News

Visit of Anders Ynnerman 24./25. January

We are looking forward to the visit of Anders Ynnerman, clearly the key visualization researcher in Sweden and in particular the leading medical visualization expert there. He is known among others for his work on interactive exploration of large medical data using modern surface and touch technology, see his popular TED talk.

Anders leads the famous visualization center in Norrköping, closely collaborates with the imaging center in Linköping and recently co-organized the Eurographics Workshop on Visual Computing in Biology in Medicine. Anders visits both, the visual computing and the visualization group and gives a talk in the visual computing colloquium (Link: http://wwwisg.cs.uni-magdeburg.de/visual/index.php?article_id=163) series on 1:15 pm on Friday early afternoon.

Good start into the New Year

Our journal submission “The LiverSurgeryTrainer – Training of Computer-Based Planning in Liver Surgery” was accepted at the International Journal of Computer Assisted Radiology and Surgery. The paper with Jeanette Mönch as Principal author documents as a summary our long-term efforts to create a software system for case-based training, including expert opinions, intraoperative videos and resection proposals. Surgeons may assess the operability and resectability and compare their decisions with expert decisions and their explanations. Many thanks for the cooperation to Fraunhofer MEVIS, in particular Christian Hansen and Prof. Karl Oldhafer, our major medical partner. We are also thankful to many other surgeons for providing the necessary feedback.

MedVis-Award 2012: The winner is Rocco!

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.

Benjamin Köhler defended his Master thesis on “Vortex extraction in PC-MRA data

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.

VisGroup@VCBM

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.

VisGroup@VisWeek

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).

Kolloquium Medizintechnik

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.

Visual Computing research seminar

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.