• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.42-47
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• 2002

No Abstract, See Full Text

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.364-367
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• 1999

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.26-32
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• 1992

Minimal deterioration of cerebral perfusion or microanatomical changes were undetectable on conventional Brain CT or MRI. So evaluation of focal functional changes of the brain parenchyme is essential in chronic head injury patients, who did not show focal anatomical changes on these radiological studies. However, the patients who had longstanding neurologic sequelae following head injury, there had been no available imaging modalities for evaluating these patients precisely. Therefore we tried to detect the focal functional changes on the brain parenchyme using $^{99m}Tc-HMPAO$ Brain SPECT on the patients of chronic head injuries. Twenty three patients who had suffered from headache, memory dysfunction, personality change and insomnia lasting more than six months fellowing head injury were included in our cases, which showed no anatomical abnormalities on Brain CT or MRI. At first they underwent psychological test whether the symptoms were organic or not. Also we were able to evaluate the cerebral perfusion changes with $^{99m}Tc-HMPAO$ Brain SPECT in 22 patients among the 23, which five patients were focal and 17 patients were nonfocally diffuse perfusion changes. Thus we can predict the perfusion changes such as local vascular deterioration or functional defects using $^{99m}Tc-HMPAO$ Brain SPECT in the patients who had suffered from post-traumatic sequelae, which changes were undetectable on Brain CT or MRI.

• Journal of The Korean Association For Science Education
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• v.32 no.3
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• pp.524-531
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• 2012

Categorization is an important human function used to process different stimuli. It is also one of the most important factors affecting measurement of a person's classification ability. Explicit categorization, the representative system by which categorization ability is measured, can verbally describe the categorization rule. The purpose of this study was to develop a prediction model for categorization ability as it relates to the classification process of living organisms using fMRI. Fifty-five participants were divided into two groups: a model generation group, comprised of twenty-seven subjects, and a model verification group, made up of twenty-eight subjects. During prediction model generation, functional connectivity was used to analyze temporal correlations between brain activation regions. A classification ability quotient (CQ) was calculated to identify the verbal categorization ability distribution of each subject. Additionally, the connectivity coefficient (CC) was calculated to quantify the functional connectivity for each subject. Hence, it was possible to generate a prediction model through regression analysis based on participants' CQ and CC values. The resultant categorization ability regression model predictor was statistically significant; however, researchers proceeded to verify its predictive ability power. In order to verify the predictive power of the developed regression model, researchers used the regression model and subjects' CC values to predict CQ values for twenty-eight subjects. Correlation between the predicted CQ values and the observed CQ values was confirmed. Results of this study suggested that explicit categorization ability differs at the brain network level of individuals. Also, the finding suggested that differences in functional connectivity between individuals reflect differences in categorization ability. Last, researchers have provided a new method for predicting an individual's categorization ability by measuring brain activation.

• Journal of The Korean Association For Science Education
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• v.29 no.7
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• pp.751-758
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• 2009

The purpose of this study was to investigate brain activation pattern and functional connectivity network during classification on the biological phenomena. Twenty six right-handed healthy science teachers volunteered to be in the present study. To investigate participants' brain activities during the tasks, 3.0T fMRI system with the block experimental-design was used to measure BOLD signals of their brain. According to the analyzed data, superior, middle and inferior frontal gyrus, superior and inferior parietal lobule, fusiform gyrus, lingual gyrus, and bilateral cerebellum were significantly activated during participants' carrying-out classification. The network model was consisting of six nodes (ROIs) and its fourteen connections. These results suggested the notion that the activation and connections of these regions mean that classification is consist of two sub-network systems (top-down and bottom-up related) and it functioning reciprocally. These results enable the examination of the scientific classification process from the cognitive neuroscience perspective, and may be used as basic materials for developing a teaching-learning program for scientific classification such as brain-based science education curriculum in the science classrooms.

