• Journal of radiological science and technology
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• v.40 no.3
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• pp.385-392
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• 2017

The purpose of this study is to investigate the image quality and exposure dose according to kVp and mAs in CT and to confirm improvement in image quality according to None IR and IR(Iterative Reconstruction) levels. Measurement results of image quality using Image J, HU(Hounsfield units) and BN(Background Noise) are decreased, while SNR(Signal to Noise Ratio) and $CTDI_{vol}$(CT dose index volume) are increased as the kVp increases and there was no change of BHU(Background Hounsfield units). BN was reduced due to increased kVp, while SNR and $CTDI_{vol}$ were increased. Also, the higher IR stage, the lower BN, SI(Signal Intensity) and HU while SNR was improved by about 10~60%. Based on this, when applying IR for clinical applications, it is necessary to finely adjust kVp and mA with a phased approach.

• Korean Journal of Optics and Photonics
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• v.31 no.1
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• pp.1-6
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• 2020

The chest wall, an organ directly affected by environmental particles through respiration, consists of ribs, a pleural layer and intercostal muscles. To diagnose early and treat disease in this body part, it is important to visualize the details of the chest wall, but the structure of the pleural layer cannot be seen by chest computed tomography or ultrasound. On the other hand, optical coherence tomography (OCT), with a high spatial resolution, is suited to observe pleural-layer response to talc, one of the fine materials. However, intensity-based OCT is weak in providing information to distinguish the detailed structure of the chest wall, and cannot distinguish the reaction of the pleural layer from the change in the muscle by the talc. Polarization-sensitive OCT (PS-OCT) takes advantage of the fact that specific tissues like muscle, which have optical birefringence, change the backscattered light's polarization state. Moreover, the birefringence of muscle associated with the arrangement of myofilaments indicates the muscle's condition, by measuring retardation change. The PS-OCT image is interpreted from three major perspectives for talc-exposure chest-wall imaging: a thickened pleural layer, a separation between pleural layer and muscle, and a phase-retardation measurement around lesions. In this paper, a rabbit chest wall after talc pleurodesis is investigated by PS-OCT. The PS-OCT images visualize the pleural layer and muscle, respectively, and this system shows different birefringence of normal and damaged lesions. Also, an analyisis based on phase-retardation slope supports results from the PS-OCT image and histology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.188-193
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• 2019

Transarterial chemoembolization (TACE) is a commonly used and rapidly evolving non-invasive treatment for hepatocellular carcinoma (HCC). It is important that understanding individual anatomical variants and planning for tumor-feeding artery access to acquire adequate treatment effectiveness. In this study, we will report acquired arteriovenous malformation which interferes with TACE for HCC. A 72-year-old man with persistent abdominal pain for 2 days visited our hospital. The patient was chronic hepatitis B carrier and had a history of HCC treated with conventional TACE 10 years ago. Hypervascular nodular HCC in the liver segment 8 and aberrant right hepatic artery from the superior mesenteric artery were detected on computed tomography (CT). When first TACE was performed, the tumor-feeding artery originating from the left hepatic artery was found and embolized. There was no tumor-feeding artery from the right hepatic artery but arteriovenous malformation was found. After a month, follow up CT showed necrotic lesion and residual HCC and we performed secondary TACE. On secondary TACE, we selected the right hepatic artery and passed through arteriovenous malformation. Superselective-angiogram showed remnant tumoral staining and remnant tumor was embolized using drug-eluting bead and Adriamycin. Final angiogram showed no remnant tumoral staining and the patient was discharged without complication. We found the rare case of arteriovenous malformation adjacent to HCC, and we performed superselective TACE beyond arteriovenous malformation to treat HCC.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.750-750
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• 2022

• Tuberculosis and Respiratory Diseases
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• v.64 no.5
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• pp.369-373
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• 2008

Tuberous sclerosis (TS) is an autosomal dominant disorder that is characterized by cutaneous lesions, seizures, mental retardation and hamartomas in various organs including the skin, kidney and brain. Pulmonary involvement is extremely rare, and occurs in approximately 0.1 to 1% of TS cases. Recent reports have indicated multiple micronodular pneumocyte hyperplasia (MMPH) as another rare form of pulmonary involvement of tuberous sclerosis. We report a case of a 35 year-old-male patient who had no pulmonary symptoms but showed multinodular pulmonary shadows on his chest CT scan. The patient was finally diagnosed with TS with MMPH of the lung. MMPH does not appear to have any malignant potential but the clinical significance of MMPH in TS patients is unknown.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.222-233
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• 2007

