• Korean Journal of Radiology
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• v.22 no.9
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• pp.1547-1554
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• 2021

Objective: We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). Materials and Methods: This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0-4-hour group) or between 4 to 48 hours (4-48-hour group). Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. Results: When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0-4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4-48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m². AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0-4-hour, and 4-48-hour groups, respectively. In the 0-4-hour and 4-48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). Conclusion: Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m².

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.7-15
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• 2020

Purpose: In modern radiotherapy technology, several methods of image guided radiation therapy (IGRT) are used to deliver accurate doses to tumor target locations and normal organs, including CBCT (Cone Beam Computed Tomography) and other devices, ExacTrac System, other than CBCT equipped with linear accelerators. In previous studies comparing the two systems, positional errors were analysed rearwards using Offline-view or evaluated only with a Yaw rotation with the X, Y, and Z axes. In this study, when using CBCT and ExacTrac to perform 6 Degree of the Freedom(DoF) Online IGRT in a treatment center with two equipment, the difference between the set-up calibration values seen in each system, the time taken for patient set-up, and the radiation usefulness of the imaging device is evaluated. Materials and Methods: In order to evaluate the difference between mobile calibrations and exposure radiation dose, the glass dosimetry and Rando Phantom were used for 11 cancer patients with head circumference from March to October 2017 in order to assess the difference between mobile calibrations and the time taken from Set-up to shortly before IGRT. CBCT and ExacTrac System were used for IGRT of all patients. An average of 10 CBCT and ExacTrac images were obtained per patient during the total treatment period, and the difference in 6D Online Automation values between the two systems was calculated within the ROI setting. In this case, the area of interest designation in the image obtained from CBCT was fixed to the same anatomical structure as the image obtained through ExacTrac. The difference in positional values for the six axes (SI, AP, LR; Rotation group: Pitch, Roll, Rtn) between the two systems, the total time taken from patient set-up to just before IGRT, and exposure dose were measured and compared respectively with the RandoPhantom. Results: the set-up error in the phantom and patient was less than 1mm in the translation group and less than 1.5° in the rotation group, and the RMS values of all axes except the Rtn value were less than 1mm and 1°. The time taken to correct the set-up error in each system was an average of 256±47.6sec for IGRT using CBCT and 84±3.5sec for ExacTrac, respectively. Radiation exposure dose by IGRT per treatment was measured at 37 times higher than ExacTrac in CBCT and ExacTrac at 2.468mGy and 0.066mGy at Oral Mucosa among the 7 measurement locations in the head and neck area. Conclusion: Through 6D online automatic positioning between the CBCT and ExacTrac systems, the set-up error was found to be less than 1mm, 1.02°, including the patient's movement (random error), as well as the systematic error of the two systems. This error range is considered to be reasonable when considering that the PTV Margin is 3mm during the head and neck IMRT treatment in the present study. However, considering the changes in target and risk organs due to changes in patient weight during the treatment period, it is considered to be appropriately used in combination with CBCT.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.497-503
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• 2003

Pulmonary aspergillosis usually results from the colonization of the existing lung lesions by chronic pulmonary diseases, such as tuberculosis. Most cases of pulmonary aspergilloma have been treated surgically for many years because it is a potentially life-threatening disease causing massive hemoptysis. Here we reviewed our results from the last 10 years. Material and Method: We reviewed 31 cases surgically treated from Aug. 1992 to Jul. 2002. retrospectively. This investigation is designed to illustrate the peak age incidence, sex ratio, chief complaints, preoperative study, anatomic location of operative site, postoperative pathologic finding and postoperative complications. Result: The peak age Incidence laid in the 3rd and 4th decade of 20 cases (64.5%). The most common complaint was hemoptysis in 27 cases (87.1%). The 31 cases had a history of treatment with anti-tuberculous drugs under impression of pulmonary tuberculosis. The 19 cases (61.3%) showed the so-called “Air-meniscus sign” on the preoperative chest X-ray. In the 31 cases (100%) on the chest computed tomography. as a preoperative diagnostic modality, positivity was shown in 37.9%, 83.3% was shown on the fungus culture of sputum for Aspergillus, serum immunodiffusion test for A. fumigatus, respectively. The anatomical location of aspergilloma was mainly in the upper lobe in 19 cases (61.3%) and the majority of cases were managed by lobectomy. The postoperative pathologic findings showed that 31 cases (100%) were combined with tuberculosis. The postoperative complications include empyema, prolonged air leakage, remained dead space, postoperative bleeding and these numbers of cases is 3 cases (9.7%), 2 cases (6.45%), 2 cases (6.45%), 1 case (3.23%), respectively. one case was died postoperatively due to massive beeding, and asphyxia. Conclusion: Compared with the previous study, there is no significant difference in results. Preoperative chest computed tomography and immunodiffusion test were more commonly available and showed high positivity. Operations often became technically difficult because of pleural space obliteration, indurated hilar structures, and poor expansion of the remaining lung, which were more prominent in the patients with complex aspergillosis. In such cases, medical treatments and interventional procedures like bronchial artery embolization are preferred. However, cavernostomy is also recommanded with few additional morbidity because of its relatively less invassiveness. Early surgical intervention is the recommended management for patients with simple aspergilloma considering the Row surgical mortality and morbidity in recent days.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.681-686
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• 2010

