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Workshops on Image processing for the medicine, 2016

作者： Dinse, Juliane Schäfer, Andreas Bazin, Pierre-Louis Weiskopf, Nikolaus Max Planck Institute of Cognitive and Brain Science Leipzig Germany Simulation and Graphics Department Faculty of Computer Science Otto-von-Guericke University Magdeburg Germany Wellcome Trust Center for Neuroimaging Institute for Neurology University College London London United Kingdom

ISBN: (纸本)9783662494646

Partial voluming is a known problem in medical imaging. It occurs at high contrast edges between different structures. Image segmentation tasks can account for this type of effect to a certain degree, but residual intensity effects in structures located further away from affected edges remain. This paper focuses on partial volume (PV) effects at the interface between gray matter and cerebrospinal fluid in the brain when imaged using high-field magnetic resonance imaging (MRI). Here, we use cortical surface normals for spatially locating PV-induced effects on MRI measures of cortical microstructure. We demonstrate that especially in very narrow sulcal banks of the cortex, PV effects significantly influence cortical MRI intensities, but only up to a certain cortical depth. The method allows to investigate and better understand PV effects in the cortex to identify locations in which the MRI intensities can be fully trusted. The results may prove to be useful for future PV correction methods in brain segmentation. Also, cortical area studies may benefit from better PV estimation in order to yield more precise and confiding results on microstructure and areal extent. © Springer-Verlag Berlin Heidelberg 2016.

关键词： Magnetic resonance imaging

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Feature lines for illustrating medical surface models: Mathematical background and survey 3rd

Feature lines for illustrating medical surface models: Mathe...

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3rd International Workshop on Visualization in Medicine and Life Sciences, VMLS 2013

作者： Lawonn, Kai Preim, Bernhard Institute of Computational Visualistics University of Koblenz - Landau Koblenz Germany Faculty of Computer Science Department of Simulation and Graphics Otto-von-Guericke University Magdeburg Magdeburg Germany

ISBN: (纸本)9783319245218

This paper provides a tutorial and survey for a specific kind of illustrative visualization technique: feature lines. We examine different feature line methods. For this, we provide the differential geometry behind these concepts and adapt this mathematical field to the discrete differential geometry. All discrete differential geometry terms are explained for triangulated surface meshes. These utilities serve as basis for the feature line methods. We provide the reader with all knowledge to re-implement every feature line method. Furthermore, we summarize the methods and suggest a guideline for which kind of surface which feature line algorithm is best suited. Our work is motivated by, but not restricted to, medical and biological surface models. © Springer International Publishing Switzerland 2016.

关键词： Surveys

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The effect of implementing cognitive load theory-based design principles in virtual reality simulation training of surgical skills: a randomized controlled trial

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Advances in simulation 2016年第1期1卷 1-8页

作者： Andersen, Steven Arild Wuyts Mikkelsen, Peter Trier Konge, Lars Cayé-Thomasen, Per Sørensen, Mads Sølvsten Department of Otorhinolaryngology—Head and Neck Surgery Rigshospitalet Blegdamsvej 9 Copenhagen 2100 Denmark Computer Graphics Lab The Alexandra Institute Aabogade 34 Aarhus 8200 Denmark Copenhagen Academy for Medical Education and Simulation Blegdamsvej 9 The Capital Region of Denmark Copenhagen 2100 Denmark

Background: Cognitive overload can inhibit learning, and cognitive load theory-based instructional design principles can be used to optimize learning situations. This study aims to investigate the effect of implementing cognitive load theory-based design principles in virtual reality simulation training of mastoidectomy. Methods: Eighteen novice medical students received 1 h of self-directed virtual reality simulation training of the mastoidectomy procedure randomized for standard instructions (control) or cognitive load theory-based instructions with a worked example followed by a problem completion exercise (intervention). Participants then completed two post-training virtual procedures for assessment and comparison. Cognitive load during the post-training procedures was estimated by reaction time testing on an integrated secondary task. Final-product analysis by two blinded expert raters was used to assess the virtual mastoidectomy performances. Results: Participants in the intervention group had a significantly increased cognitive load during the post-training procedures compared with the control group (52 vs. 41 %, p = 0.02). This was also reflected in the final-product performance: the intervention group had a significantly lower final-product score than the control group (13.0 vs. 15.4, p < 0.005). Conclusions: Initial instruction using worked examples followed by a problem completion exercise did not reduce the cognitive load or improve the performance of the following procedures in novices. Increased cognitive load when part tasks needed to be integrated in the post-training procedures could be a possible explanation for this. Other instructional designs and methods are needed to lower the cognitive load and improve the performance in virtual reality surgical simulation training of novices. © 2016, The Author(s).

