• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.6
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• pp.1569-1575
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• 2007

In oriental medicine, Sukjihwang (SJH, Rehmanniae radix preparat) has been used as one of the key ingredients for the prescription of several herbal decoctions and applied clinically for the treatment of several diseases including nervous system and cardiovascular disease. Here, possible growth-promoting effects of SJH on injured spinal cord axons were investigated in the rats. SJH administration increased levels of active form of ERK1/2 protein and Cdc2 proteins in the injured spinal cord tissue. Anterograde DiI-tracing of corticospinal tract axons showed that SJH-treatment enhanced axonal arborization in the injury area and extensive axonal extension into the caudal area. In SJH-treated group, glial scar formed after spinal cord injury was confined in a smaller area compared to the control group, and the trabecula structure was well observed within the injury cavity. Furthermore, increased proliferation and migration of astrocytes in the injury cavity were observed by SJH treatment. Thus, these present data provide a biological evidence on potential importance of SJH therapy for the treatment of injured spinal cord.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.160-163
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• 2001

Mirror movements in adult is usually accompanied with various clinical syndromes. But the pathogenesis of mirror movement is not clearly understood. A 20-year-old man visited with complaining of mirror movements in both hands, ophthalmoplegia and sensorineural hearing loss. He underwent through electromyography, transcranial magnetic stimulation, and functional magnetic resonance image. And we concluded that the mechanisms of his mirror movements were both ipsilateral innervated corticospinal tract and simultaneous activation of both motor cortex.

• Journal of Yeungnam Medical Science
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• v.22 no.2
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• pp.119-130
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• 2005

Stroke is a leading cause of chronic physical disability. The recent randomized controlled trials have that motor function of chronic stroke survivors could be improved through physical or pharmacologic intervention in the stroke rehabilitation setting. In addition, several functional neuroimaging techniques have recently developed, it is available to study the functional topography of sensorimotor area of the brain. However, the mechanisms involved in motor recovery after stroke, are still poorly understood. Four motor recovery mechanisms have been suggested, such as reorganization into areas adjacent to the injured primary motor cortex (M1), unmasking of the motor pathway from the unaffected motor cortex to the affected hand, attribution of secondary motor areas, and recovery of the damaged contralateral corticospinal tract. Understanding the motor recovery mechanisms would provide neurorehabilitation specialists with more information to allow for precise prognosis and therapeutic strategies based on the scientific evidence; this may help promote recovery of motor function. This review introduces several methodologies for neuroimaging techniques and discusses theoretical issues that impact interpretation of functional imaging studies of motor recovery after stroke. Perspectives, for future research are presented.

• Journal of Electrodiagnosis and Neuromuscular Diseases
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• v.20 no.2
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• pp.106-111
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• 2018

Transcranial magnetic stimulation (TMS) has been a gold standard for investigating central motor pathways in humans. Diffusion tensor imaging with fiber tractography (DTI FT) is known for its usefulness in detecting white matter lesion in vivo. We investigated the clinical usefulness of elucidating the integrity and continuity of corticospinal tract (CST) by combined use of TMS and DTI FT in this study. We report two cases who have presented with left hemiparesis and evaluated by both TMS and DTI FT; 10-year-old boy with Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episode syndrome and 20-year-old woman with traumatic brain injury. Combined use of TMS and DTI FT successfully led to localize the brain lesion that might cause motor impairment in patients with abnormal signal intensities in MRI. The results of this study suggest that TMS and DTI FT might provide the detailed information between function and anatomy of the CST, complementarily.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.43-47
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• 2004

Interests in human brain functionality and its connectivity have much frown up. DTI (Diffusion tensor imaging) has been known as a non-invasive MR) technique capable of providing information on water diffusion in tissues and the organization of white matter tract. Thus. It can provide us the information on the direction of brain fiber tract and the connectivity among many important cortical regions which can not be examined by other anatomical or functional MRI techniques. In this study. was used the 24 bit color coding scheme on the IDL platform in the windows environment to visualize the orientation of major fiber tracts of brain such as main association, projection, commissural fibers and corticospinal tracts. We additionally implemented a color coding scheme for each directional component and FA (fractional anisotropy), and used various color tables for them to be visualized more definitely. Consequently we implemented a fancy and basic technique to visualize the directional information of fiber tracts efficiently and we confirmed the feasibility of the 24 bit color coding scheme in DTI by visualizing main fiber tracts.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.32-34
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• 2005

Purpose: To investigate the metabolic changes in the motor and motor association cortices following axonal injury in the internal capsule that was caused by deep intracerebral hematoma. Materials and Methods: Using proton magnetic resonance spectroscopy (1H MRS), the authors studied the primary motor cortices (M-1) and supplementary motor areas (SMA) of 9 hemiparetic patients with documentable hemiparesis of varying severity, and we studied 10 normal volunteers as controls. To measure the M-1 and SMA biochemical changes, 4 separate single volumes of interest (VOIs) were located bilaterally in the affected and unaffected hemisphere (AH and UH). Results: 1H MRS provided a neuronal and axonal viability index by measuring levels of N-acetylaspartate (NAA) and creatine/phosphocreatine (Cr). The M-1/SMA NAA/Cr ratios of the AH and UH in patients, and the AH and normal volunteers were compared. The NAA/Cr ratios of the M-1 and SMA in AH, and the SMA in UH were significantly lower than those of normal volunteers. Conclusion: These 1H MRS findings indicate that axonal injury in the descending motor pathway at the level of internal capsule could induce metabolic changes in the higher centers of the motor pathway.