Background: A chest computed-tomography has become more prevalent so that it is more common to detect small sized pulmonary nodules that have not been found in previous simple chest x-ray. If those detected nodules are undersized or located in pulmonary parenchyma, it is difficult to accomplish a biopsy since it is vulnerable to explore them either grossly or digitally. Thus, in our hospital, a thoracoscopic pulmonary wedge resection was performed after locating a lesion by means of hook wire with CT-guided. Material and Method: 31 patients (17 males and 14 female patients) from December in 2006 to June in 2010 became our subjects; their 34 pulmonary nodules were subjected to the thoracoscopic pulmonary wedge resection after locating a lesion by means of hook wire with CT-guided. Also we analyzed a possibility of hook wire dislocation, a frequency of conversion to open thoracotomy, time consumed to operation after location of a lesion, operation time, post operation complication, and histological diagnosis of the lesion. Result: 12 of 34 cases were ground glass lesion, whereas 22 cases of them were solitary pulmonary lesion. The median value of the lesion was 8mm in size (range: 3 to 23 mm), while the median value was 12.5 mm in depth (range: 1 to 34 mm). The median value of time consumed from location of the lesion to anesthetic induction was 86.5 minutes (41~473 minutes); furthermore the mean value of operation time was 103 minutes (25~345 minutes). Intrathoracic wire dislocation was found in one case, but a target lesion was successfully excised. Open thoracotomy was performed in four cases due to pleural adhesion. However, there was no case of conversion to open thoracotomy due to failure to detect a target lesion. In histological diagnosis, metastatic cancer were found in 15 cases, which were the most common, primary lung cancer were in 9 cases, non-specific inflammation were in 3 cases, tuberculosis inflammation were in 2 cases, lymph nodes were in 2 cases, active tuberculosis were in 1 case, atypical adenomatous hyperplasia was in 1 case and normal lung parenchymal finding was in 1 case, respectively. Conclusion: In our hospital, in order to accomplish a precise histological diagnosis of ground-glass lesion and pulmonary nodules in lung parenchyma, location of pulmonary nodules were exactly located with hook wire under chest computed-tomography, which was followed by lung biopsy. We concluded that this was an accurate, minimally invasive and valuable method to minimize the complications and increase of cost of medical service provided.

• Journal of radiological science and technology
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• v.30 no.1
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• pp.13-23
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• 2007

In recent years, mammography system is changed rapidly from conventional screen-film system to digital system for application to screening and diagnosis. Digital mammography system provides several advantages over screen-film mammography system. According to the information provided by the manufacturer, digital mammography system offers radiation dose reduction in comparison with screen-film mammography system, because of digital detector, particularly direct digital detector has higher x-ray absorption efficiency than screen-film combination or imaging plate(IP). We measured average glandular doses(AGD) in screen-film mammography(SFM) system with slow screen-film combination, computed mammography(CM) system, indirect digital mammography(IDM) system and direct digital mammography(DDM) system using brest tissue-equivalent phantom(glandularity 30%, 50% and 70%). The results were shown as follows : AGD values for DDM system were highest than those for other systems. Although automatic exposure control(AEC) mode was selected, the curve of the AGD values against thickness or glandularity increased significantly for the SFM system with the uniform target/filter(Mo/Mo) combination. Therefore, the AGD values for the high energy examinations were highest in the SFM system, and those for the low energy examinations were highest in the DDM system. But the curve of the AGD values against thickness and glandularity increased gently for CM system with the automatic selection of the target/filter combination (from Mo/Mo to Mo/Rh or from Mo/Rh to Rh/Rh), and the AGD values were lowest. Consequently, the parameters in mammography for each exposure besides detection efficiency play an important role in oder to estimate a patient radiation dose.

