• Applied Microscopy
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• v.46 no.4
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• pp.179-183
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• 2016

Mapping brain structural and functional connections through the whole brain is essential for understanding brain mechanisms and the physiological bases of brain diseases. Although region specific structural or functional deficits cause brain diseases, the changes of interregional connections could also be important factors of brain diseases. This review will introduce common neuroimaging modalities, including structural magnetic resonance imaging (MRI), functional MRI (fMRI), diffusion tensor imaging, and other recent neuroimaging analyses methods, such as voxel-based morphometry, cortical thickness analysis, local gyrification index, and shape analysis for structural imaging. Tract-Based Spatial Statistics, TRActs Constrained by UnderLying Anatomy for diffusion MRI, and independent component analysis for fMRI also will also be introduced.

• 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.

• Korean Journal of Biological Psychiatry
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• v.9 no.2
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• pp.152-158
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• 2002

Background & Purpose:Neuropsychological disorders after traumatic brain injury(TBI) are poorly correlated with structural lesions detected by structural neuroimaging techniques such as computed tomography(CT) scan or magnetic resonance imaging(MRI). It is well known that patients with TBI have cognitive and behavioral disorders even in the absence of structural lesions of the brain. This study investigated whether there are abnormalities of regional cerebral blood flow(rCBF) in TBI patients without structural abnormality on MRI, using technetium 99m ethyl cysteinate dimer(Tc-99m-ECD) single photon emission computed tomography(SPECT) scans. Materials and Methods:Twenty-eight TBI patients without structural abnormality on MRI(mild, n=13/moderate, n=9/severe, n=6) and fifteen normal controls were scanned by SPECT. A voxel-based analysis using statistical parametric mapping(SPM) was performed to compare the patients with the normal controls. Results:rCBF was reduced in the right uncus and the right lateral orbitofrontal gyrus in the TBI patients. However, no increase of rCBF was noted in the patients in comparison to the normal controls. Conclusions:These results suggest that the TBI patients, even in the absence of structural lesion of the brain, may have dysfunction of the brain, particularly of the orbitofrontal and anterior pole of the temporal cortex. They also suggest that SPECT can be a useful method to identify brain dysfunctions in combination with structural brain imaging and neuropsychological tests.

• Journal of Neurogastroenterology and Motility
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• v.24 no.4
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• pp.512-527
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• 2018

This review provides a comprehensive overview of brain imaging studies of the brain-gut interaction in functional gastrointestinal disorders (FGIDs). Functional neuroimaging studies during gut stimulation have shown enhanced brain responses in regions related to sensory processing of the homeostatic condition of the gut (homeostatic afferent) and responses to salience stimuli (salience network), as well as increased and decreased brain activity in the emotional response areas and reduced activation in areas associated with the top-down modulation of visceral afferent signals. Altered central regulation of the endocrine and autonomic nervous responses, the key mediators of the brain-gut axis, has been demonstrated. Studies using resting-state functional magnetic resonance imaging reported abnormal local and global connectivity in the areas related to pain processing and the default mode network (a physiological baseline of brain activity at rest associated with self-awareness and memory) in FGIDs. Structural imaging with brain morphometry and diffusion imaging demonstrated altered gray- and white-matter structures in areas that also showed changes in functional imaging studies, although this requires replication. Molecular imaging by magnetic resonance spectroscopy and positron emission tomography in FGIDs remains relatively sparse. Progress using analytical methods such as machine learning algorithms may shift neuroimaging studies from brain mapping to predicting clinical outcomes. Because several factors contribute to the pathophysiology of FGIDs and because its population is quite heterogeneous, a new model is needed in future studies to assess the importance of the factors and brain functions that are responsible for an optimal homeostatic state.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.507-518
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• 2021

Magnetic resonance imaging (MRI) is a key technology that has been seeing increasing use in studying the structural and functional innerworkings of the brain. Analyzing the variability of brain connectome through tractography analysis has been used to increase our understanding of disease pathology in humans. However, there lacks standardization of analysis methods for small animals such as mice, and lacks scientific consensus in regard to accurate preprocessing strategies and atlas-based neuroinformatics for images. In addition, it is difficult to acquire high resolution images for mice due to how significantly smaller a mouse brain is compared to that of humans. In this study, we present an Allen Mouse Brain Atlas-based image data analysis pipeline for structural connectivity analysis involving structural region segmentation using mouse brain structural images and diffusion tensor images. Each analysis method enabled the analysis of mouse brain image data using reliable software that has already been verified with human and mouse image data. In addition, the pipeline presented in this study is optimized for users to efficiently process data by organizing functions necessary for mouse tractography among complex analysis processes and various functions.

