Search

Your search keyword '"Voelker, Martin"' showing total 38 results
Start Over Author "Voelker, Martin"
38 results on '"Voelker, Martin"'

1. A Research Framework for Virtual Reality Neurosurgery Based on Open-Source Tools

Author

Fiederer, Lukas D. J., Alwanni, Hisham, Völker, Martin, Schnell, Oliver, Beck, Jürgen, and Ball, Tonio

Subjects
Computer Science - Human-Computer Interaction, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

Fully immersive virtual reality (VR) has the potential to improve neurosurgical planning. For example, it may offer 3D visualizations of relevant anatomical structures with complex shapes, such as blood vessels and tumors. However, there is a lack of research tools specifically tailored for this area. We present a research framework for VR neurosurgery based on open-source tools and preliminary evaluation results. We showcase the potential of such a framework using clinical data of two patients and research data of one subject. As a first step toward practical evaluations, two certified senior neurosurgeons positively assessed the usefulness of the VR visualizations using head-mounted displays. The methods and findings described in our study thus provide a foundation for research and development aiming at versatile and user-friendly VR tools for improving neurosurgical planning and training.

Published
2019

2. Cross-paradigm pretraining of convolutional networks improves intracranial EEG decoding

Author

Behncke, Joos, Schirrmeister, Robin Tibor, Völker, Martin, Hammer, Jiří, Marusič, Petr, Schulze-Bonhage, Andreas, Burgard, Wolfram, and Ball, Tonio

Subjects
Quantitative Biology - Neurons and Cognition, Computer Science - Human-Computer Interaction
Abstract

When it comes to the classification of brain signals in real-life applications, the training and the prediction data are often described by different distributions. Furthermore, diverse data sets, e.g., recorded from various subjects or tasks, can even exhibit distinct feature spaces. The fact that data that have to be classified are often only available in small amounts reinforces the need for techniques to generalize learned information, as performances of brain-computer interfaces (BCIs) are enhanced by increasing quantity of available data. In this paper, we apply transfer learning to a framework based on deep convolutional neural networks (deep ConvNets) to prove the transferability of learned patterns in error-related brain signals across different tasks. The experiments described in this paper demonstrate the usefulness of transfer learning, especially improving performances when only little data can be used to distinguish between erroneous and correct realization of a task. This effect could be delimited from a transfer of merely general brain signal characteristics, underlining the transfer of error-specific information. Furthermore, we could extract similar patterns in time-frequency analyses in identical channels, leading to selective high signal correlations between the two different paradigms. Classification on the intracranial data yields in median accuracies up to $(81.50 \pm 9.49)\,\%$. Decoding on only $10\%$ of the data without pre-training reaches performances of $(54.76 \pm 3.56)\,\%$, compared to $(64.95 \pm 0.79)\,\%$ with pre-training.

Published
2018

3. A large-scale evaluation framework for EEG deep learning architectures

Author

Heilmeyer, Felix A., Schirrmeister, Robin T., Fiederer, Lukas D. J., Völker, Martin, Behncke, Joos, and Ball, Tonio

Subjects
Electrical Engineering and Systems Science - Signal Processing, Computer Science - Machine Learning, Computer Science - Neural and Evolutionary Computing, Quantitative Biology - Neurons and Cognition, Statistics - Machine Learning
Abstract

EEG is the most common signal source for noninvasive BCI applications. For such applications, the EEG signal needs to be decoded and translated into appropriate actions. A recently emerging EEG decoding approach is deep learning with Convolutional or Recurrent Neural Networks (CNNs, RNNs) with many different architectures already published. Here we present a novel framework for the large-scale evaluation of different deep-learning architectures on different EEG datasets. This framework comprises (i) a collection of EEG datasets currently including 100 examples (recording sessions) from six different classification problems, (ii) a collection of different EEG decoding algorithms, and (iii) a wrapper linking the decoders to the data as well as handling structured documentation of all settings and (hyper-) parameters and statistics, designed to ensure transparency and reproducibility. As an applications example we used our framework by comparing three publicly available CNN architectures: the Braindecode Deep4 ConvNet, Braindecode Shallow ConvNet, and two versions of EEGNet. We also show how our framework can be used to study similarities and differences in the performance of different decoding methods across tasks. We argue that the deep learning EEG framework as described here could help to tap the full potential of deep learning for BCI applications., Comment: 7 pages, 3 figures, final version accepted for presentation at IEEE SMC 2018 conference

Published
2018
Full Text
View/download PDF

4. Intracranial Error Detection via Deep Learning

Author

Völker, Martin, Hammer, Jiří, Schirrmeister, Robin T., Behncke, Joos, Fiederer, Lukas D. J., Schulze-Bonhage, Andreas, Marusič, Petr, Burgard, Wolfram, and Ball, Tonio

Subjects
Computer Science - Machine Learning, Quantitative Biology - Neurons and Cognition, Quantitative Biology - Quantitative Methods, Statistics - Machine Learning, I.2.6, I.2.8, I.5.0, J.2, J.3
Abstract

Deep learning techniques have revolutionized the field of machine learning and were recently successfully applied to various classification problems in noninvasive electroencephalography (EEG). However, these methods were so far only rarely evaluated for use in intracranial EEG. We employed convolutional neural networks (CNNs) to classify and characterize the error-related brain response as measured in 24 intracranial EEG recordings. Decoding accuracies of CNNs were significantly higher than those of a regularized linear discriminant analysis. Using time-resolved deep decoding, it was possible to classify errors in various regions in the human brain, and further to decode errors over 200 ms before the actual erroneous button press, e.g., in the precentral gyrus. Moreover, deeper networks performed better than shallower networks in distinguishing correct from error trials in all-channel decoding. In single recordings, up to 100 % decoding accuracy was achieved. Visualization of the networks' learned features indicated that multivariate decoding on an ensemble of channels yields related, albeit non-redundant information compared to single-channel decoding. In summary, here we show the usefulness of deep learning for both intracranial error decoding and mapping of the spatio-temporal structure of the human error processing network., Comment: 8 pages, 6 figures. Accepted at the 2018 IEEE International Conference on Systems, Man, and Cybernetics (SMC2018)

