• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.199-209
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• 2010

The locking compression plates-distal femur(LCP-DF) are being widely used for surgical management of the extra-articular complex fractures of the distal femur. They feature locking mechanism between the screws and the screw holes of the plate to provide stronger fixation force with less number of screws than conventional compression bone plate. However, their biomechanical efficacies are not fully understood, especially regarding the number of the screws inserted and their optimal configurations. In this study, we investigated effects of various screw configurations in the shaft and the condylar regions of the femur in relation to structural stability of LCP-DF system. For this purpose, a baseline 3-D finite element (FE) model of the femur was constructed from CT-scan images of a normal healthy male and was validated. The extra-articular complex fracture of the distal femur was made with a 4-cm defect. Surgical reduction with LCP-DF and bone screws were added laterally. To simulate various cases of post-op screw configurations, screws were inserted in the shaft (3~5 screws) and the condylar (4~6 screws) regions. Particular attention was paid at the shaft region where screws were inserted either in clustered or evenly-spaced fashion. Tied-contact conditions were assigned at the bone screws-plate whereas general contact condition was assumed at the interfaces between LCP-DF and bone screws. Axial compressive load of 1,610N(2.3 BW) was applied on the femoral head to reflect joint reaction force. An average of 5% increase in stiffness was found with increase in screw numbers (from 4 to 6) in the condylar region, as compared to negligible increase (less than 1%) at the shaft regardless of the number of screws inserted or its distribution, whether clustered or evenly-spaced. At the condylar region, screw insertion at the holes near the fracture interface and posterior locations contributed greater increase in stiffness (9~13%) than any other locations. Our results suggested that the screw insertion at the condylar region can be more effective than at the shaft during surgical treatment of fracture of the distal femur with LCP-DF. In addition, screw insertion at the holes close to the fracture interface should be accompanied to ensure better fracture healing.

• Journal of Veterinary Clinics
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• v.31 no.1
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• pp.46-50
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• 2014

A 7-year-old spayed female Welsh corgi presented with a mass of the skull. The mass was diagnosed as multilobular bone tumor and surgically removed. To treat a large bone defect after the tumor removal, custom-made artificial bone fabricated by a 3-dimensional ink-jet printer was implanted in the defect. Follow-up computed tomography evaluation was performed for 4.3 years. The implant was well integrated with the skull and had covered the large bone defect during the follow-up period. Gradual degradation of the implant began 6 weeks after surgery. It provides an additional option for the treatment of large bone defect.

• Imaging Science in Dentistry
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• v.47 no.3
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• pp.165-174
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• 2017

Purpose: This study was performed to investigate the influence of object shape and distance from the center of the image on the volumetric accuracy of cone-beam computed tomography (CBCT) scans, according to different parameters of tube voltage and current. Materials and Methods: Four geometric objects(cylinder, cube, pyramid, and hexagon) with predefined dimensions were fabricated. The objects consisted of Teflon-perfluoroalkoxy embedded in a hydrocolloid matrix (Dupli-Coe-Loid TM; GC America Inc., Alsip, IL, USA), encased in an acrylic resin cylinder assembly. An Alphard Vega Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) was used to acquire CBCT images. OnDemand 3D (CyberMed Inc., Seoul, Korea) software was used for object segmentation and image analysis. The accuracy was expressed by the volume error (VE). The VE was calculated under 3 different exposure settings. The measured volumes of the objects were compared to the true volumes for statistical analysis. Results: The mean VE ranged from -4.47% to 2.35%. There was no significant relationship between an object's shape and the VE. A significant correlation was found between the distance of the object to the center of the image and the VE. Tube voltage affected the volume measurements and the VE, but tube current did not. Conclusion: The evaluated CBCT device provided satisfactory volume measurements. To assess volume measurements, it might be sufficient to use serial scans with a high resolution, but a low dose. This information may provide useful guidance for assessing volume measurements.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.649-653
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• 2001

The Chiari malformation is a deformation within the central nervous system which the lower brain stem and the cerebellum migrate into the foramen magnum causing herniation. In 1891, Arnold Chiari classified such symptoms into 3 categories. This case report is of a 8-year-old female with the complaint of a slight facial swelling and pain on the upper right molar during tooth brushing since 10 days before. Clinical examination showed gingival pocket formation on distal of the upper right first molar with pain and mobility of the tooth. Radiographic examination showed generalized low bone density in the upper molar area, and especially no bone support above the upper right and left first molars were noted. With a temporary diagnosis of Early-onset periodontitis, consultations with medical doctors for the possibility of an underlying systemic disease were made during periodontal treatment. 3D CT was taken with after a final diagnosis of Chiari malformation. Generalized thinning and defect of the cranial bone was noted and the foramen magnum was slightly enlarged. The occipital and maxillary bone was low in density, and the alveolar bone of maxillary posterior teeth was especially almost non-existing causing the upper right and left first molar to be floating. For this, the patient went under consultation with the department of neurosurgery and is still under observation. Periodontitis in childreren is very rare. When symptoms of periodontitis appear in a child, due to the possibility of an underlying systemic disease such as leukemia, histiocytosis X, and hypophosphatasia, proper examinations should be carried out so that the primary factor the symptoms can be treated.

