연골 평가를 위한 지방-물 이중 억제 자기공명영상: 돼지 슬개골을 이용한 생체 외 연구

학위논문 (석사) -- 서울대학교 대학원 : 의과대학 의학과, 2020. 8. 홍성환.Objectives To describe the imaging characteristics of combined fluid-attenuated inversion recovery with fat suppression (FLAIR-FS) in cartilage imaging and compare its basic features with those of conventional MR sequences. Methods MR images of 14 porcine patellae were obtained with a 3-T MR imaging unit. A normal-saline-filled plastic container, containing two porcine patellae fixed with rubber bands, was positioned in the coil. The MR imaging sequences included T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and FLAIR-FS with an inversion time of 1500 ms. In the last two of the 14 patellae, the double-echo steady-state (DESS) (TR/TE = 14.5/5.0, flip angle 30°, slice thickness 1.0 mm) and ultrasonography (US) were additionally performed. For 28 annotated points on 14 patellae, visual grading of cartilage layer conspicuity was performed with 5-point scores on T1-, T2WI, and FLAIR-FS by two MSK radiologists. As a hypointense layer at the cartilage-water interface was unexpectedly seen with FLAIR-FS, we examined whether the interfacial hypointense layer was a part of the cartilage by comparing between FLAIR-FS and DESS. In the last two patellae with additional DESS and US scans, composite images from FLAIR-FS and DESS were made to inspect the location of the interfacial hypointense layer with FLAIR-FS relative to DESS. We also compared cartilage thickness measurements between FLAIR-FS and DESS. For FLAIR-FS, two different methods of cartilage thickness measurement were applied, including or excluding the interfacial hypointense layer. To verify the accuracy of cartilage thickness measurements on DESS, the measurements on MRI and US were compared. The degree of absolute agreement between measurements was obtained using the intraclass correlation coefficient (ICC) with a 95% confidence interval. Results FLAIR-FS (TI 1500 ms) resulted in moderate water signal suppression and showed a higher signal intensity for the articular cartilage than free water. T1WI, T2WI, and FLAIR-FS showed a trilaminar appearance of the articular cartilage. This layered appearance was most pronounced with FLAIR-FS, followed by T2WI and T1WI (p < 0.001). A thin hypointense layer (0.7 ± 0.1 mm in thickness) appeared at the cartilage-water interface with FLAIR-FS. By excluding the interfacial hypointense layer, the cartilage surfaces matched well each other on