Published
2018

5. Deep Transfer Learning for Error Decoding from Non-Invasive EEG

Author

Völker, Martin, Schirrmeister, Robin T., Fiederer, Lukas D. J., Burgard, Wolfram, and Ball, Tonio

Subjects
Computer Science - Learning, Computer Science - Human-Computer Interaction, Quantitative Biology - Neurons and Cognition, I.2.6, I.2.8, I.5.0, J.2, J.3
Abstract

We recorded high-density EEG in a flanker task experiment (31 subjects) and an online BCI control paradigm (4 subjects). On these datasets, we evaluated the use of transfer learning for error decoding with deep convolutional neural networks (deep ConvNets). In comparison with a regularized linear discriminant analysis (rLDA) classifier, ConvNets were significantly better in both intra- and inter-subject decoding, achieving an average accuracy of 84.1 % within subject and 81.7 % on unknown subjects (flanker task). Neither method was, however, able to generalize reliably between paradigms. Visualization of features the ConvNets learned from the data showed plausible patterns of brain activity, revealing both similarities and differences between the different kinds of errors. Our findings indicate that deep learning techniques are useful to infer information about the correctness of action in BCI applications, particularly for the transfer of pre-trained classifiers to new recording sessions or subjects., Comment: 6 pages, 9 figures, The 6th International Winter Conference on Brain-Computer Interface 2018

Published
2017

6. Acting Thoughts: Towards a Mobile Robotic Service Assistant for Users with Limited Communication Skills

Author

Burget, Felix, Fiederer, Lukas Dominique Josef, Kuhner, Daniel, Völker, Martin, Aldinger, Johannes, Schirrmeister, Robin Tibor, Do, Chau, Boedecker, Joschka, Nebel, Bernhard, Ball, Tonio, and Burgard, Wolfram

Subjects
Computer Science - Artificial Intelligence, Computer Science - Computer Vision and Pattern Recognition, Computer Science - Human-Computer Interaction, Computer Science - Learning, Computer Science - Robotics, I.2.4, I.2.6, I.2.8, I.2.9, I.2.10, I.4.8, I.5.1
Abstract

As autonomous service robots become more affordable and thus available also for the general public, there is a growing need for user friendly interfaces to control the robotic system. Currently available control modalities typically expect users to be able to express their desire through either touch, speech or gesture commands. While this requirement is fulfilled for the majority of users, paralyzed users may not be able to use such systems. In this paper, we present a novel framework, that allows these users to interact with a robotic service assistant in a closed-loop fashion, using only thoughts. The brain-computer interface (BCI) system is composed of several interacting components, i.e., non-invasive neuronal signal recording and decoding, high-level task planning, motion and manipulation planning as well as environment perception. In various experiments, we demonstrate its applicability and robustness in real world scenarios, considering fetch-and-carry tasks and tasks involving human-robot interaction. As our results demonstrate, our system is capable of adapting to frequent changes in the environment and reliably completing given tasks within a reasonable amount of time. Combined with high-level planning and autonomous robotic systems, interesting new perspectives open up for non-invasive BCI-based human-robot interactions., Comment: * FB, LDJF, DK, MV and JA contributed equally to the work. Accepted as a conference paper at the European Conference on Mobile Robotics 2017 (ECMR 2017), 6 pages, 3 figures

