• Hip & pelvis
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• v.30 no.4
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• pp.233-240
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• 2018

Purpose: This study aimed to evaluate the efficacy of simultaneous computed tomography (CT) and quantitative CT (QCT) in patients with osteoporotic hip fracture (OHF) by analyzing the osteoporosis detection rate and physician prescription rate in comparison with those of conventional dual-energy X-ray absorptiometry (DXA). Materials and Methods: This study included consecutive patients older than 65 years who underwent internal fixation or hip arthroplasty for OHF between February and May 2015. The patients were assigned to either the QCT (47 patients) or DXA group (51 patients). The patients in the QCT group underwent QCT with hip CT, whereas those in the DXA group underwent DXA after surgery, before discharge, or in the outpatient clinic. In both groups, the patients received osteoporosis medication according to their QCT or DXA results. The osteoporosis evaluation rate and prescription rate were determined at discharge, postoperative (PO) day 2, PO day 6, and PO week 12 during an outpatient clinic visit. Results: The osteoporosis evaluation rate at PO week 12 was 70.6% (36 of 51 patients) in the DXA group and 100% in the QCT group (P<0.01). The prescription rates of osteoporosis medication at discharge were 70.2% and 29.4% (P<0.001) and the cumulative prescription rates at PO week 12 were 87.2% and 60.8% (P=0.003) in the QCT and DXA groups, respectively. Conclusion: Simultaneous CT and QCT significantly increased the evaluation and prescription rates in patients with OHF and may enable appropriate and consistent prescription of osteoporosis medication, which may eventually lead to patients' medication compliance.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.193-198
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• 2016

In clinical computed tomography (CT), regular quality assurance (QA) has been required. This study is to evaluate the MTF for analyzing the spatial resolution using AAPM phantom in CT exam. The dual source somatom definition flash (siemens healthcare, forchheim, Germany), the brilliance 64 (philips medical system Netherlands) and aquilion 64 (toshiba medical system, Japan) were used in this study. The quantitative evaluation was performed using the image J (wayne rasband national institutes of health, USA) and chart method which is measurement of modulation transfer function (MTF). In MTF evaluation, the spatial frequencies corresponding to the 50% MTF for the CT systems were 0.58, 0.28, and $0.59mm^{-1}$, respectively and the 10% MTF for the CT systems were 1.63, 0.89, and $1.21mm^{-1}$, respectively. This study could evaluate the characteristic of spatial resolution of MTF using chart method, suggesting the quantitative evaluation method using the data.

• Journal of radiological science and technology
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• v.35 no.1
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• pp.59-64
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• 2012

Recently, SPECT/CT system has been applied to many diseases, however, the application is not extensively applied at pulmonary disease. Especially, in case that, the pulmonary embolisms suspect at the CT images, SPECT is performed. For the accurate diagnosis, SPECT/CT tests are subsequently undergoing.However, without SPECT/CT, there are some limitations to apply these procedures. With SPECT/CT, although, most of the examination performed after CT. Moreover, such a test procedures generate unnecessary dual irradiation problem to the patient. In this study, we evaluated the amount of unnecessary irradiation, and the usefulness of fusion images of pulmonary disease, which independently acquired from SPECT and CT. Using NEMA PhantomTM (NU2-2001), SPECT and CT scan were performed for fusion images. From June 2011 to September 2010, 10 patients who didn't have other personal history, except lung disease were selected (male: 7, female: 3, mean age: $65.3{\pm}12.7$). In both clinical patient and phantom data, the fusion images scored higher than SPECT and CT images. The fusion images, which is combined with pulmonary vessel images from CT and functional images from SPECT, can increase the detection possibility in detecting pulmonary embolism in the resin of lung parenchyma. It is sure that performing SPECT and CT in integral SPECT/CT system were better. However, we believe this protocol can give more informative data to have more accurate diagnosis in the hospital without integral SPECT/CT system.