composite image of FLAIR-FS and DESS. The cartilage thickness of the DESS reference standard was 2.2 ± 0.4 mm. When we compared cartilage thickness measurements on DESS and FLAIR-FS, exclusion of the interfacial hypointense layer (2.3 ± 0.3 mm, absolute ICC agreement 0.904) produced greater agreement than inclusion (3.0 ± 0.2 mm, absolute ICC agreement 0.322). The ICC of absolute agreement was 0.919 in comparison between DESS and US cartilage thickness measurements. Conclusions FLAIR-FS showed superior contrast between cartilage layers and revealed a potential restricted water layer at the cartilage-water interface.연구 목적 이 연구는 연골의 지방–물 이중억제 자기공명영상(combined fluid-attenuated inversion recovery with fat suppression, FLAIR-FS)에서 영상 특성을 설명하고, FLAIR-FS의 기본적인 특성과 기존의 자기 공명 영상 기법의 기본적인 특성을 비교해보고자 시행되었다. 연구 방법 14개의 돼지 슬개골을 3 Tesla 자기 공명 영상으로 촬영하였다. 생리식염수가 담긴 용기에 2개의 슬개골을 넣고 고무 밴드로 고정하여 coil에 위치시켰다. MRI 기법으로는 T1 강조영상, T2 강조영상과 반전시간 1500msec을 적용한 FLAIR-FS을 촬영하였다. 14개 연골 중 마지막 2개의 슬개골에 대하여는, 이중에코 항정상태 (double echo steady state, DESS) (TR/TE = 14.5/5.0, flip angle 30°, slice thickness 1.0 mm)와 초음파를 추가로 시행하였다. 14개의 슬개골에 28개의 지점을 표시한 후에, 2명의 근골격계 전문 영상의학과 의사가 5단계의 점수를 활용하여서, T1 강조영상, T2 강조영상과 FLAIR-FS에 대하여 연골 층의 구분 정도를 시각적으로 평가하였다. FLAIR-FS에서 연골-물 계면에서 저신호강도 영역이 예상외로 보였기 때문에, 우리는 이 계면사이의 저신호강도 영역이 연골의 일부인지 아닌지를, FLAIR-FS과 DESS 에서 연골을 비교하여서 평가하였다. DESS와 초음파를 추가로 시행한 2개의 슬개골에서, FLAIR-FS에서 보인 계면 사이의 저신호강도 영역의 위치를 DESS와 상대적으로 평가하기 위하여, FLAIR-FS과 DESS의 혼합 이미지를 만들었다. 또한, FLAIR-FS와 DESS의 연골 두께를 측정하여 비교하였다. FLAIR-FS에 대하여는, 연골 두께를 측정할 때, 두가지의 다른 방법이 사용되었는데, 계면 사이의 저 신호 층을 포함하거나 제외하는 방법으로 측정하였다. DESS에서의 연골 두께 측정의 정확도를 확인하기 위하여, MRI와 초음파에서의 측정이 비교되었다. 측정한 연골두께의 절대 합치도는, 급내상관계수를 이용하여 비교하였고, 95% 신뢰구간을 사용하였다. 연구 결과 FLAIR-FS (반전 시간 1500msec)은 중등도의 물 신호강도 억제를 보였고, 관절연골의 신호강도는 자유로운 물보다 높게 나타났다. 관절 연골은 T1 강조영상, T2 강조영상과 FLAIR-FS 영상 기법에서 세 층 구조를 보였다. 이러한 층 구조는 FLAIR-FS에서 가장 뚜렷하게 구분되어 보였고, 그 다음으로 T2 강조영상, 마지막으로 T1 강조영상 순으로 구분되었다 (p < 0.001). FLAIR-FS에서 연골–물 계면에 얇은 저신호강도 영역(두께: 0.7 ± 0.1 mm)이 보였다. 계면 사이의 저신호강도 영역을 제외하였을 때, FLAIR-FS과 DESS의 합성영상에서 연골의 표면이 서로 잘 일치하였다. 연골의 표준 영상인 DESS 기법에서 연골두께는 2.2 ± 0.4mm 였다. DESS와 FLAIR-FS 간 연골두께 측정 결과를 비교하면, 계면 사이의 저신호강도 영역을 제외한 경우(2.3 ± 0.3 mm, 절대합치도 0.904)가, 저신호강도 영역을 포함한 경우 (3.0 ± 0.2 mm, 절대합치도 0.322)보다 더 높은 합치도를 보였다. DESS 기법과 초음파검사의 연골두께 측정의 급내상관계수 절대합치도는 0.919이었다. 결론 지방–물 이중억제 자기공명영상은 연골 층 간의 높은 대조도를 보였고, 연골-물 계면에 움직임이 제한된 물 층의 존재 가능성을 보여주었다.Introduction 7 Methods 9 Results 14 Discussion 18 References 22 Abstract in Korean 26Maste

