News

• 

• 

Rocco Gasteiger’s work on the visual exploration of cerebral blood flow was selected for the first price from 17 submissions to this year’s Karl-Heinz Höhne Award. At the photos, Dr. Stefan Zachow from Zuse-Institute Berlin who was the head of the selection committee (together with Prof. Dorit Merhof), awards the price. Rocco was the first author of two related IEEE TVCG papers exploring features of cerebral blood flow in the presence of cerebral aneuryms.

Besides his numerous own ideas, concepts, and implementations, he carefully collaborated with colleagues and other groups. He integrated important works from our partners in flow simulation (Gabor Janiga, Dominique Thevenin), from our medical partners (Oliver Beuing, Martin Skalej), our friends from Eindhoven (Roy van Pelt, Anna Vilanova) as well our colleagues from the visual computing group (Dirk Lehmann, Holger Theisel) and finally, Rocco very effectively teamed up with Mathias in our group for many years now.

• 

• 

Ben developed tools to process these time-dependent blood flow data, searching for topologically interesting regions, like those with high helicality and vorticity. The visual exploration of blood flow in the human Aorta is then focussed on such regions.

The work was carried out in a close collaboration with the Heart Center in Leipzig (Prof. Gutberlet) where such data are acquired to assess mitral valve defects, congenital heart diseases and other pathologies. Ben did an extraordinary job in understanding this imaging technique and the resulting data as well as in the development of a mathematically sound basis for the exploration.

His written thesis, like the oral defense was assessed with the highest possible grade.

• 

• 

This year’s Eurographics Workshop on Visual Computing in Biology and Medicine (www.vcbm.org) took place at the Visualization Center in Norrköping, Sweden. From the 17 full paper presentations, three were given by our group.

Katja Mogalle presented a method for automatic label placement in 2D image slices for the reading of radiological images. Based on a case study, the main constraints for label placement have been analyzed and are evaluated for finding valid and suitable label positions.

Steffen Oeltze described a volume rendering approach for visualizing protein patterns of 3D toponome data. The utility provides multiple coordinated views and techniques for interacting with the 3D view in an exploratory analysis.

Tobias Mönch developed a framework, which allows to perform mesh smoothing and model quality estimation in real-time. Based on an OpenGL implementation, suggestions for optimal smoothing parameters may determined and used to simply the use of mesh smoothing filters. This paper has been selected as one of the three best papers and has been invited for publication in Computer Graphics Forum.

• 

• 

• 

Rocco Gasteiger lead a team that came up with a successful submission for this years IEEE VisWeek. The paper “Automatic Detection and Visualization of Qualitative Hemodynamic Characteristics in Cerebral Aneurysms” is a joint work with the Visual Computing group of the University of Magdeburg, the Biomedical Engineering group of the Technical University of Eindhoven (in particular Dr. Anna Vilanova and Dr. Roy van Pelt), the department of Fluid Dynamics and Thermodynamics at the University of Magdeburg, and the University Hospital Magdeburg. With this method, important hemodynamic characteristics such as the inflow jet and the impingement zone of blood flow in cerebral aneurysms (see the images) can be extracted and visualized automatically and reliably. The paper will appear in the IEEE Transactions on Visualization and Graphics (TVCG).

• 

Prof. Thomas Flohr, Heads of CT Physics and Application Development SIEMES Healthcare Erlangen hält am 19. Juli um 15.30 Uhr im Geb. 09, Raum 211 im Rahmen des Kolloquiums Medizintechnik einen Vortrag zum Thema “Neue Entwicklungen in der CT-Technologie”.

Abstract: Die Computertomographie hat sich seit ihrer klinischen Einführung im Jahre 1976 rasant entwickelt – sie ist heute das Ar-beitspferd in der Radiologie und aus dem klinischen Alltag nicht mehr wegzudenken. Mit modernen Computertomogra-phen können dreidimensionale Bilder der Anatomie des Patienten in wenigen Sekunden mit einer räumlichen Auflösung von 0.3 mm aufgenommen werden. Dieser Vortrag geht auf die Grundlagen und auf die Geschichte der Computertomographie ein – von den ersten Schädel-scannern bis zu modernen Mehrschicht-CT Geräten – und er gibt einen Einblick in neue Entwicklungen auf diesem Gebiet. Durch bessere zeitliche Auflösung aufgrund immer schnellerer Rotation wurden neue Anwendungsgebiete für die CT er-schlossen, wie die Untersuchung des Herzens und der Herzkranzgefäße. In vielen Fällen kann die Herz-CT heute den invasi-ven Herzkatheter ersetzen. Ein wesentlicher Entwicklungsschritt war hier die Einführung der Dual-Source CT Technologie im Jahre 2005. Eine zweite Entwicklungsrichtung betrifft die Ergänzung der anatomischen Bildinformationen um funktionelle Aussage-kraft. Mit neuen Untersuchungstechniken wie der CT-Perfusionsbildgebung oder der Dual Energy CT lässt sich z. B. bei modernen Krebstherapien durch die Visualisierung metabolischer Prozesse eine Prognose für das Therapieansprechen zeitnah abgeben. Die dritte große Stoßrichtung ist die Reduktion der Strahlendosis. Die Dosisbelastung ist zu einem großen öffentlichen Thema auch außerhalb der Medizin geworden, auf das alle Großgerätehersteller reagiert haben. Die Gefahr, langfristig ge-sundheitliche Schäden durch eine CT-Untersuchung davonzutragen, ist sehr gering. Wenn eine CT-Untersuchung medizi-nisch indiziert ist, übertrifft ihr Nutzen das mögliche Risiko bei weitem. Dennoch versuchen alle Hersteller, die Dosis mit verschiedenen Techniken so weit wie möglich zu reduzieren.

