• Journal of the Korean Society of Radiology
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• v.83 no.2
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• pp.420-424
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• 2022

Fibrous hamartoma of infancy in the middle ear is extremely rare. We report the case of a 26-month-old male patient who presented with a mass in the left middle ear. A temporal bone CT scan showed complete opacification of the left middle ear and mastoid air cells without ossicular erosion. On MRI, the mass revealed heterogeneous signal intensities indicative of fat and fibrous components. A definitive diagnosis was made postoperatively based on the histological results. Although rare, fibrous hamartoma of infancy should be considered as a differential diagnosis of a middle ear mass during childhood.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.453-458
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• 2020

Hashimoto's encephalopathy (HE) is a rare autoimmune disease characterized by a high serum concentration of antithyroid antibodies without evidence of cerebral disease. Magnetic resonance imaging (MRI) findings in HE patients are nonspecific, although diffuse or focal white matter changes have been reported in several cases. We present a rare case involving a 79-year-old woman with elevated antithyroid antibody levels and abnormal imaging findings similar to meningoencephalitis. Serial MRI initially showed multiple T2 hyperintense lesions with diffuse leptomeningeal enhancement that disappeared after steroid therapy.

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.89-97
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• 2006

Purpose : To evaluate MR image qualities we developed a new MRI phantom with the fixation structures necessary to position it into coil firmly. Materials and methods : We designed MRI phantom for eight evaluation items such as slice thickness accuracy, high contrast spatial resolution, low contrast object detectability, geometry accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting and signal to noise ratio. For the positioning of phantom at coils, the fixation structures were set up on the surface of phantom. Six different MRI units were used for test the possibility for the clinical application and their image qualities were evaluated. Results : We acquired appropriate MR image qualities enough for the evaluation on all used MR units and confirmed that their evaluations were within reliable values compared to real ones for some items. The positioning of our phantom into head coils with fixation structures worked well for proper imaging. Conclusion : We found that our prototype of MRI phantom had the possibility of clinical application for MR image quality assessment.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.51-74
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• 2023

Multiple myeloma, which is a proliferative disease of plasma cells that originate from a single clone, is the second most common hematologic malignancy following non-Hodgkin lymphoma. In the past, its diagnosis was made based on clinical findings (so-called "CRAB") and a skeletal survey using radiographs. However, since the implementation of the International Myeloma Working Group's revised guideline regarding the radiologic diagnosis of multiple myeloma, whole-body (WB) MRI has emerged to play a central role in the early diagnosis of multiple myeloma. Diffusion-weighted imaging and fat quantification using Dixon methods enable treatment response assessment by MRI. In keeping with the trend, a multi-institutional and multidisciplinary consensus for standardized image acquisition and reporting known as the Myeloma Response Assessment and Diagnostic System (MY-RADS) has recently been proposed. This review aims to describe the clinical application of WB-MRI based on MY-RADS in multiple myeloma, discuss its limitations, and suggest future directions for improvement.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.149-149
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• 2001

목적： Birdcage coil보다 SNR이 높은 Surface coil을 이용하여 시각 자극에 대한 반응 정도의 차이를 보이고자 한다. 대상 및 방법： 연구 개발 중인 Magnum 3.0T로 영상을 얻었다. 실험 대상자는 정상인 지원자로 하였고, 10Hz로 깜박거리는 발광다이오드를 이용하여 시각 자극을 실행하였다. 일정 paradigm으로 얻어진 영상은 SPM으로 분석하였다.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.3-13
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• 2004

Objectives:Functional magnetic resonance imaging(fMRI) is one of the most useful techniques for assessing localized changes in cerebral blood flow and oxygenation using diverse challenge paradigms. This review presents the results of fMRI studies relating to schizophrenia. Methods:Several fMRI articles on this subject in psychiatric journals were surveyed. Results:Even with some methodological limitations, most studies showed activity differences between schizophrenics and control subjects. Conclusion:fMRI extends our understanding of the pathophysiological basis of schizophrenia and offer an opportunity for the assessment and management of its pathology.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.183-189
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• 2009