Published
2017
Full Text
View/download PDF

7. The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

Author

European Space Agency, Centre National D'Etudes Spatiales (France), U.S. Geological Survey, Centre National de la Recherche Scientifique (France), University of Bern, European Commission, UK Space Agency, Istituto Nazionale di Astrofisica, Ministerio de Economía y Competitividad (España), University of Arizona, National Aeronautics and Space Administration (US), Ministry of Education and Science of the Russian Federation, Agencia Estatal de Investigación (España), Science and Technology Facilities Council (UK), Agenzia Spaziale Italiana, Martin-Torres, Javier [0000-0001-6479-2236], Zorzano, Maria-Paz [0000-0002-4492-9650], Fawdon, Peter, Orgel, Csilla, Adeli, Solmaz, Balme, Matt, Calef, Fred J., Davis, Joel M., Frigeri, Alessandro, Grindrod, Peter, Hauber, Ernst, Deit, Laetitia Le, Loizeau, Damien, Nass, Andrea, Quantin-Nataf, Cathy, Sefton-Nash, Elliot, Thomas, Nick, Torres, Ines, Vago, Jorge L., Volat, Matthieu, De Witte, Sander, Altieri, Francesca, Apuzzo, Andrea, Aramendia, Julene, Arana, Gorka, Singh Bahia, Rickbir, Banham, Steven G., Barnes, Robert, Barrett, Alexander M., Benedix, Wolf-Stefan, Bhardwaj, Anshuman, Boazman, Sarah Jane, Bontognali, Tomaso R. R., Bridges, John, Bultel, Benjamin, Ciarletti, Valérie, De Sanctis, Maria Cristina, Dickeson, Zach, Favaro, Elena A., Ferrari, Marco, Foucher, Frédéric, Goetz, Walter, Haldemann, Albert F. C., Harrington, Elise, Kapatza, Angeliki, Koschny, Detlef, Krzesinska, Agata M., Le Gall, Alice, Lewis, Stephen R., Lim, Tanya, Madariaga, Juan Manuel, Man, Benjamin James, Mandon, Lucia, Mangold, Nicolas, Martin-Torres, Javier, McNeil, Joseph D., Molina-Jurado, Antonio, Moral, Andoni G., Motaghian, Sara, Nikiforov, Sergei, Oudart, Nicolas, Pacifici, Andrea, Parkes Bowen, Adam, Plettemeier, Dirk, Poulakis, Pantelis, Putri, Alfiah Rizky Diana, Ruesch, Ottaviano, Sam, Lydia, Schröder, Christian, Statz, Christoph, Thomas, Rebecca, Tirsch, Daniela, Toth, Zsuzsanna, Turner, Stuart, Voelker, Martin, Werner, Stephanie C., Westall, Frances, Whiteside, Barry J., Williams, Adam, Williams, Rebecca M. E., Wright, Jack, Zorzano, Maria-Paz, European Space Agency, Centre National D'Etudes Spatiales (France), U.S. Geological Survey, Centre National de la Recherche Scientifique (France), University of Bern, European Commission, UK Space Agency, Istituto Nazionale di Astrofisica, Ministerio de Economía y Competitividad (España), University of Arizona, National Aeronautics and Space Administration (US), Ministry of Education and Science of the Russian Federation, Agencia Estatal de Investigación (España), Science and Technology Facilities Council (UK), Agenzia Spaziale Italiana, Martin-Torres, Javier [0000-0001-6479-2236], Zorzano, Maria-Paz [0000-0002-4492-9650], Fawdon, Peter, Orgel, Csilla, Adeli, Solmaz, Balme, Matt, Calef, Fred J., Davis, Joel M., Frigeri, Alessandro, Grindrod, Peter, Hauber, Ernst, Deit, Laetitia Le, Loizeau, Damien, Nass, Andrea, Quantin-Nataf, Cathy, Sefton-Nash, Elliot, Thomas, Nick, Torres, Ines, Vago, Jorge L., Volat, Matthieu, De Witte, Sander, Altieri, Francesca, Apuzzo, Andrea, Aramendia, Julene, Arana, Gorka, Singh Bahia, Rickbir, Banham, Steven G., Barnes, Robert, Barrett, Alexander M., Benedix, Wolf-Stefan, Bhardwaj, Anshuman, Boazman, Sarah Jane, Bontognali, Tomaso R. R., Bridges, John, Bultel, Benjamin, Ciarletti, Valérie, De Sanctis, Maria Cristina, Dickeson, Zach, Favaro, Elena A., Ferrari, Marco, Foucher, Frédéric, Goetz, Walter, Haldemann, Albert F. C., Harrington, Elise, Kapatza, Angeliki, Koschny, Detlef, Krzesinska, Agata M., Le Gall, Alice, Lewis, Stephen R., Lim, Tanya, Madariaga, Juan Manuel, Man, Benjamin James, Mandon, Lucia, Mangold, Nicolas, Martin-Torres, Javier, McNeil, Joseph D., Molina-Jurado, Antonio, Moral, Andoni G., Motaghian, Sara, Nikiforov, Sergei, Oudart, Nicolas, Pacifici, Andrea, Parkes Bowen, Adam, Plettemeier, Dirk, Poulakis, Pantelis, Putri, Alfiah Rizky Diana, Ruesch, Ottaviano, Sam, Lydia, Schröder, Christian, Statz, Christoph, Thomas, Rebecca, Tirsch, Daniela, Toth, Zsuzsanna, Turner, Stuart, Voelker, Martin, Werner, Stephanie C., Westall, Frances, Whiteside, Barry J., Williams, Adam, Williams, Rebecca M. E., Wright, Jack, and Zorzano, Maria-Paz

Abstract

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context.

Published
2024

10. CoRad-19-Modular Digital Teaching during the SARS-CoV-2 Pandemic

Author

Brendlin, Andreas Stefan, Molwitz, Isabel, Oechtering, Thekla Helene, Barkhausen, Joerg, Frydrychowicz, Alex, Sulkowski, Tanja, Balks, Maren Friederike, Buchholz, Michael, Lohwasser, Stefan, Voelker, Martin, Goldschmidt, Olaf, Johenning, Anja, Schlender, Sabine, Paulus, Christian, Antoch, Gerald, Dettmer, Sabine, Baessler, Bettina, Maintz, David, dos Santos, Daniel Pinto, Vogl, Thomas J., Hattingen, Elke, Stoevesandt, Dietrich, Reinartz, Sebastian, Storz, Corinna, Mueller-Peltzer, Katharina, Bamberg, Fabian, Rengier, Fabian, Weis, Meike, Frisch, Anne, Hansen, Nienke Lynn, Kolb, Manuel, Maurer, Michael, Nikolaou, Konstantin, Afat, Saif, Othman, Ahmed E., Brendlin, Andreas Stefan, Molwitz, Isabel, Oechtering, Thekla Helene, Barkhausen, Joerg, Frydrychowicz, Alex, Sulkowski, Tanja, Balks, Maren Friederike, Buchholz, Michael, Lohwasser, Stefan, Voelker, Martin, Goldschmidt, Olaf, Johenning, Anja, Schlender, Sabine, Paulus, Christian, Antoch, Gerald, Dettmer, Sabine, Baessler, Bettina, Maintz, David, dos Santos, Daniel Pinto, Vogl, Thomas J., Hattingen, Elke, Stoevesandt, Dietrich, Reinartz, Sebastian, Storz, Corinna, Mueller-Peltzer, Katharina, Bamberg, Fabian, Rengier, Fabian, Weis, Meike, Frisch, Anne, Hansen, Nienke Lynn, Kolb, Manuel, Maurer, Michael, Nikolaou, Konstantin, Afat, Saif, and Othman, Ahmed E.

Abstract

Purpose During the SARS-CoV-2 pandemic, higher education worldwide had to switch to digital formats. The purpose of this study was to evaluate CoRad-19, a digital teaching tool created by the German Radiological Society for medical students during the COVID-19 pandemic. Materials and Methods A total of 13 German-speaking universities implemented CoRad-19 in their curriculum and partially or completely replaced their classes with the online courses. Previous experience and contact with radiology and the participants' opinions regarding the medium of e-learning were surveyed using a custom questionnaire. The subjective level of knowledge regarding the individual modules was also surveyed before and after participation to measure learning effects. The data of 994 medical students from the participating sites were analyzed and compared intraindividually using the Friedman test. Results From 4/1/2020-10/1/2020, 451 complete data sets from a total of 994 surveys were included. E-learning was rated very useful both before and after course participation (4 [IQR 3-4], p = 0.527, r= 0.16). E-learning as a method was also rated as a very good medium both before and after participation (4 [IQR 3-4], p=0.414, r=0.17). After participation, participants rated radiology as particularly suitable for digital teaching (before: 3 [IQR 3-4] vs. after 4 [IQR 3-4], p = 0.005, r =0.6). Significant learning gains were measurable in all course modules (p <= 0.009). Post-hoc analysis showed interest in radiology to increase significantly after course participation (p = 0.02). Conclusion In the representative survey, significant learning effects were observed in all course modules. In addition, it should be particularly emphasized that the students' interest in radiology was increased by course participation. Thus, the German Radiological Society provided significant support to German-speaking medical faculties with respect to maintaining excellent education using CoRad-19.

