@inproceedings{solteszova-avp-2009, title = "Advanced Volume Painting with Game Controllers", author = "Veronika Solteszova and Maurice Termeer and Eduard Gr\"{o}ller", year = "2009", month = apr, location = "Budmerice, Slowakei", booktitle = "Proceedings of the 25th Spring Conference on Computer Graphics (SCCG)", pages = "125--132", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/solteszova-avp-2009/", } @misc{termeer-2009-scmr, title = "Patient-Specific Coronary Artery Supply Territory AHA Diagrams", author = "Maurice Termeer and Javier Oliv\'{a}n Besc\'{o}s and Marcel Breeuwer and Anna Vilanova i Bartroli and Frans Gerritsen and Eduard Gr\"{o}ller and Eike Nagel", year = "2009", abstract = "Introduction: The American Heart Association proposed a 17-segment model for the segmentation of the left ventricle together with a mapping from each segment to a supplying coronary artery. This proposal is based on population averages. Several studies have confirmed the inaccuracy of this mapping due to large anatomical variations of the coronary arteries among individuals. Several proposals have been made for a different mapping between the 17 segments and the coronary arteries. Purpose: Due to the large variation in coronary anatomy there is a need for a patient-specific assignment of ventricular segments to supplying coronary arteries. We propose to use a segmentation of the coronary arteries and the ventricular epicardium to compute this patient-specific mapping. Methods: The three primary coronary arteries (LAD, LCX and RCA) and the left ventricle are segmented in a whole-heart MRI (SSFP) or CT scan of at least 150 slices. For the coronary arteries we employ a semi-automatic vessel tracking algorithm. The left ventricle is segmented using a fully automatic approach. The epicardial surface of the resulting segmentation is represented as a quadrilateral mesh. The centerlines of the coronary arteries are projected on the epicardial surface. A Voronoi diagram of the projected arteries is computed using a geodesic distance metric. The patient-specific coronary supply territories are computed using a modified marching squares algorithm. The examples given here consist of three territories, but our approach is flexible enough to handle any amount of territories. Both the coronary supply territories and the coronary arteries are projected onto a bull’s eye plot using a parameterization of the left ventricle based on cylindrical coordinates, using the cardiac long axis as the primary axis of the cylinder (Figure 1a). The continuous nature of the epicardial surface is preserved in this projection. This means that the bull’s eye plot does not consist of rings representing slices, but that the distance to the center is proportional to the distance to the apex. This bull’s eye plot can for example be used as an overlay for the analysis of viability (Figure 1b). Figure 1. (a) Bull’s eye plot showing patient-specific coronary supply territories. The dotted lines represent the 17-segment model. (b) Patient-specific coronary supply territories as an overlay on a bull’s eye plot of a late enhancement scan. Results: We evaluated our method on image data from five patients. For each patient we produced both a standard 17-segment diagram and a diagram with the projection of the patient-specific coronary supply territories resulting from our approach. In both diagrams a projection of the segmented coronary arteries was shown. We then asked an experienced clinician to judge the correspondence between the coronary arteries and the suggested coronary supply territories for both diagrams. It was judged that our patient-specific coronary supply territories provide a better correlation with the position of the coronary arteries. The clinician expressed a preference to our method as compared to the standard 17-segment model. The continuous relation between the distance to the center of the bull’s eye plot and the distance to the apex caused some confusion with our clinician. Especially in combination with CMR data consisting of relatively few slices this relation should be clarified. Conclusion: With our method the relation between coronary arteries and areas supplied by these arteries is better visualized. This will help to better correlate the location of infarcted or ischemic areas to the coronaries that have caused the respective infarction or ischemia.", month = jan, journal = "Journal of Cardiovascular Magnetic Resonance", volume = "11", series = "1", location = "Orlando, Florida", issn = "1532-429X ", event = "SCMR 2009", booktitle = "Abstracts of the 12th Annual SCMR Scientific Sessions - 2009", Conference date = "Poster presented at SCMR 2009 (2009-01-29--2009-02-01)", note = "164--165", pages = "164 – 165", keywords = "coronary supply territories, patient-specific bulls eye plot", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/termeer-2009-scmr/", } @phdthesis{termeer-2009-cvc, title = "Comprehensive Visualization of Cardiac MRI Data", author = "Maurice Termeer", year = "2009", abstract = "Coronary artery disease is one of the leading causes of death in the western world. The continuous improvements in magnetic resonance imaging technology facilitate more accurate diagnoses by providing increasingly more detailed information on the viability, functioning, perfusion, and anatomy of a patient’s heart. This increasing amount of information creates the need for more efficient and more effective means of processing these data. This thesis presents several novel techniques that facilitate a more comprehensive