• Journal of Biomedical Engineering Research
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• v.26 no.4
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• pp.223-230
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• 2005

This paper presents a new approach to investigate spatial correlation between independent components of brain alpha activity in functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). To avoid potential problems of simultaneous fMRI and EEG acquisitions in imaging pure alpha activity, data from each modality were acquired separately under a 'three conditions' setup where one of the conditions involved closing eyes and relaxing, thus making it conducive to generation of alpha activity. The other two conditions -- eyes open in a lighted room or engaged in a mental arithmetic task, were designed to attenuate alpha activity. Using a Mixture Density Independent Component Analysis (MD-ICA) that incorporates flexible non-linearity functions into the conventional ICA framework, we could identify the spatiotemporal components of fMRI activations and EEG activities associated with the alpha rhythm. Then, the sources of the individual EEG alpha activity component were localized by a Maximum Entropy (ME) method that is specially designed to find the most probable dipole distribution minimizing the localization error in sense of LMSE. The resulting active dipoles were spatially transformed to 3D MRls of the subject and compared to fMRI alpha activity maps. A good spatial correlation was found in the spatial distribution of alpha sources derived independently from fMRI and EEG, suggesting the proposed method can localize the cortical areas responsible for generating alpha activity successfully in either fMRI or EEG. Finally a functional connectivity analysis was applied to show that alpha activity sources of both modalities were also functionally connected to each other, implying that they are involved in performing a common function: 'the generation of alpha rhythms'.

• Dementia and Neurocognitive Disorders
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• v.23 no.2
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• pp.89-94
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• 2024

Background and Purpose: This study aimed to evaluate the brain magnetic resonance imaging (MRI) of patients with acute transient global amnesia (TGA) using volumetric analysis to verify whether the brains of TGA patients have pre-existing structural abnormalities. Methods: We evaluated the brain MRI data from 87 TGA patients and 20 age- and sex- matched control subjects. We included brain MRIs obtained from TGA patients within 72 hours of symptom onset to verify the pre-existence of structural change. For voxel-based morphometric analyses, statistical parametric mapping was employed to analyze the structural differences between patients with TGA and control subjects. Results: TGA patients exhibited significant volume reductions in the bilateral ventral anterior cingulate cortices (corrected p<0.05). Conclusions: TGA patients might have pre-existing structural changes in bilateral ventral anterior cingulate cortices prior to TGA attacks.

• Journal of Veterinary Clinics
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• v.38 no.2
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• pp.89-93
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• 2021

2-Month-old, three related Perro de Presa Canario dogs were evaluated for similar neurological symptoms like circling, head pressing, depressed mental status, hypermetria, and vocalization. On magnetic resonance imaging (MRI) of the brain, there were large, bilaterally symmetrical lesions with involvement of thalamus, and brainstem that were T2- and FLAIR-hyperintense and T1-iso/hypointense. There was no inclusion of cerebellum. Single-voxel spectroscopy acquisition was located in the thalamus where abnormalities were found in MR images. The results of magnetic resonance spectroscopy (MRS) showed markedly decreased N-acetylaspartic acid value. Euthanasia was performed and lesions consistent with the canine spongy degeneration. Alteration in metabolites in the brain can be determined by MRS, which helps in diagnosing degeneration/leukodystrophy of the central nervous system in dogs.

• Journal of the Korean Society of Radiology
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• v.81 no.4
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• pp.985-989
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• 2020

Chlorfenapyr is widely used as an insecticide, despite it being fatal to humans. However, chlorfenapyr-induced central nervous system toxicity has rarely been reported. We report the magnetic resonance imaging (MRI) findings in a rare case of chlorfenapyr-induced toxic leukoencephalopathy. A 71-year-old man who had ingested chlorfenapyr approximately two weeks prior visited our hospital and presented with bilateral lower motor weakness and voiding dysfunction that had developed two days before admission. Brain MRI revealed extensive bilateral white matter abnormalities involving the corpus callosum, internal capsule, brain stem, and bilateral middle cerebellar peduncle. Furthermore, spine MRI revealed diffuse swelling and hyperintensity on the T2-weighted images.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.534-541
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• 1998

We describe a 27-year-old man who developed gait disturbance and dysarthria 2 years after the onset of cardinal symptoms of Behcet's disease. Positron emission tomography with $^{18}F$-fluorodeoxyglucose revealed severe hypometabolisrn in the cerebellum, in accordance with cerebellar symptoms and signs of the patient. However, single-photon emission tomography with $^{99m}Tc$-HMPAO and $^{99m}Tc$-ECD did not disclose significant perfusion abnormalities in the brain. Routine brain magnetic resonance imaging did not show signal abnormalities. The findings of imaging studies compared with neurological manifestations of the patient are discussed.

