitivity according to thickness of steel plate in MFL method based damage diagnosis, several steel plate specimens that have different thickness were prepared and three depths of artificial damage were formed to the each specimens. To measured the MFL signals, a MFL sensor head that have a constant magnetization intensity were fabricated using a hall sensor and a magnetization yoke using permanent magnets. The magnetic flux signals obtained by using MFL sensor head were improved through a series of signal processing methods. The capability of local damage detection was verified from the measured MFL signals from each damage points. And, the peak to peak values (P-P value) extracted from the detected MFL signals from each thickness specimen were compared each other to analysis the MFL based local damage detection sensitivity according to the thickness of steel plate.