• Tuberculosis and Respiratory Diseases
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• v.71 no.6
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• pp.438-444
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• 2011

Background: Lung abscess is necrosis of the pulmonary parenchyma caused by microbial infection. At present, clinical outcomes after treatment are good. However, the pulmonary parenchymal changes on the chest computed tomography (CT) after treatment are not well known. We studied the changes of pulmonary parenchyma on plane chest radiography and chest CT in patients with lung abscess following the administration of antibiotics. Methods: We retrospectively reviewed 39 patients who had lung abscess with or without combined pneumonia from January 2006 to July 2010. We studied the therapeutic response in plane chest radiography of them at 1, 2, or more than 3 months following treatment. If any chest CT of them during the study period, we reviewed. Results: Mean age of the patients was about $61.3{\pm}11.2$. Mean duration of antibiotics administration was about $36.7{\pm}26.8$ days. After 3 months of following plane chest radiography, 10 patients (36%) showed without residual sequelae among 28 patients. Findings from other patients showed decrease in densities (11 patients, 39%), fibrostreaky sequelae (4 patients, 14%) and bullae (3 patients, 10%). After more than 2 months, chest CT was checked only in 7 patients. Among the 7 patients, 4 patients showed no residual lesion, 3 patients showed decreased densities on plane chest radiography. Chest CT revealed fibrostreaky densities in 2 patients, ground glass opacities in 3 patients, bullous formation in 1 patient, and cystic bronchiectasis in 1 patient. Conclusion: After more than 2 months following treatment for lung abscess even though there were no lesions on plane chest radiography, chest CT showed fibrostreaky or ground glass opacity.

• Tuberculosis and Respiratory Diseases
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• v.79 no.2
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• pp.91-97
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• 2016

Background: Chronic obstructive pulmonary disease (COPD) is sometimes complicated with pneumonia, but little is known about the risk factors that promote the development of pneumonia in COPD. These risk factors were evaluated in the present study. Methods: The data of 324 patients with COPD from a prospective multi-center observational cohort with obstructive lung disease were evaluated retrospectively. To identify risk factors for the development of pneumonia in COPD, the clinical and radiological data at enrollment and the time to the first episode of pneumonia were analyzed by Cox proportional hazard analysis. Results: The median follow-up time was 1,099 days and 28 patients (8.6%) developed pneumonia. The Cox analysis showed that post-bronchodilator forced expiratory volume in one second ($FEV_1$, % of predicted) and the computed tomography (CT) emphysema extent (inspiratory V950) were independent risk factors for the development of pneumonia (post-bronchodilator $FEV_1$: hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.94-1.00; p=0.048 and inspiratory V950: HR, 1.04; 95% CI, 1.01-1.07; p=0.01). Conclusion: Emphysema severity measured by CT and post-bronchodilator $FEV_1$ are important risk factors for the development of pneumonia in COPD.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.171-178
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• 2003

Purpose: The purpose of this study was to report the reproducibility of intra-observer and inter-observer consistency of cephalometric measurements using three-dimensional (3D) computed tomography (CT), and the degree of difference of the cephalometric measurements. Materials and Methods: CT images of 16 adult patients with normal class I occlusion were sent to personal computer and reconstructed into 3D images using V-Works 3.5/sup TM/(Cybermed Inc., Seoul, Korea). With the internal program of V-Works 3.5/sup TM/, 12 landmarks on regular cephalograms were transformed into 21 analytic categories and measured by 2 observers and in addition, one of the observers repeated their measurements. Intra-observer difference was calculated using paired t-test, and inter-observer by two sample test. Results: There were significant differences in the intra-observer measurements (p < 0.05) in four of the categories which included ANS-Me, ANS-PNS, Cdl-Go (Lt), GoL-GoR, but with the exception of Cdl-Go (Lt), ZmL-ZmR, Zyo-Zyo, the average differences were within 2 mm of each other. The inter-observer observations also showed significant differences in the measurements of the ZmL-ZmR and Zyo-Zyo categories (p < 0.05). With the exception of the Cdl-Me (Rt), ZmL-ZmR, Zyo-Zyo categories, the average differences between the two observers were within 2 mm, but the ZmL-ZmR and Zyo-Zyo values differed greatly with values of 8.10 and 19.8 mm respectively. Conclusion: In general, 3D CT images showed greater accuracy and reproducibility, with the exception of suture areas such as Zm and Zyo, than regular cephalograms in orthodontic measurements, showing differences of less than 2 mm, therefore 3D CT images can be useful in cephalometric measurements and treatment planning.

