• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.557-559
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• 2015

Medulloblastoma is a common pediatric tumor typically diagnosed before the age of fifteen. Initial therapy includes surgical resection and radiation of the entire neuro-axis. Recurrence is common and typically occurs within 2 years of initial diagnosis. Those fitting Collin's Law is considered tumor-free. We report a case of single supratentorial recurrence 13 years after initial diagnosis. Here we present a 22 year old male presenting 13 years after initial diagnosis with isolated septum pellucidum recurrence. He underwent complete resection of the tumor. Medulloblastoma is a common in the pediatric population. Late recurrence to the ventricular system is uncommon. Long term follow-up is recommended in these patients.

• Journal of Preventive Medicine and Public Health
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• v.42 no.4
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• pp.243-250
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• 2009

Objectives : The purposes of this study is to estimate the cost of cancer care after its diagnosis and to identify factors that can influence the cost of cancer care. Methods : The study subjects were patients with an initial diagnosis one of four selected tumors and had their first two-years of cancer care at a national cancer center. The data were obtained from medical records and patient surveys. We classified cancer care costs into medical and nonmedical costs, and each cost was analyzed for burden type, medical service, and cancer stage according to cancer types. Factors affecting cancer care costs for the initial phase included demographic variables, socioeconomic status and clinical variables. Results : Cancer care costs for the initial year following diagnosis were higher than the costs for the following successive year after diagnosis. Lung cancer (25,648,000 won) had higher costs than the other three cancer types. Of the total costs, patent burden was more than 50% and medical costs accounted for more than 60%. Inpatient costs accounted for more than 60% of the medical costs for stomach and liver cancer in the initial phase. Care for latestage cancer was more expensive than care for early-stage cancer. Nonmedical costs were estimated to be between 4,500,000 to 6,000,000 won with expenses for the caregiver being the highest. The factors affecting cancer care costs were treatment type and cancer stage. Conclusions : The cancer care costs after diagnosis are substantial and vary by cancer site, cancer stage and treatment type. It is useful for policy makers and researchers to identify tumor-specific medical and nonmedical costs. The effort to reduce cancer costs and early detection for cancer can reduce the burden to society and improve quality of life for the cancer patients.

• Tuberculosis and Respiratory Diseases
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• v.82 no.3
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• pp.234-241
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• 2019

Background: The utility of computed tomography (CT) in the differential diagnosis of patients with chronic obstructive pulmonary disease (COPD) exacerbation remains uncertain. However, due to the low cost associated with CT scan along with the impact of Koreas' health insurance system, there has been a rise in the number of CT scans in the patients with initial diagnosis of COPD exacerbations. Therefore, the utility of CT in the differential diagnosis was investigated to determine whether performing CT scans affect the clinical outcomes of the patients with an initial diagnosis of COPD exacerbation. Methods: This study involved 202 COPD patients hospitalized with an initial diagnosis of COPD exacerbation. We evaluated the change in diagnosis or treatment after performing a CT scan, and compared the clinical outcomes of patient groups with vs. without performing CT (non-CT group vs. CT group). Results: After performing CT, the diagnosis was changed for two (3.0%) while additional diagnoses were made for 27 of the 64 patients (42.1%). However, the treatment changed for only one (1.5%), and six patients (9.3%) received supplementary medication. There were no difference in the median length of hospital stay (8 [6-13] days vs. 8 [6-12] days, p=0.786) and intensive care unit care (14 [10.1%] vs. 11 [16.7%], p=0.236) between the CT and non-CT groups, respectively. These findings remained consistent even after the propensity score matching. Conclusion: Utility of CT in patients with acute COPD exacerbation might not be helpful; therefore, we do not recommend chest CT scan as a routine initial diagnostic tool.