• Korean Journal of Biological Psychiatry
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• v.21 no.1
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• pp.1-13
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• 2014

Normal aging causes changes in the brain volume, connection, function and cognition. The brain changes with increases in age and difference of gender varies at all levels. Studies about normal brain aging using various brain magnetic resonance imaging (MRI) variables such as gray and white matter structural imaging, proton spectroscopy, apparent diffusion coefficient, diffusion tensor imaging and functional MRI are reviewed. Total volume of brain increases after birth but decreases after 9 years old. During adulthood, total volume of brain is relatively stable. After 35 years old, brain shrinks gradually. The changes of gray and white matters by aging show different features. N-acetylaspartate decreases or remains unchanged but choline, creatine and myo-inositol increase with aging. Apparent diffusion coefficient decreases till 20 years old and then becomes stable during adulthood and increase after 60 years old. Diffusion tensor properties in white matter tissue are variable during aging. Resting-state functional connectivity decreases after middle age. Structural and functional brain changes with normal aging are important for studying various psychiatric diseases such as dementia, schizophrenia and bipolar disorder. Our review may be helpful for studying longitudinal changes of these diseases and successful aging.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.209-217
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• 2004

Evaluation of dementia in patients with early symptoms of cognitive decline is clinically challenging, but the need for early, accurate diagnosis has become more crucial, since several medication for the treatment of mild to moderate Alzheimer' disease are available. Many neurodegenerative diseases produce significant brain function alteration even when structural imaging (CT or MRI) reveal no specific abnormalities. The role of PET and SPECT brain imaging in the initial assessment and differential diagnosis of dementia is beginning to evolve vapidly and growing evidence indicates that appropriate incorporation of PET into the clinical work up can improve diagnostic and prognostic accuracy with respect to Alzheimer's disease, the most common cause of dementia in the geriatric population. in the fast few years, studios comparing neuropathologic examination with PET have established reliable and consistent accuracy for diagnostic evaluations using PET - accuracies substantially exceeding those of comparable studies of diagnostic value of SPECT or of both modalities assessed side by side, or of clinical evaluations done without nuclear imaging. This review deals the role of functional brain imaging techniques in the evaluation of dementias and the role of nuclear neuroimaging in the early detection and diagnosis of Alzheimer's disease.

• 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.

• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.453-460
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• 2013

Objective : There is a rich literature confirming the default mode network found compatible with task-induced deactivation regions in normal subjects, but few investigations of alterations of the motor deactivation in patients with intracranial lesions. Therefore, we hypothesized that an intracranial lesion results in abnormal changes in a task-induced deactivation region compared with default mode network, and these changes are associated with specific attributes of allocated regions. Methods : Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) during a motor task were obtained from 27 intracranial lesion patients (mean age, 57.3 years; range 15-78 years) who had various kinds of brain tumors. The BOLD fMRI data for each patient were evaluated to obtain activation or deactivation regions. The distinctive deactivation regions from intracranial lesion patients were evaluated by comparing to the literature reports. Results : There were additive deactivated regions according to intracranial lesions : fusiform gyrus in cavernous hemangioma; lateral occipital gyrus in meningioma; crus cerebri in hemangiopericytoma; globus pallidus, lateral occipital gyrus, caudate nucleus, fusiform gyrus, lingual gyrus, claustrum, substantia nigra, subthalamic nucleus in GBM; fusiform gyrus in metastatic brain tumors. Conclusion : There is increasing interest in human brain function using fMRI. The authors report the brain function migrations and changes that occur in patients with intracranial lesions.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.66-74
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• 1997

fMRI, functional MRI introduced receently appears based on the gradient echo technique which is sensitive to the field inhomogeneity developed due to the local susceptibility changes of blood oxygenation and deoxygenation. There has been many variants of the basic gradient echo sequence which is sensitive to the local inhomogeniety, among others such as GRASS or SSFP to EPISTAR are the most commonly used gradient echo techniques. Common to all these gradient echo techniques is that the signal due to the susceptibility effects is generally decreased with increasing inhomogeneity due to the $T2^{*}$ effect or conventionally konwn as blood oxygenation level dependent(BOLD) effect. It is, also found that the BOLD sensitivity is also dependent on the imaging modes, namely whether the imaging is in axial, or coronal or sagittal mode as well as the directions of the vessels against the main magnetic field. We have, therefore, launched a systematic study of imaging mode dependent signal change or BOLD sensitivity as well as the signal changes due tothe tilting angle of the imaging planes. Study has been made for both TRFGE sequence and CGE sequence to compare the distinctions of the each mode since each technique has different sensitivity againsst susceptibility effect. Method of computation and both the computer simulations and their corresponding experimental results are presented.