• Journal of Radiation Protection and Research
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• v.43 no.1
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• pp.1-9
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• 2018

Background: In this study, we investigate the image quality of virtual monochromatic images synthesized from dual-energy computed tomography (DECT) at voltages of 80/140 kV and 100/140 kV. Materials and Methods: Virtual monochromatic images of a phantom are synthesized from DECT scans from 40 to 70 keV in steps of 1 keV under the two combinations of tube voltages. The dose allocation of dual-energy (DE) scan is 50% for both low- and high-energy tubes. The virtual monochromatic images are compared to single-energy (SE) images at the same radiation dose. In the DE images, noise is reduced using the 100/140 kV scan at the optimal monochromatic energy. Virtual monochromatic images are reconstructed from 40 to 70 keV in 1-keV increments and analyzed using two quality indexes: noise and contrast-to-noise ratio (CNR). Results and Discussion: The DE scan mode with the 100/140 kV protocol achieved a better maximum CNR compared to the 80/140 kV protocol for various materials, except for adipose and brain. Image noise is reduced with the 100/140 kV protocol. The CNR values of DE with the 100/140 kV protocol is similar to or higher than that of SE at 120 kV at the same radiation dose. Furthermore, the maximum CNR with the 100/140 kV protocol is similar to or higher than that of the SE scan at 120 kV. Conclusion: It was found that the CNR achieved with the 100/140 kV protocol was better than that with the 80/140 kV protocol at optimal monochromatic energies. Virtual monochromatic imaging using the 100/140 kV protocol could be considered for application in breast, brain, lung, liver, and bone CT in accordance with the CNR results.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.943-949
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• 1996

Bone mineral density depends largely on the status of dietary minerals such as Ca, P, Mg, and F and proteins, physical activities, parathyroid hormone(PTH), calcitonin(CT), and vitamin D. The decrease of bone density often results in bone fractures and osteoporosis which is prevalent among postmenopausal women. This study was intended to examine the role of parathyroid hormone, calcitonin and cholecaliferol in bone density of mice that were fed different dual photon energy beams. We have measured three major parts of the bone : whole body, head and femur. The results are summarized as follows : 1) Bone mineral density (BMD) was more increased by feeding high Ca diet compared to that of the low Ca diet. 2) Both PTH and Vit D3 enhanced BMD in all of the different Ca levels. 3) When the dietary Ca was deequate CT showed a synergistic effect with PTH in boosting bone density, while CT+Vit D3 showed a negative effect. 4) CT tended to inhibit the effect of increasing bone density by PTH and Vit D3 in medium and low Ca groups. 5) The effect of increasing bone density by PTH in the head of mouse increased when dietary Ca was lower : The increment of bone density by PTH in high, medium, and low Ca was 3%, 8%, 19%, respectively. 6) Femur bone density was affected significantly by dietary Ca levels than hormones. The above observations indicate that bone mineral density can be improved by high dietary Ca and hormone injections including PTH, CT and cholecalciferol, and thus proper dietary and hormonal treatment may be used in preventing bone fractures and osteoporosis.

• Journal of Biomedical Engineering Research
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• v.39 no.2
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• pp.80-86
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• 2018

The aim of this study were to establish the clinical references and guidelines for the maximum standardized uptake ($SUV_{max}$) value of pancreatic cancer, pancreatitis, and normal pancreas in $^{18}F-FDG$ PET-CT examinations for pancreatic disease. For this purpose, we performed the statistical analysis on the descriptive statistics, percentiles and inter quartiles range (IQR), normal distribution, and using the probability density function for pancreatic cancer, pancreatitis, and normal pancreas. As a result, the clinical reference of $SUV_{max}$ for the pancreatic cancer, pancreatitis, and normal pancreas was more than 3.45, 1.91 to 2.62, and less than 1.91, respectively. Also, optimal cut-off value for applying the dual time point PET-CT examination was determined to be 2.62. The results of this study are summarized as follows: first, we suggests the clinical reference and guideline for the pancreatic cancer, pancreatitis, and normal pancreas, and second, suggests a scientific approach to improve diagnostic accuracy of pancreatic disease by deviating from an approximate experience approach.