• Tuberculosis and Respiratory Diseases
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• v.39 no.1
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• pp.28-34
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• 1992

Background: Diffuse panbronchiolitis (DPB) is a chronic obstructive pulmonary disease distinguished from bronchial asthma, chronic bronchitis, pulmonary emphysema, bronchiectasis, or alveolitis. It is prevalent in Japan, but is known to be rare outside of Japan. Only a few cases in Chinese, Italian, Noirth American and Korean have been reported. During recent two years we have found 16 cases of DPB in Seoul National University Hospital and analyzed the clinical characteristics. Method: We reviewed the patients' age, sex, duration of illness, smoking history, occupational history and past medical history. And we analyzed patients' symptoms, physical signs, laboratory findings and responses to treatment. Results: 1) Male: female ratio was 2.2:1, the ages ranged from 27 to 72 years old, and the duration of disease varied from 1 to 20 years. 2) Most of the patients were being treated as bronchiectasis, miliary tuberculosis, chronic bronchitis or bronchial asthma before they were diagnosed as DPB. 3) Only one patient was a smoker, and 25% of patients had the occupational history of exposure to particles or gas. And all patients had paranasal sinusitis. 4) High resolution computed tomography (HRCT) was very useful in diagnosing the disease in most of the patients. 5) PFT showed obstructive and restrictive abnormalities, and blood gas revealed hypoxemia in most of the patients. 6) Pseudomonas aeruginosa was isolated in the sputum of four patients (25%). 7) The titers of cold hemaglutinin, RA factor and CRP were elevated in most of the patients. 8) Most of the patients improved after treatment with erythromycin. Conclusion: DPB might not be a rare disease in Korea. So DPB should be suspected in a patient who has chronic cough, sputum, dyspnea and diffuse fine nodular chest X-ray abnormality. HRCT and open lung biopsy should be considered in a patient suspected of DPB.

• Journal of Chest Surgery
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• v.30 no.8
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• pp.780-785
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• 1997

Mediastinal tumor had been fascinated by its location on heart, great vessels, esophagus, and nervous tissue, its convenience of surgical treatment and superiority of its operative result. Between January 1989 and June 1995, eighty-seven patients with mediastinal tumor which were treated surgically in the Department of Thoracic and Cardiovascular Surgery, Asan Medical Center, School of Medicine, University of Ulsan. To provide the appropriate surgical management of mediastinal tumor, the demographic data, diagnostic evaluation, clinical presentation, location, size, operative finding and histopathologic distribution were reviewed and we analyzed relativity between invasiveness in chest computed tomographic finding or invasiveness on operative finding and histopathologic invasiveness. The anterosuperior mediastinum was the most commonly involved site of a mediastinal tumor(57%), followed by the posterior mediastinum(35%) and middle mediastinum(8%). The most frequently encountered tumors were thymic neoplasia(31%), followed by primary cyst(22%), neurogenic tumor(22%) and teratoma(10%) in decreasing order of frequency. Histopathologically invasive tumors were present in 17 patients(20%) and its site included anterosuperior mediastinum(16%) and posterior mediastinum(4%). All patients in this study underwent chest CT. In chest CT's finding, 15 patients(17%) showed invasiveness. A total excision of the tumor was performed 80 patients(92%), subtotal excision 6 patients(7%) and biopsy only 1 patient(2%). In operative finding, 14 patients(16%) were suspected invasiveness. The mean size of the tumor was 6.0$\pm$ 3.2cm. In anterosuperior mediastinum, the mean size was 6.2$\pm$3.1cm, in middle mediastinum, it was 3.9$\pm$1.1cm, in posterior mediastinum, it was 5.8$\pm$2.6cm. In malignant tumors, the mean size was 7.3$\pm$4.6cm, in benign tumor, it was 5.5$\pm$2.6cm(P<0.05). Relativity between histopathological invasiveness(17 patients) and invasiveness in chest CT's finding(15 patients) included sensitivity 35%, specificity 87% and predictability 35%, relativity between histopathological invasiveness(17 patients) and invasiveness on operative finding included sensitivity 52%, specificity 93% and predictability 64%. In conclusion, since it was proved that the compatibility of preoperative chest CT findings or operative findings and histopathological invasiveness is quite low, it is considered that wide excision of the mediastinal tumor except cystic lesion including adjacent tissues would yield better postoperative results.

