• 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.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.4
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• pp.403-414
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• 2023

Backgrounds/Aims: Pancreatoduodenectomy (PD) is recommended in fit patients with a carcinoma (PDAC) of the pancreatic head, and a delayed resection may affect survival. This study aimed to correlate the time from staging to PD with long-term survival, and study the impact of preoperative investigations (if any) on the timing of surgery. Methods: Data were extracted from the Recurrence After Whipple's (RAW) study, a multicentre retrospective study of PD outcomes. Only PDAC patients who underwent an upfront resection were included. Patients who received neoadjuvant chemo-/radiotherapy were excluded. Group A (PD within 28 days of most recent preoperative computed tomography [CT]) was compared to group B (> 28 days). Results: A total of 595 patents were included. Compared to group A (median CT-PD time: 12.5 days, interquartile range: 6-21), group B (49 days, 39-64.5) had similar one-year survival (73% vs. 75%, p = 0.6), five-year survival (23% vs. 21%, p = 0.6) and median time-to-death (17 vs. 18 months, p = 0.8). Staging laparoscopy (43 vs. 29.5 days, p = 0.009) and preoperative biliary stenting (39 vs. 20 days, p < 0.001) were associated with a delay to PD, but magnetic resonance imaging (32 vs. 32 days, p = 0.5), positron emission tomography (40 vs. 31 days, p > 0.99) and endoscopic ultrasonography (28 vs. 32 days, p > 0.99) were not. Conclusions: Although a treatment delay may give rise to patient anxiety, our findings would suggest this does not correlate with worse survival. A delay may be necessary to obtain further information and minimize the number of PD patients diagnosed with early disease recurrence.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.421-427
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• 2016

We aim to offer basic materials about infection management through conducting bacterial contamination test about general radiography equipment and CT equipment installed in ER of three general hospitals with 100 sickbeds or more located in Gyeongsangbuk-do Province, and suggest management plan. It had been conducted from 1st December 2015 to 31st December, and objects were general radiography equipment and CT equipment of emergency room located in Gyeongsangbuk-do Province. For general radiography equipment, sources were collected from 4 places such as upper side of control box which employees use most, upper side of exposure button, whole upper side of table which is touching part of patient's skin, upper side of stand bucky's grid, and where patients put their jaws on. For CT equipment, sources were collected from 3 places such as upper side of control box which radiography room employees use most, X-ray exposure button, whole upper side of table which is touching part of patient's skin, and gantry inner. Surface contamination strain found at general radiography equipment in emergency room of radiology are Providencia stuartii(25%), Stenotrophomonas maltophilia(18%), Enterobacter cloacae(8%), Pseudomonas species(8%), Staphylococcus epidermidis(8%), Gram negative bacilli(8%), and ungrown bacteria at incubator after 48 hours of incubation (67%) which is the biggest. Most bacteria were found at upper side of stand bucky-grid and stand bucky of radiology's general radiography equipment, and most sources of CT equipment were focused at patient table, which means it is contaminated by patients who have various diseases, and patients who have strains with decreased immunity may get severe diseases. Thus infection prevention should be made through 70% alcohol disinfection at both before test and after test.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.378-388
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• 2001

Purpose: In this study, we developed a new method for the determination of renal depth with anterior and posterior renal scintigrams in a dual-head gamma camera, considering the attenuation factor $e^{-{\mu}x}$ of the conjugate-view method. Material and Method: We developed abdomen and kidney phantoms to perform experiments using Technetium-99m dimercaptosuccinic acid ($^{99m}Tc$-DMSA). The phantom images were obtained by dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators (ICONf, Siemens). The equation was derived from the linear integration of omission ${\gamma}$-ray considering attenuation from the posterior abdomen to the anterior abdomen phantom surface. The program for measurement was developed by Microsoft Visual C++ 6.0. Results : Renal depths of the phantoms were derived from the derived equations and compared with the exact geometrical values. Differences between the measured and the calculated values were the range of 0.1 to 0.7 cm ($0.029{\pm}0.15cm,\;mean{\pm}S.D.$). Conclusion: The present study showed that the use of the derived equations for renal depth measurements, combined with quantitative planar imaging using dual-head gamma camera, could provide more accurate results for individual variation than the conventional method.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.442-447
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• 1999