• Journal of the Korean Society of Radiology
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• v.83 no.5
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• pp.1046-1058
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• 2022

The hippocampus is one of the most metabolically active regions of the brain; therefore, it may be affected by various acute disorders. This study aimed to introduce and categorize various acute conditions that can involve the hippocampus and explain the findings of MRI, especially diffusion-weighted imaging (DWI). Acute hippocampal disorders are divided into six categories: infection, inflammation, metabolic, ischemic, traumatic, and miscellaneous. In this study, patients were retrospectively reviewed based on clinical findings and MRI, especially DWI. All diseases had been confirmed clinically or pathologically. Many acute hippocampal disorders overlap with the clinical manifestations. Thus, it is necessary to categorize acute hippocampal lesions and understand their specific imaging findings for differential diagnosis.

• Interdisciplinary Bio Central
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• v.3 no.3
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• pp.11.1-11.5
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• 2011

The MRI (magnetic resonance imaging) volumetric analysis of the brain was performed in 59 healthy elderly Koreans (aged 62-76 years; 34 male, 25 female) to investigate whether the previously reported significant correlations between body height and brain volumes in the young aged Koreans (20's) still exist in the old aged Koreans (60's and 70's). Unlike previously reported significant correlations in the young aged Koreans, neither the correlation between whole brain volume and body height in male nor the correlation between cerebellar volume and body height in female show any significance in the old aged Koreans. The significant correlation between body height and whole brain volume was still observed when both male and female data were combined (r=0.27, P<0.05), but the correlation coef-ficient and the level of significance markedly decreased from those of previously reported Korean youth data (r=0.67, P<0.01). Simple linear regression analysis shows decrease of explanatory power of height (measured in $r^2$) from 44% in the youth group to 7% in the old age group on the variance of whole brain volume. Multiple linear regression analysis shows that age and sex, rather than height, are major explanatory variables for whole brain volume in the old aged Koreans. The loss of correlations in the aged group is suspected to be mainly due to age related brain volume changes.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2775-2780
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• 2016

Background: Precise staging of lung cancer is usually evaluated by PET-CT and brain MRI. Recently, however, whole-body diffusion-weighted magnetic resonance imaging (WB-DWI) has be applied. The aim of this study is to determine whether the diagnostic performance of lung cancer staging by WB-DWI is superior to that of PET-CT+brain MRI. Materials and Methods: PET-CT + brain MRI and WB-DWI were used for lung cancer staging before surgery with 59 adenocarcinomas, 16 squamous cell carcinomas and 6 other carcinomas. Results: PET-CT + brain MRI correctly identified the pathologic N staging in 67 patients (82.7%), with overstaging in 5 (6.2%) and understaging in 9 (11.1%), giving a staging accuracy of 0.827. WB-DWI correctly identified the pathologic N staging in 72 patients (88.9%), with overstaging in 1 (1.2%) and understaging in 8 patients (9.9%), giving a staging accuracy of 0.889. There were no significant differences in accuracies. PET-CT + brain MRI correctly identified the pathologic stages in 56 patients (69.1%), with overstaging in 7 (8.6%) and understaging in 18 (22.2%), giving a staging accuracy of 0.691. WB-DWI correctly identified the pathologic stages in 61 patients (75.3%), with overstaging in 4 (4.9%) and understagings in16(19.7%), giving a staging accuracy of 0.753. There were no significant difference in accuracies. Conclusions: Diagnostic efficacy of WB-DWI for lung cancer staging is equivalent to that of PET-CT + brain MRI.

• Investigative Magnetic Resonance Imaging
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• v.20 no.4
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• pp.250-253
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• 2016

Acute Japanese encephalitis (JE) is an endemic viral infectious disease in various parts of Far East and Southeast Asian countries including Korea. Bilateral thalami are the most common involving sites in JE. Other areas including the basal ganglia, substantia nigra, red nucleus, pons, cerebral cortex and cerebellum may be also involved. We report an extremely unusual brain diffusion-weighted MR imaging (DWI) findings in a 53-year-old man with serologically proven JE involving unilateral deep gray matter and temporal lobe, which shows multifocal high signal intensities in left thalamus, left substantia nigra, left caudate nucleus and left medial temporal cortex on T2-weighted image and DWI with iso-intensity on apparent diffusion coefficient (ADC) map.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.345-352
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• 2016

The purpose of this study was to needed basis of measure MRI CAD development for signal to noise ratio (SNR) by pulse sequence analysis from region of interest (ROI) in brain magnetic resonance imaging (MRI) contrast. We examined images of brain MRI contrast enhancement of 117 patients, from January 2005 to December 2015 in a University-affiliated hospital, Seoul, Korea. Diagnosed as one of two brain diseases such as meningioma and cysts SNR for each patient's image of brain MRI were calculated by using Image J. Differences of SNR among two brain diseases were tested by SPSS Statistics21 ANOVA test for there was statistical significance (p < 0.05). We have analysis socio-demographical variables, SNR according to sequence disease, 95% confidence according to SNR of sequence and difference in a mean of SNR. Meningioma results, with the quality of distributions in the order of T1CE, T2 and T1, FLAIR. Cysts results, with the quality of distributions in the order of T2 and T1, T1CE and FLAIR. SNR of MRI sequences of the brain would be useful to classify disease. Therefore, this study will contribute to evaluate brain diseases, and be a fundamental to enhancing the accuracy of CAD development.