• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.154-161
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• 1997

Purpose: Traumatic rupture of the diaphragm is not easy to diagnose and often delayed. Delayed diagnosis of diaphragmatic rupture accompanied by higher chances of strangulation of herniated viscera which may result in higher morbility and mortality. The purpose of this study was to evaluate diagnostic accuracy of spiral CT, MRI and US for the diagnosis of diaphragmatic rupture in an animal model. Materials and Methods: Small, medium, and large sized transabdominal diaphragmatic ruptures were surgically made in experimental rabbits and then followed up with spiral CT, MR!, and US at 1 day, 3 day, and 1 week after operation. Results: US was superior to MR! or spiral CT in diagnosis of diaphragmatic rupture(P(0.05). The sensitivity and specificity were 94.4% and 92.9% for US, 54.0% and 85.7% for MRI, and 46.0% and 78.6% for spiral CT, respectively. The size of laceration was not related to diagnostic sensitivity in US. Sensitivity of MRI and spiral CT increased as the size of laceration were larger, but no statistical significance was present(P>0.05). All experimental animals developed pleural effusion or hemothorax one day after operation. In acute phase, US and MRI were more sensitive than spiral CT in detecting diaphragmatic rupture. Spiral CT was more sensitive than US and MRI in delayed phase but without statistical significance(P>0.05). In the experimental rabbits with accompanying visceral hernia through the diaphragmatic defect, diagnostic accuracy was found equally high among three image modalities(P>0.05). Conclusion: This study indicates that US is the most accurate diagnostic method in detecting injury to the diaphragm in a rabbit model. The findings obtained in this experimental study can be applied to the diaphragmatic rupture of human being.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.385-396
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• 2007

This study proposed a new classification system for maxillary anterior alveolar ridge deformities based on CAT-scan implant simulation as a useful concept in order to more precisely predict treatment outcomes and the necessity for ridge augmentation prior to implant placement. The results indicate that a high number of cases in the maxillary anterior area would require augmentation procedures in order to achieve ideal implant placement and restoration.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1159-1166
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• 2009

The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

• Tuberculosis and Respiratory Diseases
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• v.54 no.2
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• pp.230-235
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• 2003

A primary pulmonary artery sarcoma is a rare malignant tumor derived from the intimal layer of the pulmonary artery. Its clinical presentation can lead to a misdiagnosis of more common diseases such as thromboembolic disease. It is known to have a very poor prognosis. Therefore, the correct diagnosis of a primary pulmonary artery sarcoma is difficult and often delayed. We experienced a case of primary pulmonary artery sarcoma mimicking a pulmonary thromboembolism. The patient was admitted as a result of progressive dyspnea and coughing. The lung perfusion scan showed a large perfusion defect involving almost the entire right lung and suspicious small perfusion defects in the left upper lobe. Magnetic resonance imaging of the chest showed an enhancing nodule within the thrombus in the right pulmonary artery. The mass was removed completely by surgery, but the patient died as a result of shock.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.490-496
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• 1998

Purpose: We evaluated brain perfusion SPECT findings of MELAS syndrome and mitochondrial myopathy in correlation with MR imaging in search of specific imaging features. Materials and Methods: Subjects were five patients (four females and one male; age range, 1 to 25 year) who presented with repeated stroke-like episodes, seizures or developmental delay or asymptomatic but had elevated lactic acid in CSF and serum. Conventional non-contrast MR imaging and Tc-99m-ethyl cysteinate dimer (ECD) brain perfusion SPECT were Performed and imaging features were analyzed. Results: MRI demonstrated increased T2 signal intensities in the affected areas of gray and white matters mainly in the parietal (4/5) and occipital lobes (4/5) and in the basal ganglia (1/5), which were not restricted to a specific vascular territory. SPECT demonstrated decreased perfusion in the corresponding regions of MRI lesions. In addition, there were perfusion defects in parietal (1 patient), temporal (2), and frontal (1) lobes and basal ganglia (1) and thalami (2). In a patient with mitochondrial myopathy who had normal MRI, decreased perfusion was noted in left parietal area and bilateral thalami. Conclusion: Tc-99m ECD SPECT imaging in patients with MELAS syndrome and mitochondrial myopathy showed hypoperfusion of parieto-occipital cortex, basal ganglia, thalamus and temporal cortex, which were not restricted to a specific vascular territory. There were no specific imaging features on SPECT. The significance of abnormal perfusion on SPECT without corresponding MR abnormalities needs to be evaluated further in larger number of patients.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.409-415
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• 2018

The development of smart devices has brought about significant changes in daily life and one of the most significant changes is the virtual reality zone. Virtual reality is a technology that creates the illusion that a 3D high-resolution image has already been created using a display device just like it does in itself. Unrealized subjects are forced to rely on audiovisual materials, resulting in a decline in the concentration of practices and the quality of classes. It used virtual reality to develop effective teaching materials for radiology students. In order to produce a video clip bridge using virtual reality, a radiology clinic was selected to conduct two exposures from July to September 2017. The video was produced taking into account the radiology and work flow chart and filming was carried out in two separate locations : in the computerized tomography unit and in the LINAC room. Prior to filming the scenario and the filming route were checked in advance to facilitate editing of the video. Modeling and mapping was performed in a PC environment using the Window XP operating system. Using two leading virtual reality camera Gopro Hero, CC pixels were produced using a 4K UHD, Adobe, followed by an 8 megapixel resolution of $3,840{\times}2,160/4,096{\times}2,160$. Total regeneration time was performed in about 5 minutes during the production of using virtual reality to prevent vomiting and dizziness. Currently developed virtual reality radiation and educational contents are being used to secure the market and extend the promotion process to be used by various institutions. The researchers will investigate the satisfaction level of radiation and educational contents using virtual reality and carry out supplementary tasks depending on the results.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.2
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• pp.67-74
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• 2009