• Tuberculosis and Respiratory Diseases
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• v.69 no.3
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• pp.177-183
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• 2010

Background: Smoking reduces pulmonary function and induces various lung diseases. Recently, the rate of emphysema detection has increased due to lung cancer screening with low-dose chest computed tomography (CT). The purpose of this study was to evaluate changes in lung function associated with emphysema in healthy smokers. Methods: One hundred and ninety one healthy smokers, who had undergone a low-dose chest CT (LDCT) scan as part of lung cancer screening and had revisited the health center after a median 23.9 months' time, were recruited into this study. The severity of emphysema was calculated by the direct observation of a radiologist and a pulmonologist indipendently. Longitudinal changes in lung function according to emphysema based on LDCT and type of smoker was analyzed. Results: Of the participants in this study, 25% of healthy smokers had emphysema, which was mild in severity, in older patients (p=0.003) and in heavy smokers (p<0.001). $FEV_1/FVC$ and FEF25-75% were decreased in current smokers with emphysema (p=0.001 and p=0.009, respectively) and without emphysema (p=0.001 and p=0.042). Although lung function was not decreased in ex-smokers without emphysema, $FEV_1/FVC$ and FEF25-75% were decreased in ex-smoker with emphysema (p=0.020 and p=0.010). Conclusion: Upon examination with LDCT, the prevalence of emphysema was higher in healthy smokers was than in non-smokers. Lung function was diminished in smokers with emphysema, in spite of former smoker.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.271-278
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• 1998

In order to access the value of computed tomography in mediastinal LN staging of NSCLCa, 581 LN stations of 77 patients were selected from 552 patients who were diagnosed as Lung Ca and operated in Seoul National University Hospital from 1992 to 1995. The selection criteria were as follows ; the patients 1) whose preoperative chest CTs were available; 2) underwent curative resection (lobectomy or more) with complete lymph node dissection; 3) whose final pathologic diagnosis were proven to be non-small cell lung cancer. We adopted Receiver Operating Characteristic curve method to determine a proper size criterion for diagnosing malignant mediastinal adenopathy. From curve analysis, we decided the size criterion of lymph node to 1 cm in their short axis. Using this size criterion, it's sensitivity was 43.9%, specificity was 87.4%, and accuracy was 83.1%. Eventhough we couldn't determine the precise size criterion for the adenoca, it seemed that shorter than 1 cm size criterion should be applied in that particular cell type. Lymph node stations associated with the tuberculosis or bronchiectasis tend to be overestimated in nodal staging and have relatively high false positive rate. The low sensitivity of CT scan suggest that radical and complete dissection or precise mediastinal lymph node evaluation through the surgical approach is mandatory.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.298-303
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• 1998

Computerized tomography(CT) is an effective technique in the initial evaluation of the abdomen and head following blunt trauma. To evaluate the efficacy of CT of the thorax, a retrospective study comparing early thoracic CT scanning with initial chest roentgenogram (CXR) was carried out on 134 patients with blunt trauma on the chest. Among 134 patients, 45 patients had normal initial chest roentgenogram and 24 patients showed normal CT findings. Sensitivities of diagnosing pneumothorax and pleural effusion by CXR were low (46.2 and 62.9% respectively), whereas 71.4%(45/63) of patients had thoracostomy only by CXR. Although sometimes abused, CT of the thorax is effective in the initial diagnosis.

• Journal of Chest Surgery
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• v.32 no.8
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• pp.693-701
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• 1999

Recently non-invasive diagnostic imaging replaced the invasive catheter angiography in the diagnosis of vascular disease. Catheter methods are now almost confined to the purpose of intervention. Coronary artery or coronary artery bypass graft still needs catheter technique because of small diameter and the cardiac motion. The last challenge for radiologists in this domain is to obtain a non-invasive imaging. Electron beam tomography(EBT) for high temporal resolution is able to obtain a coronary arteriogram or coronary artery bypass graft (CABG), of which CABG imaging is quite useful for the evaluation of patency. In our experience as well as others, the accuracy of EBT angiogram in evaluating CABG patency revealed that the accuracy of patency of saphenous vein grafts(SVG) is high due to relatively wide lumen, short and straight course and less influence from cardiac motion. The sensitivity and specificity of patency of SVGs were 92%, 97% respectively in the prospective evaluat on and 100% each in the retrospective evaluation. A false positive and a false negative case are rudimentary errors in the initial learing period. In contrast the analysis of left internal mammary artery(LIMA) graft was difficult due to the inherent small size and the adjacent surgical clips provoking beam-hardening artifact; therefore, the method of combining 3 dimensional reconstruction and flow mode study was important in improving the accuracy of LIMA patency. The sensitivity and specificity of LIMA patency were 100% and 80% in both prospective and retrospective evaluation. Therefore, EBT angiography is an accurate non-invasive diagnostic modality for evaluating the patency of CABG, particularly in SVGs. The accuracy can be improved with the improvement of the EBT and the development of the image reconstruction software.