• Journal of Biomedical Engineering Research
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• v.35 no.5
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• pp.132-141
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• 2014

In an ordinary CT scan, a large number of projections with full field-of-view (FFOV) are necessary to reconstruct high resolution images. However, excessive x-ray dosage is a great concern in FFOV scan. Region-of-interest (ROI) CT or sparse-view CT is considered to be a solution to reduce x-ray dosage in CT scanning, but it suffers from bright-band artifacts or streak artifacts giving contrast anomaly in the reconstructed image. In this study, we propose an image reconstruction method to eliminate the bright-band artifacts and the streak artifacts simultaneously. In addition to the ROI scan for the interior projection data with relatively high sampling rate in the view direction, we get sparse-view exterior projection data with much lower sampling rate. Then, we reconstruct images by solving a constrained total variation (TV) minimization problem for the interior projection data, which is assisted by the exterior projection data in the compressed sensing (CS) framework. For the interior image reconstruction assisted by the exterior projection data, we implemented the proposed method which enforces dual data fidelity terms and a TV term. The proposed method has effectively suppressed the bright-band artifacts around the ROI boundary and the streak artifacts in the ROI image. We expect the proposed method can be used for low-dose CT scans based on limited x-ray exposure to a small ROI in the human body.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.211-212
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• 2014

단일에너지 복부 검사에서 사용했던 조영제 양 대비 30%, 40%, 50%, 60%, 70%로 각각 설정하여 영상을 획득한 후 대동맥, 하대정맥, 간문맥, 간실질에 관심영역을 설정하여 조영증강정도(houns -field unit; HU)를 구하여 단일에너지에서 측정된 부위와의 값을 비교 분석하였다. 그 결과 기존대비 60%로 조영제를 설정한 군에서는 대동맥 HU : $210.80{\pm}13.609$, 하대정맥 HU : $190.40{\pm}25.215$, 간문맥 $198.40{\pm}21.232$, 간실질 HU : $119.20{\pm}7.98$로 각각 측정되었으며. 단일에너지 복부 CT 검사는 대동맥 HU : $205.40{\pm}16.426$, 하대정맥 HU : $188.20{\pm}21.476$, 간문맥 HU : $195.40{\pm}22.744$, 간실질 HU : $121.00{\pm}6.595$ 이었다. 따라서 이중에너지를 이용하여 복부 조영 CT검사를 시행할 때 조영제의 양을 60%로 설정한 후 검사하는 것이 각 장기에서의 단일에너지 조영검사시와 비슷한 조영증강정도를 획득할 수 있다.

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.461-466
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• 2007

Two dogs were admitted with a history of anorexia, ataxia, shivering, lethargy, hypersalivation and seizure. Patients were suspected for portosystemic shunts on the basis of clinical signs, increased hepatic serum profiles on the blood test, microhepatica on plain abdominal radiographs, and an abnormally dilated and tortuous vessel on abdominal ultrasonographs. To diagnose PSS and to further evaluate type, shape, and location of shunt and hepatic vasculatures, the computed tomography (CT) angiography for portal and systemic circulation was performed. The shape, location and pathway of extrahepatic single shunt were confirmed in two dogs. Dual phases (the arterial phase and the venous phase) CT angiography and reformatted and three-dimensional images offered good understanding of PSS and planning surgical treatment.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.835-841
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• 2023

The aim of this study is to evaluate the diagnostic ability of dual-energy computed tomography (DECT) for Composition determination of urinary stones in phantom model. Seventeen cases with urinary stones who underwent DECT were enrolled in the study. The composition of the urinary stones was extracted from the seventeen patients were analyzed with DECT in phantom model with fresh pork. The volume scan method using Dual-energy software was used and the scanned image sets were assessed. All 17 urinary stones of the phantom model were analyzed according to the stone composition using DE stone Analysis were divided into uric acid stones (n=6, 35.29%) and non-uric acid stones (n=11, 64.71%). These urinary stones were pathologically confirmed. The mean attenuation values of uric acid stones at 135 kV, 100 kV and 80 kV was 348.87 ± 166.37 HU, 345.33 ± 151.18 HU and 337.94 ± 172.77 HU, respectively. The mean attenuation values of non-uric acid stones at 135 kV, 100 kV and 80 kV was 551.93 ± 297.09 HU, 747.04 ± 351.31 HU and 958.19 ± 424.72 HU, respectively. At 80 kV, uric acid stones and non-uric acid stones showed significant difference in the attenuation values(P<0.05). The attenuation values of DECT could differentiate the compositions of urinary stones between uric acid and non-uric acid stones at 80 kV in phantom model.