• Journal of Korean Neurosurgical Society
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• v.57 no.6
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• pp.460-464
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• 2015

Objective : Bilateral C1 lateral mass and C2 pedicle screw fixation (C1LM-C2P) is an ideal technique for correcting atlantoaxial instability (AAI). However, the inevitable situation of vertebral artery injury or unfavorable bone structure may necessitate the use of unilateral C1LM-C2P. This study compares the fusion rates of the C1 lateral mass and C2 pedicle screw in the unilateral and bilateral methods. Methods : Over five years, C1LM-C2P was performed in 25 patients with AAI in our institute. Preoperative studies including cervical X-ray, three-dimensional computed tomography (CT), CT angiogram, and magnetic resonance imaging were performed. To evaluate bony fusion, measurements of the atlanto-dental interval (ADI) and CT scans were performed in the preoperative period, immediate postoperative period, and postoperatively at 1, 3, 6, and 12 months. Results : Unilateral C1LM-C2P was performed in 11 patients (44%). The need to perform unilateral C1LM-C2P was due to anomalous course of the vertebral artery in eight patients (73%) and severe degenerative arthritis in three patients (27%). The mean ADI in the bilateral group was 2.09 mm in the immediate postoperative period and 1.75 mm in 12-months postoperatively. The mean ADI in the unilateral group was 1.82 mm in the immediate postoperative period and 1.91 mm in 12-months postoperatively. Comparison of ADI measurements showed no significant differences in either group (p=0.893), and the fusion rate was 100% in both groups. Conclusion : Although bilateral C1LM-C2P is effective for AAI from a biomechanical perspective, unilateral screw fixation is a useful alternative in patients with anatomical variations.

• Archives of Craniofacial Surgery
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• v.17 no.3
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• pp.162-164
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• 2016

Stafne bone cavity is a rare mandibular defect that was first reported by Edward C. Stafne in 1942. It commonly presents with a well-demarcated, asymptomatic, unilateral radiolucency that indicates lingual invagination of the cortical bone. A 52-year-old female patient who with nasal bone fracture, visited the hospital. During facial bone computed tomography (CT) for facial area evaluation, a well-shaped cystic lesion was accidentally detected on the right side of the mandible. Compared to the left side, no swelling or deformity was observed in the right side of the oral lesion, and no signs of deformity caused by mucosal inflammation. 3D CT scans, and mandible series x-rays were performed, which showed a well-ossified radiolucent oval lesion. Axial CT image revealed a cortical defect containing soft tissue lesion, which has similar density as the submandibular gland on the lingual surface of the mandible. The fact that Stafne cavity is completely surrounded by the bone is the evidence to support the hypothesis that embryonic salivary gland is entrapped by the bone. In most cases, Stafne bone cavity does not require surgical treatment. We believe that the mechanical pressure from the salivary gland could have caused the defect.

• Progress in Medical Physics
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• v.8 no.2
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• pp.19-26
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• 1997

3-dimensional Neuronavigator, Viewing Wand(ISG Technologies, Toronto, Cannda) is the surgery aid equipment for real time image (CT or MRI) guided surgery. The assurance of spatial accuracy of this system is important for clinical application. In this study, we have designed the acrylic brain phantom and measured the spatial error with that phantom. The phantom has designed to have capability to simulate image guided surgery. The phantom has 22 vertical rods whose diameters are 5mm and each rods has different length. CT scans were performed by 2.0mm slice and reconstructed for 3-Dimensional analysis. End point of rods can be obtained using reconstructed 3- Dimensional images and they are compared to actual position data. Average deviation was less than 2mm for various situations. Spatial error of Viewing Wand is acceptable in the clinical points of view, while cosmetics of the software needs to be modified to more user friend. Better accuracy can be expected when we apply the mixed fiducial fit registration and surface fit registration method. And even better results can be obtained if registration points distributed even and symetric around the target.

