• Journal of Yeungnam Medical Science
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• v.21 no.1
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• pp.40-50
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• 2004

Background: This study was conducted to analyze the height and width of the pedicle of the upper and lower levels on the concave and the convex sides. In addition, we checked for the appropriate pedicle screw size which could be screwed in without complications. Materials and Methods: Taking a simple AP radiography in a standing position, 99 vertebrae on the major curve with the possibility of 3-D reconstruction were analyzed after checking the CT in a supine position of 22 idiopathic scoliosis. We measured Cobb's angle from a simple radiograph, and measured the size of the isthmus by the Inner Space 3-D Editor after 3-D reconstruction with the Inner Space 3-D program in the DICOM file transformed from CT image. We then analyzed the size of pedicles of the upper and lower levels on the concave and the convex sides by measuring the height and width of the pedicle. Results: All pedicles on the concave side were smaller than those on the convex side. Their size increased as the measurement moved from the upper to lower vertebra, except for the upper thoracic vertebra. When the width of the pedicle through 3-D reconstruction was compared with the narrowest width of the pedicle measured by using CT, the width of the pedicles through 3-D reconstruction was statistically smaller (P<0.01). Most of the pedicles were tear-drop or kidney shaped rather than cylindrical. Conclusion: These results suggest that the use of the coronal plane through 3-D reconstruction would be necessary for an accurate measurement of the size of the pedicle. It is important to pay careful attention to the screw size and the screwing method considering the pedicle shape through 3-D reconstruction.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.215-219
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• 2003

Purpose : To report the 'condylar cut-off sign', a new radiographic sign in knees with discoid lateral meniscus and to report the sensitivity, specificity, positive predictive value and negative predictive value of the sign to elucidate the diagnostic significance of the sign for discoid meniscus. Materials and Methods : Fifty knees with complete discoid lateral meniscus and fifty normal knees formed the basis of this study. All of them were arthroscopically confirmed fer the discoid or normal lateral meniscus. The authors developed a method to measure the length of the medial and lateral condylar were compare and analyzed. Results : Tile average ratio was 0.716 in the discoid meniscus group, and 0.902 in the normal group. The stastistical analysis by the T-test revealed the t-value -11.13(p<0.0001). Stastistical analysis by chi-square test using cut point 0.8, also showed significant difference between the two groups, with $76\%$ sensitivity, $100\%$ specificity, $100\%$ positive predictive predictive value and $81\%$ negative predictive value. The 'condylar cut-off sign' was readily detectable in all cases of discoid lateral meniscus, suggesting that the cut off sign could serve as a simple and reliable radiographic sign fur the diagnosis of discoid meniscus. Conclusion : The condylar cut-off sign on the Tunnel view of simple radiography of the knee can serve as a good sign for the diagnosis of discoid lateral meniscus, with $100\%$ positive predictive value.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.2
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• pp.165-171
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• 2008

The aim of this study was to evaluate the incidence of panoramic radiological risk signs related with mandibular third molar extraction, and the relationship between these risk signs and inferior alveolar nerve (IAN) injury after tooth extraction. Cases were defined as 1000 mandibular third molars extracted by surgical approach at Samsung Medical Center during the period from March 2001 to December 2006. Seven radiological risk signs were assessed on the panoramic radiogram by three expert oral surgeons. Clinical demographic data and severity of IAN injury were examined on medical records. Bivariate analyses were completed to assess the relationship between radiological risk signs and IAN injury. The radiological risk signs showed in 381 cases(38.1%). The incidence of each radiological risk signs were; interruption of IAN white line, 152 cases(15.2%); deflected roots, 141 cases(14.1%); darkening root, 119 cases(11.9%); diversion of IAN, 57 cases(5.7%) ; IAN narrowing, 37 cases(3.7%); root narrowing, 17 cases(1.7%); dark and bifid apex, 10 cases(1.0%). The incidence of IAN injury in cases with risk signs were: in the case of any sign, 3.6%; interruption of IAN white line, 2.6%; deflected roots 5.7%; darkening root. 3.4%; diversion of IAN, 5.7%; IAN narrowing, 3.7%; root narrowing, 5.9%; dark and bifid apex, 0%. No IAN injury was showed in 619 cases without risk sign (p<0.05). In conclusion, the presence of panoramic risk signs was associated with an increased risk for IAN injury during mandibular third molar extraction, whereas the absence of risk signs was associated with a minimal risk of nerve injury.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.2
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• pp.88-93
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• 2013

