• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.9 no.2
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• pp.218-226
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• 1998

This study aims at investigating the effects of psychostimulant on functional cerebral localization during the attentional tasks in ADHD. Inclusional subjects were 13 boy between 6-12 years old who met the DSM-IV criteria for ADHD. In each patient, there was a drugfree period(without methyphenidate) and a drug-loaded period(with oral methylphenidate administration), and within each period there was a resting state and a stimulated state with TOVA. Comparisons were made by measuring the amplitudes of four bands(${\alpha}$, ${\beta}$, ${\delta}$, ${\theta}$) of quantitative EEG to see if there were any differences between the drug-free period(resting and stimulated) and the drug-loaded period(resting and stimulated). In the resting state, there was no difference between the drug-free and drug-loaded periods. In the stimulated state with TOVA, the presence of methylphenidate induced significant changes in the theta to beta ratio(${\theta}/{\beta}$) in the right frontal, right parieto-occipital, and left temporal-parietal areas in contrast to the drugf-ree period. These data suggest that methylphenidate shows electrophysiological influences on cerebral topographical activities during the attentional tasks in ADHD.

• Journal of Korean Neurosurgical Society
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• v.30 no.4
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• pp.522-527
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• 2001

We present a case of recurrent extraventricular neurocytoma with malignant glial differentiation in left temporoparietal area. A 37-year-old man with presentation of generalized seizure had undergone biopsy of brain tumor in left parietal area in 1987, which revealed extraventricular neurocytoma and radiotherapy was followed. Postoperative course was uneventful until eleven years after biopsy, when he became gradually aphasic and right hemiplegic. Brain CT and MRI revealed enlargement of tumor with peritumoral edema and calcifications. He underwent subtotal tumor removal in 1998. Microscopic examination of second biopsy specimen revealed presence of large areas composed of anaplastic glial cells with frequent mitosis, nuclear pleomorphism, large eosinophilic cytoplasm and eccentric nuclei, resembling gemistocytes, which were strongly immunoreactive to glial fibrillary acidic protein(GFAP) but not to synaptophysin(SNP). Also focal areas of neuronal cells were found, which were immunoreactive to SNP but not to GFAP. These histologic findings imply that this recurred tumor was a high grade, mixed tumor with divergent differentiation of neuronal and astrocyte lineage. We report a rare case of extraventricular cerebral neurocytoma with malignant glial differentiation with review of the literature.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2002.05a
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• pp.211-215
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• 2002

본 실험은 종합적 인지과정을 추론할 수 있는 결합 문제(binding problem)를 언어적인지 과정을 통해 알아 본 실험으로, 총 10 명(남:61여:4, 평균나이:24.40 $\pm$ 1.35)의 정상군을 대상으로, 4개의 음소로 이루어진 단음절 명사를 목표 자극(target stimulus)으로 하고, 4개 음소의 임의적인 조합으로서 글자를 이루지 못하는 비목표 자극(non-target stimulus)을, 각각 200 회와 800 회씩 시각적으로 0.5초씩 무작위로 제시하여 128 채널 고밀도 사건관련전위(ERP)를 측정하였다. 이번 실험 결과의 주요 특징은 글자가 아닌 비목표 자극보다 글자인 목표 자극에서 두드러지게 나타난 두정엽 부근의 P500 과 N900 이라고 할 수 있다. 자극 제시 비율의 차이에서 오는 oddball 효과로 인한 기존 P300 의 인지적 의미를 이번 결과의 P500 이 함축한다고 볼 수 있으며, 단음절 단어를 인지할 때, 글자임을 인식하는 순간은 의미적인지 과정이 진행되었다기보다 그 글자의 형태만으로 낯익은 글자인지를 분간하는 것으로 보인다 따라서, 이 경우 기존 언어 실험에 자주 등장하던 의미론적 peak 인 N400 은 보이지 않고, 곧바로 형태적이고, 통사적(syntactic)인 인지 처리 과정인 P500이 나타났다고 해석할 수 있다. 하지만, 이번 실험에서는 N400 대신에 N900 이 나타났다. 이 결과는 이번 ERP 실험과 병행된 프로토콜 분석을 통해, 피험자가 자극 제시 후, 약 900ms 정도에, 이미 제시되고 사라진 글자 자극을 다시 한번 떠올리는 인지 과정이 일어난다는 점과 관련 지어 해석하면, 기존에 의미적(semantic) 인지 과정으로만 해석했던 negative-peak 를 생각(thinking)과 같은 내재적인지 과정(internal cognitive process)으로 확장하여 일반화하는 추론도 생각해 볼 수 있다. 요컨대, 언어인지를 통한 이번 실험을 통해, 뇌파에서 검출되는 negative-peak 은 internal cognitive process로 추측되고, positive-peak 는 external cognitive process 라고 생각된다. 덧붙여, 유의해서 볼 점은 각 peak-topology 에서 Cz 의 진폭이 Fz 보다 크게 나온 점과, 일반적으로 언어 기능을 담당한다는 좌측 측두엽(T7)이 우측(T8)보다 통계적으로 더 유의미한 차이를 보였다는 점등이다.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.650-654
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• 2009

A 1-week-old, male Korean native calf with acute clinical signs of depression, mild diarrhea, ataxia, recumbency and tremor was referred to Chonbuk Veterinary Medical Center of Chonbuk National University. Vision loss and cornea edema were also observed on physical examination. The patient had been deteriorated with nystagumus, strabisumus and opisthtonus. Blood cell count test and blood biochemistry test revealed remarkable leukocytosis, and hypoalbuminemia and increased blood urea nitrogen. No remarkable findings were observed on radiography. On magnetic resonance imaging study, there were enlarge lateral, third, and forth ventricles. The cortical grey and subcortical white matter of left temporal lobe showed hypointense on T1-weighted images and hyperintense on T2-weighted images, and slightly enhanced on contrast-enhanced T1-weighted images. Escherichia coli strain was identified from cerebrospinal fluid sample. Palliative treatment was attempted but the neonatal calve was expired three days after admission. Severe multifocal fibrino-suppurative meningitis with Escherichia coli infection was confirmed histopathologically.

