• 디지털융복합연구
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• 제16권2호
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• pp.19-26
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• 2018

흉부 CT 영상에서 폐 질환의 진단을 위해서 폐 분할, 폐혈관 분할과 폐 질환 부위에 대한 괴사 세포 비율의 수치적 계산을 제안 하였다. 첫 번째 단계는 흉부 CT 영상에서 3차원 레이블링 기법과 3차원 영역 성장법을 적용하여 폐와 기관지를 분리한다. 두 번째 단계는 폐혈관 분할은 1차 다항식 회귀(Polynomial Regression)를 사용한 변화율을 적용하여 분할한 다음, 잡음 제거를 실시하여 최종의 폐혈관을 분할한다. 세 번째 단계는 2단계 이미지 에서 질환 예상 인자를 발견하고, 괴사 세포의 비율을 계산하는 것이다. 질환 예상인자는 폐에 대해서 3차원 레이블링 기법을 적용하였고, 각 레이블 중심 값을 관측하여 변화가 없는 레이블을 찾는다. 이렇게 찾은 질환 예상 인자는 조영제 투입 전/후 영상을 정합한 뒤, 면적을 비교하면 폐의 괴사 세포 비율을 계산할 수 있다.

• Korean Journal of Radiology
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• 제22권6호
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• pp.901-911
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• 2021

Objective: To evaluate the technical applicability of a semiautomatic three-dimensional (3D) hybrid CT segmentation method for the quantification of right ventricular mass in patients with cardiovascular disease. Materials and Methods: Cardiac CT (270 cardiac phases) was used to quantify right ventricular mass using a semiautomatic 3D hybrid segmentation method in 195 patients with cardiovascular disease. Data from 270 cardiac phases were divided into subgroups based on the extent of the segmentation error (no error; ≤ 10% error; > 10% error [technical failure]), defined as discontinuous areas in the right ventricular myocardium. The reproducibility of the right ventricular mass quantification was assessed. In patients with no error or < 10% error, the right ventricular mass was compared and correlated between paired end-systolic and end-diastolic data. The error rate and right ventricular mass were compared based on right ventricular hypertrophy groups. Results: The quantification of right ventricular mass was technically applicable in 96.3% (260/270) of CT data, with no error in 54.4% (147/270) and ≤ 10% error in 41.9% (113/270) of cases. Technical failure was observed in 3.7% (10/270) of cases. The reproducibility of the quantification was high (intraclass correlation coefficient = 0.999, p < 0.001). The indexed mass was significantly greater at end-systole than at end-diastole (45.9 ± 22.1 g/m² vs. 39.7 ± 20.2 g/m², p < 0.001), and paired values were highly correlated (r = 0.96, p < 0.001). Fewer errors were observed in severe right ventricular hypertrophy and at the end-systolic phase. The indexed right ventricular mass was significantly higher in severe right ventricular hypertrophy (p < 0.02), except in the comparison of the end-diastolic data between no hypertrophy and mild hypertrophy groups (p > 0.1). Conclusion: CT quantification of right ventricular mass using a semiautomatic 3D hybrid segmentation is technically applicable with high reproducibility in most patients with cardiovascular disease.

• 건설관리
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• 제12권2호
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• pp.55-58
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1407-1408
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• 2010

• Journal of Korean Neurosurgical Society
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• 제61권6호
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• pp.737-746
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• 2018

Objective : The purpose of this study was to compare the cosmetic outcome and complications after cranioplasty (CP) due to three different implant materials, and analyze the mean implant survival and cumulative survival rate based on these results. Methods : We reviewed 108 patients retrospectively who underwent CP between January 2014 and November 2016. Autologous bone (AB; 45 patients) and synthetic materials with porous polyethylene (PP; 32 patients) and custom-made 3-dimensional printed titanium mesh (CT; 31 patients) were used as implants. Results : Regardless of implanted materials, more than 89.8% of the CP patients were satisfied with the cosmetic outcome. No statistically significant difference was observed among the three groups. The overall postoperative complication rates of each group were 31.1% in the AB group, 15.6% in the PP group and 3.2% in the CT group. The CT group showed lower complication rates compared with AB and PP groups (${\chi}^2$-test : AB vs. PP, p=0.34; AB vs. CT, p=0.00; PP vs. CT, p=0.03). The AB and PP groups demonstrated a higher post-CP infection rate (11.1% and 6.3%) than the CT group (3.2%). However, no significant difference in the incidence of post-CP infection was observed among the three groups. The PP and CT groups demonstrated a higher mean implant survival time and cumulative survival rate than the AB group at the last follow-up (p<0.05). Conclusion : In comparison with AB and PP, cranioplasty with CT shows benefits in terms of lower post-CP complication, less intraoperative bleeding loss, shorter operation time and in-hospital stay. The PP and CT groups showed higher implant survival time and cumulative survival rate compared with the AB group.