• Journal of Oral Medicine and Pain
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• v.49 no.3
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• pp.57-64
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• 2024

Purpose: The aim of this study is to analyze the final diagnosis and the pain characteristics of patients with suspected nonodontogenic toothache and to contribute to the knowledge on differential diagnosis. Methods: A retrospective analysis was conducted based on medical records from 185 patients. The following data were collected: age, sex, pain characteristics, radiographic results, initial diagnosis and treatment, and final diagnosis and treatment. The final diagnosis and the pain characteristics of the 3 most common final diagnoses were analyzed. Results: Myofascial pain (MFP) was the most prevalent diagnosed condition accounting for 37.8% of cases, followed by pulpal pain (P) at 31.4%, and trigeminal neuralgia (TN) at 18.9%. There were significant differences in age, onset of the pain, and pain intensity across the 3 groups (all p<0.01). TN group exhibited a lower frequency of spontaneous and continuous pain than the MFP and P groups (all p<0.001). The proportion of patients reporting pain alleviating and aggravating factors related to dental pain was significantly higher in the P group than in the MFP and TN groups (all p<0.001). A concordance rate of 57.0% was observed between the initial and the final diagnosis. Twenty-six patients underwent tooth extractions and 24 patients had root canal treatments. Conclusions: It is important to differentiate between dental pain and nonodontogenic toothache to avoid unnecessary dental treatments. Comprehending the pain characteristics of each condition, taking a thorough history taking, and performing diagnostic tests can help differential diagnosis.

• Journal of Periodontal and Implant Science
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• v.45 no.3
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• pp.82-93
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• 2015

Purpose: This retrospective study evaluated the relationship between the timing of peri-implantitis diagnosis and marginal bone level after a 5-year follow-up of non-surgical peri-implantitis treatment. Methods: Thirty-three patients (69 implants) were given peri-implantitis diagnosis in 2008-2009 in Seoul National University Bundang Hospital. Among them, 31 implants from 16 patients were included in this study. They were treated non-surgically in this hospital, and came for regular maintenance visits for at least 5 years after peri-implantitis treatment. Radiographic marginal bone levels at each interval were measured and statistical analysis was performed. Results: Timing of peri-implantitis was one of the significant factors affecting initial bone loss and total bone loss not additional bone after peri-implantitis diagnosis. Patients with cardiovascular disease and diabetic mellitus were positively influenced on both initial bone loss and total bone loss. Patients who needed periodontal treatment after implant placement showed a negative effect on bone loss compared to those who needed periodontal treatment before implant placement during entire periods. Implant location also significantly influenced on amounts of bone loss. Mandibular implants showed less bone loss than maxillary implants. Among surgical factors, combined use of autogenous and xenogenic bone graft materials showed a negative effect on bone loss compared to autogenous bone graft materials. Use of membrane negatively affected on initial bone loss but positively on additional bone loss and total bone loss. Thread exposure showed positive effects on initial bone loss and total bone loss. Conclusions: Early peri-implantitis diagnosis led to early non-surgical intervention for peri-implantitis treatment, which resulted in the maintenance of the bone level as well as preservation of the implant.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.2
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• pp.66-72
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• 2018

Objectives: Desmoplastic melanoma of the oral cavity is an extremely rare condition that is often confused on initial diagnosis with non-melanotic benign lesion or spindle cell tumors. The purpose of this article was to raise awareness of the disease using a literature review. Materials and Methods: We analyzed 19 desmoplastic melanoma cases reported in the literature and added our experience. Data on clinical, histopathology, treatment, and survival were retrieved and analyzed. Survival analysis was by the Kaplan-Meier method. Results: Initial clinical and histopathological features were indistinctive, and a definite diagnosis of desmoplastic melanoma at initial assessment was possible in only 23.5% of cases. Among tests, immunohistochemical studies for S-100 and vimentin were all positive. The 5-year disease-free survival rate for oral desmoplastic melanoma was 0%, and the 5-year overall survival rate was 55.0%. Conclusion: Oral desmoplastic melanoma has a high percentage of initial misdiagnosis and propensity for local recurrence. Thus, careful initial diagnosis and adequate surgery may result in improved overall survival.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.213-218
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• 2017

