대퇴비구충돌증후군 진단을 위한 새로운 방사선학적 기준 수립을 위한 연구: 3차원 모델 시뮬레이션 연구

학위논문(박사) -- 서울대학교대학원 : 의과대학 의학과, 2022. 8. 구경회.Purpose Femoroacetabular impingement (FAI) is diagnosed by symptoms, impingement test, and radiological findings. However, the reliability of radiological findings is debated. Thus, we defined excursion angle (EA), impingement free range of motion between the acetabular edge and the femoral neck. The aims of this study were to develop diagnostic criteria of FAI based on EA, to evaluate the reliability and validity of the criteria, and to determine the optimal cut-off value of EA discriminating FAI and non-FAI hips. Methods Thirty-three 3-dimensional hip models were reconstructed and 14 activities of daily living were simulated. Any colliding portions of the acetabular edge were removed, and lateral and anterior EAs were measured. The reliability and validity of the EA criteria were evaluated in a validation cohort of 411 hips. The optimal cut-off values discriminating FAI and non-FAI hips were determined using the receiver operating characteristic (ROC) curve analysis. Results The mean lateral EA was 50.4° (±10.2°), and the mean anterior EA was 29.9° (±5.1°). Hips were categorized into low-risk group (lateral EA>40° and anterior EA>25°), moderate-risk group (lateral EA: 30°-40° or anterior EA:20°-25°) and high-risk group (lateral EA< 30° or anterior EA<20°). The EA measurement was highly reliable (k=0.96 and 0.97 for inter-and intra-observer reliabilities, respectively). Among the 411 validation hips, 106 (26%) were diagnosed as FAI. There was a strong correlation between FAI and risk groups: 8% (22/279) in the low-risk group, 44% (28/64) in the moderate-risk group, and 82% (56/68) in the high-risk group (x2=183.674, p<0.001). The EA criteria had excellent discrimination between FAI and non-FAI hips (area under the curve (AUC) 0.856[0.807-0.905], p<0.001). The optimal cut-off values for lateral EA were 51° in female and 43° in male; those for anterior EA were 29° in female and 25° in male. Conclusion We developed reliable and valid criteria to diagnose FAI by measuring two EAs on hip AP and modified Dunn views. The EA criteria appeared as reliable and valid radiological measurement for FAI diagnosis. Further studies are warranted to evaluate the performance of the EA criteria in the diagnosis of FAI.목 적: 대퇴비구 충돌증후군(Femoroacetabular impingement: FAI)은 임상 증상, 이학적 충돌 검사 그리고 방사선 소견으로 진단한다. 그러나 방사선학적 소견의 신뢰성에 대해서는 지속적인 논란이 있어왔다. 따라서, 저자들은 비구 가장자리와 대퇴 경부 사이의 충돌 없는(impingementfree) 운동 범위를 나타내는 excursion angle (EA)을 새로이 개발 및 정의하고자 한다. 본 연구의 목적은 FAI의 진단기준으로 사용할 수 있는 EA 값을 개발하고, 이 새로운 기준의 신뢰도와 타당도를 평가하며, FAI와 non-FAI hip을 구분하는 EA의 최적의 절단값을 결정하는 것이다. 대상 및 방법: 33개의 3차원 고관절 모델을 구성하고 충돌이 잘 발생한다고 알려진 14개의 일상 생활 활동 (Activity of daily living)을 시뮬레이션했다. 충돌이 일어나는 비구 가장자리의 부분을 제거한 모델에서 측면 (lateral) 및 전면 (anterior) EA를 측정했다. EA 기준의 신뢰성과 타당성은 411개의 고관절로 이루어진 검증 코호트에서 평가하였다. FAI와 non-FAI 를 구별하는 최적의 절단값은 수신자 조작 특성 (Receiver Operating Characteristic) 곡선 분석을 사용하여 구하였다. 결 과: 평균 외측 EA는 50.4°(±10.2°), 평균 전방 EA는 29.9°(±5.1°)였다. 이에 따라 각각의 고관절을 세 군으로 나누었다; 저위험군 (측면 EA >40° 및 전방 EA >25°), 중간 위험군 (측면 EA: 30°-40° 또는 전방 EA: 20°-25°) 및 고위험군으로 분류하였다. (측면 EA < 30° 또는 전방 EA <20°). 관찰자 간 및 관찰자 내 신뢰도는 각각 k =0.96 및 0.97로 EA 측정은 신뢰할 수 있었다. 411개의 고관절로 이루어진 검증 코호트 중 106개의 고관절이 (26%) FAI로 진단되었다. FAI와 세 군 사이에는 강한 상관관계가 있었다; 저３７위험군에서 8% (22/279), 중간 위험군에서 44% (28/64), 고위험군에서 82%(56/68)가 FAI로 진단되었다 (x2=183.674, p <0.001). EA 기준은 FAI와 non-FAI 환자를 구별하는데 용이했다 (Area under the curve, 0.856 [0.807-0.905], p <0.001). 측면 EA에 대한 최적의 절단값은 여성에서 51°, 남성에서 43°였다. 전방 EA의 경우 여성의 경우 29°, 남성의 경우 25°로 나타났다. 결 론: 이번 연구를 통해 개발한 EA가 FAI를 진단에 유용하게 쓰일 수 있다는 것을 확인하였다. EA 기준은 FAI 진단을 위한 유효하고 신뢰성이 있는 방사선학적 측정값으로 나타났다. 후속 연구를 통해 FAI 진단에서 EA 기준의 성능을 평가하는 것이 필요하겠다.Chapter 1. Introduction 1 Chapter 2. Materials and Methods 3 Chapter 3. Results 9 Chapter 4. Discussion 12 Chapter 5. Conclusion 16 Conflict of Interest 17 Source of Funding 17 Bibliography 18 Abstract in Korean 36박