• Archives of Plastic Surgery
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• v.39 no.5
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• pp.561-564
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• 2012

Nasal bone fractures are often accompanied by septal fractures or deformity. Posttraumatic nasal deformity is usually caused by septal fractures. Submucosal resection and septoplasty are commonly used surgical techniques for the correction of septal deviation. However, septal perforation or saddle nose deformity is a known complication of submucosal resection. Hence, we chose to perform septoplasty, which is a less invasive procedure, as the primary treatment for nasal bone fractures accompanied by septal fractures. During septoplasty, we used a bioabsorbable mesh as an internal splint. We used the endonasal approach and inserted the mesh bilaterally between the mucoperichondrial flap and the septal cartilage. The treatment outcomes were evaluated by computed tomography (CT) and the nasal obstruction symptom evaluation (NOSE) scale. The CT scans demonstrated a significant improvement in the septal deviation postoperatively. The symptomatic improvement rated by the NOSE scale was greater at 1 month and 6 months after surgery compared to the preoperative status. There were no cases of extrusion or infection of the implant. In cases of moderate or severe septal deviation without dislocation from the vomerine groove on the CT scan, our technique should be considered one of the treatments of choice.

• Journal of Chest Surgery
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• v.48 no.4
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• pp.238-245
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• 2015

Background: Some patients show favorable changes in the descending aortic false lumen after conventional repair of acute type A dissection, although the incidence of favorable changes has been reported to be low. We aimed to investigate the incidence of positive postoperative changes in the false lumen and the factors associated with positive outcomes. Methods: In 63 patients who underwent surgery for type A acute dissection as well as serial computed tomography (CT) scanning, morphological parameters were compared between the preoperative, early postoperative (mean interval, 5.4 days), and late CT scans (mean interval, 31.0 months) at three levels of the descending thoracic aorta. Results: In the early postoperative CT images, complete false lumen thrombosis and/or true lumen expansion at the proximal descending aorta was observed in 46% of the patients. In the late images, complete thrombosis or resolution of the proximal descending false lumen occurred in 42.9% of the patients. Multivariate analysis found that juxta-anastomotic false lumen thrombosis was predictive of favorable early changes, which were in turn predictive of continuing later improvement. Conclusion: Even after conventional repair without inserting a frozen elephant trunk, the proximal descending aortic false lumen showed positive remodeling in a substantial number of patients. We believe that the long-term prognosis of type A dissection can be improved by refining surgical technique, and particularly by avoiding large intimal tears at the anastomosis site during the initial repair.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.591-597
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• 2012

Medical device performance has been advanced while images are expected to be acquired with further higher quality and pertinent applicability as images have been increasing in importance in analyzing major organs. Recent high frequency of image processing by MATLAB in image analysis area accounts for the intent of this study to segment pulmonary vessels by means of MATLAB. This study is to consist of 3 phases including pulmonary region segmentation, pulmonary vessel segmentation and three dimensional connectivity assessment, in which vessel was segmented, using threshold level, from the pulmonary region segmented, vessel thickness was measured as two dimensional refining process and three dimensional connectivity was assessed as three dimensional refining process. It is expected that MATLAB-based image processing should contribute to diversity and reliability of medical image processing and that the study results may lay a foundation for chest CT images-related researches.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.68-70
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• 2005

To precisely localize target in prostate cancer, image-guided radiotherapy was performed using the $ExacTrac^{\circledR}$ x-ray system (Brainlab, Germany) with implanted markers. For three prostate cancer patients, three gold markers were implanted into prostate. Orthogonal portal images were acquired every treatment and CT scans were repeated 3～5 times during the course of treatment. After correcting setup errors calculated by the system, the position of the implanted markers and the distance between them were detected in daily portal images and in CT images, and analyzed retrospectively. Deviation of the relative position of the implanted markers and the distance between them were less than 1 mm in lateral, longitudinal, and vertical direction for three patients, both in portal images and CT images. This study reveals that image-guided radiotherapy using the $ExacTrac^{\circledR}$ system is useful to verify positioning errors and localize prostate target with implanted markers, reducing the planning target volume (PTV) margin as well as irradiation to rectum and bladder.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.542-545
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• 2013