• Journal of radiological science and technology
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• v.28 no.2
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• pp.91-95
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• 2005

The cervical spine of anteroposterior oblique view is essential to observe the intervertebral foramen(IVF). The morphologic changes of IVFs were proved to be abnormal with nerve roots and peripheral structures. The purpose of this study is to evaluate the effective projection angle for observing the IVFs in the Korean adults. In a prospective clinical study of 100 normal persons, $45^{\circ}$, $50^{\circ}$ and $55^{\circ}$ oblique views were compared by measuring the maximal transverse diameter of all the cervical IVFs. $45^{\circ}$ oblique views provided slightly better visualization of upper cervical level(C2-C3, C3-C4, C4-C5), but the lower cervical level(C5-C6, C6-C7, C7-T1) of IVF transverse diameters were substantially increased on the $55^{\circ}$ AP oblique projection. In the comprasion of mean differences between 8 obese person(BMI > 25) and 58 normal person(18.5 < BMI < 22.9) proved to be statistically not significant. Consequently this study shows that $55^{\circ}$AP oblique(tube angle $15^{\circ}$cephalad) view is optimal for evaluating the lower cervical IVFs.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.172-180
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• 2007

Among the nuclear medicine imaging methods available today, $H_2^{15}O-PET$ is most widely used by cognitive neuroscientists to examine regional brain function via the measurement of regional cerebral blood flow (rCBF). The short half-life of the radioactively labeled probe, $^{15}O$, often allows repeated measures from the same subjects in many different task conditions. $H_2^{15}O-$ PET, however, has technical limitations relative to other methods of functional neuroimaging, e.g., fMRI, including relatively poor time and spatial resolutions, and, frequently, insufficient statistical power for analysis of individual subjects. However, recent technical developments, such as the 3-D acquisition method provide relatively good image quality with a smaller radioactive dosage, which in turn results in more PET scans from each individual, thus providing sufficient statistical power for the analysis of individual subject's data. Furthermore, the noise free scanner environment $H_2^{15}O$ PET, along with discrete acquisition of data for each task condition, are important advantages of PET over other functional imaging methods regarding studying state-dependent changes in brain activity. This review presents both the limitations and advantages of $^{15}O-PET$, and outlines the design of efficient PET protocols, using examples of recent PET studies both in the normal healthy population, and in the clinical population.

• Journal of Nutrition and Health
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• v.48 no.4
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• pp.310-318
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• 2015

Purpose: The aim of this study is to investigate anti-arthritis activity using natural eggshell membrane (NEM). Methods: NEM was administered at 52 mg/kg, 200 mg/kg, and 400 mg/kg to SD-Rat, where arthritis was induced by monosodium iodoacetate (MIA) at 3 mg. NO production in serum was measured using Griess reagent. Cytokines including IL-$1{\beta}$, and IL-6 were measured by Luminex and $PGE_2$, MMP-2, MMP-9, TIMP-1, $LTB_4$, and hs-CRP were measured by ELISA. The cartilage of patella volume was examined and 3-D high-resolution reconstructions of the cartilage of patella were obtained using a Micro-CT system. Results: Production of NO, IL-$1{\beta}$, IL-6, $PGE_2$, MMP-2, MMP-9, TIMP-1, $LTB_4$, and hs-CRP in serum was decreased, respectively, in comparison with control. The cartilage of patella volume increased significantly. In addition, the NEM group showed a decrease in the cartilage of patella, synovial membrane, and transformation of fibrous tissue. Conclusion: The results for NEM showed significant anti-arthritis activity. These results may be developed as a raw material for new health food to ease the symptoms mentioned above.

• Investigative Magnetic Resonance Imaging
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• v.6 no.2
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• pp.152-157
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• 2002

