• 대한치과의사협회지
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• 제57권7호
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• pp.392-402
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• 2019

The most important part of everyday root canal treatment is diagnosis about the morphology of tooth, root and root canal. Usually this procedure is performed by visual examination and radiographic (panoramic/periapical) examination. However, 2-dimentional radiography has several limitations such as imposition of anatomic structures including buccal/lingual root canals and distortion of images. Recently, owing to the increased interest in dental implant and affordable cost of CBCT equipment, CBCT has been introduced widely in local dental clinics. CBCT is characterized by their lower radiation dose and shorter exposure time than conventional CT scan, and ability of 3-dimentional reconstruction of the dento-alveolar structure. Also in endodontic field, the data from CBCT could be very helpful in diagnosing complex root canal anatomy, apical periodontitis, cause of failure and in determining treatment plan. However, there are some limitations such as radiation dose and artifact. Therefore, clinicians should know about indication, advantages and limitations of CBCT, and properly use it for successful root canal treatment to save the natural teeth.

• Bulletin of the Korean Chemical Society
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• 제7권3호
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• pp.186-190
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• 1986

Effects of substituents in the nucleophile(X), the substrate(Y) and the leaving group(Z) on the structure of $S_N2$ transition states have been analyzed by considering effects of four components, electrostatic($E_{es}$), exchange repulsion ($E_{ex}$), polarization($E)_{pl}$) and charge transfer($E_{ct}$) terms, of interaction between the reactants on the degree of bond making and bond breaking. Prediction of net effects of all substituents(X, Y and Z) on the degree of bond making were found to be clearcut whereas the effect of an electron withdrawing group on the substrate (Y = EWG) on the degree of bond breaking was complex; the substituent(Y = EWG) is normally carbon-leaving group($C^{\ast}$-L) bond tightening($E_{pl}$ dominance) but becomes $C^{\ast}$-L bond loosening when the bond is strongly antibonding ($E_{ct}$ dominance). Our model calculations on the reaction of $CH_2XNH_2$ with $YCH_2COOCH_2Z$ using energy decomposition scheme have confirmed that predictions based on our analysis are correct.

• Korean Journal of Radiology
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• 제21권12호
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• pp.1305-1316
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• 2020

In approximately 10% of patients with acute myocardial infarction (MI), angiography does not reveal an obstructive coronary stenosis. This is known as myocardial infarction with non-obstructive coronary arteries (MINOCA), which has complex and multifactorial causes. However, this term can be confusing and open to dual interpretation, because MINOCA is also used to describe patients with acute myocardial injury caused by ischemia-related myocardial necrosis. Therefore, with regards to this specific context of MINOCA, the generic term for MINOCA should be replaced with troponin-positive with non-obstructive coronary arteries (TpNOCA). The causes of TpNOCA can be subcategorized into epicardial coronary (causes of MINOCA), myocardial, and extracardiac disorders. Cardiac magnetic resonance imaging can confirm MI and differentiate various myocardial causes, while cardiac computed tomography is useful to diagnose the extracardiac causes.

• Journal of Korean Neurosurgical Society
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• 제46권6호
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• pp.568-571
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• 2009

Accessory middle cerebral artery (MCA) is an infrequent vascular anomaly of the brain. Cerebral aneurysms associated with this anomalous artery are also very rare. To our knowledge, there have only been ten previous reports of an aneurysm associated with accessory MCA. The authors present two patients with accessory MCA-related aneurysms. A 38-year-old male and a 59-year-old female both presented with sudden-onset severe headache. In both patients, computed tomography (CT) scan revealed subarachnoid hemorrhage. A subsequent angiogram demonstrated an accessory MCA arising from the anterior cerebral artery (ACA) and a saccular aneurysm at the anterior communicating artery (ACoA) complex associated with an accessory MCA. Surgical clipping allowed for complete exclusion of the aneurysm from the arterial circulation. Based on our review of the ten cases of aneurysms associated with accessory MCA documented in the literature, we suggest that accessory MCA-related aneurysms can be classified according to whether the accessory MCA originates from the proximal A1 segment or from the ACoA complex. We also emphasize the importance of precise interpretation of preoperative angiograms and intraoperative precaution in determining the presence of this anomalous artery prior to temporary clip placement.

• Investigative Magnetic Resonance Imaging
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• 제19권4호
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• pp.205-211
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• 2015

The human heart is a complex organ in which many complicated congenital defects may happen and some of them require surgical intervention. Due to the vast complexity of varied anatomical presentations, establishing an accurate and consistent nomenclature system is utmost important to facilitate effective communication among pediatric cardiologists, cardiothoracic surgeons and radiologists. The Van Praagh segmental approach to the complex congenital heart disease (CHD) was developed in the 1960s and has been used widely as the language for describing complex anatomy of CHD over the decades. It utilizes a systematic and sequential method to describe the cardiac segments and connections which in turn allows accurate, comprehensive and unambiguous description of CHD. It can also be applied to multiple imaging modalities such as echocardiogram, cardiac CT and MRI. The Van Praagh notation demonstrates a group of three letters, with each letter representative for a key embryologic region of cardiac anatomy: the atria, ventricles and great vessels. By using a 3-steps approach, we can evaluate complex CHD precisely and have no difficulties in communicating with other medial colleague. This pictorial essay revisits the logical steps of segmental approach, followed by a pictorial illustration of its application.