Published
2022

11. From hot to cold? – Hydrothermal activities as a source for icy-debris flows on Dryas Mons, Terra Sirenum, Mars

Author

Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Voelker, Martin, Ruiz, Javier, Parro, Laura M., Hauber, Ernst, Cardesín-Moinelo, Alejandro, Martin, Patrick, Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Voelker, Martin, Ruiz, Javier, Parro, Laura M., Hauber, Ernst, Cardesín-Moinelo, Alejandro, and Martin, Patrick

Abstract

During an extensive grid-mapping campaign on Mars' southern hemisphere, we have detected so-called sheet flow deposits, which are defined by distinctive lobate fronts, thin and mostly planar layers, and faint sub-parallel surface lineations. They originate from the high plains of Dryas Mons, a large massif of impact and tectonic origin, and follow the topographic gradient down into the adjacent basins. Their sources often coincide with steep and multi-layered outcrops. This work addresses the formation of these deposits, and if they are related to the unique tectonic and endogenic environment of Dryas Mons. We applied photogeological mapping, age determinations by crater counts, as well as topographic and heat flow measurements in order to reconstruct the evolution of these landforms. The calculated ages (mid to late Amazonian), their location in the mid-latitudes, as well as some specific morphologies like lobate flow fronts are typical for standard viscous-flow features on Mars. In contrast to such viscous-flow features, the sheet flow deposits occur isolated in the Dryas Mons region. Aside from that, major other landforms, typical for viscous-flow features are lacking, like sublimation pits, brain terrain or arcuate deformations. Considering these similarities and differences, we suggest that both landforms viscous-flow features and the sheet flow deposits of Dryas Mons were formed by the involvement of volatiles; however, at varying amounts and by different emplacement processes. As the formation of the sheet flow deposits is located in an area with one of the highest heat flow values planet-wide, we calculated if the heat flow could be a potential trigger for the release of outcropping volatile-rich layers. However, our calculations have shown that the heat flow is still insufficient to enable near-surface melting. Instead, we suggest that the volatiles originate from deep layers affected by magmatic and/or intrusive activities in a tectonically active environm

Published
2021

12. Work and Training Conditions of German Residents in Radiology - Results from a Nationwide Survey Conducted by the Young Radiology Forum in the German Roentgen Society

Author

Oechtering, Thekla H., Panagiotopoulos, Nikolaos, Voelker, Martin, Lohwasser, Stefan, Ellmann, Stephan, Molwitz, Isabel, Storz, Corinna, Winther, Hinrich, Eisenblaetter, Michel, Antoch, Gerald, Schoenberg, Stefan O., Barkhausen, Joerg, Anton, Frank, Neumann, Stefan, Layer, Guenter, Doerfler, Arnd, Koerber, Friederike, Wessling, Johannes, Wucherer, Michael, Raspe, Matthias, Oechtering, Thekla H., Panagiotopoulos, Nikolaos, Voelker, Martin, Lohwasser, Stefan, Ellmann, Stephan, Molwitz, Isabel, Storz, Corinna, Winther, Hinrich, Eisenblaetter, Michel, Antoch, Gerald, Schoenberg, Stefan O., Barkhausen, Joerg, Anton, Frank, Neumann, Stefan, Layer, Guenter, Doerfler, Arnd, Koerber, Friederike, Wessling, Johannes, Wucherer, Michael, and Raspe, Matthias

Abstract

Zusammenfassung Ziel Eine qualitativ hochwertige Weiterbildung ist Grundlage fur eine hohe Arbeitszufriedenheit und eine exzellente Patientenversorgung in der Radiologie. Ziel dieser Umfrage war es, den aktuellen Stand der Arbeitsbedingungen von arzten in der Weiterbildung Radiologie in Deutschland zu erfassen und einen Fokus auf die Teilaspekte Weiterbildung sowie psychosoziale Arbeitsbelastung zu legen. Die Beschreibung des Ist-Zustandes soll helfen, mogliche Problemfelder zu identifizieren und Verbesserungsansatze zu entwickeln. Material und Methoden Anfang 2018 wurde ein elektronischer Fragebogen uber die Deutsche Rontgengesellschaft (DRG) e. V., die Konferenz der Lehrstuhlinhaber fur Radiologie (KLR), das Chefarztforum der DRG (CAFRAD) und das Forum Niedergelassener Radiologen (FUNRAD) an radiologische Weiterbildungsassistenten verschickt. Der Fragebogen deckte mit 63 Fragen 7 wesentliche Themenfelder arztlicher Arbeits- und Weiterbildungsbedingungen ab. Um eine facherubergreifende Vergleichbarkeit zu sichern, wurden Fragen von bisherigen Erhebungen unter arzten in Weiterbildung anderer Fachrichtungen ubernommen. Ergebnisse 643 arzte haben die Umfrage begonnen. 501 (78 %) Fragebogen wurden vollstandig bearbeitet und in die endgultige Analyse einbezogen. 65 % der Befragten waren mit ihrer derzeitigen beruflichen Situation zufrieden. Gleichzeitig wurden Defizite besonders in Bezug auf die Vereinbarkeit von Familie und Beruf sowie die Moglichkeit zu wissenschaftlichem Arbeiten deutlich. Nur 36 % der Teilnehmer mit Kindern waren zufrieden mit der Vereinbarkeit von Familie und Beruf an ihrem Arbeitsplatz. Nur 31 % der wissenschaftlich Tatigen waren zufrieden mit ihren Forschungsbedingungen. Zudem war die psychosoziale Arbeitsbelastung unter den befragten arzten stark ausgepragt. Schlussfolgerung Die Arbeitszufriedenheit ist unter radiologischen Assistenzarzten im Vergleich zu anderen Fachrichtungen hoch. Dennoch scheinen auf Basis dieser Erhebung Anpassungen der Arb