• Tuberculosis and Respiratory Diseases
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• v.72 no.1
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• pp.8-14
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• 2012

Background: Although airway obstruction in chronic obstructive pulmonary disease (COPD) is due to pathologic processes in both the airways and the lung parenchyma, the contribution of these processes, as well as other factors, have not yet been evaluated quantitatively. We therefore quantitatively evaluated the factors contributing to airflow limitation in patients with COPD. Methods: The 213 COPD patients were aged >45 years, had smoked >10 pack-years of cigarettes, and had a post-bronchodilator forced expiratory volume in one second ($FEV_1$)/forced vital capacity (FVC) <0.7. All patients were evaluated by medical interviews, physical examination, spirometry, bronchodilator reversibility tests, lung volume, and 6-minute walk tests. In addition, volumetric computed tomography (CT) was performed to evaluate airway wall thickness, emphysema severity, and mean lung density ratio at full expiration and inspiration. Multiple linear regression analysis was performed to identify the variables independently associated with $FEV_1$ - the index of the severity of airflow limitation. Results: Multiple linear regression analysis showed that CT measurements of mean lung density ratio (standardized coefficient ${\beta}$=-0.46; p<0.001), emphysema severity (volume fraction of the lung less than -950 HU at full inspiration; ${\beta}$=-0.24; p<0.001), and airway wall thickness (mean wall area %; ${\beta}$=-0.19, p=0.001), as well as current smoking status (${\beta}$=-0.14; p=0.009) were independent contributors to $FEV_1$. Conclusion: Mean lung density ratio, emphysema severity, and airway wall thickness evaluated by volumetric CT and smoking status could independently contribute to the severity of airflow limitation in patients with COPD.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.139-151
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• 2021

Purpose To retrospectively evaluate the chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) in patients with mild clinical symptoms at a single hospital in South Korea. Materials and Methods CT scans of 87 COVID-19 patients [43 men and 44 women; median age: 41 years (interquartile range: 26.1-51.0 years)] with mild clinical symptoms (fever < 38℃ and no dyspnea) were evaluated. Results CT findings were normal in 39 (44.8%) and abnormal in 48 (55.2%) patients. Among the 48 patients with lung opacities, 17 (35.4%) had unilateral disease and 31 (64.6%) had bilateral disease. One (2.1%) patient showed subpleural distribution, 9 (18.8%) showed peribronchovascular distribution, and 38 (79.2%) showed subpleural and peribronchovascular distributions. Twenty-two (45.8%) patients had pure ground-glass opacities (GGOs) with no consolidation, 17 (35.4%) had mixed opacities dominated by GGOs, and 9 (18.8%) had mixed opacities dominated by consolidation. No patients demonstrated consolidation without GGOs. Conclusion The most common CT finding of COVID-19 in patients with mild clinical symptoms was bilateral multiple GGO-dominant lesions with subpleural and peribronchovascular distribution and lower lung predilection. The initial chest CT of almost half of COVID-19 patients with mild clinical symptoms showed no lung parenchymal lesions. Compared to relatively severe cases, mild cases were more likely to manifest as unilateral disease with pure GGOs or GGO-dominant mixed opacities and less likely to show air bronchogram.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1424-1435
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• 2020

Purpose The purpose of this study was to evaluate the usefulness of multiphasic CT and ¹⁸F-fluorodeoxyglucose (FDG) PET/CT for the differentiation of combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) from hepatocellular carcinoma (HCC). Materials and Methods From January 2007 to April 2016, 93 patients with pathologically confirmed HCC (n = 84) or cHCC-CCA (n = 9) underwent CT and PET/CT imaging. Contrast enhancement patterns were divided into three types based on the attenuation of the surrounding liver parenchyma: type I (early arterial enhancement with delayed washout), type II (early arterial enhancement without delayed washout), and type III (early hypovascular, infiltrative appearance, or peripheral rim enhancement). Results cHCC-CCAs (89%) had a higher PET/CT positive rate than did HCCs (61%), but the PET/CT positive rate did not differ significantly (p = 0.095). Among the 19 cases of the type II enhancement pattern, 3 (21%) of 14 HCCs and 4 (80%) of 5 cHCC-CCAs were PET/CT positive. cHCC-CCAs had a significantly higher PET/CT positive rate (p = 0.020) in the type II enhancement pattern. Conclusion The PET/CT positive rate of cHCC-CCA was significantly higher than that of HCC in lesions with a type II enhancement pattern. The ¹⁸F-FDG PET/CT can be useful for the differentiation of cHCC-CCA from HCC in lesions with a type II enhancement pattern on multiphasic CT.