• Investigative Magnetic Resonance Imaging
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• 제11권2호
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• pp.119-126
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• 2007

상완신경총의 영상 진단은 복잡한 해부학적인 구조와 다양하게 침범하는 병들로 인해 어렵고 도전적이다. 상완신경총 영상 진단의 일차적인 목표는 외상성 손상과 비외상성 손상의 구별이다. MRI의 급속경사와 전용표면코일을 이용한 적절한 공간분해능을 가진 영상기기의 발전과 이를 이용한 다양한 펄스열의 개발이 상완신경총의 외상성 손상과 비외상성 손상에 대한 구별에 많은 도움을 주어 정확한 진단으로 수술 여부의 결정에 이용된다. MRI는 비외상성 상완신경총 병변의 진단에 가장 좋은 영상진단이며, CT 척수강조영술은 상완신경총을 침범하는 신경근견열 병변의 검사에 많이 이용된다. 그리고 일반적으로 고화질, 고해상력의 MRI 가 상완신경총 비외상성병변의 진단에 일차적인 영상검사로 중요한 역할을 하고 있다.

• Journal of Yeungnam Medical Science
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• 제27권1호
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• pp.57-62
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• 2010

Pulmonary alveolar proteinosis (PAP) is a rare disorder that's characterized by accumulation of surfactant components in the alveolar space. Idiopathic PAP is recognized as an autoimmune disease that's due to impaired alveolar macrophage function and this caused by autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). We report here a case of pulmonary alveolar proteinosis that was deemed interstitial lung disease at the initial diagnosis. A 61-year-old man presented with intermittent blood tinged sputum and dyspnea on exertion. The man was a painter for 30 years and he had a 10 pack-years smoking history. Chest computerized tomography (CT) revealed multifocal ground-glass opacity with interstitial thickening at both lungs. His pulmonary function tests and methacholine test revealed non specific results. He was diagnosed with interstitial lung disease on the basis of the chest CT finding and occupational history. However, seven months later, his symptoms progressed. Follow-up chest CT was performed. Wedge resection via video-assisted thoracoscopic surgery (the anterior basal segment of the left lower lobe) was done. Microscopic examination showed large groups of alveoli with excessive amounts of surfactant and a complex mixture of protein and lipid (fat) molecules. Finally, he was diagnosed as having pulmonary alveolar proteinosis.

• Journal of Periodontal and Implant Science
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• 제47권1호
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• pp.30-40
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• 2017

Purpose: Optical coherence tomography (OCT) is a noninvasive diagnostic technique that may be useful for both qualitative and quantitative analyses of the periodontium. Micro-computed tomography (micro-CT) is another noninvasive imaging technique capable of providing submicron spatial resolution. The purpose of this study was to present periodontal images obtained using ex vivo dental OCT and to compare OCT images with micro-CT images and histologic sections. Methods: Images of ex vivo canine periodontal structures were obtained using OCT. Biologic depth measurements made using OCT were compared to measurements made on histologic sections prepared from the same sites. Visual comparisons were made among OCT, micro-CT, and histologic sections to evaluate whether anatomical details were accurately revealed by OCT. Results: The periodontal tissue contour, gingival sulcus, and the presence of supragingival and subgingival calculus could be visualized using OCT. OCT was able to depict the surface topography of the dentogingival complex with higher resolution than micro-CT, but the imaging depth was typically limited to 1.2-1.5 mm. Biologic depth measurements made using OCT were a mean of 0.51 mm shallower than the histologic measurements. Conclusions: Dental OCT as used in this study was able to generate high-resolution, cross-sectional images of the superficial portions of periodontal structures. Improvements in imaging depth and the development of an intraoral sensor are likely to make OCT a useful technique for periodontal applications.

• 정보교육학회논문지
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• 제22권6호
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• pp.661-669
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• 2018

2015 개정교육과정에 의해 2018년부터 SW 교육이 필수화되면서 SW 교육에 대한 연구가 활발하게 이루어지고 있다. 본 논문에서는 예비교사들의 컴퓨팅 사고력 수준을 파악하기 위해 2016년부터 2018년까지 3년 동안 K 교육대학교 1학년 학생 325명을 대상으로 스크래치 수업을 실시한 후 연도별로 산출된 스크래치 프로젝트를 Dr. Scratch 분석도구로 평가하여 연도별과 학점별로 CT요소 점수의 연관성을 분석하였다. 그 결과, 연도와 학점이 높을수록 CT요소, 점수, 등급도 높아짐을 알 수 있었다. 이를 통해, 학생들은 Dr. Scratch와 같은 자동화된 평가도구를 사용하여 평가해 본 후 스스로 수정 보완해보는 과정과 필요한 자료를 직접 제작하여 활용하는 ICT 능력이 필요하며, 복잡한 조건과 논리연산 활용 등 논리적 사고 요소를 이해하고 잘 활용될 수 있도록 교육될 필요가 있다.

• 대한소아치과학회지
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• 제48권3호
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• pp.352-358
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• 2021

Molar-incisor malformation (MIM)은 치관은 정상이나 치근의 비정상적인 형태를 보이는 것이 특징적이다. 제1대구치에 가장 많이 발생하며, 제2유구치나 상악 중절치도 때때로 이환된다. 이 증례 보고에서는 제1대구치를 포함해, 제2유구치에 MIM이 나타난 환자의 증례를 보고하고, 치근이 건전하게 발거된 제2유구치의 micro computed tomography (CT)를 이용한 형태학적 분석을 시행하였다. 발거된 치아에서는 MIM의 외형적 특징인 치관 - 치근 이행부의 cervical constriction을 육안상으로 확인할 수 있었으며, micro CT 분석에서 백악법랑경계부의 광화된 부위 (Cervical Minelarized Diaphragm), 많은 부근관과 막힌 근관 등의 복잡한 근관 형태, 근관 내 석회화 물질, 영구치에 비해 상대적으로 협착된 치관부 치수강이 관찰되었다.