• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.431-438
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• 1995

Functional imaging based on the susceptibility only is achieved by separation of the susceptibility effect from the mixture of flow effect by use of a tailored RF pulse in conjunction with gradient echo sequence. Using the tailored RF pulse the susceptibility enhanced functional imaging appears to be explicitly related to the deoxygenation processes, while in the conventional gradient echo technique functional contrast on $T2^{*}$ effect images appear to be mixed with a significant fraction of blood flow (in- flow) signals of both arterial as well as venous bloods due to the nature of the fast sequence employed with the gradient echo technique. In this paper, using the tailored RF pulses, one can unambiguously separate the susceptibility and flow effects in functional imaging. Since the signal obtained can be made sufficiently high and represents oxygenation process more accurately, it seems possible to study quantitative oxygen metabolisms in brain function hitherto difficult to do with other gradient echo techniques.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.730-732
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• 2003

의료영상정합을 통해서 이상징후 발현시점과 소멸시점의 기능영상을 비교함으로써 기능이상부위를 판별하는 것은 질환의 진단에 매우 유용하다. 본 논문에서는 기존 변화시점간 기능영상 감영법이 정확한 소멸시점에서의 영상 취득이 어려움으로 인해 정확도가 떨어질 우려가 있는 점을 개선하고자 뇌 혈류이상을 나타내는 뇌기능영상인 SPECT의 변화시점 기능이상부위 추출을 위하여 정상인집단 영상의 비선형 영상정합기법과 영상평균화를 통해 뇌기능영상 템플릿을 구축하였다. 또한 이를 기반으로 영상감영을 수행함으로써 간질환자의 발작중(ictal) SPECT 뿐만 아니라 발작간(interictal) SPECT에서도 뇌혈류의 이상을 정확히 분석할 수 있는 3차원 추출가시화 방법을 제시하였다.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.50-57
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• 1998

MR acoustic sound or noise due to gradient pulsings has been one of the problems in MRI, both in patient scanning as well as in many areas of psychiatric and neuroscience research, such as brain fMRI. Especially in brain fMRI, sound noise is one of the serious noise sources which obscures the small signals obtainable from the subtle changes occurring in oxygenation status in the cortex and blood capillaries. Therfore, we have studied the effects of acoustic or sound noise arising in fMR imaging of the auditory, motor and visual cortices. The results show that the acoustical noise effects on motor and visual responses are opposite. That is, for the motor activity, it shows an increased total motor activation while for the visual stimulation, corresponding(visual) cortical activity has diminished substantially when the subject is exposed to a loud acoustic sound. Although the current observations are preliminary and require more experimental confirmation, it appears that the observed acoustic-noise effects on brain functions, such as in the motor and visual cortices, are new observations and could have significant consequences in data observation and interpretation in future fMRI studies.

• Journal of the Korean Magnetics Society
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• v.6 no.4
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• pp.272-276
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• 1996

1948년 Harvard 대학의 Purcell교수와 Stanford 대학의 Bloch교수가 핵자기 공명(Nuclear Magnetic Resonance : NMR) 현상을 발견한 이래로 NMR은 물질의 분자단위에서 화학적, 물리학적 성질을 밝혀내는 탁월한 방법으로 널리 이용되어 왔다. NMR 현상을 이용한 영상촬영법(Magnetic Resonance Imaging, MRI)은 1970년대초 Lauterber와 Damadian 교수가 처음 영상을 얻을 수 있다는 가능성을 제시한 이후 급속한 발전을 하여 1980년대 초에는 Moore와 Holland에 의해 의학분야에 응용 가능할 정도의 영상이 얻어졌다. 1980년대 중반부터 상용화 되었으며 최근 그 기법도 NMR현상과 연관된 파라미터인 $T_{1}$, $T_{2}$는 물론 혈류의 속도, 자화율, 확산(Diffusion), Perfusion의 영상기법을 비롯해 혈관조영술(MR Angiography), 뇌기능영상(Functional Imaging)등 과거에는 상상도 할 수 없었던 다양한 영상기법 개발되었다. 여기서는 먼저 MRI의 원리를 설명한 후 MRI의 여러 촬영기법들과 그 응용에 관해 설명하겠다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.298-298
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• 2004