Purpose: To evaluate the results of absorbed and effective doses using two different modes, standard mode (A-mode) and low-dose mode (B-mode) settings for prostate cancer IGRT from CBCT. Materials and Methods: This experimental study was obtained using Clinac iX integrated with On Board Imager (OBI) System and CBCT. CT images were obtained using a GE Light Speed scanner. Absorbed dose to organs from ICRP recommendations and effective doses to body was performed using A-mode and B-mode CBCT. Measurements were performed using a Anderson rando phantom with TLD-100 (Thermoluminescent dosimeters). TLD-100 were widely used to estimate absorbed dose and effective dose from CBCT with TLD System 4000 HAWSHAW. TLD-100 were calibrated to know sensitivity values using photon beam. The measurements were repeated three times for prostate center. Then, Evaluations of effective dose and absorbed dose were performed among the A-mode and B-mode CBCT. Results: The prostate absorbed dose from A-mode and B mode CBCT were 5.5 cGy 1.1 cGy per scan. Respectively Effective doses to body from A mode and B-mode CBCT were 19.1 mSv, 4.4 mSv per scan. Effective dose from A-mode CBCT were approximately 4 times lower than B-mode CBCT. Conclusion: We have shown that it is possible to reduce the effective dose considerably by low dose mode(B-mode) or lower mAs CBCT settings for prostate cancer IGRT. Therefore, we should try to select B-mode or low condition setting to decrease extra patient dose during the IGRT for prostate cancer as possible.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.63-70
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• 2003

SMAS(Superior Mesenteric Artery Syndrome) is a disease caused by a chronic obstruction of the duodenum(transverse portion), which is hardly detectable. However, it is known that when the superior mesenteric artery and abdominal aorta form a narrow angle, that the transverse portion of the duodenum is pressed down between the superior mesenteric artery and the abdominal aorta, and that this can lead to obstruction of the duodenum. Measuring this angle is a complicated job using conventional angiography, and results often turns out to be inaccurate. In addition, no attempt has been made to determine the value of this angle in Koreans. In this study, we conducted abdominal CT angiography using MIP(maximum intensity projection) on patients with no clinical evidence of SMAS in order to determine the angle at which the superior mesenteric artery branches from the abdominal aorta by using PC based software(Rapidia ver. 1.2) for the image reconstruction. Accordingly, we found that the mean angle between the abdominal aorta and the superior mesenteric artery was $50.05{\pm}15.87^{\circ}$ on average, and that the angle in men($53.64{\pm}16.57^{\circ}$) is higher than in women($46.46{\pm}14.98^{\circ}$). We hope that the angles determined by our study will serve as an important indicator for detecting SMAS.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.208-213
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• 2007

A 15 kg 6-year-old intact male Jindo dog with a history of a respiratory distress, hindlimb paralysis with necrosed skin of dorsal digit for three weeks was referred to Animal Medical Center, Chonbuk National University. Heartworm infection was identified by kit examination. In plain thoracic radiographs, dilated pulmonary arteries reverse D sign and focal interstitial pattern was compatible with heartworm infection and possible pulmonary thromboembolism. Abdominal radiographs showed poor serosal detail indicating fluid accumulation within peritoneal cavity. No evidence of musculoskeletal abnormalities was found. Ultrasonography presented focal wedge-shaped hyperechogenecity on the both poles of left kidney, weak or absent pulse on the distal to the external iliac artery as well as ascites and irregular liver margin. Multi-organ failure was strongly supposed by blood profile including leukocytosis, anemia, hemoglobinuria bililubinemia, hypoalbuminemia, imbalance of electrolytes, and increased hepatic and renal function values. Interestingly, the glucose level is remarkably lower in pelvic limb compared to thoracic limb. Suspected pulmonary thromboembolism, renal infarction and femoral arterial embolization causing hindlimb paralysis and dermatic necrosis were confirmed by 3D reconstructed CT imaging. Prior to taking a consideration of euthanasia, interventional radiology was experimentally attempted but failed due to not recovered from general anesthesia. Early and accurate diagnosis of thromboembolism is valuable and 3D reconstructed CT images might be very useful to show the correct way to treat effectively.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.29-35
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• 2021

The purpose of this study was to investigate whether there is a difference in image quality before and after reducing the amount of contrast medium in cerebral hemorrhagic patients who periodically follow up CT, and after reducing the amount of contrast medium, the image before and after reduction was examined, and the image quality was assessed by setting ROI at each vessel location using MMWP program. First Rt. CCA, Lt.CCA. Rt.MCA, Lt.MCA and Basilar Artery each got an ROI. Second, the mean and standard deviation values for the ROI were obtained. Third, SNR and CNR were obtained through the average and standard deviation values obtained. T-test statistics show that the SNR and CNR values obtained show that the result values for SNR are Rt.CCA 0.765, Ltd.CCA 0.871, Rt.MCA 0.343 LT.MCA 0.235, Basilar alternative 0.916, result value for CNR Rt.CCA 0.088, Ltd.CCA 0.069, Rt.MCA 0.818, Let's...MCA 0.579 and Basilar Artery 0.878. The results obtained through the obtained SNR and CNR values showed no difference in the quality of the images before and after reducing contrast medium. Therefore, we hope that this study will be an indicator that reduces the burden on contrast agents on patients who do CT examinations periodically.