• Imaging Science in Dentistry
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• v.48 no.1
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• pp.41-44
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• 2018

Purpose: To evaluate the effect of different numbers of basis images and the use of metal artifact reduction (MAR) on the production and reduction of artifacts in cone-beam computed tomography images. Materials and Methods: An acrylic resin phantom with a metal alloy sample was scanned, with 450 or 720 basis images and with or without MAR. Standard deviation values for the test areas (around the metal object) were obtained as a way of measuring artifact production. Two-way analysis of variance was used with a 5% significance level. Results: There was no significant difference in artifact production among the images obtained with different numbers of basis images without MAR (P=.985). MAR significantly reduced artifact production in the test areas only in the protocol using 720 basis images (P=.017). The protocol using 450 basis images with MAR showed no significant difference in artifact production when compared to the protocol using 720 basis images with MAR (P=.579). Conclusion: Protocols with a smaller number of basis images and with MAR activated are preferable for minimizing artifact production in tomographic images without exposing the patient to a greater radiation dose.

• Tuberculosis and Respiratory Diseases
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• v.78 no.2
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• pp.128-132
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• 2015

Bronchopulmonary dysplasia (BPD) is related to decreased lung function throughout life. However, the pathology and radiology pattern of BPD of adults are not documented well yet. In this case report, we present BPD case of an adult monozygotic twin showing nearly identical lesions on chest computed tomography (CT). CT images showed mixed areas of ground-glass and reticular opacities in both lungs. They had common histories of pneumonias requiring mechanical ventilations in period of infants. Pulmonary function test of one patient showed a pulmonary insufficiency with airway obstruction. Pathologic findings showed bronchiolar hyperplasia and peribronchiolar fibrosis which was similar to classic BPD patients. Our twin case report might help provide distinguishing pathology and radiology pattern of an adult pulmonary sequelaes of BPD. It might be reasonable to make close follow-up for BPD patients to evaluate the long-term outcomes of BPD survivors.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.282-285
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• 2018

A 7 years old, male, Afghan hound (case 1) and a 10 years old, castrated male, Pekingese (case 2) were referred with dyspnea. In case 1, thoracic radiographs showed moderate amount of pleural effusion and lobar sign in the left cranial lung lobe. Following computed tomographic (CT) examination, lung lobe torsion in left cranial lung lobe was diagnosed. In case 2, thoracic radiographs showed increased cranial lobar opacity but there was no evidence of pleural effusion. CT examination revealed an abrupt ending bronchus in the left cranial lung lobe. Based on the imaging diagnosis, left cranial lung lobectomy was performed in both cases. Case 1 showed increased lobar opacity and pleural effusion, while case 2 just showed less concrete evidence of lung lobe torsion on thoracic radiographs and marked severe chronic suppurative pneumonia was histopathologically confirmed. In conclusion, CT could be an important modality when atypical lung disease is suspicious.

• Imaging Science in Dentistry
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• v.49 no.2
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• pp.131-137
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• 2019

Purpose: This study was designed to investigate the effects of voxel size, the oversampling technique, and the direction and area of measurement on modulation transfer function (MTF) values to identify the optimal method of MTF measurement. Materials and Methods: Images of the wire inserts of the SedentexCT IQ phantom were acquired, and MTF values were calculated under different conditions(voxel size of 0.1, 0.2, and 0.3 mm; 5 oversampling techniques; simulated pixel location errors; and different directions and areas of measurement). The differences in the MTF values across various conditions were evaluated. Results: The MTF 10 values showed smaller standard deviations than the MTF 50 values. Stable and accurate MTF values were obtained in the 0.1-mm voxel images. In the 0.3-mm voxel images, oversampling techniques of 11 lines or more did not show significant differences in MTF values depending on the presence of simulated location errors. MTF 10 values showed significant differences according to the direction and area of the measurement. Conclusion: To measure more accurate and stable MTF values, it is better to measure MTF 10 values in small-voxel images. In large-voxel images, the proper oversampling technique is required. MTF values from the radial and tangential directions may be different, and MTF values vary depending on the measured area.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.203-208
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• 2021

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant neoplasm characterized by the presence of ghost cells. It is considered to originate from either a calcifying odontogenic cyst(COC) or a dentinogenic ghost cell tumor(DGCT). Its clinical and radiographic characteristics are non-specific, including slow growth, locally aggressive behavior, and eventual metastasis. This case report describes a 43-year-old Thai man with plain radiographs and cone-beam computed tomographic images revealing a unilocular radiolucency with non-corticated borders surrounding an impacted left canine associated with radiopaque foci around the cusp tip. Based on the microscopic findings, the lesion was diagnosed as GCOC. Partial maxillectomy of the right maxilla was performed, and radiotherapy was administered. An obturator was made to support masticatory functions Three years later, the lesion showed complete bone remodeling and no signs of recurrence, and long-term follow-up was done regularly.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.455-460
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• 2021