청소년기 그릿의 관련 요인 탐색: 만 4세부터 만 14세까지의 종단적 연구

학위논문 (석사)-- 서울대학교 대학원 : 사회과학대학 심리학과, 2018. 2. 곽금주.Various studies examine the predictors of success, one of which is grit. Grit is defined as perseverance and passion for long-term goals (Duckworth, Peterson, Matthews, & Kelly, 2007, p. 1087). Although research on grit has been carried out over the past decade, studies on Eastern populations are still lacking compared with studies on Western. In addition, most studies have been conducted with college students. Moreover, most studies focus on the effects of grit, but there has yet to be a study on the precedent factors of grit. Therefore, in the present study, Korean adolescents were examined, and the signs of grit were examined in longitudinal settings. A total of 106 Korean adolescents participated in this study. In Study 1, the relationships between implicit theories of intelligence, academic achievement, and grit were explored. All variables were collected via self-reporting. The results showed that individuals theories of intelligence and grit were related to academic achievement. In addition, the theory of intelligence was related to grit. Finally, grit fully mediated the relationship between the implicit belief of intelligence and academic achievements. In Study 2, signs of adolescents grit in adolescence were studied using 10-year longitudinal data. At age 4, parental education level, unrealistically optimistic beliefs, and the delay of gratification were measured. Parental education level was reported by the parents of the participants. Unrealistically optimistic beliefs were measured to investigate participants overestimated cognitive bias regarding their ability or future. Both the positive change of negative traits and the maintenance of positive traits were measured, adopted from Choi and Kwak (2007). The ability to delay gratification was assessed using a waiting period originally developed by Mischel and Baker (1975), whereby children waited in front of their desired sweets to obtain bigger rewards in the future. In addition, grit was measured by self-reporting when children turned 14 years old. Using stepwise regression analysis, we found that only the ability to delay gratification predicted grit in adolescence. While two factors of grit were analyzed independently, the delay of gratification only predicted perseverance of effort, not consistency of interest. In the present study, Korean adolescents grit was extensively examined. The results suggest the possibility of early intervention in children with a low ability to delay gratification to prevent low grit in adolescence. Moreover, this is the first empirical study in which the signs of grit have been longitudinally investigated from a developmental psychological perspective. The implications and directions for future research are discussed.Introduction 1 The Present Study 7 Study1 9 Grit and Academic Achievement 10 Theory of Intelligence and Academic Achievement 11 Grit and Theory of Intelligence 14 Research Questions and Hypotheses 16 Method 17 Participants 17 Procedures and Measures 18 Results 20 Descriptive statistics: Theory of Intelligence, Grit, and Academic Achievement 21 The Relationship between Theory of Intelligence, Grit, and Academic Achievement 22 Differences in Academic Achievement by the Theory of Intelligence and Grit 23 Effects of Implicit Theory of Intelligence and Grit on Academic Achievement 26 Grit as a Mediator in the Relationship between Theory of Intelligence and Academic Achievement 27 Discussion 31 Study2 34 Parental Education Level and Grit 35 Unrealistically Optimistic Beliefs and Grit 37 Delay of Gratification and Grit 39 Research Questions and Hypotheses 42 Method 43 Participants 43 Procedures and Measures 44 Results 50 Descriptive Statistics: Parents Education Level, Delay of Gratification, Unrealistically Optimistic Beliefs, and Grit 50 The Relationship between Delay of gratification, Unrealistically Optimistic Beliefs, and Grit 53 Exploring Childhood Variables Predicting Adolescence Grit 55 Discussion 57 General Discussion 61 Reference 65 Appendix 84 국문초록 87Maste

센더스트/다중벽 탄소나노튜브/폴리머 복합체의 전자기적 특성에 대한 연구

학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2015. 2. 서용석.This dissertation is about a study of making an electromagnetic wave absorption material that has high permeability and high permittivity. As a first step to make a hybrid composite that satisfy these two properties, a magnetic absorber (mixing Sendust with polymer) and a dielectric absorber (mixing MWCNTs with polymer) was made through melt mixing and solution mixing process. And to measure the permeability and permittivity of each absorber, vector network analyzer was used as a measurement tool. The measurement results showed that the complex permeability and the electromagnetic wave absorption ability of a magnetic absorber increased in two conditions: when more amount of Sendsut was mixed and by using flake shape Sendust instead of bulk shape. While the complex permittivity and the electromagnetic wave absorption ability of a dielectric absorber proportionated to the weight ratio of MWCNTs. Sendust/MWCNTs/polymer composites were created in order to make an electromagnetic wave absorption material as initially planned. We challenged to make the best hybrid composite that could gratify the conditions of preserving high permeability and high permittivity by changing the proportion of filler. In order to get a fixed permeability value contain of Sudust was fixed to 100 phr and 3 composites were made by adjusting the amount of MWCNTs to 5 phr, 10 phr and 15 phr. The result showed that the complex permittivity and the power loss increases as more filler was mixed but this was not promising because there was great reduction of reflection loss. The most realistic and effective hybrid composite was the composite with 5 phr of MWCNTs which was lighter and had excellent electromagnetic wave absorption with only 16 dB at a 4.6 GHz frequency.ChapterⅠ. Introduction I-1. Electromagnetic interference (EMI) shielding I-2. Materials for absorption of electromagnetic waves I-2.1. Dielectric Absorption Material I-2.2. Magnetic Absorption Materials I-3. The Purpose of the Experiment ChapterⅡ. Experimental Section II-1. Materials II-2. Sample preparation Process II-2.1. Fabrication of Sendust/polymer composites II-2.2. Fabrication of MWCNTs/polymer composites II-2.3. Fabrication of MWCNTs/Sendust/polymer composite II-3. Measurement of Electromagnetic Properties ChapterⅢ. Results and Discussion III-1. Electromagnetic Properties of Sendust/Polymer Composites III-2. Electromagnetic Properties of MWCNTs/Polymer Composites III-3. Electromagnetic Properties o Sendust/MWCNTs/Polymer Composites Chapter Ⅳ. ConclusionMaste

Optical Coherence Tomography Findings Facilitate the Diagnosis of Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay

