• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.205-211
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• 2015

At a recent medical imaging technology, the major issue of X-ray diagnosis in breast cancer is the early detection of breast cancer and low patient's exposure dose. As one of studies to acquire a monochromatic X-ray, Technologies using multilayer mirror had been preceded. However, a uniform multilayer mirror that consists of uniform thin-film thickness can acquire a monochromatic X-ray only in the partial area corresponds to angle of incidence of white X-ray, so there are limits for X-ray imaging technology applications. In this study, we designed laterally graded multilayer mirror(below GML) that reflects same monochromatic X-ray over the entire area of thin-film mirror, which have the the thickness of the linear gradient that correspond to angle of incidence of white X-ray. By using ion-beam sputtering system added the mask control system we fabricated a GML which has size of $100{\times}100mm^2$. The GML is designed to achieve the monochromatic X-ray of 17.5kev energy and has thin-film thickness change from 4.62nm to 6.57nm(3.87nm at center). It reflects the monochromatic X-ray with reflectivity of more than 60 percent, FWHM of below 2.6keV and X-ray beam width of about 3mm. The monochromatic X-ray corresponded to 17.5keV using GML would have wide application in development of mammography system with high contrast and low dose.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.14 no.2
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• pp.155-160
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• 2011

Purpose: This study was performed to evaluate the role of colonoscopy in children with hematochezia. Methods: We retrospectively reviewed the medical records of 277 children who underwent colonoscopy because of hematochezia between January, 2003 and July, 2010. Results: The mean age of the patients was $6.0{\pm}4.4$ (7 days~17.8 years) years. The male to female ratio was 2.2:1. The duration between the 1st episode of hematochezia and colonoscopy was $4.9{\pm}12.1$ months. Characteristics of hematochezia included red stool (65.1%), blood on wipe (12.8%), bloody toilet (11.9%), and blood dripping (10.2%). The most proximal region of colonoscopic approach was terminal ileum (84.5%), cecum (9.5%), hepatic flexure (2.8%), and splenic flexure (3.2%). Eighty five patients (30.6%) had no specific abnormal findings. Major causes of hematochezia were polyp (26.4%), food protein induced proctocolitis (6.9%), infectious colitis (5.4%), lymphofolliculitis (5.7%), non specific colitis (5.7%), and vascular ectasia (5.1%). The hemorrhagic sites included the rectum (24.0%), rectosigmoid junction (18.1%), sigmoid colon (13.5%), ascending colon (14.2%), transverse colon (11.3%), descending colon (7.8%), cecum (8.1%), and terminal ileum (3.1%). The recurrence rate of hematochezia after colonoscopy was 19.1%. Colonoscopy was performed in 262 patients (94.6%) with conscious sedation. Endoscopic hemostasis was performed in 5 patients. Complications of colonoscopy or sedation were not found. Conclusion: The causes and lesional localization of pediatric hematochezia were diverse. Colonoscopy has an important role in the diagnosis and treatment of hematochezia in children. Total colonoscopy is recommended to detect the cause of hematochezia.

• Pediatric Infection and Vaccine
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• v.14 no.2
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• pp.136-144
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• 2007

Purpose : Human bocavirus (HBoV) was recently identified world widely in clinical specimens from infants and children with respiratory tract illness, but the role of HBoV in respiratory tract illnesses is unknown. The aim of this study was to investigate the frequency and the clinical manifestation of HBoV in pediatric patients. Methods : We retrospectively investigated 1,777 throat swab obtained between 2005 and 2006 from pediatric in-patients with acute respiratory tract diseases at the Kwang-ju Christian Hospital. The medical records of patients with positive results were reviewed for demographic and clinical data of HBoV infections. Results : HBoV DNA was found in 84 (4.7%) of the 1,777 hospitalized children and the mean age was 19 months. The most common diagnosis were pneumonia (67.8%), bronchiolitis (35.7%). HBoV infections were found year-round, though most occurred in spring and winter months. Conclusion : HBoV is frequently found in hospitalized infants and children with acute respiratory tract diseases in Korea, but an association of HBoV with a distinct respiratory tract manifestation was not apparent. To clarify the clinical significance of HBoV, further evaluation of various age groups and clinical groups is needed.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.510-518
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• 2002

