Quantitative analysis of digital images requires detection and segmentation of the borders of the object of interest. Accurate segmentation is required for volume determination, 3D rendering, radiation therapy, and su...Quantitative analysis of digital images requires detection and segmentation of the borders of the object of interest. Accurate segmentation is required for volume determination, 3D rendering, radiation therapy, and surgery planning. In medical images, segmentation has traditionally been done by human experts. Substantial computational and storage requirements become especially acute when object orientation and scale have to be considered. Therefore, automated or semi-automated segmentation techniques are essential if these software applications are ever to gain widespread clinical use. Many methods have been proposed to detect and segment 2D shapes, most of which involve template matching. Advanced segmentation techniques called Snakes or active contours have been used, considering deformable models or templates. The main purpose of this work is to apply segmentation techniques for the definition of 3D organs (anatomical structures) when big data information has been stored and must be organized by the doctors for medical diagnosis. The processes would be implemented in the CT images from patients with COVID-19.展开更多
目的探讨在采用全内技术进行的前交叉韧带重建中,使用FiberTape缝线内支架加固移植的腘绳肌腱能否进一步提高患者的膝关节功能、活动度,以及减轻患者术后疼痛,同时降低移植物失败率。方法对照组为采用无线带内支架加固的全内技术进行腘...目的探讨在采用全内技术进行的前交叉韧带重建中,使用FiberTape缝线内支架加固移植的腘绳肌腱能否进一步提高患者的膝关节功能、活动度,以及减轻患者术后疼痛,同时降低移植物失败率。方法对照组为采用无线带内支架加固的全内技术进行腘绳肌腱移植治疗前交叉韧带断裂的30(男21,女9)例患者,年龄(27.95±6.29)岁。内支架组为采用有线带内支架加固的全内技术进行腘绳肌腱移植治疗前交叉韧带断裂的30(男22,女8)例患者,年龄(27.05±7.20)岁。分别对所有患者的术前及术后6个月进行Tegner评分、Lysholm评分和国际膝关节文献委员会(IKDC)主观膝关节评估表评分,以及术后3 d的视觉模拟量表(VAS)疼痛评分,同时记录各组的移植物失败率。组内、组间比较分别采用配对样本t检验和独立样本t检验。结果两组术前Tegner评分、Lysholm评分和IKDC评分差异均无统计学差异(P>0.05),两组术后6个月的上述评分较术前均显著增加(均P<0.001)。两组术后6个月的Tegner评分差异无统计学意义(P=0.228),内支架组术后6个月的Lysholm评分、IKDC评分略高于对照组,术后3 d VAS疼痛评分、移植物失败率稍低于对照组,但差异无统计学意义(均P>0.05)。结论有或无线带内支架加固的全内技术进行腘绳肌腱移植治疗前交叉韧带断裂患者的效果相当,但线带内支架的联合应用在改善患者膝关节功能、减轻患者术后疼痛方面展现出一定的潜在优势。展开更多
In this study the medium-term response of beach profiles was investigated at two sites： a gently sloping sandy beach and a steeper mixed sand and gravel beach. The former is the Duck site in North Carolina, on the ea...In this study the medium-term response of beach profiles was investigated at two sites： a gently sloping sandy beach and a steeper mixed sand and gravel beach. The former is the Duck site in North Carolina, on the east coast of the USA, which is exposed to Atlantic Ocean swells and storm waves, and the latter is the Milford-on-Sea site at Christchurch Bay, on the south coast of England, which is partially sheltered from Atlantic swells but has a directionally bimodal wave exposure. The data sets comprise detailed bathymetric surveys of beach profiles covering a period of more than 25 years for the Duck site and over 18 years for the Milford-on-Sea site. The structure of the data sets and the data-driven methods are described. Canonical correlation analysis （CCA） was used to find linkages between the wave characteristics and beach profiles. The sensitivity of the linkages was investigated by deploying a wave height threshold to filter out the smaller waves incrementally. The results of the analysis indicate that, for the gently sloping sandy beach, waves of all heights are important to the morphological response. For the mixed sand and gravel beach, filtering the smaller waves improves the statistical fit and it suggests that low-height waves do not play a primary role in the medium-term morohological resoonse, which is primarily driven by the intermittent larger storm waves.展开更多
文摘Quantitative analysis of digital images requires detection and segmentation of the borders of the object of interest. Accurate segmentation is required for volume determination, 3D rendering, radiation therapy, and surgery planning. In medical images, segmentation has traditionally been done by human experts. Substantial computational and storage requirements become especially acute when object orientation and scale have to be considered. Therefore, automated or semi-automated segmentation techniques are essential if these software applications are ever to gain widespread clinical use. Many methods have been proposed to detect and segment 2D shapes, most of which involve template matching. Advanced segmentation techniques called Snakes or active contours have been used, considering deformable models or templates. The main purpose of this work is to apply segmentation techniques for the definition of 3D organs (anatomical structures) when big data information has been stored and must be organized by the doctors for medical diagnosis. The processes would be implemented in the CT images from patients with COVID-19.