Published
2020

13. Structured Reporting of Solid and Cystic Pancreatic Lesions in CT and MRI: Consensus-Based Structured Report Templates of the German Society of Radiology (DRG)

Author

Persigehl, Thorsten, Baumhauer, Matthias, Baessler, Bettina, Beyer, Lukas Philipp, Bludau, Marc, Bruns, Christiane, Bunck, Alexander Christian, Germer, Christoph-Thomas, Grenacher, Lars, Hacklaender, Thomas, Haneder, Stefan, Heinrich, Stefan, Heusch, Philipp, Hoffmann, Matthias, Juchems, Markus S., Kroeger, Jan Robert, Kotter, Elmar, Layer, Guenter, Maintz, David, Menke, Jan, Palmowski, Moritz, Pantelis, Dimitrios, dos Santos, Daniel Pinto, Popp, Felix Christoph, Schaefer, Nico, Schlemmer, Heinz-Peter, Schreyer, Andreas G., Siedek, Florian, Stippel, Dirk, Voelker, Martin, Waldschmidt, Dirk Thomas, Weber, Tim Frederik, von Winterfeld, Moritz, Wybranski, Christian, Zander, Thomas, Wessling, Johannes, Persigehl, Thorsten, Baumhauer, Matthias, Baessler, Bettina, Beyer, Lukas Philipp, Bludau, Marc, Bruns, Christiane, Bunck, Alexander Christian, Germer, Christoph-Thomas, Grenacher, Lars, Hacklaender, Thomas, Haneder, Stefan, Heinrich, Stefan, Heusch, Philipp, Hoffmann, Matthias, Juchems, Markus S., Kroeger, Jan Robert, Kotter, Elmar, Layer, Guenter, Maintz, David, Menke, Jan, Palmowski, Moritz, Pantelis, Dimitrios, dos Santos, Daniel Pinto, Popp, Felix Christoph, Schaefer, Nico, Schlemmer, Heinz-Peter, Schreyer, Andreas G., Siedek, Florian, Stippel, Dirk, Voelker, Martin, Waldschmidt, Dirk Thomas, Weber, Tim Frederik, von Winterfeld, Moritz, Wybranski, Christian, Zander, Thomas, and Wessling, Johannes

Abstract

Background Radiological reports of pancreatic lesions are currently widely formulated as free texts. However, for optimal characterization, staging and operation planning, a wide range of information is required but is sometimes not captured comprehensively. Structured reporting offers the potential for improvement in terms of completeness, reproducibility and clarity of interdisciplinary communication. Method Interdisciplinary consensus finding of structured report templates for solid and cystic pancreatic tumors in computed tomography (CT) and magnetic resonance imaging (MRI) with representatives of the German Society of Radiology (DRG), German Society for General and Visceral Surgery (DGAV), working group Oncological Imaging (ABO) of the German Cancer Society (DKG) and other radiologists, oncologists and surgeons. Results Among experts in the field of pancreatic imaging, oncology and pancreatic surgery, as well as in a public online survey, structured report templates were developed by consensus. These templates are available on the DRG homepage under www.befundung.drg.de and will be regularly revised to the current state of scientific knowledge by the participating specialist societies and responsible working groups. Conclusion This article presents structured report templates for solid and cystic pancreatic tumors to improve clinical staging (cTNM, ycTNM) in everyday radiology. Key Points: Structured report templates offer the potential of optimized radiological reporting with regard to completeness, reproducibility and differential diagnosis. This article presents consensus-based, structured reports for solid and cystic pancreatic lesions in CT and MRI. These structured reports are available open source on the homepage of the German Society of Radiology (DRG) under www.befundung. drg.de.

