• Journal of Korean Neurosurgical Society
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• v.30 no.9
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• pp.1120-1126
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• 2001

Objective : The development of magnetic resonance neurography(MRN) has made it possible to produce highresolution images of peripheral nerves themselves, as well as associated intraneural and extraneural lesions. We evaluated the clinical application and utility of high-resolution MRN techniques for the diagnosis and treatment of a variety of peripheral nerve disorder(PND)s. Material and Method : MRN images were obtained using T1-weighted spin echo, T2-weighted fast spin echo with fat suppression, and short tau inversion recovery(STIR) fast spin-echo pulse sequences. Fifteen patients were studied, three with brachial plexus tumors, five with chronic entrapment syndromes, and seven with traumatic peripheral lesions. Ten patients underwent surgery. Results : In MRN with STIR sequences of axial and coronal imagings, signals of the peripheral nerves with various lesions were detected as fairly bright signals and were discerned from signals of the uninvolved nerves. Increased signal with proximal swelling and distal flattening of the median nerve were seen in all patients of carpal tunnel syndrome. Among the eight patients with brachial plexus injury or tumors, T2-weighted MRN showed increased signal intensity in involved roots in five, enhanced mass lesions in three, and traumatic pseudomeningocele in three. Other associated MRI findings were adjacent bony signal change, neuroma, root adhesion and denervated muscle atophy with signal change. Conclusion : MRN with high-resolution imaging can be useful in the preoperative evaluation and surgical planning in patients with peripheral nerve lesions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.513-519
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• 2021

Metallic suture anchors are very useful and common fixation devices that are inserted into the target bone to sustain the tendon of a patient with musculus supraspinatus tendon ruptures. On the other hand, the presence of a metallic material prosthesis, such as a metal suture anchor, causes severe MR imaging artifacts, including field distortion, signal loss, and failure of fat suppression. The difference in magnetic susceptibility between metal and other organic materials causes magnetic field distortion surrounding the prosthesis. The resulting magnetic field inhomogeneity makes the images with a lower signal-to-noise ratio and distortion. For a patient with a suture anchor implanted, MR imaging is the golden standard for determining the postoperative prognosis, and a fat-saturation sequence is one of the imaging methods most affected by metal-induced artifacts. In this study, three fat-saturation sequences were compared. Artifact quantification and contrast comparison between the supraspinatus tendon and the surrounding muscle were presented. The images obtained using the STIR pulse sequence showed fewer susceptibility artifacts and better visibility in the supraspinatus tendon and the tissue area. Therefore, the STIR sequence is the most appropriate fat-saturation imaging method for patients with a metallic prosthesis.

• Dementia and Neurocognitive Disorders
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• v.17 no.4
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• pp.163-173
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• 2018

Background and Purpose: Behavioral variant frontotemporal dementia (bvFTD) is a subtype of frontotemporal dementia, which has clinical symptoms of progressive personality and behavioral changes with deterioration of social cognition and executive functions. The pathology of bvFTD is known to be tauopathy or TDP-43 equally. We analyzed the $^{18}F-THK5351$ positron emission tomography (PET) scans, which were recently developed tau PET, in patients with clinically-diagnosed bvFTD. Methods: Forty-eight participants, including participants with behavioral variant frontotemporal dementia (bvFTD, n=3), Alzheimer's disease (AD, n=21) and normal cognition (NC, n=24) who completed 3T magnetic resonance images, $^{18}F-THK5351$ PET scans, and detailed neuropsychological tests were included in the study. Voxel-wise statistical analysis and region of interest (ROI)-based analyses were performed to evaluate the retention of THK in bvFTD patients. Results: In the voxel-based and ROI-based analyses, patients with bvFTD showed greater THK retention in the prefrontal, medial frontal, orbitofrontal, anterior cingulate, insula, anterior inferior temporal and striatum regions compared to NC participants. Left-right asymmetry was noted in the bvFTD patients. A patient with extrapyramidal symptoms showed much greater THK retention in the brainstem. Conclusions: The distribution of THK retention in the bvFTD patients was mainly in the frontal, insula, anterior temporal, and striatum regions which are known to be the brain regions corresponding to the clinical symptoms of bvFTD. Our study suggests that $^{18}F-THK5351$ PET imaging could be a supportive tool for diagnosis of bvFTD.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.04a
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• pp.25-44
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• 2007