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A Prototype of a Stereoacuity Test Using a Head-Mounted Display

Purpose To evaluate the test-retest reliability of a contour-based stereoacuity test using a head-mounted display (HMD) and compare it with other stereotests. Methods Thirty-two healthy adults aged 23-47 years were recruited from a tertiary hospital between August 2017 and July 2018. Two separate contour-based circles (crossed disparity: 135-1,350 arcsecs) were generated on a high-resolution phone display (Galaxy S7; Samsung, Seoul, Korea) using an HMD (Galaxy Gear VR). Two images were independently projected to each eye as graded circles with a random dot background. The results of the new HMD stereotest were compared to those of the standard Randot and TNO stereotests. The test-retest reliability was assessed using the Bland-Altman plot and Cohen’s kappa statistics. Results Among the 32 study participants, 17 (53%) were males and the mean age was 30.1 ± 4.8 years (range: 23-47). The mean stereoacuity was 160.3 ± 53.5 arcsecs in the first HMD stereotest (HMD1), 28.4 ± 12.5 arcsecs in the Randot stereotest, 96.1 ± 83.5 arcsecs in the TNO stereotest, and 143.3 ± 47.7 arcsecs in the second HMD stereotest (HMD2). The Bland-Altman plot showed a mean difference of 0.042 (-0.189 to +0.272, 95% limits of agreement) between HMD1 and HMD2. The reliability analysis showed an intraclass correlation coefficient of 0.499 (p = 0.022) and agreement of 81.25% in Cohen’s kappa statistics (Cohen’s kappa index = 0.119, p = 0.017). Conclusions The HMD stereotest without monocular cues showed fair test-retest reliability and reproducibility. Further studies using a high resolution display are needed to confirm the validity of the HMD stereotest.ope

urgical Management of Concurrent Strabismus and Face Turn in Patients with Infantile Nystagmus

Purpose: To investigate the effect of adjusted Kestenbaum surgery in patients with idiopathic infantile nystagmus who were affected by both strabismus and face turn. Methods: This retrospective consecutive case series included 12 patients with infantile nystagmus who had face turn and strabismus. All patients underwent adjusted Kestenbaum surgery between 1996 and 2014, and primary outcome measures were the postoperative degree of face turn and strabismus. Results: All patients had jerky nystagmus with compensatory face turn and strabismus. Of the 12 patients, eight patients were exotropes and four patients were esotropes. The mean age at surgery was 12.5 ± 10.7 years (range, 2-36 years). The mean postoperative follow-up was 17.8 ± 12.0 months (range, 7-43 months). Surgery was successful in eight (66.7%) out of 12 patients. Improvement of anomalous head posture was satisfactory in all patients, but an angle of deviation within 10 prism diopters was not achieved in four patients. Conclusions: Adjusted Kestenbaum surgery simultaneously improved both ocular misalignment and face turn with one-stage surgery. Two or three rectus muscles surgery can be considered in these patients because it is not only simpler than four muscles surgery but also can preserve one or two rectus muscles.ope

What Are the Factors Associated with the Structural Damage Differences in Open-Angle Glaucoma? RNFL- and GCIPL-Dominant Progression

We sought to analyze the parameters associated with retinal nerve fiber layer (RNFL)-dominant progression or ganglion cell-inner plexiform layer (GCIPL)-dominant progression in patients with open-angle glaucoma. A prospective observational study was conducted. Overall, 58 eyes from 33 patients with open-angle glaucoma were categorized into the following two groups: patients with RNFL- and GCIPL-dominant progression, and the primary outcome was the difference in associated factors between two groups. Higher pre-treatment and mean IOP, greater lamina cribrosa curvature index (LCCI), and younger age were more significantly associated with the RNFL-dominant progression group than the GCIPL-dominant progression group. When adjusting for mean IOP, age, LCCI, and microvascular dropout (MVD), only pre-treatment IOP was significantly associated with the RNFL-dominant progression group. However, when adjusting for pre-treatment IOP, age, LCCI, and MVD, both higher mean IOP and greater LCCI were significantly associated with RNFL-dominant progression. In conclusion, pre-treatment and mean IOP and LCCI were more strongly associated with the RNFL-dominant progression group than the GCIPL-dominant progression group. In contrast, age, peripapillary choroidal microvascular dropout, and systolic and diastolic blood pressures tended to damage the GCIPL predominantly rather than the RNFL. Therefore, our findings suggest the potential to set different treatment targets and identify various treatment methods for each groupope