Effect of Cyclosporin A on Tear Film and Corneal Aberration after Cataract Surgery

Purpose: To evaluate the efficacy of 0.05% cyclosporine A on tear film parameters and corneal aberration after cataract surgery. Methods: Patients who underwent cataract surgery were divided into 2 groups. Patients in Group I (23 eyes) were treated with cyclosporine A from 1 week before surgery to 3 months after surgery. Patients in Group II (24 eyes) underwent surgery without cyclosporine treatment. Tear film break-up time (BUT), Schirmer’s test I, Oxford scheme, Ocular surface disease index (OSDI), and corneal aberrations were evaluated before surgery and at 1 and 3 months after surgery. Results: In Group I, BUT was significantly improved at 3 months (p = 0.026) after surgery compared with the preoperative value. OSDI decreased significantly at 1 (p = 0.033) and 3 months (p = 0.003) after surgery compared with the preoperative value. However, there were no significant differences between preoperative and postoperative values of BUT and OSDI in Group II. Schirmer’s test results and the Oxford scheme were not significantly changed in either group. Preoperative root mean square (RMS) total values were not different between the 2 groups, but was different at postoperative 3 months (p = 0.015). Group I had a significantly lower value for total RMS than Group II. In Group I, Coma 7 (Z3-1) (p = 0.018) and spherical aberration (Z4 0) (p =0.031) were significantly decreased after surgery. In Group II, Trefoil 6 (Z3-3) (p = 0.033) was significantly increased after surgery. Conclusions: 0.05% cyclosporine A may be effective for improving dry eye syndrome and corneal aberration after cataract surgery.ope

제2형 과립각막이상증에서 각막혼탁의 변화 양상 분석과 앞기질 혼탁의 생성 기전 제시

의과대학/석사Background: Granular corneal dystrophy type 2 (GCD2) is a hereditary disease, which is caused by an autosomal dominant Arg124His mutation in the transforming growth factor-β induced gene (TGFBI). In GCD2, corneal deposits appear as granular lesion, linear (lattice-like) lesion and diffuse haze. GCD2 has known to show profound differences in the severity of phenotype. TGFBIp is understood to be the main substance forming various types of deposits. But there are no studies that explain the development of TGFBIp into 3 types of deposits. TGFBIp is thought to be generated in epithelial cell and move gradually to deep stroma forming deposits in various levels. Linear lesion is considered to be formed with the degraded TGFBIp fragments. Diffuse haze is formed with the undegraded TGFBIp. Late onset developing of diffuse haze demonstrates the possibility that an increase of age is associated with decrease of the ability of degrading TGFBIp. Methods: We retrospectively reviewed the records and slit-lamp photographs of 533 patients with GCD2. All patients were diagnosed as being GCD2 heterozygous by DNA analysis from peripheral blood. Deposits were classified into granular lesion, linear lesion and diffuse haze. We evaluated the area of each type of deposit using inForm® software (Perkin Elmer, Inc, Waltham, MA, USA), and the tendency of the area of each type was investigated according to age. The correlation among the area of 3 types was analyzed. To study the relationship between diffuse haze and linear lesion especially, we evaluated the difference of the amount of the diffuse haze in proportion of the linear lesion (paired eye test). The relationship between visual acuity and the area of each type was also evaluated. Results: For all types of deposits, the area had an increasing tendency with age (all for p<0.001). In detail, the area of diffuse haze increased in earnest since 40’s. Linear lesion showed a tendency of increase until 40’s, but this tendency of increase stopped from 40’s. The area of diffuse haze and linear lesion significantly showed negative correlation (Pearson correlation coefficient; -0.10, p=0.04). Diffuse haze also had negative correlation with linear lesion between granular and linear lesion (Pearson correlation coefficient; -0.15, p<0.01). In paired eye study, there was statistically significant negative tendency showing that cornea with more linear lesion had less area of diffuse haze than apposite eye (p<0.001). In logistic analysis, the group with larger linear lesion between granular and linear lesion significantly had less diffuse haze comparing to the group with smaller linear lesion (adjusted OR=0.50, p=0.02). In 3 types of deposits, diffuse haze had the worst effect on visual acuity. Conclusion: In GCD2, diffuse haze is the main cause of visual impairment and formed mostly after 40’s. This late onset formation is associated with the stop of the linear lesion formation, and this association would suggest that decline of the degradability of TGFBIp in corneal cells with age might be related with the formation of diffuse haze.ope