The glucocorticoid receptor (GR) is an intracellular protein that is widely distributed throughout hippocampal and neocortical brain tissue. Mifepristone (RU486) is a potent GR antagonist that has also been shown to exhibit partial agonist-like effects. The precise location of the GR domain involved in the agonist-like activity of RU486 is unknown. Here, we examine this aspect of GR signaling by comparing human GR (hGR) construct with a Guyanese squirrel monkey GR (gsmGR) construct in which nuclear translocation and transactivation are known to be impaired. Using an objective translocation scoring method, we found that both hGR and gsmGR are translocated by RU486, and that nuclear translocation of hGR is significantly increased compared to gsmGR at 10 nM, 100 nM and 1000 nM RU486 in transiently transfected COS1 cells. While addition of RU486 to the cells transfected with hGR results in a 16-fold dose-dependent increase in transactivation compared to non-treated cells, no significant change in transactivation is observed with gsmGR at doses up to 100 nM RU486. Further experiments using six GR chimeras indicate that replacement of the hGR carboxyl-terminus of tau-1 transactivation domain (C-AF1, amino acids 132-428) with that from gsmGR diminishes hGR transactivation by RU486. These results demonstrate that RU486-induced transactivation of GR is determined in part by amino acids in the C-AF1 domain.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.51-54
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• 2018

Purpose $^{18}F-THK5351$ is the newly developed PET probe for tau imaging in alzheimer's disease. The purpose of study was to establish the automated production of $^{18}F-THK5351$ on a commercial module. Materials and Methods Two different approaches were evaluated for the synthesis of $^{18}F-THK5351$. The first approach (method I) included the nucleophilic $^{18}F$-fluorination of the tosylate precursor, subsequently followed by pre-HPLC purification of crude reaction mixture with SPE cartridge. In the second approach (method II), the crude reaction mixture was directly introduced to a semi-preparative HPLC without SPE purification. The radiosynthesis of $^{18}F-THK5351$ was performed on a commercial GE $TRACERlab^{TM}$ $FX-_{FN}$ module. Quality control of $^{18}F-THK5351$ was carried out to meet the criteria guidelined in USP for PET radiopharmaceuticals. Results The overall radiochemical yield of method I was $23.8{\pm}1.9%$ (n=4) as the decay-corrected yield (end of synthesis, EOS) and the total synthesis time was $75{\pm}3min$. The radiochemical yield of method II was $31.9{\pm}6.7%$ (decay-corrected, n=10) and the total preparation time was $70{\pm}2min$. The radiochemical purity was>98%. Conclusion This study shows that method II provides higher radiochemical yield and shorter production time compared to the pre-SPE purification described in method I. The $^{18}F-THK5351$ synthesis by method II will be ideal for routine clinical application, considering short physical half-life of fluorine-18 ($t_{1/2}=110min$).

• Progress in Medical Physics
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• v.19 no.4
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• pp.269-275
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• 2008

Although MR imaging is generally applicable to depict knee joint deterioration it, is sometimes occurred to mis-read and mis-diagnose the common knee joint diseases. In this study, we employed magnetization transfer ratio (MTR) method to improve the diagnosis of the various knee joint diseases. Spin-echo (SE) T2-weighted images (TR/TE 3,400-3,500/90-100 ms) were obtained in seven cases of knee joint deterioration, FSE T2-weighted images (TR/TE 4,500-5,000/100-108 ms) were obtained in seven cases of knee joint deterioration, gradient-echo (GRE) T2-weighted images (TR/TE 9/4.56/$50^{\circ}$ flip angle, NEX 1) were obtained in 3 cases of knee joint deterioration, In six cases of knee joint deterioration, fat suppression was performed using a T2-weighted short T1/tau inverse recovery (STIR) sequence (TR/TE =2,894-3,215 ms/70 ms, NEX 3, ETL 9). Calculation of MTR for individual pixels was performed on registration of unsaturated and saturated images. After processing to make MTR images, the images were displayed in gray color. For improving diagnosis, three-dimensional isotropic volume images, the MR tristimulus color mapping and the MTR map was employed. MTR images showed diagnostic images quality to assess the patients' pathologies. The intensity difference between MTR images and conventional MRI was seen on the color bar. The profile graph on MTR imaging effect showed a quantitative measure of the relative decrease in signal intensity due to the MT pulse. To diagnose the pathologies of the knee joint, the profile graph data was shown on the image as a small cross. The present study indicated that MTR images in the knee joint were feasible. Investigation of physical change on MTR imaging enables to provide us more insight in the physical and technical basis of MTR imaging. MTR images could be useful for rapid assessment of diseases that we examine unambiguous contrast in MT images of knee disorder patients.