Background : Bronchial anthracofibrosis (BAF) is a dark black or brown pigmentation of multiple large bronchi associated with a fibrotic stenosis or obliteration that is incidentally found during a diagnostic bronchoscopy some reporters have suggested endobronchial tuberculosis or tuberculous lymphadenitis as a possible cause of BAF. However, some BAF patients do not have any medical history of tuberculosis. The aim of this study was to elucidate the clinical features of simple BAF patients, which were not associated with tuberculosis. Methods : We reviewed the patients' charts retrospectiely and interviewed all BAF patients who were followed up for 1 year or more. Among the 114 BAF patients, 43 patents (38 %) had no associated tuberculosis, cancer and pneumoconiosis. The clinical characteristics, radiological findings and associated pulmonary diseases of these patients were evaluated. Results : Most patients were non-smokers, old aged, housewifes who resided in a farming village. The common respiratory symptoms were dyspnea, cough and hemoptysis. The predominant X-ray findings were a multiple bronchial wall thickening(89%), bronchial narrowing or atelectasis (76%) and a mediastinal lymph node enlargement with/without calcification (78%). Pulmonary function test usually showed mild obstructive ventilatory abnormalities but no patient showed a restrictive ventilatory pattern and the patients were frequently affected with chronic bronchitis(51%), post-obstructive pneumonia(40%) and chronic asthma(4%). Conclusion : Because BAF is frequently associated with chronic bronchitis and obstructive pneumonia as well as tuberculosis, a careful clinical evaluation and accurate differential diagnosis is more essential than empirical anti-tuberculous medication.

• Journal of Chest Surgery
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• v.38 no.9 s.254
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• pp.609-615
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• 2005

Background: Some controversy still exists concerning the operative indications of coronary fistulas. Nevertheless, a short-term and long-term outcomes are excellent with surgical interventions. In this study, we assessed our surgical results on this disease entity during the last 20 years. Anatomic diversity was described as well. Material and Method: From April 1986 to March 2005, 20 patients with coronary fistulas underwent surgical correction in Seoul National University Children's Hospital. Their medical records were reviewed retrospectively. Result: Twelve patients ($60\%$) were asymptomatic prior to surgery. All had electrocardiogram and echocardiogram and all but 3 had coro-nary angiogram preoperatively. Anatomically, none of them had two or more coronary fistulas. The sites of origin were left coronary system in 11 patients and right in 9. The draining sites were right ventricle in 11, right atrium in 3, left ventricle in 3, main pulmonary artery in 2, and superior vena cavae in 1. All of the involved, the coro-nary arteries were dilated or aneurismal. In 1 case, there was atherosclerotic change but no ischemic evidence in preoperative electrocardiogram. Operative techniques included external obliteration (13), internal obliteration (5), and both (2). External obliteration was done by ligation of the fistulous tract only in T patients, by fstula ligation plus plication in 3 and by plication or patch closure via fistulotomy in 3. There was no operative mortality. All of postoperative morbidities including transient sinus arrhythmia (2), complete atrioventricular block (1), decreased left ventricular function (2), ventricular tachycardia (1), pericarditis (1), and seizure (1) improved on discharge. The mean follow-up was 55.1$\pm$50.2 months (4.0 months${\~}$18.0 years) and there were no recurrences of fistula. There was 1 second operation for aortic root aneurysm, which developed after external patch closure of right coronary fistula. Conclusion: We demonstrated here that coronary fistulas can be cured with excellent clinical outcome and low operative risk under precise diagnosis. Understanding the anatomic diversity will help to construct surgical plans.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.1
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• pp.69-76
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• 2003