One of the most important and basic test of dental restorative materials is the evaluation of microleakage into the tooth-restorative interface. There are many techniques to test microleakage, but most of them have several disadvantages. Recently developed microtomography(micro-CT) can provide the three dimensional image and information about the internal component in non-destructive way, therefore using micro-CT, it is possible to evaluate microleakage exactly in quantitative manner. The purpose of this study is to find a new method for quantitative and non-destructive evaluation of microleakage in composite resin restorations using micro-CT and to compare the new method with conventional dye penetration method. Thus, microleakages of two kinds of dentin bonding systems were evaluated with above two methods. 40 extracted sound human premolars were randomly divided into two groups consisting of 20 samples and restored accordingly. Group 1 : Class V resin restorations with $Adper^{TM}$ Singe Bond Group, 2 : Class V resin restorations with $Adper^{TM}\;Promp^{TM}$ L-pop. The $Filtek^{TM}$ Supreme was applied to the Class V cavities of all teeth. After that, 10 teeth from each group were applied to evaluation of microleakage using micro-CT, and other 10 teeth from each group were using conventional dye penetration method. The conclusions of this study were as follow : 1 Using micro-CT, Group 1 showed significantly less microleakage than Group 2 and there was statistically significant difference(p<0.01) between two groups. 2. Using conventional dye penetration method, Group 1 leaked less than Group 2 and there was statistically significant difference(p<0.01) between two groups 3. The difference between two groups is more evident in the method using micro-CT. 4. In all two methods, microleakage appeared more into the cavities to dentinal margins than enamel margins.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.50-63
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• 2021

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II) is an autosomal recessive inherited disorder form of primordial dwarfism, caused by mutations in the pericentrin gene. The purpose of the study was to examine the clinical and radiological features, physicochemical properties and microstructures of the tooth affected with MOPD II. The mandibular 2nd molar was collected from the MOPD II patient. Micro-computerized tomography, scanning electron microscopy, energy dispersive spectrometry and Vickers microhardness analysis were performed on the MOPD II and the normal control. The morphology of the MOPD II tooth appeared to have malformed pulp and root and showed a small size. The mineral density measurement showed that the MOPD II tooth had similar scores in the enamel, but lower scores in the root 1/2 and apical dentin compared to the normal control. The microhardness values were smaller in the cusp enamel, root 1/2 dentin and apical dentin of the MOPD II compared to the normal control. In this study, the dental characteristics and the physicochemical properties of a tooth affected with MOPD II were analyzed to improve understanding of the oral manifestations of the disease and to assist in proper dental treatment by identifying precautions.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.134-141
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• 2010

This study analyzed the regional morphological and mechanical characteristics of vertebrae by using micro-computed tomography (micro-CT) and micro finite element analysis (FEA). For the present study, the $12^{th}$ human thoracic vertebral bones (an 85-years female and a 48-years male) were used. These were scanned by using micro-CT. Structural parameters were evaluated from the acquired 20 image data for fifteen $4{\times}4mm^2$ regions (five regions in respective layers of superior, middle and inferior part) in the thoracic vertebral trabecular bones. $4{\times}4{\times}4mm^3$ cubic finite element models of each regions were created at $70{\mu}m$ voxel resolution to investigate effective modulus ($E^+$). The present study indicated that there were significant differences in morphological and elastic mechanical characteristics of each region. There are close relationship between effective modulus and structural model index (SMI) in the bone of the 48-years male and between effective modulus and bone volume fraction (BV/TV) in the bone of the 85-years female. In addition, the effective modulus of central regions is about 80% stiffer than that of lateral regions at transverse plane. These findings may be likely to explain the previous result that a change of loading distribution of the vertebral trabecular bones is caused by spinal curvature and nucleus pulpous degeneration of the intervertebral disc.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.4
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• pp.95-101
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• 2010

The aim of this study was to detect longitudinal alterations on lumbar vertebral trabecular bone quality (microarchitecture and degree of mineralization) and bone mineral density (BMD) during pregnancy Virginal eighteen mice were used. Then, twelve mice were mated. Mice lumbar vertebrae were scanned before mate, at 7 days of pregnancy (early pregnancy, 6 mice) and immediately after delivery (late pregnancy, 6 mice) by using in-vivo micro-computed tomography Structural parameters, degree of mineralization and BMD were measured. During early pregnancy, there were no significant alterations on structural parameters, degree of mineralization and BMD. At late pregnancy, Tb.Th (11.8%) and BMD (12.7%) were significantly decreased and Tb.N (6.3%), Tb.Pf (43.0%) and BS/BV (15.1%) were significantly increased (p<0.05). Additionally, the lower degree of mineralization was increased, although, the higher degree of mineralization was decreased. These results indicated that the quality and BMD might be not affected during early pregnancy. At late pregnancy, however the bone quality and BMD were likely to be negatively affected.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1385-1391
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• 1996

Solitary fibrous tumor of the pleura has been classified as a type of mesothelioma. This tumor have been recently described and distinguished from the mesothelioma, immunohistochemically and elect r om ic ro scop ical 1 y Thls 65 years female was admitted with right chest pain, coughing and dysnea. Chest X-ray and C-T scan showed a huge mass in the right thorax. Right thoracotomy was done and a 12$\times$12$\times$6cm(400gm) sized mass was excised, and the tumor had metastasized to the diaphragm, parietal pleura and lung parenchyma. Microscopically, the tumor Is composed of oval-round and plump spindle cells with diffuse pattern. There are occasional mitoses (311 OHPFS) and invasion to lung parenchyma. The immunohistochemical and electromicroscopical findings are consistent with malignant solitary fibrous tumor of the pleura. We experienced a case of pleural malignant solitary fibrous tumor and report this case with the review of literature.