• 응용통계연구
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• 제34권2호
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• pp.127-139
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• 2021

독립성분분석은 혼합 데이터로부터 독립된 신호들을 분리해내는 대표적인 통계적 방법론이며, 그룹 독립성분분석은 독립성분분석을 여러 개체에 적용할 수 있도록 확장한 방법론이다. 그룹 독립성분분석은 기능적 자기 공명 영상 데이터에 활용되어 의학적으로 유의미한 결과를 줌이 알려져있다. 그러나 자기 공명 영상 스캔에서 흔히 일어나는 이상치가 포함되어 있는 경우, 기존의 그룹 독립성분분석은 그 효과가 떨어짐이 알려져있다. 본 연구에서는 ROBPCA 기반의 로버스트한 그룹 독립성분분석 방법론을 제안하였다. 시뮬레이션과 실제 자료 분석을 통해 제안한 방법과 기존 방법을 비교하였고, 그 결과 제안한 방법론의 로버스트성을 입증했다.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2003년도 추계학술대회 논문집
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• pp.191-191
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• 2003

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 1996년도 추계학술대회 초록집
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• pp.79-84
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• 1996

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2003년도 제8차 학술대회 초록집
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• pp.85-85
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• 2003

Purpose： To investigate whether or not acupuncture of GB34 produces a significant response of the modulation of somatomotor areas by functional magnetic resonance imaging (fMRI) study. Materials and methods： The acupoint, GB34, located in the back of the knee, is known to be effective in recovering motor function after stroke. Using 3T MRI scanner, functional MR imaging of the whole brain was peformed in 12 normal healthy subjects during two stimulation paradigms; acupuncture manipulation on GB34 and sham points. This study investigates the activation of the motor cortex elicited by a soft and an intensified stimulation of GB 34.Three different paradigms were carried out to detect any possible modulation of the Blood Oxygenation Level Dependent (BOLD) response in the somatomortor area to motor stimulation through acupuncture.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.15-19
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• 2001

지난 10년간 신경계의 MR영상은 컴퓨터를 비롯한 하드웨어적인 발달에 힘입어 functional imaging, perfusion imaging, diffusion imaging, MR spectroscopy, MR angiography 등의 분야에서 괄목한 만한 성장이 있었다. 지난 2001년 4월 국제자기공명의과학회 (ISMRM) 학술대회에 약 2300개의 논문이 발표되었으며 이 중 신경계와 관련된 논문의 수는 저자가 파악하기에 약 500개 정도이었다. 매년 수많은 논문이 발표되고 있으나 이 중 기초 또는 임상의학적으로 유용한 논문만이 후속 연구로 연결되어 궁극적으로 많은 사람들이 활용할 수 있게 되고 있다. 따라서 지난 수 년 동안의 연구 동향을 모두 follow-up하는 것은 무의미하며, 이 중 functional, perfusion, diffusion imaging을 중심으로 이들 영상 기법의 기술적 측면과 적용 분야를 알아보고자 한다.

• Journal of Neurogastroenterology and Motility
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• 제24권4호
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• pp.512-527
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• 2018

This review provides a comprehensive overview of brain imaging studies of the brain-gut interaction in functional gastrointestinal disorders (FGIDs). Functional neuroimaging studies during gut stimulation have shown enhanced brain responses in regions related to sensory processing of the homeostatic condition of the gut (homeostatic afferent) and responses to salience stimuli (salience network), as well as increased and decreased brain activity in the emotional response areas and reduced activation in areas associated with the top-down modulation of visceral afferent signals. Altered central regulation of the endocrine and autonomic nervous responses, the key mediators of the brain-gut axis, has been demonstrated. Studies using resting-state functional magnetic resonance imaging reported abnormal local and global connectivity in the areas related to pain processing and the default mode network (a physiological baseline of brain activity at rest associated with self-awareness and memory) in FGIDs. Structural imaging with brain morphometry and diffusion imaging demonstrated altered gray- and white-matter structures in areas that also showed changes in functional imaging studies, although this requires replication. Molecular imaging by magnetic resonance spectroscopy and positron emission tomography in FGIDs remains relatively sparse. Progress using analytical methods such as machine learning algorithms may shift neuroimaging studies from brain mapping to predicting clinical outcomes. Because several factors contribute to the pathophysiology of FGIDs and because its population is quite heterogeneous, a new model is needed in future studies to assess the importance of the factors and brain functions that are responsible for an optimal homeostatic state.