Purpose: Maxillary sinus elevation has been widely used to enable insertion of endosseous implants in severely resorbed maxilla. Maxillary sinusitis after this procedure was considered to be the major drawback, therefore, preoperative evaluation of paranasal sinus is considered to be important. In order to evaluate the condition of the sinus, we used Waters' projection. In this study, asymptomatic patients were evaluated by Waters' view, and compared to timing to assess the sinus cavity. Methods: The retrospective study was based on 14 patients who were performed sinus elevation surgery in Seoul National University Dental Hospital. These patients did not show any signs of maxillary sinusitis. These patients were taken Waters' view at preoperative, postoperative 1 day, 3 months, 6 months. In Waters' view, presence of air fluid level, radiopacity of sinus wall, or radiopacity of entire maxillary sinus were evaluated. The density, and sinus dimension changes were assessed using Adobe Photoshop CS5$^{(R)}$ (Adobe Systems Inc., San Jose, CA, USA). Results: Findings of Waters views in patients with clear maxillary sinus at preoperative time were followed by elevated sinus floor with transplanted bone, mucosal swelling, and air fluid level. At postoperative 3 months, and 6 months, the radiographic findings were similar to preoperative state. By contrast, patients with preoperative mucosal swelling, or haziness in sinus cavity showed radiopacity entire sinus in Waters' view. In cases of the patients who were treated with simultaneous treatment to mucosal swelling, good status of sinus cavity were found. Conclusion: Although Waters' projections provide the limited information, and is less sensitive method compared with computed tomography, it is simple, easy, and economical method to assess of maxillary sinus. We suggest using Waters' view as radiographic routine tool for evaluation of sinus condition, especially in the sinus elevation surgery.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.388-397
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• 2005

The purpose of this study was to redefine the cephalometric landmarks in three-dimensional (3D) images, which are used in orthodontic cephalometric radiography, and to evaluate the reproducibility of each landmark for 3D cephalometric analysis. Eighteen CT scans were taken at the Department of Diagnostic Radiology at Seoul National University Dental Hospital and manipulated with V works 4.0(Cybermed Inc., Seoul, Korea). The coordinate system was established using 7 reference points, with no more than 4 points on the same plane. These 7 points were generated as a volume model, the voxel size of which was 4 by 4 by 2 (threshold value=639). The cephalometric landmarks were selected at the multiplanar reformation (MPR) window on the volume mode of V works 4.0. The selected landmarks were exported to V surgery (Cybermed Inc., Seoul, Korea) for the calculation of coordinate values. All the data were taken twice with a lapse of 2 weeks by one investigator The reproducibility of each landmark was $0.17\~1.21mm$ in the x axis, $0.30\~1.53mm$. In the y axis, and $0.27\~1.81mm$ in the z axis. In all three axes, the range of error was similar. These error ranges were acceptable with regards to the pixel space and slice thickness. The most reproducible points were 1 points which were selected on the basis of the volume model. The least reproducible points were J points that were defined by sutures.

• Imaging Science in Dentistry
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• v.37 no.3
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• pp.165-170
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• 2007

Purpose: To estimate the shape of root and pulp canal using a dental cone beam computed tomography (CBCT) and to evaluate the accuracy of imaging reformation. Materials and Methods: CBCT images were obtained with incisors, premolars, and molars as the destination by using PSR $9000N^{TM}$ Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) and i-CAT (Imaging Sciences International, Inc, USA) cone beam CT unit that have different kind of detector and field of view, and compared these with the shape and the size of actual root and root canal. Results: When the measuring value of cone beam computed tomography concerning to each root's bucco-lingual diameter and mesio-distal diameter was compared with the value of the actual root, it reveals an error range $-0.49{\sim}+0.63$ mm at PSR900N and $-0.97{\sim}+1.14$ mm at i-CAT (P>0.05). It was possible to identify and measure PSR$9000N^{TM}$ Dental CT system to the limit $0.48{\pm}0.06mm$ (P>0.05) and i-CAT CBCT to the limit $0.86{\pm}0.09mm$ (P<0.05) on estimating the size and the shape of root canal. Two kinds of CBCT images revealed the useful reproducibility to estimate the shape of root, but there was the difference to estimate the shape of root according to apparatus. The reproducibility of root shape in the image of three-dimensions at PSR 900N is low such as 0.65 mm in a case of minute root canal. Conclusions: CBCT images revealed higher accuracy of the imaging reformation for root and pulp and clinically CBCT is a useful diagnostic tool for the assessment of root and canal. However, there are different qualities of imaging reformation according to CBCT apparatus and limitation of reproducibility for minute root canals.