Purpose : To evaluate the usefulness of three-dimensional (3D) maximal intensity projection (MIP) reconstruction method in breast MRI. Materials and Methods : Total 54 breasts of consecutive 27 patients were examined by breast MRI. Breast MRI was performed using GE Signa Excite Twin speed (GE medical system, Wisconsin, USA) 1.5T. We obtained routine breast MR images including axial T2WI, T1WI, sagittal T1FS, dynamic contrast-enhanced T1FS, and subtraction images. 3D MIP reconstruction images were obtained as follows; subtraction images were obtained using TIPS and early stage of contrast-enhanced TIPS images. And then 3D MIP images were obtained using the subtraction images through advantage workstation (GE Medical system). We detected and analyzed the lesions in the 3D MIP and routine MRI images according to ACR $BIRADS^{(R)}$ MRI lexicon. And then we compared the findings of 3D MIP and those of routine breast MR images and evaluated whether 3D MIP had additional information comparing to routine MR images. Results : 3D MIP images detect the 43 of 56 masses found on routine MR images (76.8%). In non-mass like enhancement, 3D MIP detected 17 of 20 lesions (85 %). And there were one hundred sixty nine foci at 3D MIP images and one hundred nine foci at routine MR images. 3D MIP images detected 14 of 23 category 3 lesions (60.9%), 11 of 16 category 4 lesions (68.87%), 28 of 28 Category 5 lesions (100%). In analyzing the enhancing lesions at 3D MIP images, assessment categories of the lesions were correlated as the results at routine MR images (p-value < 0.0001). 3D MIP detected additional two daughter nodules that were descriped foci at routine MR images and additional one nodule that was not detected at routine MR images. Conclusion : 3D MIP image has some limitations but is useful as additional image of routine breast MR Images.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.295-296
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• 2016

본 연구에서는 LED 광 자극이 뇌의 어느 영역을 자극하여 신경신호를 전달하는지에 관해서 관찰하고자 연구를 진행하였다. 광 자극에 의한 뇌 영역의 활성변화를 관찰하기 위하여 실험용 소동물과 영상장비인 9.4T MRI를 이용하여 연구를 수행 하였다. 실험용 소동물은 Balb/c 마우스를 이용하였으며 기능적 자기공명영상 획득 방법 중 하나인 에코평면영상 기법을 이용하여 뇌 영상을 획득 하였다. 획득한 영상을 바탕으로 뇌 영역의 자극 정도를 확인해보기 위해 영상처리기법인 재편성(realignment), 일치(co-registration), 표준화(normalization), 평활화(smoothing) 방법으로 영상을 전처리 하고, statistical parametric map (SPM12)을 사용하여 분석하였다. 본 연구에서는 광자극이 소동물 뇌 영역 중 하나인 상구(Superior colliculus)영역과 대뇌의 시각피질 (visual cortex, V1) 영역에서 자극을 일으키는 것을 확인할 수 있었다.

• Progress in Medical Physics
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• v.9 no.4
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• pp.207-215
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• 1998

There have been many radiation measurement methods so far among which film dosimetry, TLD, and ion chamber are the most frequently used methods. But this study describes a new radiation measurement method which uses polymer gel and magnetic resonance imaging(MRI). The objective of this study is to fabricate a polymer gel sensitive to radiation and to generate a dose to MRI contrast relationship, and to apply this results to the radiation measurement for the brachytherapy. To do this, 12 cm diameter cylindrical gel phantom was made, and the phantom was irradiated using the 30 mm diameter circular collimator which was used for radiosurgery. And this irradiated phantom was scanned with MRI. To find out the relationship between the radiation dose and the transversal relaxation time, an image processing software(IDL) was used. From this study it is found out that the radiation dose showed linear relationship to the transversal relaxation time of the gel up to 17 Gy($R^2$=0.993) and they had a different relationship above 17 Gy. The dose distributions were calculated using these results for the Ir-192 sources, one for the HDR afterloading system and the other for a 2 mCi seed source. And these calculated dose distributions were compared to the ones from the treatment planning computers. From this study the dose to the irradiated gel's transversal relaxation time relationship was examined, and this result was tried for the measurement of the brachytherapy.

• Journal of Science and Technology Studies
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• v.14 no.2
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• pp.199-222
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• 2014

Functional Magnetic Resonance Angiography (fMRA) was a technoscientific innovation that allows scientists to directly view the changes made in the blood vessels of a brain. fMRA was first developed at Neuroscience Research Institute (NRI) in Korea. fMRA mainly utilizes 7 Tesla MRI technology, and NRI is equipped with the instrument. First article on fMRA was published in 2008, and two more papers in 2010 and 2012 consecutively had been published on the newly developed technique. However, fMRA is a competitive technology with existing fMRI. Both techniques capture microvascular changes in a brain, and by doing it, both techniques visualize the cognitive and affective changes. fMRI technology was introduced by Seiji Ogawa in the early 1990's and has been widely used since then. In contrast, fMRA was a newer technology and rather unknown. Developers of fMRA in NRI used series of signifiant-politics in order to make it better known to scientific community as well as public. By resetting the boundaries of existing concept of fMRI, they tried to lower the threshold of a new concept/technique. This case study shows how technoscientists use semiotic strategies governing new technology.