• Imaging Science in Dentistry
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• 제45권3호
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• pp.141-145
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• 2015

Purpose: This study evaluated the diagnostic accuracy of the reverse contrast mode in intraoral digital radiography for the detection of proximal dentinal caries, in comparison with the original digital radiographs. Materials and Methods: Eighty extracted premolars with no clinically apparent caries were selected, and digital radiographs of them were taken separately in standard conditions. Four observers examined the original radiographs and the same radiographs in the reverse contrast mode with the goal of identifying proximal dentinal caries. Microscopic sections $5{\mu}m$ in thickness were prepared from the teeth in the mesiodistal direction. Four slides prepared from each sample used as the diagnostic gold standard. The data were analyzed using SPSS (${\alpha}=0.05$). Results: Our results showed that the original radiographs in order to identify proximal dentinal caries had the following values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, respectively: 72.5%, 90%, 87.2%, 76.5%, and 80.9%. For the reverse contrast mode, however, the corresponding values were 63.1%, 89.4%, 87.1%, 73.5%, and 78.8%, respectively. The sensitivity of original digital radiograph for detecting proximal dentinal caries was significantly higher than that of reverse contrast mode (p<0.05). However, no statistically significant differences were found regarding specificity, positive predictive value, negative predictive value, or accuracy (p>0.05). Conclusion: The sensitivity of the original digital radiograph for detecting proximal dentinal caries was significantly higher than that of the reversed contrast images. However, no statistically significant differences were found between these techniques regarding specificity, positive predictive value, negative predictive value, or accuracy.

• 대한정형외과 초음파학회지
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• 제1권1호
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• pp.40-49
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• 2008

고관절은 인체에서 가장 깊이 위치라는 관절인데다가 고관절에 생긴 병변에 의한 증상은 대부분 모호하고 혼란스럽다. 이러한 이유로 고관절의 영상검사에 대한 연구와 개발은 매우 활발하게 진행되었다. 그 결과 현재는 단순 방사선 사진으로부터 복잡한 자기공명관절조영술에 이르기까지 다양한 방법이 사용되고 있다. 이 간단한 글에서 저자는 각 영상 검사법의 장단점과 흔한 고관절 질환의 영상 진단에 대해 다루고자 한다. 이러한 고관절의 영상 검사법의 중요성은 그것이 임상적인 연관이 있을 때뿐이다. 만일 우리가 각 검사법과 해당 질환들의 특성을 잘 알고 있다면 환자에 대한 가장 이상적인 접근이 가능할 것이지만 그렇지 못하다면 비싼 영상 검사는 의미 없는 그림에 지나지 않을 것이기 때문이다.

• 한국정밀공학회지
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• 제30권9호
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• pp.991-999
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• 2013

Lower limbs deformity is a congenital disease and can also be occurred by an acquired factor. This paper suggests a new technique for surgical planning of Corrective Osteotomy for Lower Limbs (COLL) using 2D-3D medical image registration. Converting to a 3D modeling data of lower limb based on CT (computed tomography) scan, and divide it into femur, tibia and fibula; which composing the lower limb. By rearranging the model based on the biplane 2D images of X-ray data, a 3D upright bone structure was acquired. There are two ways to array the 3D data on the 2D image: Intensity-based registration and feature-based registration. Even though registering Intensity-based method takes more time, this method will provide more precise results, and will improve the accuracy of surgical planning.

• 한국치위생학회지
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• 제11권5호
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• pp.783-790
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• 2011

Objectives : The purpose of this study was to examine students' difficulties in the process of oral radiography practice, to raise awareness of the importance and necessity of oral radiography and decipher, and to provide some information on effective ways of oral radiography practice. Methods : The subjects in this study were 285 dental hygiene students at K college, who included 153 sophomores and 132 graduates-to-be from June to November, 2010. Results : 1. The parts of the anatomy structure that they found it most difficult to decipher were maxillary molar(25.3%) and lower molar(22.1%). 2. They made during oral radiography was an improper film positioning(35.1%). 3. The part of bisecting technique was adjusting vertical and horizontal angles(53.0%). 4. The part of paralleling technique was positioning XCP in the oral cavity(44.2%). 5. The part of bite-wing technique was adjusting vertical and horizontal angles(38.2%). 6. The part of occlusion technique was positioning film and tube head(36.5%). 7. The part of panorama technique was finding out program setting(42.5%). Conclusions : The findings of the study indicated that in terms of anatomy structure decipher, it's especially difficult to decipher maxillary molar and lower molar, and that film positioning was difficult to do in the process of oral radiography. What difficulties they faced in applying each kind of oral radiography techniques and which part of the oral cavity they found it hard to radiograph were analyzed as well in this study. Given the findings of the study, more intensive practice is required to help students to acquire accurate oral radiography techniques to ensure their successful job performance in the future.