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.53-60
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• 2014

Purpose: This study was performed to investigate the incidence and configuration of the bifid mandibular canal in a Korean population by using cone-beam computed tomography (CBCT) imaging. Materials and Methods: CBCT images of 1933 patients (884 male and 1049 female) were evaluated using PSR-9000N and Alphard-Vega 3030 Dental CT units (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan). Image analysis was performed by using OnDemand3D software (CyberMed Inc., Seoul, Korea). The bifid mandibular canal was identified and classified into four types, namely, the forward canal, buccolingual canal, dental canal, and retromolar canal. Statistical analysis was performed by using the chi-squared test and one-way analysis of variance (ANOVA). Results: Bifid mandibular canals were observed in 198 (10.2%) of 1933 patients. The most frequently observed type of bifid mandibular canal was the retromolar canal (n=104, rate: 52.5%) without any significant difference among the incidence of each age and gender. The mean diameter of the accessory canal was 1.27 mm (range: 0.27-3.29 mm) without any significant difference among the mean diameter of each type of the bifid mandibular canal. The mean length of the bifid mandibular canals was 14.97mm(range: 2.17-38.8 mm) with only a significant difference between the dental canal and the other types. Conclusion: The bifid mandibular canal is not uncommon in Koreans and has a prevalence of 10.2% as indicated in the present study. It is suggested that a CBCT examination be recommended for detecting a bifid canal.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.397-402
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• 2009

Objective : In this study, the authors assessed the ability of rat bone marrow derived mesenchymal stem cells (BMDMSCs), in the presence of a growth factor, fibroblast growth factor-4 (FGF-4) and hydroxyapatite, to act as a scaffold for posterolateral spinal fusion in a rat model. Methods : Using a rat posterolateral spine fusion model. the experimental study comprised 3 groups. Group 1 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite only. Group 2 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite containing $1{\times}10^6/60{\mu}L$ rat of BMDMSCs. Group 3 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite containing $1{\times}10^6/60{\mu}L$ of rat BMDMSCs and FGF-4 $1{\mu}G$ to induce the bony differentiation of the BMDMSCs. Rats were assessed using radiographs obtained at 4, 6, and 8 weeks postoperatively. After sacrifice, spines were explanted and assessed by manual palpation, high-resolution microcomputerized tomography, and histological analysis. Results : Radiographic, high-resolution microcomputerized tomographic, and manual palpation revealed spinal fusion in five rats (83%) in Group 2 at 8 weeks. However, in Group 1, three (60%) rats developed fusion at L4-L5 by radiography and two (40%) by manual palpation in radiographic examination. In addition, in Group 3, bone fusion was observed in only 50% of rats by manual palpation and radiographic examination at this time. Conclusion : The present study demonstrates that 0.08 gram of hydroxyapatite with $1{\times}10^6/60{\mu}L$ rat of BMDMSCs induced bone fusion. FGF4, added to differentiate primitive $1{\times}10^6/60{\mu}L$ rat of BMDMSCs did not induce fusion. Based on histologic data, FGF-4 appears to induce fibrotic change rather than differentiation to bone by $1{\times}10^6/60{\mu}L$ rat of BMDMSCs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2760-2766
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• 2013

Introduction : The projection method to check existence and nonexistence of radius groove penetration of screw after distal radius fracture operation clinical using the T-type plate and the radiation of radial groove tangential is to propose a new test. Material and Methods : On the tangential projection view of radius groove, elevation angle of distal radius is 2.5, 5, 7.5, 10 degree. and forearm and radiation detector of angle is 60, 70, 80, degree each changed. that analyzed check existence and nonexistence of radius groove penetration of screw. Results : For the image of Radial groove tangential. the case of not radius groove penetration of screw(63.95%, n=55), medial penetration of radius groove(10.47%, n=9) or lateral penetration of radius groove(25.58%, n=22) was analysis. The radius groove penetrating of screw length was a range of 0.43 ~ 2.72mm, the average was 1.06mm. the check existence and nonexistence of radius groove penetration of medial or lateral was analysis that it accurate for the image of Radial groove tangential. the radiography of radial groove is well described elevation angle of distal radius 2.5 to 7.5 degree(90% over), forearm and radiation detector of angle 70degree(80%over) Conclusion : It is elevation angle of distal radius is 5degree, forearm and radiation detector of angle 70degree recommended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.96-107
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• 2020

This study aimed to identify the associated factors of protective behaviors for radiation exposure among some radiology technologists using the Health Belief Model. The subjects of the study were 541 radiology technologists working at hospitals or clinics in Honam Province. Using the SPSS version 18.0 program, data were analyzed using a t-test, ANOVA, Pearson's correlation analysis, and hierarchical multiple logistic regression analysis. To modify the factors, the performance of subjects who had a higher level of education and nuclear medicine rooms were higher than those who worked in simple radiography rooms. The radiation protective behaviors performance of the subjects who had more exercise, medium-level stress, and worked in higher-quality protection facilities was higher. Regarding the personal perceptions, the cues to action (β=.292, p=.0001), and perceived seriousness (β =.075, p=.010) were factors that had effects on the performance of radiation protection behaviors. Regarding the likelihood of action, the benefits (β=.168, p<.0001), self-efficacy (β=.148, p=.007), and the performance of protective behaviors were higher. In conclusion, protection education as a cue to action should be provided to stimulate protective behaviors, and the benefits of protective behaviors should be emphasized. To increase the performance of protection behaviors, self-efficacy should be enhanced, and the subjects are offered appropriate information that helps perceive seriousness.