Systemic Arterial Stiffness Is Associated With Structural Progression in Early Open-Angle Glaucoma

Purpose: The purpose was to identify association between systemic arterial stiffness predicted by brachial-ankle pulse wave velocity (PWV) and initial location of structural progression in early open-angle glaucoma. Methods: Patients with early open-angle glaucoma who underwent PWV measurements were subjected to a retrospective review of medical records. A total of 160 eyes of 160 patients were subjected to analyses. Patients were categorized into three PWV groups. Structural progression was determined using event-based analysis of the Guided Progression Analysis software of Cirrus optical coherence tomography. Results: Thirty-eight patients had a PWV of 1400 cm/s or less on both the left and right sides (low PWV, 39.5% females, 53.9 ± 8.8 years old), and 46 patients showed a PWV of 1800 cm/s or more on either side (high PWV; 54.3% females, 71.3 ± 5.8 years old). The rest of the patients had an intermediate PWV (n = 76, 50.0% females, 59.8 ± 8.6 years old). Among patients who showed progression in 69.3 ± 41.5 months, macular ganglion cell-inner plexiform layer (mGCIPL) loss preceded peripapillary retinal nerve fiber layer (ppRNFL) loss in 86.7% of high PWV group (n = 15, 60.0% females, 70.0 ± 6.0 years old) in comparison with 26.7% of the low PWV group (P = 0.002). The PWV was significantly higher in patients whose structural progression was first observed at mGCIPL (1744.1 ± 347.7 cm/s) than patients whose initial location was ppRNFL (1452.0 ± 201.0 cm/s; P = 0.012). A high PWV was associated with increased likelihood of structural progression at mGCIPL (odds ratio, 7.484; 95% confidence interval, 1.212-49.196; P = 0.030) among patients who showed progression. Conclusions: PWV is a significant predictor of the location of structural progression in open-angle glaucoma. Vascular insufficiency may be an important aspect in the pathogenesis of glaucoma.ope

TUBB3 M323V Syndrome Presents with Infantile Nystagmus

Variants in the TUBB3 gene, one of the tubulin-encoding genes, are known to cause congenital fibrosis of the extraocular muscles type 3 and/or malformations of cortical development. Herein, we report a case of a 6-month-old infant with c.967A>G:p.(M323V) variant in the TUBB3 gene, who had only infantile nystagmus without other ophthalmological abnormalities. Subsequent brain magnetic resonance imaging (MRI) revealed cortical dysplasia. Neurological examinations did not reveal gross or fine motor delay, which are inconsistent with the clinical characteristics of patients with the M323V syndrome reported so far. A protein modeling showed that the M323V mutation in the TUBB3 gene interferes with αβ heterodimer formation with the TUBA1A gene. This report emphasizes the importance of considering TUBB3 and TUBA1A tubulinopathy in infantile nystagmus. A brain MRI should also be considered for these patients, although in the absence of other neurologic signs or symptoms.ope

Peripapillary choroidal microvasculature dropout is associated with poor prognosis in optic neuritis

Purpose: To identify peripapillary choroidal microvasculature dropout (MvD) in eyes with optic neuritis and its association with longitudinal changes in retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIP) thicknesses following diagnosis. Methods: A total of 48 eyes with optic neuritis was evaluated to identify the presence of peripapillary choroidal MvD, defined as a focal capillary loss with no visible microvascular network in choroidal layer, using optical coherence tomography (OCT) angiography (OCTA). Patients were divided based on the presence of MvD. OCT and standard automated perimetry (SAP) conducted at 1, 3 and 6 months follow-up were analyzed. Results: MvD was identified in 20 of 48 eyes (41.7%) with optic neuritis. MvD was most commonly found in the temporal quadrant (85.0%), and peripapillary retinal vessel density in the temporal quadrant was significantly lower in eyes with MvD (P = 0.012). At 6 months follow-up, optic neuritis eyes with MvD showed significantly thinner GCIP in superior, superotemporal, inferior and inferotemporal sectors (P<0.05). No significant difference was noted in SAP parameters. The presence of MvD was significantly associated with thinner global GCIP thickness at 6 months follow-up (OR 0.909, 95% CI 0.833-0.992, P = 0.032). Conclusion: Optic neuritis showed peripapillary choroidal microvascular impairment in the form of MvD. MvD was associated with structural deterioration at macular GCIP. Further studies are necessary to identify the causal relationship between microvascular impairment and retinal nerve fiber layer damage in optic neuritis. Copyright: © 2023 Lee et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ope