关键词： Cognitive load theory Mastoidectomy Surgical skills training Temporal bone surgery Virtual reality simulation

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Bilateral Depth Filtering for Enhanced Vessel Reformation 16

Bilateral Depth Filtering for Enhanced Vessel Reformation

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16th Eurographics Conference on Visualization, EuroVis 2014

作者： Kretchmer, Jan Preim, Bernhard Stamminger, Marc Department of Computer Graphics Fau Erlangen Germany Siemens Healthcare Computed Tomography Forchheim Germany Department of Simulation and Graphics Otto-von-Guericke University of Magdeburg Germany

ISBN: (纸本)9783905674699

Curved Planar Reformation is a powerful visualization technique for the diagnosis of vascular diseases. It allows an accurate centerline-driven investigation of vessel lumen while providing valuable anatomical context. Extended methods like Multipath Curved Planar Reformation, Centerline Reformation or Curved Surface Reformation provide additional flexibility by condensing entire vascular systems into rotatable views. Unfortunately, all these methods produce depth discontinuities because they operate in a projective fashion. While large discontinuities provide valuable hints about distinct anatomical contexts, small discontinuities, which frequently arise, have distracting effects on the visualization result and do not contribute significant information. In this paper we present a bilateral filtering technique which allows to selectively remove depth discontinuities without affecting discontinuities that carry information. The presented approach significantly improves the quality of vessel reformations, can be applied at interactive frame rates and is orthogonal to existing methods. © The Eurographics Association 2014.

关键词： Diagnosis

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Information technology for communities: Development of a web-based 3D visualization and cluster computing system for disaster management

Information technology for communities: Development of a web...

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121st ASEE Annual Conference and Exposition: 360 Degrees of Engineering Education

作者： Jin, Ge Dekker, Gerald A. Moreland, John Nicolai, Barbara Jean Department of Computer Information Technology and Graphics College of Technology Purdue University Calumet United States Department of Computer Science Purdue University Calumet United States Center for Innovation through Visualization and Simulation Purdue University Calumet United States

Natural disasters can cause huge loss of life, enormous amounts of property damage to the local communities. Although it is impossible to avoid the natural disasters, human sufferings can be reduced by adopting information technologies to the disaster response missions. In this paper, a web-based 3D visualization and cluster computing system was developed to facilitate and expedite the resource distribution process during a disaster. Our disaster management system utilizes state-of- The- Art computing cluster with 16 nodes of Intel Xeon-E5 processors (16 cores per node) to process the emergency supply requests from the disaster victims, and calculate the optimal resource distribution routes with the consideration of the damaged transportation infrastructures. The optimized resource distribution problem was solved with distributed all pair shortest path algorithm and the vehicle routing algorithm. The web-based 3D visualization system was developed with Google earth engine to display the disaster areas, affected households and resource distribution routes. The computation result from the cluster was automatically uploaded to the web-based 3D visualization system, enabling the users to immediately see the optimal resource distribution routes in a virtual 3D environment. The visualization system is flexible and can be easily adapted to a Google earth enabled mobile devices, desktop monitors as well as a Cave automatic virtual environment (CAVE). A historical disaster data from the Northwest Indiana was used to demonstrate the functionalities of the developed system. © American Society for Engineering Education, 2013.

关键词： Virtual reality

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From individual to population: Challenges in medical visualization

Mathematics and Visualization

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Mathematics and Visualization 2014年 37卷 265-282页

作者： Botha, C.P. Preim, B. Kaufman, A.E. Takahashi, S. Ynnerman, A. Vxlabs Somerset WestSA South Africa Department of Simulation and Graphics University of Magdeburg Magdeburg Germany Department of Computer Science Stony Brook University NY United States Graduate School of Frontier Sciences The University of Tokyo Tokyo Japan Norrköping Visualization and Interaction Studio Linköping University Linköping Sweden

Due to continuing advances in medical imaging technology, and in medicine itself, techniques for visualizing medical image data have become increasingly important. In this chapter, we present a brief overview of the past 30 years of developments in medical visualization, after which we discuss the research challenges that we foresee for the coming decade. © 2014, Springer-Verlag London.