• Journal of Periodontal and Implant Science
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• v.41 no.5
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• pp.218-226
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• 2011

Purpose: Micro-computed tomography (micro-CT) has been widely used in the evaluation of regenerated bone tissue but the reliability of micro-CT has not yet been established. This study evaluated the correlation between histomorphometric analysis and micro-CT analysis in performing new bone formation measurement. Methods: Critical-size calvarial defects were created using a 8 mm trephine bur in a total of 24 Sprague-Dawley rats, and collagen gel mixed with autogenous rat bone marrow stromal cells (BMSCs) or autogenous rat BMSCs transduced by adenovirus containing bone morphogenic protein-2 (BMP-2) genes was loaded into the defect site. In the control group, collagen gel alone was loaded into the defect. After 2 and 4 weeks, the animals were euthanized and calvaria containing defects were harvested. Micro-CT analysis and histomorphometric analysis of each sample were accomplished and the statistical evaluation about the correlation between both analyses was performed. Results: New bone formation of the BMP-2 group was greater than that of the other groups at 2 and 4 weeks in both histomorphometric analysis and micro-CT analysis (P=0.026, P=0.034). Histomorphometric analysis of representative sections showed similar results to histomorphometric analysis with a mean value of 3 sections. Measurement of new bone formation was highly correlated between histomorphometric analysis and micro-CT analysis, especially at the low lower threshold level at 2 weeks (adjusted $r^2=0.907$, P<0.001). New bone formation of the BMP-2 group analyzed by micro-CT tended to decline sharply with an increasing lower threshold level, and it was statistically significant (P<0.001). Conclusions: Both histomorphometric analysis and micro-CT analysis were valid methods for measurement of the new bone in rat calvarial defects and the ability to detect the new bone in micro-CT analysis was highly influenced by the threshold level in the BMP-2 group at early stage.

• Journal of Trauma and Injury
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• v.27 no.4
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• pp.145-150
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• 2014

Purpose: To assess the accuracy and role of single-contrast computed tomography (CT) in the management of anterior abdominal stab wound (AASW). Methods: During 8-years period, single-contrast CT was performed in 21 hemodynamically stable AASW patients (age range, 22-64 years; median age, 45 years), including 19 men and 2 women. CT scans were evaluated by one trauma surgeon and one senior resident to determine the depth of injury(peritoneal violation or not), and abnormal findings of intraperitoneal cavity associated with stab injury. We retrospectively reviewed medical records regarding operative findings. Results: Nine patients underwent abdominal surgery and 12 patients nonoperative management. In the abdominal surgery group, abnormal CT findings included peritoneal violation in 14 patients and abnormal intraperitoneal cavity findings in 5 patients. There was no statistical significant difference regarding abnormal CT findings between abdominal surgery group and nonoperative management group. Among the nine abdominal surgery patients, therapeutic laparotomy was performed on 4 patients. The positive predictive value (PPV) and negative predictive value (NPV) of peritoneal violation to predictive therapeutic laparotomy were 28.6% and 100%, respectively. In addition, the PPV and NPV of abnormal intraperitoneal cavity CT findings to predict therapeutic laparotomy were 40.0% and 87.5%, respectively. There was no statistical significant difference regarding the abnormal CT findings between therapeutic laparotomy group and non therapeutic laparotomy group. Conclusion: CT is a good adjunctive method to evaluate hemodynamicaly stable AASW patients. If peritoneal violation is not seen on CT scan, conservative treatment on local wound may be safely performed without additional abdominal surgery. However, further study is warranted to evaluate the exact role of CT in the diagnostic workup of AASW patients.

• Toxicological Research
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• v.31 no.2
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• pp.157-163
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• 2015

Nanotechnology has advanced at an extremely rapid pace over the past several years in numerous fields of research. However, the uptake of nanoparticles (NPs) into the body after administration through various routes may pose a risk to human health. In this study, we investigated the potential ocular toxicity of 20-nm, negatively- charged zinc oxide (ZnO) NPs in rats using micro-computed tomography (micro-CT) and histopathological assessment. Animals were divided into four groups as control group, ZnO NPs treatment group (500 mg/kg/day), control recovery group, and ZnO NPs treatment and recovery group. Ocular samples were prepared from animals treated for 90 days (10 males and 10 females, respectively) and from recovery animals (5 males and 5 females, respectively) sacrificed at 14 days after final treatment and were compared to age-matched control animals. Micro-CT analyses represented the deposition and distribution of foreign materials in the eyes of rats treated with ZnO NPs, whereas control animals showed no such findings. X-ray fluorescence spectrometry and energy dispersive spectrometry showed the intraocular foreign materials as zinc in treated rats, whereas control animals showed no zinc signal. Histopathological examination revealed the retinopathy in the eyes of rats treated with ZnO NPs. Neuronal nuclei expression was decreased in neurons of the ganglion cell layer of animals treated with ZnO NPs compared to the control group. Taken together, treatment with 20-nm, negatively-charged ZnO NPs increased retinopathy, associated with local distribution of them in ocular lesions.