Published
2020

17. Glacial and Fluvial Evolution of Landforms in Hellas Planitia, Mars

Author

Voelker, Martin

Subjects
planetary sciences, Mars, geomorphology
Abstract

The focus of this thesis is the geospatial analysis of both fluvial and glacial landforms in Hellas Planitia Mars. The ancient impact structure contains the deepest point on the surface, and hence, the highest air pressure. Its interior is among the places with the highest likelihood for the transient existence of liquid water and the highest protection against solar radiation (both with implications for potential past or present habitability). The investigation of landforms with respect to their geographical distribution, evolution, and mutual relation, is essential for any attempt to link form to process, i.e. to reconstruct climatic conditions through the study of surface morphology. In order to quantify the distribution of 24 pre-selected landforms in Hellas Planitia, the so-called grid-mapping method has been applied; i. a. for glacier-like flows, gullies, sheet deposits, and latitude-dependent ice-dust deposits. The results provided evidence about possible clockwise-rotating wind circulation systems within Hellas Planitia. Moreover, a lack of glacial features and gullies in the lowest parts of the basin has been detected; despite the high air pressure potentially allowing water to be liquid. The systematic search at high-resolution scale did also not reveal clear evidence for extensive shoreline morphologies as suggested by several authors; hence a hypothesized lake within Hellas Planitia could not be confirmed. Among others, grid-mapping revealed widespread lobate sheet deposits at the lower reaches of Dao Vallis in eastern Hellas Planitia (being one of the big outflow channels draining into the basin). Similar features have already been interpreted in several regions of the planet as either volcanic or fluvial origin. Assessing both scenarios, a water-related formation is more likely, as most surface features can be better explained by fluvial rather than volcanic processes. The result is consistent with other stratigraphic findings and formation scenarios of the related Dao Vallis system. This work revealed that Hellas Planitia has always been a matter of environmental change. While there is many evidence for fluvial activities during all Martian epochs (e. g., light-toned deposits, channels, gullies), there are also several indications of glacial activities (glacier-like flows or viscos-flow features). However, the results of this work do not support the existence of a lake within that vast depression. This thesis has demonstrated that grid mapping is a very helpful and effective method for quantifying the distribution of landforms over huge areas, revealing information and relations about climate and landscape evolution, which are only visible from a much wider perspective; from ancient Noachian to very recent Amazonian landforms. For future research this approach can also be applied to other terrestrial bodies and space missions., Im Zentrum der folgenden Arbeit steht die räumliche Analyse fluvialer und glazialer Oberflächenformen im Hellas Becken, Mars. Die sehr alte Impaktstruktur beinhaltet die tiefsten Punkte der planetaren Oberflächen, und Folge dessen auch den höchsten Luftdruck. Daher gilt das Innere des Beckens als einer der wahrscheinlichsten Orte, an dem flüssiges Wasser temporär an der Oberfläche existieren kann. Des Weiteren bietet die hohe Luftsäule auch einen erhöhten Schutz gegen lebensgefährdende solare Strahlung. Diese beiden Aspekte machen das Hellas-Becken zu einem besonderen Ort auf der Suche nach heutigem und historischem Leben außerhalb der Erde. Die Untersuchung von Oberflächenformen bezogen auf ihre geographische Verteilung, Evolution und gegenseitige Wechselwirkungen, ist daher ein wesentlicher Bestandteil die Prozesse zu verstehen, die jene Morphologien entstehen ließen. Dadurch ist es möglich, klimatische Bedingungen zu rekonstruieren, die zur Entwicklung bedeutsamer Geländeformen geführt haben. Um die geographische Verteilung von 24 vordefinierten Oberflächenformen im Hellas-Becken zu quantifizieren, wird im Folgenden die sogenannte Grid-Mapping Methode angewandt. Unter anderem für gletscher-ähnliche Formen, Erosionsrinnen, Schichtablagerungen, und breitengradabhängige Eis/Staub Ablagerungen. Die Ergebnisse geben Hinweise auf einen im Uhrzeigersinn wehenden Windfluss innerhalb des Beckens. Darüber hinaus wurde trotz des hohen Luftdrucks (welcher flüssiges Wasser ermöglicht) ein weitgehendes Fehlen glazialer Formen und Erosionsrinnen in den tiefsten Bereichen des Impaktbeckens festgestellt. Das systematische Sichten auf Basis hochauflösender Bilddaten konnte ebenfalls keine klaren Indizien für die Existenz alter Küstenlinien auffinden, wie von einigen Wissenschaftlern vermutet. Dadurch kann die Theorie eines ehemaligen Meeres in Hellas Planitia nicht unterstützt werden. Des Weiteren enthüllte die Grid-Mapping Methode die Existenz sogenannter Schichtablagerungen am Unterlauf des Dao Vallis im östlichen Hellas-Becken; einer der großen Talsysteme die sich einst in Hellas ergossen. Ähnliche Ablagerungen wurden bereits in anderen Regionen des Mars als vulkanischen oder fluvialen Ursprungs interpretiert. Werden beide Szenarien gegenübergestellt, so erscheint eine hydrogene Entstehung plausibler, da die hier vorgestellten Ergebnisse stratigraphisch und genetisch zur hydrogenen Entstehung des anliegenden Dao Vallis passen. Die vorliegende Arbeit belegt, dass Hellas Planitia seit jeher Änderungen unterlegen war. Nebst vielen Hinweisen auf fluvialen Aktivitäten (helle, geschichtete Ablagerungen, ausgetrocknete Fließgewässer und Runsen), gibt es auch Hinweise auf glaziale Prozesse (gletscherförmige Zungen und viskose Fließformen). Aber die bedeutende Frage, ob es jemals einen großen See in dieser großen Niederung gab, kann basierend auf den Ergebnisse dieser Arbeit nicht unterstützt werden. Die vorliegende Arbeit hat belegt, dass Grid-Mapping eine sehr hilfreiche und effektive Methode bei der räumlichen Quantifizierung von Oberflächenformen über große Gebiete ist. Sie ist in der Lage Informationen und Beziehungen über Klima und Landschaftsentwicklung zu enthüllen, welche nur aus einem größeren Blickwinkel festgestellt werden können; angefangen bei alten den Noachischen Formen bis hin zu den sehr jungen Amazonischen Morphologien. Für künftige geowissenschaftliche Untersuchungen anderer terrestrischer Himmelskörper kann dieser Ansatz daher auch von großem Nutzen sein.

Published
2018

33. Gene duplication and fragmentation in the zebra finch major histocompatibility complex

Author

Balakrishnan, Christopher N., Ekblom, Robert, Voelker, Martin, Westerdahl, Helena, Godinez, Ricardo, Kotkiewicz, Holly, Burt, David W., Graves, Tina, Griffin, Darren K., Warren, Wesley C., Edwards, Scott V., Balakrishnan, Christopher N., Ekblom, Robert, Voelker, Martin, Westerdahl, Helena, Godinez, Ricardo, Kotkiewicz, Holly, Burt, David W., Graves, Tina, Griffin, Darren K., Warren, Wesley C., and Edwards, Scott V.

Abstract

Background: Due to its high polymorphism and importance for disease resistance, the major histocompatibility complex (MHC) has been an important focus of many vertebrate genome projects. Avian MHC organization is of particular interest because the chicken Gallus gallus, the avian species with the best characterized MHC, possesses a highly streamlined minimal essential MHC, which is linked to resistance against specific pathogens. It remains unclear the extent to which this organization describes the situation in other birds and whether it represents a derived or ancestral condition. The sequencing of the zebra finch Taeniopygia guttata genome, in combination with targeted bacterial artificial chromosome (BAC) sequencing, has allowed us to characterize an MHC from a highly divergent and diverse avian lineage, the passerines. Results: The zebra finch MHC exhibits a complex structure and history involving gene duplication and fragmentation. The zebra finch MHC includes multiple Class I and Class II genes, some of which appear to be pseudogenes, and spans a much more extensive genomic region than the chicken MHC, as evidenced by the presence of MHC genes on each of seven BACs spanning 739 kb. Cytogenetic (FISH) evidence and the genome assembly itself place core MHC genes on as many as four chromosomes with TAP and Class I genes mapping to different chromosomes. MHC Class II regions are further characterized by high endogenous retroviral content. Lastly, we find strong evidence of selection acting on sites within passerine MHC Class I and Class II genes. Conclusion: The zebra finch MHC differs markedly from that of the chicken, the only other bird species with a complete genome sequence. The apparent lack of synteny between TAP and the expressed MHC Class I locus is in fact reminiscent of a pattern seen in some mammalian lineages and may represent convergent evolution. Our analyses of the zebra finch MHC suggest a complex history involving chromosomal fission, gene dupli

Published
2010
Full Text
View/download PDF

34. Employment paradox

Author

Voelker, Martin

Subjects
Business, Engineering and manufacturing industries
Abstract

* I just finished reading your article (in the June issue) titled 'Employment Paradox' and am concerned that there may be more to this problem than available, skilled, warm bodies. [...]