关键词： Visualization

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Visually guided mesh smoothing for medical applications

Visually guided mesh smoothing for medical applications

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3rd Eurographics Workshop on VisualComputing in Biology and Medicine, EG VCBM 2012

作者： Moench, Tobias Kubisch, Christoph Lawonn, Kai Westermann, Ruediger Preim, Bernhard Department of Simulation and Graphics University of Magdeburg Germany Computer Science Department Technische Universitaet Muenchen Germany

ISBN: (纸本)9783905674385

Surface models derived from medical image data often exhibit artifacts, such as noise and staircases, which can be reduced by applying mesh smoothing filters. Usually, an iterative adaption of smoothing parameters to the specific data and continuous re-evaluation of accuracy and curvature is required. Depending on the number of vertices and the filter algorithm, computation time may vary strongly and interfere with an interactive mesh generation procedure. In this paper, we present an approach to improve the handling of mesh smoothing filters. Based on a GPU mesh smoothing implementation, model quality is evaluated in real-time and provided to the user as quality graphs to support the mental optimization of input parameters. Moreover, this framework is used to find optimal smoothing parameters automatically and to provide data-specific parameter suggestions. © The Eurographics Association 2012.

关键词： Mesh generation

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Automatic detection and recognition of engineered nanoparticles in SEM images

Automatic detection and recognition of engineered nanopartic...

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17th Annual Workshop on Vision, Modeling and Visualization, VMV 2012

作者： Kockentiedt, S. Toennies, K. Gierke, E. Dziurowitz, N. Thim, C. Plitzko, S. Department of Simulation and Graphics Faculty of Computer Science University of Magdeburg Germany Federal Institute for Occupational Safety and Health Germany

ISBN: (纸本)9783905673951

Engineered nanoparticles have gained importance in recent years and will do so in the future, but their potential toxicity remains an open question. To better understand their effects on the human body, it is necessary to determine their concentration in ambient air. We propose a method to automatically detect nanoparticles in SEM images and differentiate engineered particles from other particles common in ambient air. The method reached Gmeans of 0.985, 0.779 and 0.820 for the classification against non-engineered particles of silver, titanium dioxide and zinc oxide respectively. This is comparable to manual classification. © 2012 The Eurographics Association.

关键词： Nanoparticles

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Reliable adaptive modelling of vascular structures with non-circular cross-sections

Reliable adaptive modelling of vascular structures with non-...

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14th Eurographics Conference on Visualization 2012, EuroVis 2012

作者： Kretschmer, Jan Beck, Thomas Tietjen, Christian Preim, Bernhard Stamminger, Marc Computer Graphics Group University of Erlangen Germany Institute for Anthropomatics Karlsruhe Institute of Technology Germany Siemens Healthcare Sector Computed Tomography Forchheim Germany Department of Simulation and Graphics Otto-von-Guericke University of Magdeburg Germany

Accurate visualizations of complex vascular structures are essential for medical applications, such as diagnosis, therapy planning and medical education. Vascular trees are usually described using centerlines, since they capture both the topology and the geometry of the vasculature in an intuitive manner. State-of-the-art vessel segmentation algorithms deliver vascular outlines as free-form contours along the centerline, since this allows capturing anatomical pathologies. However, existing methods for generating surface representations from centerlines can only cope with circular outlines. We present a novel model-based technique that is capable of generating intersection-free surfaces from centerlines with complex outlines. Vascular segments are described by local signed distance functions and combined using Boolean operations. An octree-based surface generation strategy automatically computes watertight, scale-adaptive meshes with a controllable quality. In contrast to other approaches, our method generates a reliable representation that guarantees to capture all vessels regardless of their size. © 2012 The Author(s).

关键词： Medical applications

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Automating transfer function design with valley cell-based clustering of 2D density plots

Automating transfer function design with valley cell-based c...

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14th Eurographics Conference on Visualization 2012, EuroVis 2012

作者： Wang, Yunhai Zhang, Jian Lehmann, Dirk J. Theisel, Holger Chi, Xuebin Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences China Computer Network Information Center Chinese Academy of Sciences China Department of Simulation and Graphics University of Magdeburg Germany

Two-dimensional transfer functions are an effective and well-accepted tool in volume classification. The design of them mostly depends on the user's experience and thus remains a challenge. Therefore, we present an approach in this paper to automate the transfer function design based on 2D density plots. By exploiting their smoothness, we adopted the Morse theory to automatically decompose the feature space into a set of valley cells. We design a simplification process based on cell separability to eliminate cells which are mainly caused by noise in the original volume data. Boundary persistence is first introduced to measure the separability between adjacent cells and to suitably merge them. Afterward, a reasonable classification result is achieved where each cell represents a potential feature in the volume data. This classification procedure is automatic and facilitates an arbitrary number and shape of features in the feature space. The opacity of each feature is determined by its persistence and size. To further incorporate the user's prior knowledge, a hierarchical feature representation is created by successive merging of the cells. With this representation, the user is allowed to merge or split features of interest and set opacity and color freely. Experiments on various volumetric data sets demonstrate the effectiveness and usefulness of our approach in transfer function generation. © 2012 The Author(s).

关键词： Cells

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