Background The aims of alveolar bone grafting are closure of the fistula, stabilization of the maxillary arch, support for the roots of the teeth adjacent to the cleft on each side. We observed nostril base augmentation in patients with alveolar clefts after alveolar bone grafting. The purpose of this study was to evaluate the nostril base augmentation effect of secondary alveolar bone grafting in patients with unilateral alveolar cleft. Methods Records of 15 children with alveolar clefts who underwent secondary alveolar bone grafting with autogenous iliac cancellous bone between March of 2011 and May of 2012 were reviewed. Preoperative and postoperative worm's-eye view photographs and reconstructed three-dimensional computed tomography (CT) scans were used for photogrammetry. The depression of the nostril base and thickness of the philtrum on the cleft side were measured in comparison to the normal side. The depression of the cleft side pyriform aperture was measured in comparison to the normal side on reconstructed three-dimensional CT. Results Significant changes were seen in the nostril base (P=0.005), the philtrum length (P=0.013), and the angle (P=0.006). The CT measurements showed significant changes in the pyriform aperture (P<0.001) and the angle (P<0.001). Conclusions An alveolar bone graft not only fills the gap in the alveolar process but also augments the nostril base after surgery. In this study, only an alveolar bone graft was performed to prevent bias from other procedures. Nostril base augmentation can be achieved by performing alveolar bone grafts in children, in whom invasive methods are not advised.

• Journal of radiological science and technology
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• v.43 no.5
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• pp.343-351
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• 2020

This study analyzed dose reduction and quality of images through dose reduction tools and shielding board to protect sensitive eye lens in radiation during orbit CT examinations for clinical data use. During CT scans of the phantom, surface dose (CT scanner dosimetry phantom, ion chamber-3 times) and quality of image (radiosurgery head phantom, visual assessment-2 times, HU standard deviation) were evaluated using X-care which is dose reduction tools and bismuth shielding board. The results of experiments of eight conditions showed a relatively reduced dose in all other conditions compared to when no conditions were set. In particular, the area corresponding to the ophthalmic part reduced the surface dose by up to 45.7 %. The visual evaluation of images by specialists and the quality evaluation of images analyzed by HU standard deviation were clinically closest to the use of X-care and shielding board (1 cm in height). Therefore, it is believed that the use of shielding board in a suitable location with dose reduction tools while investigating the optimal radiation dose will reduce the exposure dose of sensitive lens at radiation while maintaining the quality of the images with high diagnostic value.

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.19-26
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• 2017

Objectives: Recently, bioceramic sealers like EndoSequence BC Sealer (BC Sealer) have been introduced and are being used in endodontic practice. However, this sealer has limited research related to its retreatability. Hence, the aim of this study was to evaluate the retreatability of two sealers, BC Sealer as compared with AH Plus using micro-computed tomographic (micro-CT) analysis. Materials and Methods: Fifty-six extracted human maxillary incisors were instrumented and randomly divided into 4 groups of 14 teeth: 1A, gutta-percha, AH Plus retreated with chloroform; 1B, gutta-percha, AH Plus retreated without chloroform; 2A, gutta-percha, EndoSequence BC Sealer retreated with chloroform; 2B, gutta-percha, EndoSequence BC Sealer retreated without chloroform. Micro-CT scans were taken before and after obturation and retreatment and analyzed for the volume of residual material. The specimens were longitudinally sectioned and digitized images were taken with the dental operating microscope. Data was analyzed using an ANOVA and a post-hoc Tukey test. Fisher exact tests were performed to analyze the ability to regain patency. Results: There was significantly less residual root canal filling material in the AH Plus groups retreated with chloroform as compared to the others. The BC Sealer samples retreated with chloroform had better results than those retreated without chloroform. Furthermore, patency could be re-established in only 14% of teeth in the BC Sealer without chloroform group. Conclusion: The results of this study demonstrate that the BC Sealer group had significantly more residual filling material than the AH Plus group regardless of whether or not both sealers were retreated with chloroform.