• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.48-53
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• 1995

This study investigates a simple mathematical model for the quantitative estimation of regional myocardial blood flow in experimental canine coronary artery thrombosis using Rb-82 dynamic myocardial positron emission tomography. The coronary thrombosis was induced using the new catheter technique by narrowing the lumen of coronary vessel gradually, which finally led to partial obstruction of coronary artery. Ten Rb-82 dynamic myocardial PET scans were performed sequentially for each experiment using our 5, 10 and 20 second acquisition protocol, respectively, and three regions of interest were drawn on the transaxial slices, one on left ventricular chamber for input function and the other two on normal and decreased perfusion segments for the flow estimation in those regions. Single compartment model has been applied to the measured sets of regional PET data, and the rate constants of influx to myocardial tissue were calculated for regional myocardial flow estimates with the three parameter fits of raw data by the Levenberg-Marquardt method. The results showed that, (1) single compartment model suggested by Kety-Schmidt could be used for the simple estimation of regional myocardial blood flow, (2) the calculated regional myocardial blood flow estimates were dependent on the selection of input function, which reflected partial volume effect and left ventricular wall motion, and (3) mathematically fitted input and tissue time activity curves were more suitable than the direct application of the measured data in terms of convergence.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.59-64
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• 1993

To evaluate the usefulness and differences in diagnosing coronary artery disease (CAD) between men and women of intravenous dipyridamole $^{99m}Tc$-MIBI myocardial SPECT, we obtained $^{99m}Tc$-MIBI myocardial SPECT and compared with the findings of coronary angiographies. Ninety eight male and 37 female patients who underwent dipyridamole $^{99m}Tc$-MIBI myocardial imaging within one month of cardiac catheterization were studied. Scans were considered abnormal if perfusion defect was detected and the defect size was more than 12% for left anterior descending artery (LAD) and circumflex (LCX) and 8% for right coronary artery (RCA) territories. Lesions${\geqq}$50% luminal diameter narrowing were considered significant CAD. Overall sensitivity for detection of CAD was 94.3% in men and 96.4% in women; specificity was 70% in men and 52.6% in women (P=not significant, ns). Vessel-matched sensitivity was 75.3% in men and 72.7% in women (P=ns): specificity was 84.6% in men and 67.9% in women (P < 0.025). For individual coronary artery, the sensitivity in men and women was 87.7%, 81.8% for LAD; 78%, 83.3% for RCA and 52.2%, 46.7% for LCX (P=ns): the specificity was 80%, 40% for LAD (P<0.01), 82.5%, 68.4% for RCA, 88.9%, 86.4% for LCX (P=ns). The hemodynamic parameter after intravenous dipyridamole in men and women were significantly changed; the heart rate was increased and systolic, diastolic blood pressure was decreased. Adverse effects were reported in 58.8% of men and 72.7% in women (P=ns). The incidence of chest pain and headache were higher in women. There was no significant difference in the incidences of nausea, abdominal pain, dizziness, facial flushing, dyspnea. In conclusion, dipyridamole $^{99m}Tc$-MIBI myocardial SPECT is a safe, noninvasive test for evaluation of CAD. There was no gender difference to detect CAD, but more false-positive rate in women especially in the territory of LAD.

• Informatization Policy
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• v.25 no.3
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• pp.3-28
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• 2018

The purpose of this study is to analyze the research trends and present future research directions in the field of Cyber Physical System (CPS), a key element in the 4th Industrial Revolution, Industry 4.0, and Smart Manufacturing that are currently promoted as important innovation agenda both at home and abroad. In this study, (1) the concepts of industry 4.0, smart manufacturing and CPS are summarized; (2) analysis criteria of these fields are established; and 3) analysis results are presented and future research direction is proposed. 74 overseas and 8 domestic literature on manufacturing CPS from 2013 to 2017 are identified through 'Google Scholar Search'. Major results of the analysis are summarized as follows: (1) research on a common methodology and framework for the manufacturing CPS needs to be done based on the analysis of the existing methodologies and frameworks of various perspectives; (2) in order to improve the maturity of the manufacturing CPS, it is necessary to study actual deployment and operations of CPS, including the existing systems; (3) it is necessary to study the diagnostic methodology that can evaluate manufacturing CPS and suggest improvement strategy; and (4) as for the detailed model and tool, it is necessary to reinforce research on SCM production planning and human-machine collaboration while considering the characteristics of CPS.

