• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.297-299
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• 2022

Malignant glioma has a poor prognosis with the reported median survival of between 6 months to 14 months. Thus, it is crucial to predict the accurate survival of patients with malignant glioma. In this paper, we propose a convolutional neural network to predict the overall survival and age of the patients. A total of four MRI modalities, T1, T1-contrast enhanced, T2, and fluid-attenuated inversion recovery, which effectively capture spatial characteristics of malignant glioma, were used as input images. Age is an important factor impacting the overall survival, thus incorporating it into the model will thereby improve the performance of the proposed model. Our model successfully predicted overall survival and age of the patients with pearson correlation coefficients of 0.1748 and 0.3056, respectively.

• Korean Journal of Cognitive Science
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• v.18 no.2
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• pp.139-157
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• 2007

We compared brain activation areas during participants drawn from contrasting two college majors performed intentionality detection (known as the basic mechanism of theory of mind) task using fMRI. The main purpose of this study was to identify whether individual differences are present in intentionality detection or not. In psychology major, the left inferior frontal gyrus, the fusiform gyrus, the superior temporal gyrus and the right fusiform gyrus, the supramarginal gyrus were activated. In engineering major, the inferior parietal lobule and the superior parietal lobule were found. This result suggests that according to participants' major, different brain areas were activated. The relations between performance of the intentionality detection task and the individual variants of participants were discussed.

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.55-63
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• 2002

Purpose : We investigated the predictive values of relative CBV measured with perfusion MR imaging, and relative CBF measured with SPECT for tissue outcome in acute ischemic stroke. Material and Methods : Thirteen patients, who had acute unilateral middle cerebral artery occlusion, underwent perfusion MR imaging, and $^{99m}Tc-HMPAO$ SPECT within 6 hours after the onset of symptoms. Lesion-to-contralateral ratios of perfusion parameters were measured, and best cut-off values of both parameter ratios with their accuracy to discriminate between regions with and without evolving infarction were calculated. Results : Mean relative CBV ratios in regions with evolving infarction and without evolving infarction were $0.58{\pm}0.27$ and $0.9{\pm}0.17$ (p < 0.001), and mean relative CBF ratios in those regions were $0.41{\pm}0.22$ and $0.71{\pm}0.14$ (p < 0.001). The best cutoff values to discriminate between regions with and without evolving infarction were estimated to be 0.80 for relative CBV ratio and 0.56 for relative CBF ratio. The sensitivity, specificity and efficiency of each cutoff value were 80.6, 87.5, 82.7% for relative CBV ratio, and 72.2, 75.0, 73.0% for relative CBF ratio (p > 0.05 between two parameters). Conclusion Measurement of relative CBV and relative CBE may be useful in predicting tissue outcome in acute ischemic stroke.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.463-468
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• 1996

본 연구는 간질 병소의 국소화에 있어 발작기 및 발작간 뇌스캔의 정확도를 알아보고 발작기 뇌 스캔에서 나타나는 간질 확산이 정확한 간질 병소를 국소화 하는데 어떠한 영향을 미치는가에 대하여 알아보고자 하였다. 15명의 복잡 부분 발작 환자를 대상으로 하였으며, 간질 병소의 최종적인 국소화는 두피 및 발작 뇌파, 피질 뇌파, 자기 공명 영상, 임상양상 및 병리 소견을 종합한 근거로 하였다. 발작기 뇌스캔은 뇌파상 발작 중 또는 환자가 aura를 호소할 때 Tc-99m HMPAO 20mCi(740 MBq)를 정맥주입후 시행하였으며 발작간 뇌스캔은 발작기 뇌스캔 후 3일 이내 임상적으로 발작 증상이 없는 기간에 시행하였다. 간질 병소는 우측 측두엽이 8예, 좌측 측두엽이 6예, 측두엽 이외의 기원이 1예 였다. 발작기 뇌스캔상, 모두 11예(73.3 %)에서 단발성 또는 다발성 섭취 증가가 간질 병소 및 간질확산 부위에서 관찰되었으며, 간질 병소에만 국한된 섭취 증가는 4예(26.7%)에 불과 하였다. 발작간 뇌스캔에는 모두 11예(73.3 %)에서 간질 병소에만 섭취가 감소되었다. 자기 공명 영상에서는 8예(53.3 %)에서 hippocampal sclerosis를 포함한 간질 병소가 확인되었다. 본 연구로 복잡 부분 발작 환자에서, 간질 확산이 발작기 뇌 스캔 중 자주 관찰됨을 알 수 있었으며, 이러한 간질 확산에 따른 다발성 방사능 섭취가 발작기 뇌스캔상, 간질 병소의 국소화에있어 한계가 있음을 결론 내릴 수 있었다.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.51-57
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• 2016

