• 대한족부족관절학회지
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• 제21권2호
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• pp.61-65
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• 2017

Purpose: The purpose of this study was to determine the correlation and ratio between the calcaneal length and width for predicting the width of calcaneus. Materials and Methods: A total of 190 feet (190 patients) were included based on computed tomography scans. The length of calcaneus (CL) was measured on the line connecting the center of a circle tangent to the cortical margin in the anterior and posterior parts of the calcaneus in a sagittal plane (W1, W2). The width of the calcaneus was defined as the horizontal line of each part (W1, W2, W3) on the same axial plane. The relationship between the measurement was determined through a correlation analysis. The reliability was assessed based on intraclass correlation coefficients. Results: The CL and widths of calcaneus (W1, W2, W3) had a good positive correlation (r=0.848 [W1/CL], r=0.738 [W2/CL], r=0.769 [W3/CL]; p<0.001). The mean CL and widths ratios were 0.33 (W1/CL), 0.37 (W2/CL), and 0.37 (W3/CL). Using these ratios to estimate the widths by multiplying each ratio by the measured calcaneal length, we found a difference between the estimated calcaneal widths and the actual measured calcaneal widths values was 0.25 mm, 0.43 mm, and 0.16 mm. All measurements showed good-to-excellent inter- and intraobserver reliability. Conclusion: This study analyzed the correlation and ratio between the length and width of the calcaneus. The results will help orthopedic surgeons fixate screws in a stable manner to prevent iatrogenic injuries to the medial neurovascular structures of the calcaneus.

• 대한치과교정학회지
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• 제50권3호
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• pp.157-169
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• 2020

Objective: The aim of this retrospective study was to evaluate the pre- and postsurgical bone densities at alveolar and extra-alveolar sites following two-jaw orthognathic surgery. Methods: The sample consisted of 10 patients (mean age, 23.2 years; range, 18.0-27.8 years; 8 males, 2 females) who underwent two-jaw orthognathic surgery. A three-dimensional imaging program (Invivo 5) was used with multidetector computed tomography images taken pre- and postoperatively (obtained 32.3 ± 6.0 days before surgery and 5.8 ± 2.6 days after surgery, respectively) for the measurement of bone densities at the following sites: (1) alveolar bone in the maxilla and mandible, (2) extra-alveolar sites, such as the top of the head, menton (Me), condyle, and the fourth cervical vertebrae (C4). Results: When pre- and postsurgical bone densities were compared, an overall tendency of decrease in bone density was noted. Statistically significant reductions were observed in the densities of cancellous bone at several areas of the maxillary alveolar bone; cortical and cancellous bone in most areas of the mandibular alveolar bone; cortical bone in Me; and cancellous bone in C4. There was no statistically significant difference in bone density in relation to the depth of the alveolar bone. In a comparison of the bone densities between groups with and without genioplasty, there was almost no statistically significant difference. Conclusions: Accelerated tooth movement following orthognathic surgery may be confirmed with reduced bone density. In addition, this study could offer insights into bone metabolism changes following orthognathic surgery, providing direction for further investigations in this field.

• Imaging Science in Dentistry
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• 제39권3호
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• pp.149-156
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• 2009

Purpose : The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. Materials and Methods : We devised a patient-specific stent for patient-to-image registration and navigation. Three-dimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. Results : The accuracy over 8 anatomical landmarks showed an overall mean of $0.56{\pm}0.16\;mm$. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. Conclusion : The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.

• 한국광학회지
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• 제19권5호
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• pp.376-380
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• 2008

본 논문에서는 라인스캔 카메라를 통해 모든 영역의 영상을 획득하는 연구를 제안한다. 이 방법은 기존의 면적 카메라를 이용했던 방법에 비해 투영격자의 이동 횟수를 획기적으로 줄일 수 있으며, 그로 인해 측정시간이 매우 빠르고 측정정밀도도 뛰어난 장점을 가진다. 본 논문의 스캐닝 모아레 측정 방법은 넓은 영역의 3차원 형상 정보를 얻는데 매우 유익하며, 대면적의 대상물 측정 시 일반적으로 사용하는 stitching 기법을 사용할 필요가 없으므로 한번에 전 영역의 3차원 형상의 복원이 가능하여 보다 빠른 속도로 3차원 형상 정보를 얻을 수 있는 효과가 있다. 또한, 투영격자 하나만을 이용한 영사식 모아레 방식을 이용하여 작은 높이 단차를 갖는 물체의 3차원 형상을 복원하고 그 높이를 용이하게 측정 할 수 있다. 본 연구는 양산환경(Mass production)의 웨이퍼 범프 높이 검사 및 FC-CSP나 FC-BGA 범프 높이 검사 등에 활용 할 수 있으며, 실험을 통해 기존의 방법에 비해 투영격자의 이동횟수 및 측정 속도가 향상되었음을 확인하였다.