Introduction: Understanding the normal distribution of the tracheal diameter and crross- sectional area is one of the key elements in the management of various tracheal pathologies or tracheal reconstruction for the patients in growing age. However, data for Korean standard has been lacking. This study was designed to analyze retrospectively the distribution of tracheal diameter and cross-sectional area in young Koreans, which can afford fundamental data for the management of tracheal diseases. Material and Method: Of the patients who underwent computerized tomogram of the chest between May 1996 and August 1998, one hundred six young patients(age range: 0-20 years) were included. Patients with any conditions which might affect the tracheal cross-sectional area or diameter, such as tracheal disease, previous operation, mediastinal tumor, or obstructive lung disease were excluded from the study. Gender distribution was 69 males and 37 females. Tracheal diameters, anterior-posterior and transverse, were measured at the level of the thoracic inlet(level I) and the aortic arch(level II). Types of the trachea were divided into round, oval, or horseshoe shaped on cross-sectional view, and the dimension was calculated by using the equation of A=1/4$\pi$ab(A; area, $\pi$; 3.14, a; anterior-posterior diameter, b; transverse diameter). We analyzed the distribution of the diameter at each level and compared the cross-sectional area with respect to age and gender. A p-value lower than 0.05 wa considered significant. Result: The trachea of patients less than 5 years old were round in shape at both of level I and II, and no differences in cross-sectional area was observed between the levels(p=NS). As the age increased, the trachea become oval in shape at level I while it remained round in shape at level II(p=0.020). The tracheal diameter and cross-sectional area increased as the age increased with a linear correlation(r>0.9). In patients less than 5 years of age, female patients showed larger cross-sectional area than male patients (p=0.020), and it was reversed in patients older than 15 years of age(p=0.002). Conclusion: From the above results, we suggest chest computerized tomogram as a safe and reliable tool in measuring the tracheal diameter and cross-sectional area. We also provide the data as a standard for distribution of the tracheal diameter and cross-sectional area in young Korean population.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.403-407
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• 2018

Currently, the highest cancer death rate in Korea is lung cancer, which is a typical cancer that is difficult to detect early. Low-dose chest CT is being used for early detection, which has a greater lung cancer diagnosis rate of about three times than regular chest x-ray images. However, low-dose chest CT not only significantly reduces image resolution but also has a weak signal and is sensitive to noise. Also, air filled lungs are low-density organs and the presence of noise can significantly affect early diagnosis of cancer. This study used Visual C++ to set a circle inside a large circle with a density of 2.0, with a density of 1.0, which is the density of water, in which five small circle of mathematics have different densities. Gaussian noise was generated by 1%, 2%, 3%, and 4% respectively to determine the effect of noise on the mean value, the standard deviation value, and the relative noise ratio(SNR). In areas where the density difference between the large and small circles was greatest in the event of 1 % noise, the SNR in the area with the greatest variation in noise was 4.669, and in areas with the lowest density difference, the SNR was 1.183. In addition, the SNR values can be seen to be high if the same results are obtained for both positive and negative densities. Quality was also clearly visible when the density difference was large, and if the noise level was increased, the SNR was reduced to significantly affect the noise. Low-density organs or organs in areas of similar density to cancers, will have significant noise effects, and the effects of density differences on the probability of noise will affect diagnosis.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.113-117
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• 2006

Purpose: Post-mastectomy radiotherapy (PMR) is known to decrease loco-regional recurrence. Adequate skin and dermal dose are achieved by adding bolus. The more difficult clinical issue is determining the necessary number of bolus treatment, given the limits of normal skin tolerance. The aim of this study is to evaluate the necessary number of bolus treatment after PMR in patients with breast cancer. Materials and Methods: Four female breast cancer patients were included in the study. The median age was 53 years(range, $38{\sim}74$), tumor were left sided in 2 patients and right sided in 2patients. All patients were treated with postoperative radiotherapy after MRM. Radiotherapy was delivered to the chest wall (C.W) and supraclavicular lymph nodes (SCL) using 4 MV X-ray. The total dose was 50 Gy, in 2 Gy fractions (with 5 times a week). CT was peformed for treatment planning, treatment planning was peformed using $ADAC-Pinnacles^3$ (Phillips, USA) for all patients without and with bolus. Bolus treatment plans were generated using image tool (0.5 cm of thickness and 6 cm of width). Dose distribution was analyzed and the increased skin dose rate in the build-up region was computed and the skin dose using TLD-100 chips (Harshaw, USA) was measured. Results: No significant difference was found in dose distribution without and with bolus; C.W coverage was $95{\sim}100%$ of the prescribed dose in both. But, there was remarkable difference in the skin dose to the scar. The skin dose to the scar without and with bolus were $100{\sim}105%\;and\;50{\sim}75%$. The increased skin dose rates in the build-up region for Pt. 1, Pt. 2. Pt. 3 and Pt. 4 were 23.3%, 35.6%, 34.9%, and 41.7%. The results of measured skin dose using TLD-100 chips in the cases without and with bolus were 209.3 cGy and 161.1 cGy, 200 cGy and 150.2 cGy, 211.4 cGy and 160.5 cGy, 198.6 cGy and 155.5 cGy for Pt. 1, Pt. 2, Pt. 3, and Pt. 4. Conclusion: It was concludes through this analysis that the adequate number of bolus treatments is 50-60% of the treatment program. Further, clinical trial is needed to evaluate the benefit and toxicity associated with the use of bolus in PMR.