• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.941-946
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• 2019

Computed tomography (CT) has been increasing in frequency and indications for use in clinical diagnosis and treatment decisions. Multidetector CT has the advantage of shortening the inspection time and obtaining a high resolution image compared to a single detector CT, but has been pointed out the disadvantage of increasing the radiation exposure. In addition, when the low tube voltage is used to reduce the exposure dose in the CT, noise increases relatively. In the existing method, the method of finding the optimal image quality using the method of adjusting the parameters of the image reconstruction method is not a fundamental measure. In this study, we applied a double-tree complex wavelet algorithm and analyzed the results to maintain the normal signal and remove only noise. Experimental results show that the noise is reduced from 8.53 to 4.51 when using a complex oriented 2D method with 100kVp and 0.5sec rotation time. Through this study, it was possible to remove the noise and reduce the patient dose by using the optimal noise reduction algorithm. The results of this study can be used to reduce the exposure of patients due to the low dose of CT.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1363-1366
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• 2006

Aneurysmal dilatation of the ductus arteriosis has been considered a rare but potentially fatal abnormality. The mechanism of ductal aneurysmal formation remains uncertain. Plain chest radiography has proven helpful in the diagnosis of ductus arteriosus aneurysm (DAA), before the application of transthoracic echocardiography. The transthoracic echocardiography is an important tool for the diagnosis and follow-up of DAA. We present a case of congenital ductus arteriosus aneurysm in a newborn, that was an incidental discovery. The diagnosis was made by echocardiography, three-dimensional surface rendering computed tomography (CT), and spontaneous regression after four weeks of follow-up.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.179-185
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• 2015

The cost of advanced medical technologies is commonly considered to be a major factor in the overall escalation of expenditures on health. The use of computed tomography (CT) scanning has increased dramatically over the past decade. CT has been rapidly adopted, despite their high cost. The aim of this study is to analysis the increasing factor of the frequency of the CT, using the decision tree model. Finally, we propose the effective policy option of diagnostic imaging technology in Korea.

• Journal of Chest Surgery
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• v.43 no.2
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• pp.208-211
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• 2010

An occurrence of hemangioma in the mediastinum is a very rare, accounting for less than 0.5% of mediastinal tumors. Capillary hemangiomas and cavernous hemangiomas consists of over 90% of mediastinal hemangiomas. However, venous hemangioma has never been reported in South Korea and has also very rarely been reported worldwide. We found mediastinal solid mass, as an incidental finding during a follow-up chest CT scan of a 44-year-old female patient who had undergone colon cancer surgery. We performed a mediastinoscopic biopsy. We did a thoracotomy to remove this mass because hemorrhage and found a totally resected venous hemangioma.

• Journal of Chest Surgery
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• v.29 no.5
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• pp.585-588
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• 1996

We experienced a case of upper esophageal leiomyoma successfully excised by thoracoscopic surgery. A 29-year-old male was presented with retrosternal discomfort and mild dysphagia and an esophagogram revealed smooth fElling defect In the upper third of the intrathor cic esophagus, and esophagoscopy showed a submucosal tumor without mucosal infiltration. Chest CT and MRI were performed to confirm size, character and location of the esophageal mass, the absence of infiltration of surrounding structures, and to define mediastinal Iymphadenopathy. The tumor was excised by thoracoscopic surgery and it was diagnosed as leiomyoma (4$\times$2xlcm in size). The postoperative course was uneventful.

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.225-230
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• 2010

The purpose of the study was to apply and to expand the six sigma to reduce waiting times for computed tomography (CT) examination which manipulated by the department of radiology. It was preceded by DMAIC (Define, Measure, Analyze, Improve, and Control). In the stage of definition, it wereselected for total 5 critical to quality (CTQ), which were the kindness, the waiting time, the examination explanation, the waiting day and the waiting stand environment, that increased the reserved time of CT examination. In the stage of measurement, the number of examinations and of reservation waiting days performed and resulted in final CTQ(Y) which measured each 1.68 and 1.85 sigma. In the stage of analysis, the examination concentrated on morning time, non-scheduled examination of the day, the delayed time of booking, frequent telephone contacting and equipment malfunction were determined as variable key causes. In the stage of improvement, it were performed with expansion of the examination in the morning time, integration of laboratories that used to in each steps, developing the ability of simultaneous booking schedule for the multiple examinations, developing program of examination request, and the customer management team operations. For the control, the number of examinations and reserved waiting days were measured each 3.14 and 1.13 sigma.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.1025-1033
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• 2019