본 연구는 외부에서 고 농도 (30％)의 산소 공급이 공간 인지 능력에 어떠한 변화를 유발하는지 뇌기능 영상의 시계열 신호 분석을 통해 관찰하고자 한다. 8명의 오른손잡이 남자 대학생 (평균 23.5세)이 피험자로 참여하였다. 21％와 30％ 산소 농도를 각각 BL/min의 양으로 일정하게 공급할 수 있는 장치를 개발하였다. 공간 인지 능력 측정을 위해 20 문항을 포함하는 두 개의 문제지를 제작하였고, 과제 수행 결과로부터 정답률을 산출하였다. 3T MRI 기기를 사용하였고, single-shot EPI 방법으로 뇌기능 영상을 획득하였다.(중략)

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.26-26
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• 2003

목적： 본 연구의 목적은 미각자극에 대한 인간 뇌의 활성화 영역을 측정하고 가시화하여 미각의 뇌 활성화 부위에 대한 기초자료를 마련하는데 있다. 대상 및 방법： 5명의 남자 대학생 (평균 24.8세)을 뇌기능 연구의 실험 대상자로 선정하였고, 대상자들은 미각에 이상이 없고 구강수술 경험이 없는 오른손잡이를 대상으로 3번에 걸쳐 EPI 혈액산 소농도의존(blood oxygen level dependent)법을 이용하여 미각자극에 의한 기능적 자기공명영상 실험을 수행하였다. 미각 자극을 위하여 5％의 saline을 사용하였으며 자체적으로 제작한 Stimulator를 사용하여 자극하였다. 자극은 3회의 휴식기간과 2회의 자극기간에 걸쳐 시행하였으며, 각 자극기간은 30초씩 5초 간격으로 이스 당 42개의 영상을 획득했다. Post-processing은 SPM99 (Statistical Parametric Mapping 99, The Wellcome Department of Cognitive Neurology, Oxford 1999)의 correlation법을 사용하여 threshold 0.4∼0.7의 범위에서 통계처리 하였으며, 활성화 영상은 EPI영상과 같은 부위의 T1 강조영상에 overlapping시켰다. 이렇게 얻어진 fMRI 영상으로 활성 영역의 위치를 분석하였다.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.854-862
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• 2014

Attention deficit hyperactivity disorder (ADHD) students' intellctual defects, learning problems, and poor academic achievements seem to be due to significantly lower intelligence compared to the normal students, but rather the characteristic of inability to pay attention at a given time can be seen as the more attributing reason. In this study, a comparison between the ADHD students and the normal students will be performed using a fMRI analysis in order to differentiate the brain function between the two groups during a working memory task performance and to assess the difference in the activated regions of the brain. Clinical survey examinations and fMRI measurements were performed for a group of 26 elementary students from the Incheon area. The stimulus of fMRI was a working memory. Cartography statistically analyzed parameters and the Statistical Package of Social Sciences using single-sample t-test, two-sample t-test, were analyzed by multiple regression analysis, the statistical significance level was p<0.05 in, respectively. The disproportionate developments could be seen in the ADHD students group such as the frontal cortex, parietal cortex, thalamus, and caudate nucleus, among others. In addition, as some students felt the increase in the difficulty of working memory task performance, the orbitofrontal cortex and the hippocampus were activated, which seems to be the result of an effort for looking for an answer. More types of ADHD students needs to be secured as research subjects, and more stimulations for fMRI experiments should be considered as it would be useful in the overall evaluation of brain function.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.27 no.4
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• pp.43-49
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• 2009

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.233-244
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• 2002

The purpose of this study is to assess the ability of balance control in moving surround using head mount device and force platform and to examine the clinical usefulness of COP parameters. Fifteen patients with stroke and healthy persons were participated. COP parameters were obtained as total path distance, frequency of anterior-posterior and medial-lateral component by FFT analysis, weight-spectrum analysis in the two different conditions; (1) in comfortable standing with opened or closed eyes, (2) in virtual moving surround delivered using HMD to four different moving pattern. In virtual moving surround setting, moving pattern was composed of close-far, superior-inferior tilting(pitch), right-left tilting(roll) and horizontal rotation(yaw) movement. In all parameters, the reliebility of COP analysis system was significantly high. Also, the construct validity compared between fifteen patients with stroke and normal persons was excellent in virtual moving surround condition(p

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.16 no.12
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• pp.32-35
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• 1998