文摘目的探讨在采用全内技术进行的前交叉韧带重建中,使用FiberTape缝线内支架加固移植的腘绳肌腱能否进一步提高患者的膝关节功能、活动度,以及减轻患者术后疼痛,同时降低移植物失败率。方法对照组为采用无线带内支架加固的全内技术进行腘绳肌腱移植治疗前交叉韧带断裂的30(男21,女9)例患者,年龄(27.95±6.29)岁。内支架组为采用有线带内支架加固的全内技术进行腘绳肌腱移植治疗前交叉韧带断裂的30(男22,女8)例患者,年龄(27.05±7.20)岁。分别对所有患者的术前及术后6个月进行Tegner评分、Lysholm评分和国际膝关节文献委员会(IKDC)主观膝关节评估表评分,以及术后3 d的视觉模拟量表(VAS)疼痛评分,同时记录各组的移植物失败率。组内、组间比较分别采用配对样本t检验和独立样本t检验。结果两组术前Tegner评分、Lysholm评分和IKDC评分差异均无统计学差异(P>0.05),两组术后6个月的上述评分较术前均显著增加(均P<0.001)。两组术后6个月的Tegner评分差异无统计学意义(P=0.228),内支架组术后6个月的Lysholm评分、IKDC评分略高于对照组,术后3 d VAS疼痛评分、移植物失败率稍低于对照组,但差异无统计学意义(均P>0.05)。结论有或无线带内支架加固的全内技术进行腘绳肌腱移植治疗前交叉韧带断裂患者的效果相当,但线带内支架的联合应用在改善患者膝关节功能、减轻患者术后疼痛方面展现出一定的潜在优势。
基金supported by the UK Natural Environment Research Council(Grant No.NE/J005606/1)the UK Engineering and Physical Sciences Research Council(Grant No.EP/C005392/1)the Ensemble Estimation of Flood Risk in a Changing Climate(EFRa CC)project funded by the British Council under its Global Innovation Initiative
文摘In this study the medium-term response of beach profiles was investigated at two sites： a gently sloping sandy beach and a steeper mixed sand and gravel beach. The former is the Duck site in North Carolina, on the east coast of the USA, which is exposed to Atlantic Ocean swells and storm waves, and the latter is the Milford-on-Sea site at Christchurch Bay, on the south coast of England, which is partially sheltered from Atlantic swells but has a directionally bimodal wave exposure. The data sets comprise detailed bathymetric surveys of beach profiles covering a period of more than 25 years for the Duck site and over 18 years for the Milford-on-Sea site. The structure of the data sets and the data-driven methods are described. Canonical correlation analysis （CCA） was used to find linkages between the wave characteristics and beach profiles. The sensitivity of the linkages was investigated by deploying a wave height threshold to filter out the smaller waves incrementally. The results of the analysis indicate that, for the gently sloping sandy beach, waves of all heights are important to the morphological response. For the mixed sand and gravel beach, filtering the smaller waves improves the statistical fit and it suggests that low-height waves do not play a primary role in the medium-term morohological resoonse, which is primarily driven by the intermittent larger storm waves.
