Background In this work,we focus on the label layout problem:specifying the positions of overlaid virtual annotations in Virtual/Augmented Reality scenarios.Methods Designing a layout of labels that does not violate d...Background In this work,we focus on the label layout problem:specifying the positions of overlaid virtual annotations in Virtual/Augmented Reality scenarios.Methods Designing a layout of labels that does not violate domain-specific design requirements,while at the same time satisfying aesthetic and functional principles of good design,can be a daunting task even for skilled visual designers.Presenting the annotations in 3D object space instead of projection space,allows for the preservation of spatial and depth cues.This results in stable layouts in dynamic environments,since the annotations are anchored in 3D space.Results In this paper we make two major contributions.First,we propose a technique for managing the layout and rendering of annotations in Virtual/Augmented Reality scenarios by manipulating the annotations directly in 3D space.For this,we make use of Artificial Potential Fields and use 3D geometric constraints to adapt them in 3D space.Second,we introduce PartLabeling:an open source platform in the form of a web application that acts as a much-needed generic framework allowing to easily add labeling algorithms and 3D models.This serves as a catalyst for researchers in this field to make their algorithms and implementations publicly available,as well as ensure research reproducibility.The PartLabeling framework relies on a dataset that we generate as a subset of the original PartNet dataset consisting of models suitable for the label management task.The dataset consists of 10003D models with part annotations.展开更多
目的:探究双参数3D动脉自旋标记灌注成像(3D A SL)技术联合磁共振血管成像(MRA)在单侧大脑中动脉(MCA)闭塞后的侧支循环代偿评估中的应用价值。方法:收集单侧MCA闭塞的患者38例,测定双侧MCA供血区脑血流量(CBF),进行统计学分析。结果:单...目的:探究双参数3D动脉自旋标记灌注成像(3D A SL)技术联合磁共振血管成像(MRA)在单侧大脑中动脉(MCA)闭塞后的侧支循环代偿评估中的应用价值。方法:收集单侧MCA闭塞的患者38例,测定双侧MCA供血区脑血流量(CBF),进行统计学分析。结果:单侧MCA闭塞患者患侧CBF在PLD 1525ms组与2525ms组具有显著统计学差异,而健侧两组之间无统计学差异。结论:双参数3D ASL联合3D-TOF-MRA在评估单侧MCA闭塞后侧支循环代偿评估中具有很重要的临床价值。展开更多
文摘Background In this work,we focus on the label layout problem:specifying the positions of overlaid virtual annotations in Virtual/Augmented Reality scenarios.Methods Designing a layout of labels that does not violate domain-specific design requirements,while at the same time satisfying aesthetic and functional principles of good design,can be a daunting task even for skilled visual designers.Presenting the annotations in 3D object space instead of projection space,allows for the preservation of spatial and depth cues.This results in stable layouts in dynamic environments,since the annotations are anchored in 3D space.Results In this paper we make two major contributions.First,we propose a technique for managing the layout and rendering of annotations in Virtual/Augmented Reality scenarios by manipulating the annotations directly in 3D space.For this,we make use of Artificial Potential Fields and use 3D geometric constraints to adapt them in 3D space.Second,we introduce PartLabeling:an open source platform in the form of a web application that acts as a much-needed generic framework allowing to easily add labeling algorithms and 3D models.This serves as a catalyst for researchers in this field to make their algorithms and implementations publicly available,as well as ensure research reproducibility.The PartLabeling framework relies on a dataset that we generate as a subset of the original PartNet dataset consisting of models suitable for the label management task.The dataset consists of 10003D models with part annotations.
文摘目的探讨3D动脉自旋标记成像(ASL)全脑灌注成像技术在颅脑肿瘤中的应用价值。方法 28例脑肿瘤(其中胶质瘤12例,脑膜瘤5例,转移瘤7例,脉络丛乳头状瘤1例,髓母细胞瘤1例,淋巴瘤1例,胆脂瘤1例)患者均经手术病理证实。测量3D ASL血流灌注图像肿瘤实质部分最大肿瘤血流量(TBFmax)和对侧半球、白质、灰质的脑血流量(CBF),分析不同脑肿瘤MRI灌注表现;通过MRI常规扫描序列做出脑肿瘤初步诊断,联合3D ASL灌注成像技术再次诊断后,将两种方法的诊断符合率进行比较。结果 3D ASL灌注成像技术所得rCBF定量参数在低级别胶质瘤与高级别胶质瘤、脑膜瘤、转移瘤之间差异均有统计学意义(P<0.05),而高级别胶质瘤、脑膜瘤和转移瘤三者之间差异无统计学意义(P>0.05)。通过常规MRI扫描得出的脑肿瘤定性诊断的符合率为82.1%,联合应用3D ASL灌注成像技术的诊断符合率为89.2%,两种方法差异无明显统计学意义(P>0.05)。结论 3D ASL能定量反映肿瘤微循环的灌注情况,与MRI常规序列联合应用,可作为其重要补充,对脑肿瘤的定性诊断以及胶质瘤的术前分级有重要参考价值。
文摘目的:探究双参数3D动脉自旋标记灌注成像(3D A SL)技术联合磁共振血管成像(MRA)在单侧大脑中动脉(MCA)闭塞后的侧支循环代偿评估中的应用价值。方法:收集单侧MCA闭塞的患者38例,测定双侧MCA供血区脑血流量(CBF),进行统计学分析。结果:单侧MCA闭塞患者患侧CBF在PLD 1525ms组与2525ms组具有显著统计学差异,而健侧两组之间无统计学差异。结论:双参数3D ASL联合3D-TOF-MRA在评估单侧MCA闭塞后侧支循环代偿评估中具有很重要的临床价值。
