• Korean Journal of Radiology
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• 제25권1호
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• pp.24-32
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• 2024

Despite improvements in operative techniques and perioperative care, post-hepatectomy liver failure (PHLF) remains the most serious cause of morbidity and mortality after surgery, and several risk factors have been identified to predict PHLF. Although volumetric assessment using imaging contributes to surgical simulation by estimating the function of future liver remnants in predicting PHLF, liver function is assumed to be homogeneous throughout the liver. The combination of volumetric and functional analyses may be more useful for an accurate evaluation of liver function and prediction of PHLF than only volumetric analysis. Gadoxetic acid is a hepatocyte-specific magnetic resonance (MR) contrast agent that is taken up by hepatocytes via the OATP1 transporter after intravenous administration. Gadoxetic acid-enhanced MR imaging (MRI) offers information regarding both global and regional functions, leading to a more precise evaluation even in cases with heterogeneous liver function. Various indices, including signal intensity-based methods and MR relaxometry, have been proposed for the estimation of liver function and prediction of PHLF using gadoxetic acid-enhanced MRI. Recent developments in MR techniques, including high-resolution hepatobiliary phase images using deep learning image reconstruction and whole-liver T1 map acquisition, have enabled a more detailed and accurate estimation of liver function in gadoxetic acid-enhanced MRI.

• 척추신경추나의학회지
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• 제13권2호
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• pp.47-63
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• 2018

Objectives : The purpose of this study was to analyze the effects of lumbar spinal herniated intervertebral Disc on MRI accompanying or not High-intensive zone(HIZ) by Korean Medical Combination Treatment Methods : 324 patients who received inpatient treatment from January 2017 to September 2017 in the Daejeon-Jaseng of Korean Medicine Hospital were divided into 2 groups by High-intensive zone(HIZ) confirmed with a Lumbar spine magnetic resonance imaging. All patients received a combination of treatment including acupunture, chuna manual therapy, pharmacopunture, herbal medication. They were compared and analyzed on the basis of improvement between measuring Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), EuroQol-5 Dimension Index (EQ5D Index), physical examination as they were hospitalized and as they were discharged. The statistically significance was evaluated by SPSS 18.0 for windows. Results : After treatment, Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), EuroQol-5 Dimension Index (EQ5D Index), physical examination was improved respectively. But there was no statistically significance between 2 group's improvement after treatment. Conclusions : After inpatient treatment by Korean Medical Combination Treatment, Most patient's pain, disability and Health Related Quality of Life was improved significantly. But there was no statistically difference between accompanying or not High-intensive zone(HIZ). So We think that future research of higher quality and correct statistics shall be necessary.

• 조명전기설비학회논문지
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• 제20권8호
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• pp.54-62
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• 2006

3상 4선식 전원공급 시스템에서 단상 및 3상 부하의 운전하에서 전압 불평형은 부하의 불평형 운전에 의해 발생되고, 전류 불평형은 떨어진 전압 품질에 의해 더욱 심해진다. 에너지 변환장치로 사용되는 여러 형태의 컨버터는 3상 4선식 배전시스템에 직접적으로 고조파 전류를 주입함으로서 고조파 왜란을 증가시킨다. 고조파 전류는 전동기 출력 토크를 감소시키고, 전동기를 과열 또는 소음을 증가시키며 회전자에 토크 맥동을 증가하여 기계적인 공진과 진동을 발생하는 등 여러 가지 부작용을 낳고 있다. 따라서 본 논문은 3상 4선식 배전시스템에서 선형 및 비선형 부하의 혼합 운전시 불평형과 고조파 성분에 의해 유도전동기의 특성 변화에 대한 연구로서 선형 단독운전, 비선형 부하 결합에 따른 특성 변화를 해석한 것으로서 단상 비선형 부하의 추가 운전시 5 고조파 필터로도 저감이 어려운 고조파로 인해 토크 맥동 횟수는 줄고 리플값은 증가함을 확인할 수 있었다.