통계적 모델에 기반한 오디오 워터마크와 향상된 검출을 위한 백색화 필터

Thesis (master`s)--서울대학교 대학원 :전기공학부,2000.Maste

Electrical conductivity, thermoelectric power & hall effect of undoped La₂NiO₄

학위논문(석사) --서울대학교 대학원 :재료공학부,2007.Maste

머시닝센터 이송계의 온라인 열변형 보정

학위논문(석사)--서울대학교 대학원 :기계항공공학부,2001.Maste

Teeth optimization of rotary ultrasonic motor for maximizing velocity

학위논문(석사) --서울대학교 대학원 :전기. 컴퓨터공학부,2007.Maste

A Study on Simulation of Flexible Aircraft Turning Flight Considering Reduced Order Model and Machine Learning

학위논문(석사)--서울대학교 대학원 :공과대학 기계항공공학부(멀티스케일 기계설계전공),2020. 2. 조맹효.유연항공기의 거동을 해석할 때 강체항공기와 달리 공력와 구조의 결합에 의해 발생하는 영향을 고려하여야 하며 이를 공력탄성학이라 한다. 유연항공기가 비행할 때 작용하는 공력에 의해 구조에 변형이 발생하게 되며, 이에 의해 항공기에 작용하는 공력이 다시 변하게 되어 항공기의 거동에 큰 영향을 미친다. 따라서 비행동역학, 공력, 구조의 결합에 의한 영향을 고려한 해석이 필수적이다. 본 논문에서는 유연항공기의 수평선회비행을 전사 모사 하기 위해서 다물체동역학 기법 중 하나인 FFRF(Floating Frame of Reference Formulation)을 이용하여 유연항공기를 모델링하였고, finite state inflow theory에 기반한 공력 모델을 사용하였다. 항공기 수평 선회 비행을 하기 위해서는 구심력이 필요하고 이로 인해 발생하는 공력과 구조의 강한 결합을 갖게 되어 초기비행조건을 유지하며 일정한 상태로 수평 선회 비행을 하기 어렵다. 이에 본 논문에서는 조종면과 추력의 상태를 지속 조작하며 초기비행조건을 유지하는 strong coupled analysis를 사용하여 수평선회비행을 전산 모사하였다. 또한 strong coupled analysis의 최대 단점인 계산 시간 문제를 해결하기 위해 차수 축소 모델과 기계 학습을 통해 대리모델을 구축하고 이를 사용하여 계산시간을 단축시켰다.When the flexible aircraft is flying, deformation occurs in the structure due to aerodynamics. And changed aerodynamics affect flight trajectory. So coupling effects of aerodynamics and structural deformation should be considered, when analyzing the behaviors of flexible aircraft. In this paper, the flexible aircraft was modeled using the floating frame of reference formulation(FFRF), which is one of the multibody dynamics methods, to simulate the level turn flight of the flexible aircraft. And strong coupled analysis was used to solve the problem of strong coupling between aerodynamics and structural deformation caused by the centripetal force required for level turn flight. In addition, a surrogate model constructed using machine learning and POD-based reduced order model are used to improve computational efficiency제 1 장 서 론 1 제 2 장 Floating Frame of Reference Formulation 3 제 1 절 좌표계 정의 3 제 2 절 질량행렬 및 강성행렬 구성 5 제 3 절 운동방정식 6 제 3 장 Finite state inflow theory 7 제 4 장 Flight dynamics 9 제 1 절 Trim analysis 9 제 2 절 Transient analysis 13 제 5 장 Reduced order model & Surrogate model 14 제 1 절 Reduced Order Model(ROM) 14 제 2 절 Surrogate model 16 제 6 장 Numerical Result 18 제 1 절 Rigid & Flexible Aircraft 10°Bank turn 18 제 2 절 Reduced order model 11°Bank turn 19 제 3 절 Surrogate model 10.5°Bank turn 20 제 7 장 결론 22 참고문헌 23 Abstract 25Maste