• 한국추진공학회지
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• 제6권2호
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• pp.45-52
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• 2002

2차원 수중 초음속 제트의 구조 및 유동 불안정성에 대한 실험적 연구를 수행하였다. 제트의 구조 및 시간에 따른 변화를 관찰하기 위하여 고속 디지털 카메라 촬영과 정압을 측정하였다. 공기 유량의 변화에 따른 제트의 구조를 초고속 촬영하여 이로부터 얻어진 장면에서 확산각을 구했다. 일련의 제트의 주기적인 특성에 따른 구조를 관찰하였고 불안정성의 초당 주기 발생 횟수가 5-6회 정도로 측정되었다. 세 가지 특성 길이 $L_1$, $L_2$, $L_3$를 정의하였다. $L_1$은 불안정적 주기가 발생할 경우 최대제트의 폭 스케일, $L_2$는 2차적인 유동이 유입되는 곳의 제트의 폭 스케일, $L_3$는 노즐 출구로부터 2차적으로 유도된 유동이 유임되는 곳까지의 길이다. $L_1$/$L_2$는 전압 즉, 탱크 압력이 증가함에 따라 감소하는 경향성을 가지고 있고 $L_3$는 전압이 증가함에 따라 증가하는 경향성을 띄었다. 시간에 따른 정압 변화를 측정하였으며 FFT결과를 통해서 불안정성으로 인해 발생하는 주파수와 유사한 값인 5Hz에서 고유진동이 발생하는 것을 확인하였다.

• 공업화학
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• 제31권2호
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• pp.220-225
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• 2020

모발은 여러 가지 아미노산들을 포함하는 단백질로 이루어져 있다. 자외선(UV)은 태양광선중에서 모발손상에 가장 큰 영향을 미치며 모발 노화에 주된 역할을 한다. 본 연구의 목적은 전자현미경(SEM), 공초점현미경(CLSM) 및 적외선 현미경분광법(IR micro spectroscopy)을 이용하여 정상모발에 UVB를 조사한 후 특징적인 형태학적 및 화학적 구조변화를 알아보는 것이다. 에너지 분산형 X선 분광기가 부착된 전자현미경은 자외선 조사모발의 표면이 정상모발과 비교했을 때 거칠고 높은 산소원소의 함량을 보였다. 형광 및 3차원 위상 이미지를 CLSM으로 분석한 결과 정상모발의 초록색 형광방출이 UVB 조사모발에 비해 매우 높았다. 또한 fluorescamine 형광 염색법을 통해 UVB 조사모발은 정상모발에 비해 펩타이드 결합의 파괴로 생성된 자유 아미노기가 많음을 확인할 수 있었다. UVB 조사모발의 강한 푸른색 형광은 아미노기의 함량이 높다는 것을 의미하며, 이는 CLSM에서도 관찰되었다. 따라서 fluorescamine은 UVB 조사모발에서 펩타이드 결합의 파괴를 관찰하는데 유용한 도구가 될 수 있다. 정상모발과 UVB 조사모발의 단면을 IR micro-spectroscopy를 통해 이미지 맵핑(mapping)한 결과, UVB 조사모발은 정상 모발에 비해 모발의 표면은 물론 내부에 걸쳐 디설파이드 결합(disulfide bond)의 산화가 일어나고 있음을 확인할 수 있었다. 이러한 분광학적 방법은 단독 또는 다른 분석법과 함께 모발화장품의 개발에 응용될 수 있을 것이다.

• 박물관보존과학
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• 제25권
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• pp.63-84
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• 2021

본 연구는 전통도자기의 제작 전과 후, 소성 전과 후에 기물의 내부에서 일어나는 다양한 물리화학적 변화를 알아보고자 청자상감운학문매병의 재현품을 성형 → 조각 → 상감 → 초벌 → 유약 → 재벌 등의 6단계로 제작하여 과학적 조사 및 3차원의 정밀한 투과 이미지 촬영으로 획득한 이미지를 세부 영역별로 분석하였다. 재현편의 제작 재료는 각각의 재료가 가진 성분에 따라 다른 광물상이 존재하며, 산화철(Fe₂O₃)의 함량이 높은 흑상감은 어두운 색을 나타냈고, 알루미나(Al₂O₃)의 함량이 높은 백상감은 백색이 나타나는 것과 같이 색상에도 영향을 준다. 재현편의 색도와 전암대자율, 주요성분 등의 물리화학적 특성을 CT이미지를 통해 밀도의 차이로 확인할 수 있었으며, 미세조직과 흡수율, 겉보기기공률, 주요구성광물 등의 번조에 따른 특성 변화는 영상 분석에서 기물 내부의 기공 유무와 존재량, 균열의 발달과 확장으로 파악하였다.