• 생약학회지
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• 제40권2호
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• pp.109-117
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• 2009

We examined the purity of six heparin samples by using heparinase, chondroitinase, $^{1}H-NMR$, and polyacrylamide gel electrophoresis. To obtain high molecular weight contaminants from heparin samples, heparinase I - digested samples were subjected to the exhaustive microcon filtration. The filtration process removed heparin-derived di- and oligosaccharides effectively. By combining chondroitinase ABC treatment and strong anion exchange - high performance liquid chromatography, the result showed all six samples contained chondroitin sulfate as a contaminant ranging from 1.3 to 14.9%. Among them, sample S3 showed the highest content of 14.9%, which was further analyzed by chondroitinase AC treatment to confirm chondroitin sulfate B (dermatan sulfate). $^{1}H-NMR$ chemical shifts of N-acetyl groups clearly suggested the existence of chondroitin sulfate B (sample S3) and oversulfated chondroitin sulfate (samples S2 and S4) as contaminants. In addition, polyacrylamide gel electrophoresis was useful for qualitative detection on the sample's purity. These results suggest that the tools of heparinase I and chondroitinase ABC in combination with NMR spectroscopy would give very useful information for investigation of heparin contaminants such as oversulfated chondroitin sulfate and dermatan sulfate in heparin samples.

• 한국임상수의학회지
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• 제27권4호
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• pp.462-467
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• 2010

A Maltese (5-years old, castrated male) and a Yorkshire Terrier (8-years old, intact female) were referred to Seoul National University Hospital for Animals with ataxia, circling, depression and anorexia. It was suspected to meningoencephalitis of unknown etiology (MUE) based on neurological signs, magnetic resonance imaging findings, cerebrospinal fluid analysis and canine distemper virus antigen test. Immunosuppressive dose of corticosteroid was initially chosen to treat in two dogs. However, the clinical signs were relapsed and side effects had arisen including polyuria, polydipsia, calcinosis cutis, liver enzyme elevation, weight gain and abdominal distension. Combination therapy of cytosine arabinoside (CA) and prednisolone (PDS) was tried. With this combination, the clinical signs were resolved and the side effects were alleviated. The dose of PDS was tapered to 0.5 mg/kg q48h in one case and the PDS was discontinued in the other case. These cases suggested that combined CA and PDS therapy may be significantly useful for the treatment of MUE uncontrolled by PDS alone.

• 대한화학회지
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• 제28권5호
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• pp.335-341
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• 1984

${\alpha},{\beta}$-불포화 알데히드의 아세탈은 브롬화 방향족화합물들과 팔라듐 촉매와 트리에틸아민 존재하에서 쉽게 반응하여 방향족의 conjugated enals을 생성하였다. 불포화 아세탈로서 acrolein diethyl acetal과 methacrolein diethyl acetal을 사용하여 이들을 메틸기와 이소프로필기로 치환된 브롬화 방향족화합물들과 $100^{\circ}C$에서 반응시킨 뒤 생성물들을 옥살산 수용액으로 처리하여 방향족의 conjugated enals를 합성하였다. o-bromotoluene과 methacrolein diethyl acetal과의 반응을 제외하고는 모두 60% 이상의 좋은 수득율을 얻을 수 있었으며 생성물의 구조는 proton NMR과 IR스펙트럼으로 확인하였다. 3-bromopropenal dimethyl acetal 및 (E)-3-bromo-2-methylpropenal diethyl acetal을 할로겐화 비닐화합물의 반응 부위로 하고 1-알켄과 ethyl acrylate등을 올레핀 반응 부위로 하는 반응물들의 역조합(reverse combination)에 의하여 지방족의 2,4-dienals를 50% 이상의 수득율로 합성 할 수 있다.