• Progress in Medical Physics
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• v.18 no.4
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• pp.214-220
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• 2007

Diffusion tensor tractorgraphy which is based on line propagation method with brute force approach is implemented and the vector correlation function is proposed in addition to the conventional fractional anisotrophy value as a criterion to select seed points. For the whole tractography, the proposed method used 41 % less seed points than the conventional brute force approach for $FA{\geq}0.3$ and most of the fiber tracks in the outer region of white matter were removed. For the corticospinal tract passing through region of interest, the proposed method has produced similar results with 50% less seed points than conventional one.

• Annals of Clinical Neurophysiology
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• v.14 no.2
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• pp.64-71
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• 2012

Background: It is generally accepted that upper motor neuron (UMN) lesion can alter lower motor neuron (LMN) function by the plasticity of neural circuit. However there have been only few researches regarding the axonal excitability of LMN after UMN injury especially during the acute stage. The aim of this study was to investigate the nerve excitability properties of the LMNs following an acute to subacute supratentorial corticospinal tract lesion. Methods: An automated nerve excitability test (NET) using the threshold tracking technique was utilized to measure multiple excitability indices in median motor axons of 15 stroke patients and 20 controls. Testing of both paretic and non-paretic side was repeated twice, during the acute stage and subacute stage. The protocols calculated the strength-duration time constant from the duration-charge curve, parameters of threshold electrotonus (TE), the current-threshold relationship from sequential sub-threshold current, and the recovery cycle from sequential supra-threshold stimulation. Results: On the paretic side, compared with the control group, significant decline of superexcitablity and increase in the relative refractory period were observed during the subacute stage of stroke. Additionally, despite the absence of statistical significance, a mildly collapsing in ('fanning in') of the TE was found. Conclusions: Our results suggest that supratentorial brain lesions can affect peripheral axonal excitability even during the early stage. The NET pattern probably suggests background membrane depolarization of LMNs. These features could be associated with trans-synaptic regulation of UMNs to LMNs as one of the "neural plasticity" mechanisms in acute brain injury.

• Journal of Yeungnam Medical Science
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• v.40 no.2
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• pp.136-145
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• 2023

Hepatic encephalopathy (HE) is a severe neuropsychiatric abnormality in patients with either acute or chronic liver failure. Typical brain magnetic resonance imaging findings of HE are bilateral basal ganglia high signal intensities due to manganese deposition in chronic liver disease and hyperintensity in T2, fluid-attenuated inversion recovery, or diffusion-weighted imaging (DWI) with hemispheric white matter changes including the corticospinal tract. Low values on apparent diffusion coefficient mapping of the affected area on DWI, indicating cytotoxic edema, can be observed in acute HE. However, neuropsychological impairment in HE ranges from mild deficits in psychomotor abilities affecting quality of life to stupor or coma with higher grades of hepatic dysfunction. In particular, the long-lasting compensatory mechanisms for the altered metabolism in chronic liver disease make HE imaging results variable. Therefore, the clinical relevance of imaging findings is uncertain and differentiating HE from other metabolic diseases can be difficult. The recent introduction of concepts such as "acute-on-chronic liver failure (ACLF)," a new clinical entity, has led to a change in the clinical view of HE. Accordingly, there is a need to establish a corresponding concept in the field of neuroimaging diagnosis. Herein, we review HE from a historical and etiological perspective to increase understanding of brain imaging and help establish an imaging approach for advanced new concepts such as ACLF. The purpose of this manuscript is to provide an understanding of HE by reviewing neuroimaging findings based on pathological and clinical concepts of HE, thereby assisting in neuroimaging interpretation.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.4
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• pp.30-39
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• 2010

Since Diffusion tensor from Diffusion Tensor Magnetic Resonance Imaging(DT-MRI) is so sensitive to noise, the principle eigenvector(PEV) calculated from Diffusion tensor could be erroneous. Tractography obtained from PEV could be deviated from the real fiber tract. Therefore regularization process is needed to eliminate noise. In this paper, to reduce noise in DT-MRI measurements, the Dyadic Sorting(DS) method as regularization of the eigenvalue and the eigenvector is applied in the tractography. To resort the eigenvalues and the eignevectors, the DS method uses the intervoxel overlap function which can measure the overlap between eigenvalue-eigenvector pairs in the $3\times3$ pixel. In this paper, we applied the DS method to the three-dimensional volume. We discuss the error analysis and numerical study to the synthetic and the experimental data. As a result, we have shown that the DS method is more efficient than the median filtering methods as much as 79.97%~83.64%, 85.62%~87.76% in AAE, AFA respectively for the corticospinal tract of the experimental data.