Published
2003

35. Gene Duplication and Fragmentation in the Zebra Finch Major Histocompatibility Complex

Author

Balakrishnan, Christopher N, Ekblom, Robert, Völker, Martin, Westerdahl, Helena, Kotkiewicz, Holly, Burt, David W, Graves, Tina, Griffin, Darren K, Warren, Wesley C, Godinez, Ricardo, and Edwards, Scott V.

Abstract

Background: Due to its high polymorphism and importance for disease resistance, the major histocompatibility complex (MHC) has been an important focus of many vertebrate genome projects. Avian MHC organization is of particular interest because the chicken Gallus gallus, the avian species with the best characterized MHC, possesses a highly streamlined minimal essential MHC, which is linked to resistance against specific pathogens. It remains unclear the extent to which this organization describes the situation in other birds and whether it represents a derived or ancestral condition. The sequencing of the zebra finch Taeniopygia guttata genome, in combination with targeted bacterial artificial chromosome (BAC) sequencing, has allowed us to characterize an MHC from a highly divergent and diverse avian lineage, the passerines. Results: The zebra finch MHC exhibits a complex structure and history involving gene duplication and fragmentation. The zebra finch MHC includes multiple Class I and Class II genes, some of which appear to be pseudogenes, and spans a much more extensive genomic region than the chicken MHC, as evidenced by the presence of MHC genes on each of seven BACs spanning 739 kb. Cytogenetic (FISH) evidence and the genome assembly itself place core MHC genes on as many as four chromosomes with TAP and Class I genes mapping to different chromosomes. MHC Class II regions are further characterized by high endogenous retroviral content. Lastly, we find strong evidence of selection acting on sites within passerine MHC Class I and Class II genes. Conclusion: The zebra finch MHC differs markedly from that of the chicken, the only other bird species with a complete genome sequence. The apparent lack of synteny between TAP and the expressed MHC Class I locus is in fact reminiscent of a pattern seen in some mammalian lineages and may represent convergent evolution. Our analyses of the zebra finch MHC suggest a complex history involving chromosomal fission, gene duplication and translocation in the history of the MHC in birds, and highlight striking differences in MHC structure and organization among avian lineages., Organismic and Evolutionary Biology

Published
2010
Full Text
View/download PDF

36. The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

Author

Fawdon, Peter, Orgel, Csilla, Adeli, Solmaz, Balme, Matt, Calef, Fred J., Davis, Joel M., Frigeri, Alessandro, Grindrod, Peter, Hauber, Ernst, Le Deit, Laetitia, Loizeau, Damien, Nass, Andrea, Quantin-Nataf, Cathy, Sefton-Nash, Elliot, Thomas, Nick, Torres, Ines, Vago, Jorge L., Volat, Matthieu, De Witte, Sander, Altieri, Francesca, Apuzzo, Andrea, Aramendia, Julene, Arana, Gorka, Bahia, Rickbir Singh, Banham, Steven G., Barnes, Robert, Barrett, Alexander M., Benedix, Wolf-Stefan, Bhardwaj, Anshuman, Boazman, Sarah Jane, Bontognali, Tomaso R. R., Bridges, John, Bultel, Benjamin, Ciarletti, Valérie, De Sanctis, Maria Cristina, Dickeson, Zach, Favaro, Elena A., Ferrari, Marco, Foucher, Frédéric, Goetz, Walter, Haldemann, Albert F. C., Harrington, Elise, Kapatza, Angeliki, Koschny, Detlef, Krzesinska, Agata M., Le Gall, Alice, Lewis, Stephen R., Lim, Tanya, Madariaga, Juan Manuel, Man, Benjamin James, Mandon, Lucia, Mangold, Nicolas, Martin-Torres, Javier, McNeil, Joseph D., Molina, Antonio, Moral, Andoni G., Motaghian, Sara, Nikiforov, Sergei, Oudart, Nicolas, Pacifici, Andrea, Parkes Bowen, Adam, Plettemeier, Dirk, Poulakis, Pantelis, Putri, Alfiah Rizky Diana, Ruesch, Ottaviano, Sam, Lydia, Schröder, Christian, Statz, Christoph, Thomas, Rebecca, Tirsch, Daniela, Toth, Zsuzsanna, Turner, Stuart, Voelker, Martin, Werner, Stephanie C., Westall, Frances, Whiteside, Barry J., Williams, Adam, Williams, Rebecca M. E., Wright, Jack, Zorzano, Maria-Paz, Fawdon, Peter, Orgel, Csilla, Adeli, Solmaz, Balme, Matt, Calef, Fred J., Davis, Joel M., Frigeri, Alessandro, Grindrod, Peter, Hauber, Ernst, Le Deit, Laetitia, Loizeau, Damien, Nass, Andrea, Quantin-Nataf, Cathy, Sefton-Nash, Elliot, Thomas, Nick, Torres, Ines, Vago, Jorge L., Volat, Matthieu, De Witte, Sander, Altieri, Francesca, Apuzzo, Andrea, Aramendia, Julene, Arana, Gorka, Bahia, Rickbir Singh, Banham, Steven G., Barnes, Robert, Barrett, Alexander M., Benedix, Wolf-Stefan, Bhardwaj, Anshuman, Boazman, Sarah Jane, Bontognali, Tomaso R. R., Bridges, John, Bultel, Benjamin, Ciarletti, Valérie, De Sanctis, Maria Cristina, Dickeson, Zach, Favaro, Elena A., Ferrari, Marco, Foucher, Frédéric, Goetz, Walter, Haldemann, Albert F. C., Harrington, Elise, Kapatza, Angeliki, Koschny, Detlef, Krzesinska, Agata M., Le Gall, Alice, Lewis, Stephen R., Lim, Tanya, Madariaga, Juan Manuel, Man, Benjamin James, Mandon, Lucia, Mangold, Nicolas, Martin-Torres, Javier, McNeil, Joseph D., Molina, Antonio, Moral, Andoni G., Motaghian, Sara, Nikiforov, Sergei, Oudart, Nicolas, Pacifici, Andrea, Parkes Bowen, Adam, Plettemeier, Dirk, Poulakis, Pantelis, Putri, Alfiah Rizky Diana, Ruesch, Ottaviano, Sam, Lydia, Schröder, Christian, Statz, Christoph, Thomas, Rebecca, Tirsch, Daniela, Toth, Zsuzsanna, Turner, Stuart, Voelker, Martin, Werner, Stephanie C., Westall, Frances, Whiteside, Barry J., Williams, Adam, Williams, Rebecca M. E., Wright, Jack, and Zorzano, Maria-Paz