• Journal of Veterinary Clinics
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• v.22 no.2
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• pp.148-152
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• 2005

An intact female, 5-year-old, Pekingese, weighing 3.5kg with a history of a palpated abdominal mass was referred to Veterinary Medical Teaching Hospital, Seoul National University. In laboratory examination, there were no remarkable abnormalities. Radiographic findings included a left mid-abdominal mass with ill-defined margin, serosal detail loss of peritoneal space, non-uniform opacity of retroperitoneal space, and a radiopaque cystic calculus. On abdominal ultrasonography, a heterogeneous parenchymal mass with irregular contour in the left renal region was found. Computed tomographic findings showed a tumor embolus within the caudal vena cava and an invasion into mesentery, small bowel loops, spleen and pancreas around the large left renal mass. Unilateral nephroureterectomy was performed. Histopathologic examination of the resected mass confirmed the diagnosis of renal cell carcinoma. The dog died one day after surgery. Although ultrasonography could give diagnostic information about mass characteristics, computed tomography (CT) can provide key imaging features of mass characteristics.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.2
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• pp.88-99
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• 2007

Soil moisture is one of the essential components in determining surface hydrological processes such as infiltration, surface runoff as well as meteorological, ecological and water quality responses at watershed scale. This paper discusses soil moisture transfer processes measured at hillslope scale in the Gwangneung forest catchment to understand and provide the basis of stochastic structures of soil moisture variation. Measured soil moisture series were modelled based upon the developed univariate model platform. The modeling consists of a series of procedures: pre-treatment of data, model structure investigation, selection of candidate models, parameter estimation and diagnostic checking. The spatial distribution of model is associated with topographic characteristics of the hillslope. The upslope area computed by the multiple flow direction algorithm and the local slope are found to be effective parameters to explain the distribution of the model structure. This study enables us to identify the key factors affecting the soil moisture distribution and to ultimately construct a realistic soil moisture map in a complex landscape such as the Gwangneung Supersite.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.204-212
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• 1998

Bronchiolitis obliterans organizing pneumonia(BOOP) is a type of diffuse interstitial lung disease that has emerged in the past decade as an important cause of acute respiratory illness in adult. Clinically, the entity usually starts with a subacute influenza-like illness, followed by cough, progressive dyspnea, and weight loss. Organized inflammatory polypoid materials predominantly affecting distal bronchioles, alveolar ducts, and peribronchial alveolar spaces are a key pathologic findings. BOOP is characterized by a good response to glucocorticoid and an excellent prognosis. However, there is a subset of BOOP who presents with a fulminant course leading to death or chronic severe fibrosis with marked impairment of lung function. Recently, we have experienced a case of rapidly progressive BOOP, diagnosed by open lung biopsy and showed a reluctant response to corticosteroid.

• Korean Journal of Psychosomatic Medicine
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• v.28 no.2
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• pp.99-107
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• 2020