Although magnetic resonance imaging without linear hardening of CT is recognized as a method of obtaining high contrast of tissue and excellent resolution image in brain disease and head and neck examination, magnetic susceptibility artifact is generated in case of metal implants in the oral cavity, which is an obstacle to image diagnosis. Therefore, an effort was made in this thesis to find a method to reduce artifacts caused by dental implants and prosthesis in MRI. Implant-induced artifacts in magnetic resonance imaging showed that the signal size increased with shorter TE in GE technique and was inconsistent with water temperature change. In SE technique as well, the signal size of water was generally higher than that of air, but the signal to noise ratio (SNR) was not different by air and temperature. In EPI technique, images with fewer artifacts were obtained quantitatively and qualitatively when there was more water than air, and the signal to noise ratio was measured the highest, especially at water temperatures of 20° and 30°. In conclusion, when examining using the EPI technique rather than the SE or the GE technique, obtaining brain diffusion using a 20° and 30° water bag reduces the magnetic susceptibility artifacts caused by implants and prosthesis, suggesting that it may provide images with high diagnostic value.

• Journal of the Korean Society of Radiology
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• v.81 no.5
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• pp.1260-1265
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• 2020

Kaposi's sarcoma (KS) is a multicentric human immunodeficiency virus-associated neoplasm characterized by multiple vascular nodules in the skin, mucous membranes, and viscera. Gastrointestinal acquired immunodeficiency syndrome (AIDS)-related KS is the most common visceral involvement reported in disseminated disease. Here, we present the findings of a rare case of KS involving multiple organs with abdominal pain and active bleeding in the colon. Multiple intraluminal lesions were found in the terminal ileum, sigmoid colon, and rectum by ileocolonoscopy, and in the jejunum and ileum by fluoroscopy. Abdominopelvic CT revealed multiple enhanced flat lesions in the ileum and enlarged lymph nodes. The diagnosis was confirmed by histopathology, and antiretroviral therapy was initiated as the treatment of choice for KS. Owing to the increasing number of AIDS patients, it is essential for radiologists and clinicians to be aware of the imaging characteristics of KS to protect physicians from indiscriminate exposure to AIDS.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.591-602
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• 2021

Acute ischemic stroke(AIS) should be diagnosed within a few hours of onset of cerebral infarction symptoms using diagnostic radiology. In this study, we evaluated the clinical usefulness of SVD and the Bayesian algorithm to measure the volume of cerebral infarction using computed tomography perfusion(CTP) imaging and magnetic resonance diffusion-weighted imaging(MR DWI). We retrospectively included 50 patients (male : female = 33 : 17) who visited the emergency department with symptoms of AIS from September 2017 to September 2020. The cerebral infarct volume measured by SVD and the Bayesian algorithm was analyzed using the Wilcoxon signed rank test and expressed as a median value and an interquartile range of 25 - 75 %. The core volume measured by SVD and the Bayesian algorithm using was CTP imaging was 18.07 (7.76 - 33.98) cc and 47.3 (23.76 - 79.11) cc, respectively, while the penumbra volume was 140.24 (117.8 - 176.89) cc and 105.05 (72.52 - 141.98) cc, respectively. The mismatch ratio was 7.56 % (4.36 - 15.26 %) and 2.08 % (1.68 - 2.77 %) for SVD and the Bayesian algorithm, respectively, and all the measured values had statistically significant differences (p < 0.05). Spearman's correlation analysis showed that the correlation coefficient of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was higher than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (r = 0.915 vs. r = 0.763 ; p < 0.01). Furthermore, the results of the Bland Altman plot analysis demonstrated that the slope of the scatter plot of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was more steady than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (y = -0.065 vs. y = -0.749), indicating that the Bayesian algorithm was more reliable than SVD. In conclusion, the Bayesian algorithm is more accurate than SVD in measuring cerebral infarct volume. Therefore, it can be useful in clinical utility.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.315-324
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• 2011

The purpose of this study was to use as basic data for the is systematic and efficient facility inventory of policeman and the riot police, conscripted policeman. First, the analysis was performed for the patient implementing the simple x-ray, CT, and MRI examination to the policeman and the riot police, conscripted policeman within the radiologic examination. As to the classification by disease, it classified into the partial body as the common disease and musculoskeletal system disease. As to the fixed quantity comparison of the policeman and the riot police, conscripted policeman the basic X-ray, CT, MRI examination by part average personnel was compared. As to the research result the riot police, conscripted policeman, the Lower extremity examination occupies the simple X-ray, CT, and MRI examination in comparison with the other part altogether much and particularly, the Knee examination ratio occupies much among the Lower extremity examination.