In the course of the Visual Computing research seminar Christian Dick from the visualization group of TU Munich will give a talk with subsequent discussion about the topic Computational Steering for Implant Planning in Orthopedics on Friday, 22/06/2012.

Abstract: The selection of a patient-specific optimal implant with respect to shape, size, and position during preoperative planning requires the consideration of geometrical and biomechanical criteria. In particular, the selected implant should lead to a physiological stress distribution in the bone, in order to avoid a degeneration of bone tissue and eventually a loosening of the implant or a fracturing of the bone.

In this talk, I present the first planning system that allows for an implant selection based on the patient-specific prediction of the stress distribution. The system provides a virtual 3D planning environment, where the physician can interactively insert implants into the bone. During this process, the system insantaneously computes and visualizes the resulting stress distribution. In my talk, I first address the interactive simulation of the stress distribution by means of a highly efficient hexahedral multigrid finite element method, including the implementation of this method on the GPU using the CUDA computing API. I then discuss the interactive visualization of the resulting 3D stress tensor fields, including the comparative visualization of these fields to allow for a clear rating of an implant with respect to stress shielding. Finally, I present methods for the interactive visualization of the spatial distances between bone and implant that support the validation of the specific geometrical criteria. All simulation and visualization methods have been implemented on the GPU to exploit its massive computing power and memory bandwidth.

Last week, we visited our dear fellow visualization researchers Roy van Pelt and Ralph Brecheisen, who successfully defended their PhD-theses in Eindhoven, Netherlands. Both presented their outstanding work in the fields of illustrative flow visualization (Real-time Illustrative Visualization of Cardiovascular Hemodynamics – Roy van Pelt) and DTI visualization (Visualization of Uncertainty in Fiber Tracking based on Diffusion Tensor Imaging – Ralph Brecheisen). We also witnessed the interesting formal procedure of defending a thesis in the Netherlands.

Vortrag im Rahmen des “User Interface Kolloquiums” am 31. Mai 2012 um 13.15 Uhr im Raum 29-301: Dr. Felix Ritter (Fraunhofer MEVIS Bremen): “Advancing the User Experience in Reading of Medical Images”

Abstract: The analysis of patient data acquired by current image modalities offers previously unattained opportunities for diagnosis, therapy support, and therapy assessment. While image analysis methods have progressed far in recent years, the interaction and user experience in reading these data has not received the same amount of care. The talk will present concepts of the Fraunhofer MEVIS institute that try to challenge several aspects of conventional reading and handling of medical images for diagnosis and intra-operative inspection.

Vita: Felix Ritter is head of visualization and human computer interaction at Fraunhofer MEVIS, Bremen, Germany. His research interests include medical visualization, perception, and human factors in visualization. His current work is focused on the usability of medical workstations and the development of intra-operative user interfaces. He received a Ph.D. in Computer Science from the University of Magdeburg, Germany, in 2005.

We are happy to have two guests this week. Charl Botha (TU Delft) came already last week and stays for five weeks as a guest professor. Charl looks at our projects and gives advice, he give a talk in the visual computing colloquium on April 20 and work with Bernhard on the MedVis-book.

Peter Kohlmann, senior researcher from Fraunhofer MEVIS will visit us on Thursday, exchanging particularly with respect to perfusion data and blood flow data. Peter will give a talk in the Medical Technology colloquium series on April 19.

The long and fruitful collaboration between the Visualization group and Fraunhofer MEVIS Bremen lead to another nice success. Benjamin Köhler, currently student assistant in our group, will be awarded with the BVM-Award from the German medical image processing society, acknowledging his extraordinary Bachelor thesis. The thesis was based on an internship at Fraunhofer MEVIS Bremen, supervised jointly by Dr. Jan Klein (Fraunhofer MEVIS) and Bernhard Preim. Ben’s work was integrated in the MEVIS activities on the reconstruction of HARDI data, a relatively new kind of data for analysing human white matter. Ben’s work was an extraordinarily deep analysis of fiber reconstruction with global optimization methods. The award will be presented at the BVM workshop where Ben will present the results of his current research on visualizing blood flow data and now may also report on his award-winning work.