Purpose: This study was designed to provide the data base for the diagnosis and treatment of the foot tumor by investigation of the clinical and pathological characteristics and distribution of the foot tumor. Materials and Methods: 142 foot tumors of 141 patients were studied. All patients were diagnosed with surgical biopsy. We investigated clinical and pathological characteristics and epidemiologic distribution of the foot tumor by reviewing the medical records and imaging materials. The location of the tumors were classified with zone of Kirby et al. Results: 75 patients were female and 66 were male. The average age of the patients was 33.2 years old. Benign soft tissue tumors were the most as 68 cases, and followed by 57 benign bone tumors, 12 malignant soft tissue tumors and 5 malignant bone tumors. Ganglia were the most in benign soft tissue tumors as 36 cases, subungual exostoses in benign bone tumors as 18, squamous cell carcinomas in malignant soft tissue tumors as 7, and metastatic lung cancers in malignant bone tumors as 2. The rate of pain complaints was the highest in malignant bone tumors, the duration of symptom was longest in benign soft tissue tumors, and the size of the tumor was the biggest in malignant bone tumors. Neurological symptoms were found in only 3 benign soft tissue tumors. For the zonal distribution, zone 5 was the most in 59 cases and zone 4 was the least as 10. The most numbers of the benign bone tumors located in zone 5, of benign soft tissue tumors in zone 1, of malignant bone tumors in zone 1 and 2, and of malignant soft tissue tumors in zone 5. The methods of surgical treatment included intralesional or marginal resection, curettage with or without bone graft, toe amputation, below knee amputation and limb salvage. Conclusion: The tumors of the foot were rare and various, and mostly benign (88%), but we can do proper treatment of those tumors without excluding malignant tumors by considering the age of patients, pain, duration of symptom, size of the tumors, and zonal distribution.

• Clinical and Experimental Pediatrics
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• v.48 no.11
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• pp.1193-1200
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• 2005

Purpose : Invasive bacterial infection is a major cause of morbidity and mortality in children. Previously, we reported etiology of invasive infections in healthy children in 1985-1995. This study was performed to update etiology of invasive bacterial infections in the previously healthy children. Methods : We reviewed medical records of 98 episodes of invasive bacterial infections in immunocompetent children at the Seoul National University Children's Hospital in 1996-2004. Results : The frequent pathogens identified over all age groups were Streptococcus pneumoniae (33%) and Staphylococcus aureus(33%). The proportion of Salmonella species and Haemophilus influenzae has been declined to 4% each from 23% and 14%, respectively, compared to previous study. S. agalactiae was the most common isolate in the infants ${\leq}3$ months. Among the infants and children aged 3 months to 2 years and children of 2-5 years, S. pneumoniae(57%, 52%, respectively, in each group) was the most common isolates followed by S. aureus(17% and 24%, respectively). S. aureus was the most common isolates(73%) in children >5 years. Primary bacteremia was the most common clinical diagnosis(27%). S. pneumoniae was responsible for 42% of primary bacteremia, 50% of meningitis, and 69% of bacteremic pneumonia and empyema. S. aureus accounted for 80% of bone and joint infections. The case fatality rate was 8.1% for all invasive infections. Conclusion : We reviewed frequency of bacterial agents of invasive infections in children. The data may be useful for pediatricians to select adequate empirical antibiotics in the management of invasive bacterial infections.

• Clinical and Experimental Pediatrics
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• v.46 no.5
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• pp.490-494
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• 2003