• 대한관절경학회지
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• 제12권2호
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• pp.118-124
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• 2008

Purpose: Recent development and advances in the arthroscopic surgical techniques for anterior cruciate ligament(ACL) reconstruction have led to the ideal location for more oblique anatomic point of the femur from 10 to 10:30 o'clock(in the right knee) and from 2 to 1:30 o'clock(in the left knee) in the frontal plane. This study was performed to compare the operative methods and the radiologic results of the femoral tunnels made through the tibial tunnel(trans-tibial approach) and the anteromedial portal. Materials and Methods: From January 2003 to May 2004, on hundred reconstructions of ACL were performed. Group I(the femoral tunnel made through the tibial tunnel) consisted of 50 cases and group I(the femoral tunnel made through the anteromedial portal) consisted of 50 cases. The operative methods and the radiographic results of the femoral tunnels were compared. Results: Femoral tunnel was made more easily at more oblique anatomic point in group II than in group I. In group II, better visual field was achieved at the angle of 100? flexion of the knee joint, the risks of the posterior cortical breakage and the tunnel-graft mismatching were reduced more, and the divergence of femoral interference screw from the radiograph decreased more than in group I(p<0.05). The angle between the femoral tunnel and the longitudinal axis of ACL increased in group II. Conclusion: Anteromedial portal technique was useful for femoral tunneling toward 10 to 10:30 o'clock(in the right knee) and 2 to 1:30 o'clock(in the left knee) in ACL reconstruction. Level of Evidence:Level III, case-control study.

• 한국콘텐츠학회논문지
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• 제15권1호
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• pp.308-315
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• 2015

본 연구는 3D 프린터를 이용하여 통풍이 원활하고 위생적이며 선명한 방사선영상을 구할 수 있는 그물형 손목 부목을 제작하고자 하였다. 스캐너는 의료용 다중단층영상장치(MDCT)를 이용했으며, 3D 프린터 기기는 용융 적층 조형술(fused deposition modeling, FDM)의 프린팅 방식을 이용했다. 소재는 분해성 플라스틱 (poly lactic acid, PLA)을 사용하였다. 손목의 3 차원 볼륨렌더링은 MDCT에서 획득된 단층영상으로 구현하였다. 구현된 손목 3 차원 영상을 바탕으로 가상의 그물형 부목 모형을 디자인하고 출력하였다. 그 결과 3D 프린터로 출력된 부목이 기존 부목보다도 우수한 방사선 손목영상을 획득할 수 있었으며 가려움증 및 비위생적인 단점을 개선하고 부목 해체 작업이 용이하였다. 결론적으로 본 연구에서 모델링된 3D 부목 모형은 향후 3D 프린팅 부목 제작에 기초자료로 활용할 수 있으며 환자들의 실생활에 도움을 줄 것으로 기대한다.

• Imaging Science in Dentistry
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• 제32권4호
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• pp.213-219
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• 2002

Purpose : Computed radiography (CR) has been used in cephalometric radiography and many studies have been carried out to improve image quality using various digital enhancement and filtering techniques, During CR image acquisition, the frequency rank and type affect to the image quality. The aim of this study was to compare the diagnostic quality of conventional cephalometric radiographs to those of computed radiography. Materials and Methods : The diagnostic quality of conventional cephalometric radiographs (MO) and their digital image counterparts were compared, and at the same time, six modalities (M1-M6) of spatial frequency-processed digital images were compared by evaluating the reproducibility of 23 cephalometric landmark locations. Reproducibility was defined as an observer's deviation (in mm) from the mean between all observers. Results and Conclusion: In comparison with the conventional cephalometric radiograph (MO), Ml showed statistically significant differences in 8 locations, M2 in 9, M3 12, M4 in 7, M5 in 12, and M6 showed significant differences in 14 of 23 landmark locations (p < 0.05). The number of reproducible landmarks that each modality possesses were 7 in M6, 6 in M5, 5 in M3, 4 in M4, 3 in M2, 2 in Ml, and 1 location in MO. The image modality that observers selected as having the best image quality was M5.