• Korean Journal of Biological Psychiatry
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• v.3 no.1
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• pp.66-74
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• 1996

There has been an increase in head trauma due to rapid industralization and improvement in transportation. This poses difficulties in differentiating between neuropsychiatric disabilities resulting from real organic changes and those arising from compensation issues. It is the purpose of this study to seek out the differences between normal and abnormal finding group in the structural brain imaging studies via the results of the functional brain imaging studies and psychological tests. Out of 132 subjects, 62 comprised normal and 70 the abnormal finding group. EEG and SPECT were chosen for inspection of functional brain imaging. MMPI and K-WAIS were chosen for psychological test. The subjects were further divided into right hemispheric damage, left hemispheric damage, both hemispheric damage, diffuse damage group and negative group in order to find out whether any differences in the psychological lest results could be localized. The results are as follows : 1) The abnormal finding group, the EEG and SPECT were proven to be a good predictor of brain lesion. This implies that even in the functional brain studies, abnormalities are more easily detected if there are visible brain lesions. 2) The FSIQ of the abnormal finding group is lower than that of normal finding group. this difference is mainly due to low V1Q. The left hemispheric damage group lend to shaw low V1Q. This lowered in was the difference between left hemispheric damage group and negative group. Furthermore, there were no group differences in the PIQ. It is concluded that K-WAIS is effective as evaluator of VIQ mainly of those patients with left hemispheric damage and it is ineffective as a evaluator of PIQ. 3) In the MMPI profile, the both groups displayed high neurotic profiles. There was no difference in the psychotic profiles. The scores of the Depression and Hystery were high in abnormal finding group. This can be seen as one of the lypical findings of chronic head trauma patients. 4) The abnormal finding group tend to be diagnosed as organic mental disorder in the psychological tests more frequently.

• Korean Journal of Veterinary Service
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• v.47 no.2
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• pp.101-105
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• 2024

Three dogs (7-year-old, neutered male Chihuahua; case 1, 1-year-old, spayed female mixed breed; case 2, 10-month-old, female Maltese; case 3) were referred to Jeju Veterinary Medicine Teaching Hospital for traumatic brain injury. All three patients exhibited abnormal neurological symptoms. The patients were diagnosed through medical history obtained from their caregivers and through computed tomography (CT) or magnetic resonance imaging (MRI) scans. Structural brain abnormalities were observed in two dogs through CT scans and in one dog through MRI. Decompression therapy with mannitol was administered to all three dogs. Case 1, which showed CT findings of pulmonary hemorrhage but no significant brain injury, and case 2, which had mild brain damage on CT imaging, showed improvement in neurological symptoms and gait abnormalities after decompression therapy. However, case 3, which showed suspected brain hemorrhage and brain edema on MRI, did not respond to decompression therapy and was euthanized one month later. Imaging evaluation through CT or MRI in dogs with traumatic brain injury can assist clinical veterinarians in assessing the prognosis of patients.

• 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.

• Korean Journal of Biological Psychiatry
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• v.28 no.2
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• pp.36-49
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• 2021

Suicide is a leading cause of death worldwide, especially among adolescents and young adults. Considering this fact, it is imperative that we understand the neural mechanisms underlying suicidal thoughts and behaviors in youth from a neurodevelopmental perspective. In this review, we focused on the magnetic resonance imaging studies that examined the neural correlates of suicidal ideations (SI) or attempts (SA) in youth. We reviewed twenty-three cross-sectional studies reporting the structural and functional alterations in association with SI or SA among adolescents and young adults with various mental disorders. The previous literature suggests that the dorsolateral prefrontal cortex, anterior cingulate cortex, and ventral frontolimbic circuit, may play an important role in the pathophysiology of suicidal behavior in youth through altered top-down control over emotion and impulsivity. Future studies with a longitudinal design and using multimodal imaging techniques may be of help to identify novel therapeutic targets specific for youth with suicidal thoughts and behaviors.

• 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.