• Investigative Magnetic Resonance Imaging
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• 제24권1호
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• pp.38-45
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• 2020

Background: Differentiation of cerebellopontine angle (CPA) schwannoma from meningioma is often a difficult process to identify. Purpose: To identify imaging features for distinguishing CPA schwannoma from meningioma and to investigate the usefulness of susceptibility-weighted imaging (SWI) in differentiating them. Materials and Methods: Between March 2010 and January 2015, this study pathologically confirmed 11 meningiomas and 20 schwannomas involving CPA with preoperative SWI were retrospectively reviewed. Generally, the following MRI features were evaluated: 1) maximal diameter on axial image, 2) angle between tumor border and adjacent petrous bone, 3) presence of intratumoral dark signal intensity on SWI, 4) tumor consistency, 5) blood-fluid level, 6) involvement of internal auditory canal (IAC), 7) dural tail, and 8) involvement of adjacent intracranial space. On CT, 1) presence of dilatation of IAC, 2) intratumoral calcification, and 3) adjacent hyperostosis were evaluated. All features were compared using Chi-squared tests and Fisher's exact tests. The univariate and multivariate logistic regression analysis were performed to identify imaging features that differentiate both tumors. Results: The results noted that schwannomas more frequently demonstrated dark spots on SWI (P = 0.025), cystic consistency (P = 0.034), and globular angle (P = 0.008); schwannomas showed more dilatation of internal auditory meatus and lack of calcification (P = 0.008 and P = 0.02, respectively). However, it was shown that dural tail was more common in meningiomas (P < 0.007). In general, dark spots on SWI and dural tail remained significant in multivariate analysis (P = 0.037 and P = 0.012, respectively). In this case, the combination of two features showed a sensitivity and specificity of 80% and 100% respectively, with an area under the receiver operating characteristic curve of 0.9. Conclusion: In conclusion, dark spots on SWI were found to be helpful in differentiating CPA schwannoma from meningioma. It is noted that combining dural tail with dark spots on SWI yielded strong diagnostic value in differentiating both tumors.

• 한국방사선학회논문지
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• 제12권3호
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• pp.335-341
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• 2018

의료수준의 향상과 더불어 환자들의 첨단의료장비에 대한 기대수준이 증가하고 있으며 특히 자기공명영상(Magnetic Resonance Image : MRI)은 현재 모든 임상 분야에서 가장 핵심적인 영상진단 도구로서 사용되고 있다. 그러나 검사 중에 발생하는 심각한 소음으로 많은 환자가 심리적인 불안을 경험한다고 한다. 이에 본 연구에서는 자기공명영상검사실의 기존 헤드셋 흡음재에서 차음재를 추가한 헤드셋의 소음저감평가와 차음재별 영상 아티팩트(artifact) 유무를 알아보고자 하였다. 3D 프린팅한 헤드셋 내부에 흡음재(스펀지)와 차음재(아크릴판, 구리판, 3D copper plate)를 교차 배열하여 MRI 검사소음을 녹음하여 스피커로 같은 dB 값의 소음을 발생시키며 3D 프린팅 된 두부모형의 내부에 소음측정기로 dB 값을 측정하여 정량분석을 하며 자체 제작한 헤드셋을 물팬텀에 밀착시킨 후 MRI영상 아티팩트 유무를 검사한다. 드셋의 정량평가를 한 결과, 헤드셋 평균 dB 값은 81.8 dB로 나타났으며, 차음재를 추가한 헤드셋에서 가장 방음효과가 뛰어난 재료조합(구리, 아크릴판, 스펀지, 스펀지) 헤드셋의 평균 dB 값은 70.4 dB 값이 측정되었지만 MRI 시뮬레이션 결과 구리가 반자성체이기 때문에 아티팩트가 나타나 배제하였고 두 번째로 방음효과가 뛰어난 (스펀지, 아크릴판, e-copper plate, 스펀지) 헤드셋의 평균 dB 값은 70.6 dB 값이 측정되었고 MRI 시뮬레이션 결과 인공물 나타나지 않았다. 구리분말이 약 40%가 포함된 e-copper PLA로 출력한 재료를 동일하게 시뮬레이션을 한 결과 인공물 나타나지 않았으므로 3D 프린팅 재료의 사용이 적합하였고 구리보다 경제성이 우수하며 가공이 용이하므로 적합한 재료로 선정하였다. MRI관련 연구에 있어 3D 프린팅을 이용한 상호발전이 매우 기대된다.