• Clinics in Shoulder and Elbow
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• 제20권3호
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• pp.153-161
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• 2017

Background: This study was conducted to compare the clinical and radiological outcomes of the locking hook plate fixation (HP) technique and the single tight rope (TR) technique applied for acute high-grade acromioclavicular (AC) joint separations. Methods: Between 2009 and 2014, 135 consecutive patients with acute AC joint separation Rockwood types III, IV, and V were subjected to surgical reconstruction. One hundred fourteen patients (84.4%) were available for retrospective evaluation. Of them, 62 and 52 were treated using the single TR group and clavicular HP group techniques, respectively. The visual analogue scale, Constant, American Shoulder and Elbow Surgeons (ASES), and Taft scores were used for clinical assessment. Postoperative shoulder range of motion was also assessed. An anteroposterior radiograph of the coracoclavicular distance (CCD) was obtained to evaluate the radiographic signs of recurrence. Results: The TR group patients had better Constant, ASES, and Taft scores than the HP group patients. The loss of reduction in terms of the CCD did not differ between groups. Subacromial osteolysis was observed in 34.6% of the cases in the HP group. However, there were no significant differences in the clinical outcomes between the patients with and without osteolysis in the HP group. Subcoracoid osteolysis, drill tunnel widening, and metal displacement were observed in 3.2%, 22.6%, and 4.8% of the cases in the TR group, respectively. Conclusions: The single TR technique was relatively more effective at treating acute high-grade AC joint injuries than the HP fixation technique (level of evidence: therapeutic; retrospective comparative study, Level III).

• Journal of Korean Neurosurgical Society
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• 제39권4호
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• pp.256-259
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• 2006

Objective : Having a reliable and reproducible measurement technique to measure the sagittal contour in vertebral fractures is paramount to clinical decision making. This study is designed to determine the most reliable measurement technique in osteoporotic vertebral compression fracture. Methods : Fifteen lateral radiographs of thoracic and lumbar fractures were selected and measured on two separate occasions by three spine surgeons using six different measurement techniques [Centroid, Harrison Posterior Tangent Methods and 4 different types of modified Cobb method]. The radiograph quality was assessed and the center beam location was determined. Statistical analysis including ANOVA for repeated measures was carried out using the SAS software [v 8.0]. Results : The inter and intraobserver variance of the Cobb method 4 and Harrison posterior tangent method were significantly lower than the other four methods. The intraobserver correlation coefficients were the most consistent using the Cobb method 4 [0.982]. which was followed by the Harrison posterior tangent [0.953] and Cobb methods 1 [0.874]. The intraobserver agreement [% of repeated measures within 5 degrees of the original measurement] ranged from 42% to 98% for each technique for all three observers, with the Cobb method 4 showing the best agreement [97.8%] followed by the Harrison posterior tangent method [937%]. Conclusion : The Cobb method-4 and Harrison posterior tangent methods, when applied to measuring the kyphosis, are reliable and have a similar small error range. The Cobb method 4 shows the best overall reliability. However, the centroid method and Cobb method using a fractured endplate do not produce an accurate result due to inter and intraobserver differences in determining the baseline.

• Imaging Science in Dentistry
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• 제52권2호
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• pp.155-164
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• 2022

Purpose: The aim of this study was to systematically screen the literature for studies reporting cosmetic material in the oral and maxillofacial complex to shed light on the types of cosmetic materials, their radiographic appearance, and possible complications. Materials and Methods: Five electronic databases were reviewed for eligible studies. The general search terms were "cosmetic," "filler," "face," and "radiograph." Demographics, material types, clinical and radiographic presentation, and complications were recorded. Results: Thirty-one studies with 53 cases met the inclusion criteria. The mean age was 52.6±15.4 years with a 4 : 3 female-to-male ratio. The most common material was calcium hydroxyapatite (CaHa) (n=14, 26.4%), found incidentally. The materials were generally located within the upper cheek and zygoma (n=35, 66.0%), radiographically well-defined (n=44, 83%), and had no effects on the surrounding structures (n=27, 50.9%). The internal structure was radiopaque (calcification, hyperdensity) for gold wires, CaHa, bone implants, and secondary calcification or ossification. Outdated cosmetic materials or non-conservative techniques were infiltrative, had effects on the surrounding structures, and presented with clinical signs, symptoms, or complications. Conclusion: Conventional radiography, cone-beam computed tomography, and multi-detector computed tomography are useful to differentiate several cosmetic materials. Their magnetic resonance imaging appearance was highly variable. The infrequent inclusion of cosmetic materials in the differential diagnosis implies that medical and dental specialists may be unfamiliar with the radiographic appearance of these materials in the face.