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.47-54
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• 2002

Purpose : Hippocampal atrophy is one of the characteristic pathologic findings of hippocampal sclerosis, for which MR imaging of the hippocampus is essential in the evaluation of hippocampal sclerosis. The purpose of this study is to present the normal MR volumetric data of the hippocampus in normal adult Korean and to compare those with MR volumetric data of hippocampus in patients with hippocampal s-clerosis, providing the diagnostic volume criteria of the hippocampal atrophy. Materials and methods : MR volumetry was performed in 30 normal adults and 28 patients with temporal lobe epilepsy whose final diagnosis was hippocampal sclerosis. The volumetric data were compared between sexes, right and left sides, and normal and abnormal hippocampus, and the volume criteria for the diagnosis of hippocampal atrophy was determined. Results : The mean $volumes({\pm}standard$ deviation) of normal Korean adult were $2.20{\pm}0.73\textrm{cm}^3$ (right) and $2.17{\pm}0.72\textrm{cm}^3$ (left) in male and $2.27{\pm}0.47{\;}\textrm{cm}^3$ (right) and $2.23{\pm}0.48\textrm{cm}^3$ (left) in female. The mean right-left differences were $0.14{\pm}0.11\textrm{cm}^3$ and $0.19{\pm}0.13\textrm{cm}^3$ in male and female, respectively. The MR volumetry showed no significant statistical differences between sexes and between right and left. The mean volume and standard deviation of the hippocampus in hippocampal sclerosis patients was $1.46{\pm}0.60{\;}\textrm{cm}^3$, and the right-left difference was $0.51{\pm}0.41\textrm{cm}^3$, In comparison of two volume distributions between normal adult group and hippocampal sclerosis patients group, the reasonable diagnostic volume criteria was $0.4{\;}\textrm{cm}^3$ as right-left volume difference, in which the sensitivity and specificity are 0.61 and 0.90. In all patients with right-left volume difference more than $0.4{\;}\textrm{cm}^3$, visual determination of unilateral hippocampal atrophy was possible. Conclusion : The MR-based hippocampal volumetry is a useful add-on of visual MR diagnosis, only when visual diagnosis of hippocampal sclerosis is difficult.

• Progress in Medical Physics
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• v.24 no.2
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• pp.108-118
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• 2013

Currently, an arterial spin labeling (ASL) magnetic resonance imaging (MRI) technique does not routinely used in clinical studies to measure perfusion in brain because optimization of imaging protocol is required to obtain optimal perfusion signals. Therefore, the objective of this study was to investigate changes of perfusion-weighed signal intensities with varying several parameters on a pulsed arterial spin labeling MRI technique obtained from a 3T MRI system. We especially evaluated alternations of ASL-MRI signal intensities on special brain areas, including in brain tissues and lobes. The signal targeting with alternating radiofrequency (STAR) pulsed ASL method was scanned on five normal subjects (mean age: 36 years, range: 29~41 years) on a 3T MRI system. Four parameters were evaluated with varying: 1) the labeling gap, 2) the labeling delay time, 3) the labeling thickness, and 4) the slice scan order. Signal intensities were obtained from the perfusion-weighted imaging on the gray and white matters and brain lobes of the frontal, parietal, temporal, and occipital areas. The results of this study were summarized: 1) Perfusion-weighted signal intensities were decreased with increasing the labeling gap in the bilateral gray matter areas and were least affected on the parietal lobe, but most affected on the occipital lobe. 2) Perfusion-weighted signal intensities were decreased with increasing the labeling delay time until 400 ms, but increased up to 1,000 ms in the bilateral gray matter areas. 3) Perfusion-weighted signal intensities were increased with increasing the labeling thickness until 120 mm in both the gray and white matter. 4) Perfusion-weighted signal intensities were higher descending scans than asending scans in both the gray and white matter. We investigated changes of perfusion-weighted signal intensities with varying several parameters in the STAR ASL method. It should require having protocol optimization processing before applying in patients. It has limitations to apply the ASL method in the white matter on a 3T MRI system.

• The Korean Journal of Nuclear Medicine
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• v.36 no.2
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• pp.91-101
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• 2002

Purpose : The aim of this study was to identify the brain areas in which reductions of regional cerebral blood flow (rCBF) were correlated with decline of general mental function, measured by Mini-Mental State Examination (MMSE). Materials and Methods : Tc-99m HMPAO brain SPECT was peformed in 9 probable AD patients at the initial and follow-up periods of 1.8 years (average) after the first study. MMSE scores were also measured in both occasions. The mean MMSE score of the initial study 16.4 (range: 5 - 24) and the mean MMSE score of the follow-up was 8.1 (range: 0 - 17). Each SPECT image was normalized to the cerebellar activity and a correlation analysis was peformed between the level of rCBF in AD patients and the MMSE scores by voxel-based analysis using SPM99 software. Results : Significant correlation was found between the blood-flow decrease in left inferior prefrontal region (BA 47) and left middle temporal legion (BA 21) and the MMSE score changes. Additional areas such as anterior and posterior cingulate cortices, precuneus, and bilateral superior and middle prefrontal regions showed the similar trends. Conclusions : A relationship was found between reduction of regional cerebral blood flow in left prefrontal and temporal areas and decline of cognitive function in Alzheimer's disease(AD) patients. This voxel-based analysis is useful in evaluating the progress of cognitive function in Alzheimer's disease.