This report presents a rare case of maxillary osteoblastoma in a 17-year-old female. The patient presented with dull pain and facial asymmetry inferior to the left zygoma. An intraoral examination found a painless swelling on the buccal gingival tissue in the left posterior maxilla. Panoramic radiographs and multidetector computed tomographic images revealed an ill-defined, non-corticated, mixed attenuating entity of osseous density located within the left posterior maxilla apical to the left maxillary molars. The entity exhibited a heterogeneous internal structure with a fine granular appearance, and the periphery showed a partial hypo-attenuating rim along the antero-medial aspect. Expansion of the left posterior maxilla accompanied with displacement of the left maxillary sinus floor was noted. External root resorption of the first and second molars was noted, as well as postero-superior displacement of the third molar. The histopathologic diagnosis of the biopsy was osteoblastoma. Complete excision of the tumor was performed.

• Parasites, Hosts and Diseases
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• v.60 no.6
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• pp.413-417
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• 2022

We retrospectively evaluated the clinical and imaging features of 6 patients with bone hydatid disease confirmed by surgery and pathological examination. Among the 6 patients, 2 were infected with Echinococcosis granulosus metacestode and 4 were infected with E. multilocularis metacestode. The 2 cases with cystic echinococcosis were diagnosed by computed tomographic (CT) examination, and other 4 cases were diagnosed by magnetic resonance (MR) imaging. On the initial evaluation, 1 case each was misdiagnosed as a giant cell tumor or neurogenic tumor, and 2 were misdiagnosed as tuberculosis. The imaging manifestations of bone hydatid disease are complex, but most common findings include expansive osteolytic bone destruction, which may be associated with sclerosing edges or dead bone formation, localized soft tissue masses, and vertebral lesions with wedge-shaped changes and spinal stenosis. Combining imaging findings with the patient's epidemiological history and immunological examinations is of great help in improving the diagnosis and differential diagnosis of bone hydatid disease.

• Journal of Korean Neurosurgical Society
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• v.66 no.2
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• pp.155-161
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• 2023

Objective : To analyze the anatomical location of the ureter in relation to lateral lumbar interbody fusion and evaluate the potential risk of ureteral injury. Methods : One hundred eight patients who performed contrast-enhanced computed tomographic scans were enrolled in this study. The location of the ureter from L2-L3 to L4-L5 was evaluated. The distances between the ureter and psoas muscle, intervertebral disc, and retroperitoneal vessels were also recorded bilaterally. Results : Over 30% of the ureters were close to the working corridor of extreme lumbar interbody fusion at L2-L3. Most of the ureters were close to working corridor of oblique lumbar interbody fusion, especially at L4-L5. The distance from the ureter to the great vessels on the left side was significantly narrowing from L2-L3 to L4-L5 (28.8±9.5 mm, 22.0±8.0 mm, 15.5±8.4 mm), and it was significantly larger than that on the right side (12.3±6.1 mm, 7.4±5.7 mm, 5.4±4.4 mm). Conclusion : Our findings indicate that the location of the ureter varies widely among individuals. To avoid unexpected damage to the ureter, it is imperative to directly visualize it and verify the ureter is not in the surgical pathway during lateral lumbar interbody fusion.

• Journal of Mechanical Science and Technology
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• v.14 no.1
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• pp.1-10
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• 2000

This work shows that it is possible to obtain information about more than one parameter from acoustic field information. A variety of ultrasonic Lamb wave modes were utilized to reconstruct thickness and density of an isotropic plate. An image reconstruction of one parameter (thickness of a plate) was carried out for four cases, i.e., the lowest symmetrical and anti symmetrical modes, and the fastest symmetrical and anti symmetrical Lamb waves among multiple modes. For two parameter reconstructions (thickness and density), the image processing was performed using the lowest symmetrical and antisymmetrical modes simultaneously. In this work, a modified version of algebraic reconstruction technique (ART), which is a form of finite-series expansion method, was employed to reconstruct the ultrasonically computed tomographic images. Results from several sample geometries are presented.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.5
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• pp.310-315
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• 2013

Micromorphometric and histological examinations were conducted with a collected tissue specimen nine months after sinus bone graft using autogenous tooth bone graft material (AutoBT). As a result of micro-computed tomographic analysis, the total bone volume (graft material+new bone) was 76.45%, and the proportion of new bone was 45.4%. The bone mineral density and the average Hounsfield Unit of new bone were 0.26 and 1,164.69, respectively. The histological examination showed that AutoBT particles were united well with new bone. AutoBT was considered to have excellent bone healing ability after sinus graft and bone density that can resist repneumatization.