• Imaging Science in Dentistry
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• v.49 no.1
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• pp.59-63
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• 2019

Purpose: This study evaluated the prevalence and characteristics of maxillary antroliths using cone-beam computed tomography (CBCT) scans performed for maxillofacial diagnostic purposes. Materials and Methods: CBCT scans of 13,946 patients over the age of 20 were reviewed for maxillary antroliths, and prevalence according to sex, age, and the side of the jaw was calculated. The relationships of single or multiple antroliths with sex, side, and the degree of sinus inflammation were evaluated. The shape and dimension of antroliths were also assessed. The data were analyzed using descriptive statistics, the chi-square or Fisher exact tests, and Kendall's tau-b. Results: A total of 138 (0.99%) of the 13,946 patients showed an antrolith in at least 1 sinus. Only 18 patients presented a bilateral manifestation, which brought the total number of sinuses containing an antrolith to 156 (0.56%). Multiple antroliths were observed in 36 sinuses, and the total number of antroliths was 207: 110 punctate, 65 linear, and 32 amorphous. The antrolith dimensions varied from $1mm^2$ to $91mm^2$ (average, $10.2{\pm}15.5mm^2$). No statistically significant differences were found according to sex, side, and age group (P>0.05). However, there was a statistically significant difference between the multiplicity of antrolith and the degree of sinus inflammation (P<0.05). Conclusion: Cone-beam computed tomography is an effective modality for the detection of incidental antroliths. Maxillary antroliths were found to be very rare and were usually asymptomatic. Dentists should have a comprehensive understanding of their diagnosis and treatment in light of possible associated dental problems.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.486-507
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• 2022

Cerebral small vessel disease (CSVD) includes vascular lesions detected on brain MRI, such as white matter hyperintensities, lacunar infarctions, microbleeds, or enlarged perivascular spaces. There is accumulating evidence that vascular changes may play an important role in development of Alzheimer's disease (AD), and CSVD lesions detected on brain MRI were reported to be associated with β-amyloid and tau proteins accumulation. As the vascular contribution has therapeutic potential, it is important to understand the association of CSVD with AD and AD biomarkers. This review begins with a brief introduction of AD and AD biomarkers, explains the association between AD and vascular changes, and then details the pathogenesis and MR imaging findings of CSVD. Afterwards, we discuss the association of CSVD with AD and AD biomarkers.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.33-39
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• 2006

Purpose: To determine appropriate sampling frequency and time of multiple blood sampling dual exponential method with $^{99m}Tc$-DTPA for calculating glomerular filtration rate (GFR). Materials & Methods: Thirty four patients were included in this study. Three mCi of $^{99m}Tc$-DTPA was intravenously injected and blood sampling at 9 different times, 5ml each, were done. Using the radioactivity of serum, measured by gamma counter, the GFR was calculated using dual exponential method and corrected with the body surface area. Using spontaneously chosen 2 data points of serum radioactivity, 15 collections of 2-sample GFR were calculated. And 10 collections of 3-sample GFR and 12 collections of 4-sample GFR were also calculated. Using the 9-sample GFR as a reference value, degree of agreement was analyzed with Kendall's $\tau$ correlation coefficients, mean difference and standard deviation. Results: Although some of the 2-sample GFR showed high correlation coefficient, over or underestimation had evolved as the renal function change. The 10-120-240 min 3-sample GFR showed a high correlation coefficient (${\tau}=0.93$), minimal difference ($Mean{\pm}SD=-1.784{\pm}3.972$), and no over or underestimation as the renal function changed. The 4-sample GFR showed no better accuracy than the 3-sample GFR. Conclusions: In the wide spectrum of renal function, the 10-120-240 min 3-sample GFC could be the best choice for estimating the patients' renal function.

• The Journal of Internal Korean Medicine
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• v.41 no.3
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• pp.326-338
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• 2020

Background: Alzheimer's disease (AD) is a chronic neurodegenerative disease that causes disorientation, mood swings, problems with language, and difficulty remembering recent events. Acetylcholinesterase inhibitors (AchEIs) and memantine have been used to slow the course of the disease, but they can neither modify its progression nor prevent disease onset. Previous studies have suggested that Kami-guibi-tang (KGT) could be beneficial for supporting cognitive function in AD patients, but few clinical trials have been published. This pilot study aimed to evaluate the effect of KGT in improving cognitive function in AD patients. Methods: The study will be a randomized, placebo-controlled, double-blind, single-center trial conducted using subjects diagnosed with mild AD by neurologists. Study subjects will be randomly assigned to either a treatment or control group. The treatment group will receive KGT granules for 24 weeks, while the control group will receive placebo granules. AchEI administration will be maintained in both groups during the entirety of the study. Subjects will be assessed using the following exams: the Seoul Neuropsychologic Screening Battery (SNSB) for cognitive function; brain magnetic resonance imaging (MRI) for brain metabolite, neurotransmitter, and cerebral blood flow (CBF) measurements; the Korean version of Quality of Life-Alzheimer's Disease (KQol-AD) for quality of life; the Caregiver-Administered Neuropsychiatric Inventory (CGA-NPI) for neurobehavioral symptoms; blood tests for amyloid and tau proteins and general blood parameters; and electrocardiography (ECG) before and after taking the medication. Discussion: Our findings will provide insight into the feasibility of large-scale trials to consolidate evidence for the efficacy of KGT for dementia treatment. Registration ID in CRIS: KCT0002904 (Clinical Research Information Service of the Republic of Korea).