Purpose : The differential diagnosis between Modic type I degenerative spine and infectious spondylitis sometimes is difficult, because the affected bone marrows in both disease show similar signal intensity on conventional MR imaging. We evaluate the usefulness of diffusion-wighted MR imaging for differential diagnosis between Modic type I degenerative spine and infectious spondylitis. Materials and methods : The spin-echo and diffusion-weighted MR images of eight patients with Modic type I degenerative spines and 14 patients with infectious spondylitis diagnosed by clinical findings or CT-guided biopsies we re analyzed. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the vertebral bone marrow on conventional spin-echo and diffusion-weighted MR imaging were compared between degenerative spine and infectious spondylitis. Results : On T1-weighte d images, the affeted bone marrow in both disease showed hypointense signals. On T 2-weighted images, all of type I degenerative spine and 11 of infectious spondylitis showed hyperintensity, and three of infectious spondylitis showed heterogeneo us mixed signal intensity. On diffusion-weighted MR images, all of type I degenerative spine were hypointense with peripheral high signal intensity to normal vertebral body, but infectious spondylitis was hyperintense (n = 11) and hypointense (n=3). Conclusion : Diffusion-weighted MR imaging is useful to differentiate Modic type I degenerative spine from infectious spondylitis. On diffusion-weighted images, the high singal intensity of bone marrow suggests infectious spondylitis, whereas the low signal intensity of bone marrow with peripheral focal high signal intensity suggests type I degenerative spine.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.29-38
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• 2008

Purpose: The aim of this study was to investigate the feasibility of 3 ' -[F-18]fluoro-3 ' -deoxythymidine positron emission tomography(FLT-PET) for the detection of locally advanced breast cancer and to compare the degree of FLT and 2' -deoxy-2 ' -[F-18]fluoro-d-glucose(FDG) uptake in primary tumor, lymph nodes and other normal organs. Material & Methods: The study subjects consisted of 22 female patients (mean age; $42{\pm}6$ years) with biopsy-confirmed infiltrating ductal carcinoma between Aug 2005 and Nov 2006. We performed conventional imaging workup, FDG-PET and FLT PET/CT. Average tumor size measured by MRI was $7.2{\pm}3.4$ cm. With visual analysis, Tumor and Lymph node uptakes of FLT and FDG were determined by calculation of standardized uptake value (SUV) and tumor to background (TB) ratio. We compared FLT tumor uptake with FDG tumor uptake. We also investigated the correlation between FLT tumor uptake and FDG tumor uptake and the concordant rate with lymph node uptakes of FLT and FDG. FLT and FDG uptakes of bone marrow and liver were measured to compare the biodistribution of each other. Results: All tumor lesions were visually detected in both FLT-PET and FDG-PET. There was no significant correlation between maximal tumor size by MRI and SUVmax of FLT-PET or FDG-PET (p>0.05). SUVmax and $$SUV_{75} (average SUV within volume of interest using 75% isocontour) of FLT-PET were significantly lower than those of FDG-PET in primary tumor (SUVmax; $6.3{\pm}5.2\;vs\;8.3{\pm}4.9$, p=0.02 /$SUV_{75};\;5.3{\pm}4.3\;vs\;6.9{\pm}4.2$, p=0.02). There is significant moderate correlation between uptake of FLT and FDG in primary tumor (SUVmax; rho=0.450, p=0.04 / SUV75; rho=0.472, p=0.03). But, TB ratio of FLT-PET was higher than that of FDG-PET($11.7{\pm}7.7\;vs\;6.3{\pm}3.8$, p=0.001). The concordant rate between FLT and FDG uptake of lymph node was reasonably good (33/34). The FLT SUVs of liver and bone marrow were $4.2{\pm}1.2\;and\;8.3{\pm}4.9$. The FDG SUVs of liver and bone marrow were $1.8{\pm}0.4\;and\;1.6{\pm}0.4$. Conclusion: The uptakes of FLT were lower than those of FDG, but all patients of this study revealed good FLT uptakes of tumor and lymph node. Because FLT-PET revealed high TB ratio and concordant rate with lymph node uptakes of FDG-PET, FLT-PET could be a useful diagnostic tool in locally advanced breast cancer. But, physiological uptake and individual variation of FLT in bone marrow and liver will limit the diagnosis of bone and liver metastases.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.171-179
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• 2002

It is well known that the geometry of the articular surface plays a major role in the kinematic and kinetic analysis to understand human knee joint function during motion. The functionality of the knee joint cannot be accurately modeled without considering the effects of sliding and lolling motions. We Present a 3-D human knee joint model considering sliding and rotting motion and major ligaments. We employ more realistic articular geometry using two cam profiles obtained from the extrusion of the sagittal Plain view of the representative Computerized Tomography image of the knee joint compared to the previously reported model. Our model shows good agreement with the already reported experimental results on Prediction of the lines of force through the human joint during gait. The contact point between femur and tibia moves toward the Posterior direction as the knee undergoes flexion, reflecting the coupling of anterior and Posterior motion with flexion/extension. The anterior/posterior displacement of the contact Point on the tibia plateau during one gait cycle is about 16 mm. for the lateral condyle and 25 mm. for the medial condyle using the employed model Also. the femur motion on the tibia undergoes lateral/medial movement about 7 mm. and 10 mm. during one gait cycle for the lateral condyle and medial condyle. respectively. The developed computational model maybe Potentially employed to identify the joint degeneration.