• Tuberculosis and Respiratory Diseases
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• 제80권4호
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• pp.368-376
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• 2017

Background: A ground-glass nodule (GGN) represents early-stage lung adenocarcinoma. However, there is still no consensus for preoperative staging of GGNs. Therefore, we evaluated the need for the routine use of positron emission tomography/computed tomography (PET)/computed tomography (CT) scans and brain magnetic resonance imaging (MRI) during staging. Methods: A retrospective analysis was undertaken in 72 patients with 74 GGNs of less than 3 cm in diameter, which were confirmed via surgery as malignancy, at the Samsung Medical Center between May 2010 and December 2011. Results: The median age of the patients was 59 years. The median GGN diameter was 18 mm. Pure and part-solid GGNs were identified in 35 (47.3%) and 39 (52.7%) cases, respectively. No mediastinal or distant metastasis was observed in these patients. In preoperative staging, all of the 74 GGNs were categorized as stage IA via chest CT scans. Additional PET/CT scans and brain MRIs classified 71 GGNs as stage IA, one as stage IIIA, and two as stage IV. However, surgery and additional diagnostic work-ups for abnormal findings from PET/CT scans classified 70 GGNs as stage IA, three as stage IB, and one as stage IIA. The chest CT scans did not differ from the combined modality of PET/CT scans and brain MRIs for the determination of the overall stage (94.6% vs. 90.5%; kappa value, 0.712). Conclusion: PET/CT scans in combination with brain MRIs have no additional benefit for the staging of patients with GGN lung adenocarcinoma before surgery.

• Korean Journal of Radiology
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• 제25권1호
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• pp.43-54
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• 2024

Objective: To evaluate the added value of diffusion-weighted imaging (DWI)-based quantitative parameters to distinguish uterine sarcomas from atypical leiomyomas on preoperative magnetic resonance imaging (MRI). Materials and Methods: A total of 138 patients (age, 43.7 ± 10.3 years) with uterine sarcoma (n = 44) and atypical leiomyoma (n = 94) were retrospectively collected from four institutions. The cohort was randomly divided into training (84/138, 60.0%) and validation (54/138, 40.0%) sets. Two independent readers evaluated six qualitative MRI features and two DWI-based quantitative parameters for each index tumor. Multivariable logistic regression was used to identify the relevant qualitative MRI features. Diagnostic classifiers based on qualitative MRI features alone and in combination with DWI-based quantitative parameters were developed using a logistic regression algorithm. The diagnostic performance of the classifiers was evaluated using a cross-table analysis and calculation of the area under the receiver operating characteristic curve (AUC). Results: Mean apparent diffusion coefficient value of uterine sarcoma was lower than that of atypical leiomyoma (mean ± standard deviation, 0.94 ± 0.30 10^-3 mm²/s vs. 1.23 ± 0.25 10^-3 mm²/s; P < 0.001), and the relative contrast ratio was higher in the uterine sarcoma (8.16 ± 2.94 vs. 4.19 ± 2.66; P < 0.001). Selected qualitative MRI features included ill-defined margin (adjusted odds ratio [aOR], 17.9; 95% confidence interval [CI], 1.41-503, P = 0.040), intratumoral hemorrhage (aOR, 27.3; 95% CI, 3.74-596, P = 0.006), and absence of T2 dark area (aOR, 83.5; 95% CI, 12.4-1916, P < 0.001). The classifier that combined qualitative MRI features and DWI-based quantitative parameters showed significantly better performance than without DWI-based parameters in the validation set (AUC, 0.92 vs. 0.78; P < 0.001). Conclusion: The addition of DWI-based quantitative parameters to qualitative MRI features improved the diagnostic performance of the logistic regression classifier in differentiating uterine sarcomas from atypical leiomyomas on preoperative MRI.