Acoustic noise during magnetic resonance imaging (MRI) is the main source for patient discomfort. we report our preliminary experience with this technique in neuroimaging with regard to subjective and objective noise levels and image quality. 60 patients(29 males, 31 females, average age of 60.1) underwent routine brain MRI with 3.0 Tesla (MAGNETOM Tim Trio; Siemens, Germany) system and 12-channel head coil. Q-$T_2$ and $T_2$ sequence were performed. Measurement of sound pressure levels (SPL) and heart rate on Q-$T_2$ and $T_2$ was performed respectively. Quantitative analysis was carried out by measuring the SNR, CNR, and SIR values of Q-$T_2$, $T_2$ and a statistical analysis was performed using independent sample T-test. Qualitative analysis was evaluated by the eyes for the overall quality image of Q-$T_2$ and $T_2$. A 5-point evaluation scale was used, including excellent(5), good(4), fair(3), poor(2), and unacceptable(1). The average noise and peak noise decreased by $15dB_A$ and $10dB_A$ on $T_2$ and Q-$T_2$ test. Also, the average value of heartbeat rate was lower in Q-$T_2$ for 120 seconds in each test, but there was no statistical significance. The quantitative analysis showed that there was no significant difference between CNR and SIR, and there was a significant difference (p<0.05) as SNR had a lower average value on Q-$T_2$. According to the qualitative analysis, the overall quality image of 59 case $T_2$ and Q-$T_2$ was evaluated as excellent at 5 points, and 1 case was evaluated as good at 4 points due to a motion artifact. Q-$T_2$ is a promising technique for acoustic noise reduction and improved patient comfort.

• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.103-114
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• 2010

Purpose : To generate a Korean specific brain template, especially in patients with Alzheimer's disease (AD) by optimizing the voxel-based analysis. Materials and Methods : Three-dimensional T1-weighted images were obtained from 123 subjects who were 43 cognitively normal subjects and patients with 44 mild cognitive impairment (MCI) and 36 AD. The template and the corresponding aprior maps were created by using the matched pairs approach with considering differences of age, gender and differential diagnosis (DDX). We measured several characteristics in both our and the MNI templates, including in the ventricle size. Also, the fractions of gray matter and white matter voxels normalized by the total intracranial were evaluated. Results : The high resolution template and the corresponding aprior maps of gray matter, white matter (WM) and CSF were created with the voxel-size of $1{\times}1{\times}1\;mm$. Mean distance measures and the ventricle sizes differed between two templates. Our brain template had less gray matter and white matter areas than the MNI template. There were volume differences more in gray matter than in white matter. Conclusion : Gray matter and/or white matter integrity studies in populations of Korean elderly and patients with AD are needed to investigate with this template.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.2
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• pp.256-262
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• 2001