Abstract

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context.

37. Current Status of Cardiovascular Imaging in Germany: Structured Data from the National Certification Program, ESCR Registry, and Survey among Radiologists

Author

Sieren, Malte Maria, Maintz, David, Gutberlet, Matthias, Krombach, Gabriele Anja, Bamberg, Fabian, Hunold, Peter, Lehmkuhl, Lukas, Fischbach, Katharina, Reinartz, Sebastian, Antoch, Gerald, Barkhausen, Joerg, Sandstede, Joern, Voelker, Martin, Naehle, Claas, Sieren, Malte Maria, Maintz, David, Gutberlet, Matthias, Krombach, Gabriele Anja, Bamberg, Fabian, Hunold, Peter, Lehmkuhl, Lukas, Fischbach, Katharina, Reinartz, Sebastian, Antoch, Gerald, Barkhausen, Joerg, Sandstede, Joern, Voelker, Martin, and Naehle, Claas

Abstract

Purpose In the light of the increasing importance of cardiovascular cross-sectional imaging in current guidelines, the goal of this study is to provide a comprehensive overview of cardiovascular imaging (CVI) offered by radiological institutions across Germany. Materials and Methods Data were extracted from the national certification program database of the German Roentgen Society (DRG) from 2015-2021. A nationwide online survey among radiology institutes (university hospitals, non-university hospitals, and private practices) was conducted for 2019, and data was extracted from the European Society of Cardiovascular Radiology (ESCR) registry. The data collection's key points included the number of centers and individuals certified for CVI, the number of cardiac CT and MRI examinations performed, the reporting habits, and the participation in the ESCR registry. Results 71 centers and 1278 persons, both with a substantial increase since 2015, were registered and certified by the DRG to perform CVI. According to the survey, a total of 69,286 CT and 64,281 MRI examinations were performed annually. Data from the survey and the ESCR registry indicated that reporting was mostly done solely by radiologists or, to a lesser degree, in joint consensus meetings with non-radiologists. The overall participation rate in the ESCR registry was 48 % among the survey 's participants. Conclusion This comprehensive analysis demonstrates that high-quality CVI by radiologists is available nationwide. The current challenges are to provide the best medical and technical quality of CVI by radiology for patient care and to ensure economic sustainability in the German health care system to accommodate the predicted substantial need for CVI in the future. Citation Format Sieren M, Maintz D, Gutberlet M et al. Current Status of Cardiovascular Imaging in Germany: Structured Data from the National Certification Program, ESCR Registry, and Survey among Radiologists. Fortschr Rontgenstr 2021; DOI: 10

38. Current Status of Cardiovascular Imaging in Germany: Structured Data from the National Certification Program, ESCR Registry, and Survey among Radiologists

Author

Sieren, Malte Maria, Maintz, David, Gutberlet, Matthias, Krombach, Gabriele Anja, Bamberg, Fabian, Hunold, Peter, Lehmkuhl, Lukas, Fischbach, Katharina, Reinartz, Sebastian, Antoch, Gerald, Barkhausen, Joerg, Sandstede, Joern, Voelker, Martin, Naehle, Claas, Sieren, Malte Maria, Maintz, David, Gutberlet, Matthias, Krombach, Gabriele Anja, Bamberg, Fabian, Hunold, Peter, Lehmkuhl, Lukas, Fischbach, Katharina, Reinartz, Sebastian, Antoch, Gerald, Barkhausen, Joerg, Sandstede, Joern, Voelker, Martin, and Naehle, Claas

Abstract

Purpose In the light of the increasing importance of cardiovascular cross-sectional imaging in current guidelines, the goal of this study is to provide a comprehensive overview of cardiovascular imaging (CVI) offered by radiological institutions across Germany. Materials and Methods Data were extracted from the national certification program database of the German Roentgen Society (DRG) from 2015-2021. A nationwide online survey among radiology institutes (university hospitals, non-university hospitals, and private practices) was conducted for 2019, and data was extracted from the European Society of Cardiovascular Radiology (ESCR) registry. The data collection's key points included the number of centers and individuals certified for CVI, the number of cardiac CT and MRI examinations performed, the reporting habits, and the participation in the ESCR registry. Results 71 centers and 1278 persons, both with a substantial increase since 2015, were registered and certified by the DRG to perform CVI. According to the survey, a total of 69,286 CT and 64,281 MRI examinations were performed annually. Data from the survey and the ESCR registry indicated that reporting was mostly done solely by radiologists or, to a lesser degree, in joint consensus meetings with non-radiologists. The overall participation rate in the ESCR registry was 48 % among the survey 's participants. Conclusion This comprehensive analysis demonstrates that high-quality CVI by radiologists is available nationwide. The current challenges are to provide the best medical and technical quality of CVI by radiology for patient care and to ensure economic sustainability in the German health care system to accommodate the predicted substantial need for CVI in the future. Citation Format Sieren M, Maintz D, Gutberlet M et al. Current Status of Cardiovascular Imaging in Germany: Structured Data from the National Certification Program, ESCR Registry, and Survey among Radiologists. Fortschr Rontgenstr 2021; DOI: 10

Catalog

Books, media, physical & digital resources
See catalog results