• 한국정밀공학회지
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• 제22권10호
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• pp.202-209
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• 2005

In this study, two dimensional and three dimensional finite element models of lower first premolar were analyzed. The mandibular specimen including a premolar was obtained from a cadaver and scanned with micro-CT. Finite element method models were reconstructed from CT images at mid-sagittal plane of the tooth. Most studies have used a wide range of value(0.07${\~}$1000MPa) for elastic modulus of periodontal ligament. The elastic modulus of the periodontal ligament was analyzed by finite element method and compared with that of experiment model. This study indicated that the model without pulp was more suitable than that with pulp in two dimensional finite element analysis.

• 대한치과교정학회지
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• 제41권4호
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• pp.224-236
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• 2011

본 연구는 정상교합자의 치열궁과 기저골 형태를 파악하기 위해 시행하였다. 정상교합자 27명(남-15명: 25Y $10M{\pm}4Y$ 4M/여-12명: 26Y $1M{\pm}7Y$ 4M)을 대상으로 두개골의 전산화 단층촬영을 시행하고 입체영상을 제작한 뒤, 상악 중절치의 FA point의 중점을 원점으로 하는 3차원 좌표계를 형성하였다. 또한 상악 교합평면과 평행한 면으로 절단하여 상하악의 치열궁과 기저골의 형태에 대해 분석하였다. 상하악기저골은 A point, B point 부위와 양측 제1대구치 부위의 좌표에서 통계적으로 유의한 차이가 나타나지 않았다. 또한 상하악의 치열궁은 기저골악궁에 비해 전치부에서 순측으로 위치하였다. 또한 치열궁과 기저골악궁의 협설측 교차는 상악은 대구치 부위에서, 하악은 소구치 부위에서 이루어졌다.

• 대한의용생체공학회:의공학회지
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• 제31권4호
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• pp.285-291
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• 2010

Recently, advance on various modalities of diagnosing, prostate volume estimation became possible not only by the existing two-dimension medical images data but also by the three-dimensional medical images data. In this study, magnetic resonance image (MRI), computer tomography (CT) and ultrasound (US) were employed to evaluate prostate phantom volume measurements for estimation, comparison and analysis. For the prostate phantoms aimed at estimating the volume, total of 17 models were developed by using devils-tongue jelly and changing each of the 5ml of capacity from 20ml to 100ml. For the volume estimation through 2D US, the calculation of the diameter with C9-5Mhz transducer was conducted by ellipsoid formula. For the volume estimation through 3D US, the Qlab software (Philips Medical) was used to calculate the volume data estimated by 3D9-3Mhz transducer. Moreover, the images by 16 channels CT and 1.5 Tesla MRI were added by the method of continuous cross-section addition and each of imaginary prostate model's volume was yielded. In the statistical analysis for comparing the availability of volume estimation, the correlation coefficient (r) was more than 0.9 for all indicating that there were highly correlated, and there were not statistically significant difference between each of the correlation coefficient (p=0.001). Therefore, the estimation of prostate phantom volume using three-dimensional modalities of diagnosing was quite closed to the actual estimation.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.227-233
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• 2013

Purpose: This study was performed to analyze human maxillary and mandibular trabecular bone using the data acquired from micro-computed tomography (micro-CT), and to characterize the site-specific microstructures of trabeculae. Materials and Methods: Sixty-nine cylindrical bone specimens were prepared from the mandible and maxilla. They were divided into 5 groups by region: the anterior maxilla, posterior maxilla, anterior mandible, posterior mandible, and mandibular condyle. After the specimens were scanned using a micro-CT system, three-dimensional microstructural parameters such as the percent bone volume, bone specific surface, trabecular thickness, trabecular separation, trabecular number, structure model index, and degrees of anisotropy were analyzed. Results: Among the regions other than the condylar area, the anterior mandibular region showed the highest trabecular thickness and the lowest value for the bone specific surface. On the other hand, the posterior maxilla region showed the lowest trabecular thickness and the highest value for the bone specific surface. The degree of anisotropy was lowest at the anterior mandible. The condyle showed thinner trabeculae with a more anisotropic arrangement than the other mandibular regions. Conclusion: There were microstructural differences between the regions of the maxilla and mandible. These results suggested that different mechanisms of external force might exist at each site.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제19권4호
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• pp.343-350
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• 1997

Diagnosis of maxillofacial lesions is very difficult. Recent developments in computed tomography enable the production of three dimnesional images of complex anatomical structures from a series of conventional computed tomographic sections. Methods of three-dimensional analysis of computed tomographic images have recently been described. Mostly, reports have concentrated on applications relative to congenital deformities. In this report, one method of three dimensional reformatting is reviwes. Images formed by this method have solid surface appearance and can be color enhanced and manipulated to isolate anatomic structures of interest. The program allows tissue densitis, volumes, and distances. This report emphasizes maxillofacial applications other than those previously reported in the surgical and radiological literature.