Objective：The enlargement of the lateral ventricle is well established finding in adult-onset schizophrenia, but in the patients with early-onset psychotic disorder(EOPD) is still controversal. To identify structural abnormalities of the lateral ventricle in patients with EOPD and difference of the brain developmental course in EOPD group, planimetrical assessment of the lateral ventricle was conducted by means of retrospective quantitative neuroimaging. Methods：The brain MR images of 14 patients with EOPD(mean age $14.0{\pm}2.1$ years) who met the DSM-III-R diagnostic criteria for schizophrenia and bipolar disorder and 24 control subjects with simple headache(mean age $10.0{\pm}2.1$ years) were collected. Single best view for the lateral ventricle, one axial slice was selected for analysis. MR images were redigitalized with flatbed scanner and data were analyzed with NIH IMAGE software. Results：In the patients with EOPD, there were significant correlations between aging and lateral ventricular sizes and between aging and ventricular brain ratio(VBR). The statistical significance of normal asymmetry of the lateral ventricle was not observed for the EOPD group. The EOPD group had larger lateral ventricular sizes and VBR than control group, but these results were not statistically significant. Conclusion：These findings suggest that the brain abnormalities in patients with EOPD progress from the earlier course of the disorders and the course of brain development in EOPD group is different from control group.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.184-196
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• 2024

Purpose We investigated potentially promising imaging findings and their combinations in the evaluation of cognitive decline. Materials and Methods This retrospective study included 138 patients with subjective cognitive impairments, who underwent brain MRI. We classified the same group of patients into Alzheimer's disease (AD) and non-AD groups, based on the neuropsychiatric evaluation. We analyzed imaging findings, including white matter hyperintensity (WMH) and cerebral microbleeds (CMBs), using the Kruskal-Wallis test for group comparison, and receiver operating characteristic (ROC) curve analysis for assessing the diagnostic performance of imaging findings. Results CMBs in the lobar or deep locations demonstrated higher prevalence in the patients with AD compared to those in the non-AD group. The presence of lobar CMBs combined with periventricular WMH (area under the ROC curve [AUC] = 0.702 [95% confidence interval: 0.599-0.806], p < 0.001) showed the highest performance in differentiation of AD from non-AD group. Conclusion Combinations of imaging findings can serve as useful additive diagnostic tools in the assessment of cognitive decline.

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.103-109
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• 2007

To develop an advanced non-linear curve fitting (NLCF) algorithm for performing dynamic susceptibility contrast study of the brain. The first pass effects give rise to spuriously high estimates of $K^{trans}$ for the voxels that represent the large vascular components. An explicit threshold value was used to reject voxels. The blood perfusion and volume estimation were accurately evaluated in the $T2^*$-weighted dynamic contrast enhanced (DCE)-MR images. From each of the recalculated parameters, a perfusion weighted image was outlined by using the modified non-linear curve fitting algorithm. The present study demonstrated an improvement of an estimation of the kinetic parameters from the DCE $T2^*$-weighted magnetic resonance imaging data with using contrast agents.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.626-637
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• 2021

Purpose To explore cerebrovascular reservoir (CVR) and arterial transit time (ATT) changes using acetazolamide-challenged multi-phase arterial spin labeling (MP-ASL) perfusion-weighted MRI in chronic cerebrovascular steno-occlusive disease. Materials and Methods This retrospective study enrolled patients with chronic steno-occlusion who underwent acetazolamide-challenged MP-ASL between June 2019 and October 2020. Cerebral blood flow, CVR, basal ATT, and ATT changes associated with severe stenosis, total occlusion, and chronic infarction lesions were compared. Results There were 32 patients (5 with bilateral steno-occlusion) in our study sample. The CVR was significantly reduced during total occlusion compared with severe stenosis (26.2% ± 28.8% vs. 41.4% ± 34.1%, respectively, p = 0.004). The ATT changes were not significantly different (p = 0.717). The CVR was marginally lower in patients with chronic infarction (29.6% ± 39.1% vs. 38.9% ± 28.7%, respectively, p = 0.076). However, the ATT was less shortened in patients with chronic infarction (-54 ± 135 vs. -117 ± 128 ms, respectively, p = 0.013). Conclusion Acetazolamide-challenged MP-ASL provides an MRI-based CVR evaluation tool for chronic steno-occlusive disease.