Fibromyalgia is a disorder characterized by the core symptom of chronic widespread pain, along with fatigue, sleep disturbances, mood changes, and cognitive difficulties. The etiology of fibromyalgia involves a combination of biological factors, such as genetic vulnerability, alterations in pain processing and stress response system ; psychological factors, such as anxiety, depression, anger, and perceived stress ; environmental factors, such as infections, febrile diseases, and trauma. Central sensitization, which is amplified in the process of sensory stimulation, has been emphasized as a key etiological factor, as supported by enhanced wind-up, delayed aftersensation, decreased nociceptive flexion reflex threshold and functional imaging studies. Several guidelines recommend that a multimodal approach be used to treat fibromyalgia, including both pharmacological and non-pharmacological treatments, tailored to each individual, and that clinicians should provide an intellectual framework through sufficient education and emphasis on the importance of self-management. The prevalence of mood disorders, anxiety disorders, and other psychiatric problems is 7-9 times higher in patients with fibromyalgia than in the general population ; moreover, the association between fibromyalgia and certain psychopathologies or sleep problems has also been suggested. Since psychiatric problems, with shared vulnerabilities and risk factors, interact with fibromyalgia bidirectionally and also affect the disease course, an integrated management approach is needed to determine the risk of comorbidities.

• Journal of the Korean Society of Radiology
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• v.79 no.6
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• pp.303-310
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• 2018

Purpose: To evaluate the CT features of incidental breast lesions on chest CT and to suggest useful criteria for referral to a specialized breast unit. Materials and Methods: Between May 2009 and April 2014, enhanced chest CT examination reports containing the key word 'breast' were reviewed retrospectively. Patients who had incidental breast lesion and were referred to a specialized breast unit and then underwent pathological confirmation or follow-up over a 1-year period were included. Finally, 86 patients (all female, mean age, $48.9{\pm}12.6years$) were enrolled. Two radiologists evaluated lesion characteristics, including size, shape, margins, and enhancement. The correlations between the CT features and pathologies were evaluated, and the diagnostic accuracy of CT features in various combinations was assessed. Results: Among the CT features, irregular shape, non-circumscribed margin, and high contrast enhancement were different between malignant and benign lesions (p < 0.05). The combination of non-circumscribed margin and high contrast enhancement had the highest accuracy (97.7%). Conclusion: Reliable CT features for incidental malignant breast masses are irregular shape, non-circumscribed margin, and high contrast enhancement. The combination of non-circumscribed margin and high contrast enhancement could help distinguish incidental malignant breast lesions and indicate referral to a specialized breast unit.

• Journal of Life Science
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• v.32 no.3
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• pp.263-269
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• 2022

Cancer cachexia-anorexia is a multi-organ metabolic syndrome characterized by anorexia and weight loss. Generally, such symptoms are a serious problem in cancer patients, adversely affecting chemotherapy success and survival rate. Cachexia has been reported to accompany up to 80% of gastrointestinal cancers, such as pancreatic, lung, and colon cancer, though it is relatively rare in lymphoma or breast cancer patients. It is also known that cancer-induced anorexia occurs independently of chemotherapy, although decreased appetite due to chemotherapy is well reported. In terms of pathoflammatory cytokines that are excessively increased by tumor tissues. Since the mechanism of cancer cachexia is not yet fully understood, there are currently no therapeutic agents or diagnostic markers to treat it. A recently published study identified a substance secreted from cancer cells that induces cancer anorexia, and the molecular mechanism causing the eating disorder was discovered. An increase in the expression of this substance has been shown to be statistically correlated with the symptoms of cachexia in cancer patients, and it is therefore expected to be applicable in the diagnosis and development of therapeutic agents for cancer cachexia. This review article aims to provide an overview of the key molecular mechanisms of the anorexia and tissue wasting caused by cancer cachexia.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.1-6
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• 2022

Deep learning is a collection of algorithms that enable learning by summarizing the key contents of large amounts of data; it is being developed to diagnose lesions in the medical imaging field. To evaluate the accuracy of the cerebral hemorrhage diagnosis, we used a convolutional neural network (CNN) to derive the diagnostic accuracy of cerebral parenchyma computed tomography (CT) images and the cerebral parenchyma CT images of areas where cerebral hemorrhages are suspected of having occurred. We compared the accuracy of CNN with different numbers of hidden layers and discovered that CNN with more hidden layers resulted in higher accuracy. The analysis results of the derived CT images used in this study to determine the presence of cerebral hemorrhages are expected to be used as foundation data in studies related to the application of artificial intelligence in the medical imaging industry.