• Korean Journal of Radiology
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• 제21권8호
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• pp.998-1006
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• 2020

Objective: To compare the accuracies of quantitative computed tomography (CT) parameters and semiquantitative visual score in evaluating clinical classification of severity of coronavirus disease (COVID-19). Materials and Methods: We retrospectively enrolled 187 patients with COVID-19 treated at Tongji Hospital of Tongji Medical College from February 15, 2020, to February 29, 2020. Demographic data, imaging characteristics, and clinical data were collected, and based on the clinical classification of severity, patients were divided into groups 1 (mild) and 2 (severe/critical). A semiquantitative visual score was used to estimate the lesion extent. A three-dimensional slicer was used to precisely quantify the volume and CT value of the lung and lesions. Correlation coefficients of the quantitative CT parameters, semiquantitative visual score, and clinical classification were calculated using Spearman's correlation. A receiver operating characteristic curve was used to compare the accuracies of quantitative and semi-quantitative methods. Results: There were 59 patients in group 1 and 128 patients in group 2. The mean age and sex distribution of the two groups were not significantly different. The lesions were primarily located in the subpleural area. Compared to group 1, group 2 had larger values for all volume-dependent parameters (p < 0.001). The percentage of lesions had the strongest correlation with disease severity with a correlation coefficient of 0.495. In comparison, the correlation coefficient of semiquantitative score was 0.349. To classify the severity of COVID-19, area under the curve of the percentage of lesions was the highest (0.807; 95% confidence interval, 0.744-0.861: p < 0.001) and that of the quantitative CT parameters was significantly higher than that of the semiquantitative visual score (p = 0.001). Conclusion: The classification accuracy of quantitative CT parameters was significantly superior to that of semiquantitative visual score in terms of evaluating the severity of COVID-19.

• Journal of Cardiovascular Imaging
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• 제31권1호
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• pp.18-23
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• 2023

BACKGROUND: Three-dimensional (3D) transesophageal echocardiogram (TEE) is the gold standard for the diagnosis of degenerative mitral regurgitation (dMR) and preoperative planning for transcatheter mitral valve repair (TMVr). TEE is an invasive modality requiring anesthesia and esophageal intubation. The severe acute respiratory syndrome coronavirus 2 pandemic has limited the number of elective invasive procedures. Multi-detector computed tomographic angiography (MDCT) provides high-resolution images and 3D reconstructions to assess complex mitral anatomy. We hypothesized that MDCT would reveal similar information to TEE relevant to TMVr, thus deferring the need for a preoperative TEE in certain situations like during a pandemic. METHODS: We retrospectively analyzed data on patients who underwent or were evaluated for TMVr for dMR with preoperative MDCT and TEE between 2017 and 2019. Two TEE and 2 MDCT readers, blinded to patient outcome, analyzed: leaflet pathology (flail, degenerative, mixed), leaflet location, mitral valve area (MVA), flail width/gap, anterior-posterior (AP) and commissural diameters, posterior leaflet length, leaflet thickness, presence of mitral valve cleft and degree of mitral annular calcification (MAC). RESULTS: A total of 22 (out of 87) patients had preoperative MDCT. MDCT correctly identified the leaflet pathology in 77% (17/22), flail leaflet in 91% (10/11), MAC degree in 91% (10/11) and the dysfunctional leaflet location in 95% (21/22) of patients. There were no differences in the measurements for MVA, flail width, commissural or AP diameter, posterior leaflet length, and leaflet thickness. MDCT overestimated the measurements of flail gap. CONCLUSIONS: For preoperative TMVr planning, MDCT provided similar measurements to TEE in our study.

• Korean Journal of Radiology
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• 제21권6호
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• pp.670-683
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• 2020

Objective: The presence of coagulative necrosis (CN) in clear cell renal cell carcinoma (ccRCC) indicates a poor prognosis, while the absence of CN indicates a good prognosis. The purpose of this study was to build and validate a radiomics signature based on preoperative CT imaging data to estimate CN status in ccRCC. Materials and Methods: Altogether, 105 patients with pathologically confirmed ccRCC were retrospectively enrolled in this study and then divided into training (n = 72) and validation (n = 33) sets. Thereafter, 385 radiomics features were extracted from the three-dimensional volumes of interest of each tumor, and 10 traditional features were assessed by two experienced radiologists using triple-phase CT-enhanced images. A multivariate logistic regression algorithm was used to build the radiomics score and traditional predictors in the training set, and their performance was assessed and then tested in the validation set. The radiomics signature to distinguish CN status was then developed by incorporating the radiomics score and the selected traditional predictors. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performance. Results: The area under the ROC curve (AUC) of the radiomics score, which consisted of 7 radiomics features, was 0.855 in the training set and 0.885 in the validation set. The AUC of the traditional predictor, which consisted of 2 traditional features, was 0.843 in the training set and 0.858 in the validation set. The radiomics signature showed the best performance with an AUC of 0.942 in the training set, which was then confirmed with an AUC of 0.969 in the validation set. Conclusion: The CT-based radiomics signature that incorporated radiomics and traditional features has the potential to be used as a non-invasive tool for preoperative prediction of CN in ccRCC.