The DC electrolytic capacitor for DC-link of power converter is widely used in various power electronic circuits and system application. Its functions include, DC Bus voltage stabilization, conduction of ripple current due to switching events, voltage smoothing, etc. Unfortunately, DC electrolytic capacitors are some of the weakest components in power electronics converters. Many papers have proposed different algorithms or diagnosis method to determinate the ESR and tan ${\delta}$ capacitance C for fault alarm system of the electrolytic capacitor. However, both ESR vary with frequency and temperature. Accurate knowledge of both parameters at the capacitors operating conditions is essential to achieve the best reference data of fault alarm. According to parameter analysis, the capacitance increases with temperature and the initial ESR decreases. Higher frequencies make the reference ESR with the initial ESRo value to decrease. Analysis results show that the proposed DC Bus electrolytic capacitor reference ESR model setting technique can be applied to advanced reference signal of capacitor diagnosis systems successfully.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1014-1026
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• 2017

The traditional fault diagnosis method for photovoltaic (PV) inverters has a difficult time meeting the requirements of the current complex systems. Its main weakness lies in the study of nonlinear systems. In addition, its diagnosis time is long and its accuracy is low. To solve these problems, a hidden Markov model (HMM) is used that has unique advantages in terms of its training model and its recognition for diagnosing faults. However, the initial value of the HMM has a great influence on the model, and it is possible to achieve a local minimum in the training process. Therefore, a genetic algorithm is used to optimize the initial value and to achieve global optimization. In this paper, the HMM is combined with a genetic algorithm (GHMM) for PV inverter fault diagnosis. First Matlab is used to implement the genetic algorithm and to determine the optimal HMM initial value. Then a Baum-Welch algorithm is used for iterative training. Finally, a Viterbi algorithm is used for fault identification. Experimental results show that the correct PV inverter fault recognition rate by the HMM is about 10% higher than that of traditional methods. Using the GHMM, the correct recognition rate is further increased by approximately 13%, and the diagnosis time is greatly reduced. Therefore, the GHMM is faster and more accurate in diagnosing PV inverter faults.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.9
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• pp.413-422
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• 2002

In a power plant, disturbance detection and diagnosis are massive and complex problems. Once a disturbance occurs, it can be either persistent, self cleared, cleared by the automatic controllers or propagated into another disturbance until it subsides in a new equilibrium or a stable state. In addition to the Physical complexity of the power plant structure itself, these dynamic behaviors of the disturbances further complicate the fault monitoring and diagnosis tasks. A data structure called a disturbance interrelation analysis graph(DIAG) is proposed in this paper, trying to capture, organize and better utilize the vast and interrelated knowledge required for power plant disturbance detection and diagnosis. The DIAG is a multi-layer directed AND/OR graph composed of 4 layers. Each layer includes vertices that represent components, disturbances, conditions and sensors respectively With the implementation of the DIAG, disturbances and their relationships can be conveniently represented and traced with modularized operations. All the cascaded disturbances following an initial triggering disturbance can be diagnosed in the context of that initial disturbance instead of diagnosing each of them as an individual disturbance. DIAG is applied to a typical cooling water system of a thermal power plant and its effectiveness is also demonstrated.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.4
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• pp.264-270
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• 2018

Purpose: The aim of this study was to describe functional gastrointestinal disorders (FGID) presented in a tertiary medical center, characteristics of patients and results of the diagnostic work-up together with an outcome during the follow up. Methods: This was a retrospective, single center, observational study including all patients who were diagnosed with FGID based on Rome III criteria from January to December 2015 in tertiary medical center. Results: Overall 294 children were included (mean age, 8.9 years [range, 1-18 years]; 165 females). Majority had functional constipation (35.4%), followed by functional abdominal pain (30.6%), irritable bowel syndrome (17.0%), functional dyspepsia (12.6%), functional nausea (3.4%) and abdominal migraine (1.0%). Regression model found that only significant factor associated with improvement of symptoms is the establishment of the functional diagnosis at the first visit (hazard ratio, 2.163; 95% confidence inverval, 1.029-4.544). There was no association between improvement of symptoms and presence of alarm signs/symptoms (weight loss, nocturnal symptoms and severe vomiting) at diagnosis. Furthermore, in pain symptoms (functional abdominal pain, irritable bowel syndrome, dyspepsia) no treatment positively correlated with pain improvement. Conclusion: Regardless of the initial diagnosis of FGID, positive diagnosis at the first visit increases a chance for resolution of symptoms.