Purpose : We'd like to determine the incidence of congenital heart disease and arrhythmia in elementary school children in Busan, and to provide adequate prevention and treatment. Methods : A total of 23,802(male 12,909, female 10,893) 1st grade elementary school children living in Busan were studied. All children were 7-8 years old. We obtained their medical history by questionnaire and checked elecrocardiography(ECG). Subsequent screening tests including a 2nd ECG, chest X-ray, phonocardiogram and CBC for the students who had abnormal findings at the first screening test. The third screening test was done for students who had cardiac murmurs or abnormal ECG findings in the second screening test by echocardiogram, treadmill test and 24-hour Holter monitoring. Results : Among 23,802 children participants, 605(2.54%) had abnormal ECG findings at the first screening test. Q wave abnormality(0.58%) was observed most frequently, and complete right bundle branch block(RBBB)(0.26%), sinus tachycardia(0.24%), right axis deviation(0.22%) and ventricular premature contraction(VPC)(0.21%) followed in order. Four hundred and twenty four children participated in the second ECG screening test. Two hundred and two children(47.6%) had an abnormality such as sinus tachycardia(18.8%), VPC(17.8%), or complete RBBB(17.3%). After completing the third examination including echocardiogram, we couldn't find the students with ventricular tachycardia (VT) or SVT at the third arrhythmia screening test. Conclusion : A high incidence of arrhythmia was found in the 1st grade elementary school children in Busan despite their healthy appearances, although fatal heart diseases were not noted. Early diagnosis, adequate preventative measures and treatment will prevent and decrease the frequency of emergent situations like syncope and sudden death.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.161-169
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• 2008

Since measuring the size of kidney with sonography becomes an important index for diagnosis, treatment, and prognostic prediction in kidney disease, the accurate measurement and evaluation on this are clinically very important. Accordingly, the purpose of this study was to increase reproducibility and objectivity in measuring the size of kidney by enumerating factors that have an impact for measurement. It targeted 44 adults in Korea at the age of 21-27. It measured in order for both kidneys to be seen most largely while changing a subject-examiner's position in a state of fasting for 8 hours and a transducer's approaching direction. It compared a size of kidney by measuring, respectively, with the same method in 30 minutes and in 1 hour after drinking water in 700-1,000cc. In case of the lateral approach scan in decubitus position, the average length of the kidney both to the right and the left and the deviation of measurement to be the largest. In NPO(None Per Oral) state, the average length in the right kidney was 10.19cm, and the average length in the left kidney was 10.33cm. In 60 minutes after taking moisture, the average length in the right kidney was 10.94cm, and the average length in the left kidney was 11.13cm. In comparing the average length of the kidney in NPO state and its average length in 60 minutes after taking moisture, the size swelled by 7.3% for the length in the right kidney and by 7.7% in the left, thereby having been indicated to be statistically significant(P<0.003). The measurement in a size of kidney by using ultrasound may be measured differently depending on a patient's state of taking moisture and a transducer's approaching direction. It is thought that when the measurement in a size of kidney is especially important clinically, the intake and intake time in moisture need to be considered and that measuring with the posterior approach in prone position is a good method aiming to increase reproducibility in measuring length of the kidney.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.2
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• pp.146-153
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• 2010

Purpose: Recent studies have reported an increase in the incidence of community-acquired Clostridium difficile-associated disease (CA-CDAD) among children. There is an overall lack of information on CA-CDAD in the pediatric population. The aim of our study was to compare the epidemiologic and clinical features between CA-CDAD and hospital-acquired C. difficile-associated disease (HA-CDAD) in children. Methods: We retrospectively reviewed the medical records of all patients who were diagnosed with C. difficile-associated disease (CDAD) at Gil Hospital between April 2008 and March 2009. The diagnosis of CDAD was made when patients with gastrointestinal symptoms had positive results for C. difficile toxins A and B assay or stool culture. Results: Sixty-one (male, 32 and female, 29) patients were included. The mean age was 3.79${\pm}$4.54 years. Of the 61 patients, 22 (36.1%) were <1 year of age. Twenty-three patients (37.7%) had a history of antibiotic exposure in the previous 3 months. Forty-one patients (67.2%) were diagnosed with CA-CDAD. There were no significant differences in age, gender, symptoms, laboratory findings, recovery period, complications, and recurrence between the CA-CDAD and HA-CDAD groups. On the other hand, exposure to antibiotics was significantly more frequent among patients in the HA-CDAD group (p=0.005). Conclusion: This study suggests that the occurrence of CA-CDAD is increasing in the pediatric population, especially in younger children with no history of exposure to antibiotics and in outpatients. Awareness of the increasing incidence of CA-CDAD and prompt investigation of C. difficile in susceptible patients is needed to avoid misdiagnosis and for appropriate therapy.