• Korean Journal of Radiology
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• 제24권11호
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• pp.1114-1130
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• 2023

Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial and lumbosacral plexi are challenging because of the anatomical complexity and technical limitations. The purpose of this article was to review the clinical context of MRN, describe advanced magnetic resonance (MR) techniques for plexus imaging, and list the general categories of utility of MRN with pertinent imaging examples. The selection and optimization of MR sequences are centered on the homogeneous suppression of fat and blood vessels while enhancing the visibility of the plexus and its branches. Standard 2D fast spin-echo sequences are essential to assess morphology and signal intensity of nerves. Moreover, nerve-selective 3D isotropic images allow improved visualization of nerves and multiplanar reconstruction along their course. Diffusion-weighted and diffusion-tensor images offer microscopic and functional insights into peripheral nerves. The interpretation of MRN in the brachial and lumbosacral plexi should be based on a thorough understanding of their anatomy and pathophysiology. Anatomical landmarks assist in identifying brachial and lumbosacral plexus components of interest. Thus, understanding the varying patterns of nerve abnormalities facilitates the interpretation of aberrant findings.

• 한국초등과학교육학회지:초등과학교육
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• 제26권1호
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• pp.49-62
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• 2007

The higher cognitive functions of the human brain including teaming are hypothesized to be selectively distributed across large-scale neural networks interconnected to the cortical and subcortical areas. Recently, advances in functional imaging have made it possible to visualize the brain areas activated by certain cognitive activities in vivo. Neural substrates for teaming and motivation have also begun to be revealed. Functional magnetic resonance imaging (fMRI) provides a non-invasive indirect mapping of cerebral activity, based on the blood- oxygen level dependent (BOLD) contrast which is based on the localized hemodynamic changes following neural activities in certain areas of the brain. The fMRI method is now becoming an essential tool used to define the neuro-functional mechanisms of higher brain functions such as memory, language, attention, learning, plasticity and emotion. Further research in the field of education will accelerate the verification of the effects on loaming or help in the selection of model teaching strategies. Thus, the purpose of this study was to review brain study methods using fMRI in science education. In conclusion, a number of possible strategies using fMRI for the study of elementary science education were suggested.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 춘계학술대회
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• pp.21-24
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• 1993

The experimental results of visual stimulation with the tailored RF pulse are reported. Tailored RF pulse is used for the susceptibility effect imaging. Around 25% signal change of visual cortex area is detected during photic stimulation. Interestingly, with the tailored RF pulse, the signal intensity of visual cortex is deceased during photic stimulation. It is, however, increased with normal $T_2$ weighted imaging. The comparison between normal $T_2$ weighted imaging and the tailored RF pulse imaging are performed with 4T NMR system and the results with human volunteer are also presented.

• 한국멀티미디어학회논문지
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• 제24권5호
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• pp.684-694
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• 2021

Resting-state Functional Magnetic Resonance Imaging(fMRI) data detects the temporal correlations in Blood Oxygen Level Dependent(BOLD) signal and these temporal correlations are regarded to reflect intrinsic cortical connectivity, which is deactivated during attention demanding, non-self referential tasks, called Default Mode Network(DMN). The relationship between fMRI and anatomical connectivity has not been studied in detail, however, the preceded studies have tried to clarify this relationship using Diffusion Tensor Imaging(DTI) and fMRI. These studies use method that fMRI data assists DTI data or vice versa and it is used as guider to perform DTI tractography on the brain image. In this study, we hypothesized that functional connectivity in resting state would reflect anatomical connectivity of DMN and the combined images include information of fMRI and DTI showed visible connection between brain regions related in DMN. In the previous study, functional connectivity was determined by subjective region of interest method. However, in this study, functional connectivity was determined by objective and advanced method through Independent Component Analysis. There was a stronger connection between Posterior Congulate Cortex(PCC) and PHG(Parahippocampa Gyrus) than Anterior Cingulate Cortex(ACC) and PCC. This technique might be used in several clinical field and will be the basis for future studies related to aging and the brain diseases, which are needed to be translated not only functional connectivity, but structural connectivity.