visualization of a patient’s heart to assist in the diagnosis of coronary artery disease using magnetic resonance imaging (MRI). The volumetric bull’s eye plot is introduced as an extension of an existing visualization technique used in clinical practice---the bull’s eye plot. This novel concept offers a more comprehensive view on the viability of a patient’s heart by providing detailed information on the transmurality of scar while not suffering from discontinuities. Anatomical context is often lost due to abstract representations of data, or may be scarce due to the nature of the scanning protocol. Several techniques to restore the relation to anatomy are presented. The primary coronary arteries are segmented in a whole heart scan and mapped onto a volumetric bull’s eye plot, adding anatomical context to an abstract representation. Similarly, segmented late enhancement data are rendered along with a three-dimensional segmentation of the patient-specific myocardial and coronary anatomy. Additionally, coronary supply territories are computed from patient-specific data as an improvement over models based on population averages. Information on the perfusion of the myocardium provided by MRI is typically of fairly low resolution. Using high-resolution anatomical data, an approach to visualize simulated myocardial perfusion is presented, taking full advantage of the detailed information on perfusion. Finally, a truly comprehensive visualization of a cardiac MRI exam is explored by combining whole heart, late enhancement, functional, and perfusion scans in a single visualization. The concepts introduced help to build a more comprehensive view of the patient and the additional information may prove to be beneficial for the diagnostic process.", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "Cardiac MRI Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/termeer-2009-cvc/", } @article{termeer-2008-vis, title = "Visualization of Myocardial Perfusion Derived from Coronary Anatomy", author = "Maurice Termeer and Javier Oliv\'{a}n Besc\'{o}s and Marcel Breeuwer and Anna Vilanova i Bartroli and Frans Gerritsen and Eduard Gr\"{o}ller and Eike Nagel", year = "2008", abstract = "Visually assessing the effect of the coronary artery anatomy on the perfusion of the heart muscle in patients with coronary artery disease remains a challenging task. We explore the feasibility of visualizing this effect on perfusion using a numerical approach. We perform a computational simulation of the way blood is perfused throughout the myocardium purely based on information from a three-dimensional anatomical tomographic scan. The results are subsequently visualized using both three-dimensional visualizations and bull's eye plots, partially inspired by approaches currently common in medical practice. Our approach results in a comprehensive visualization of the coronary anatomy that compares well to visualizations commonly used for other scanning technologies. We demonstrate techniques giving detailed insight in blood supply, coronary territories and feeding coronary arteries of a selected region. We demonstrate the advantages of our approach through visualizations that show information which commonly cannot be directly observed in scanning data, such as a separate visualization of the supply from each coronary artery. We thus show that the results of a computational simulation can be effectively visualized and facilitate visually correlating these results to for example perfusion data. ", month = oct, journal = "TVCG", volume = "14", number = "6", issn = "1077-2626", pages = "1595--1602", keywords = "myocardial perfusion, coronary artery territories, cardiac visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/termeer-2008-vis/", } @misc{termeer-2008-scmr, title = "The Volumetric Bulls Eye Plot", author = "Maurice Termeer and Javier Oliv\'{a}n Besc\'{o}s and Marcel Breeuwer and Anna Vilanova i Bartroli and Frans Gerritsen and Eduard Gr\"{o}ller", year = "2008", abstract = "Introduction: The bull's eye plot is a commonly used schematic for the visualization of quantitative late enhancement cardiac MRI data. It gives an intuitive overview of the viability of the entire left ventricular myocardium in a single diagram. However, common implementations do not provide a continuous transition between slices and provide poor or no information about the exact location and transmurality of non-viable tissue. Purpose: We propose a novel visualization technique that relieves the drawbacks of the bull's eye plot but maintains its advantages. Our hypothesis is that our technique will enable a more accurate assessment of the relation between viable and non-viable myocardial tissue (scar). Methods: Short-axis late enhancement cardiac MRI acquisitions consist of 10-20 slices. We segment the left-ventricular myocardium in all slices using manually drawn contours on both the epicardium and the endocardium. The segmented myocardium is subsequently unfolded along the long axis and reformatted to form a thin cylinder (Figure 1a). In this process myocardial cross-sections are mapped to equidistant rings within this cylinder. The volumetric nature of the myocardium is preserved during the unfolding. A projection of the cylinder is generated using the technique of volume rendering (Figure 1b). The viewing direction in this projection is oriented from the apex towards the base of the ventricle. This makes the viewer perceive the endocardium to be behind the epicardium. This view is further augmented with the main coronary arteries extracted from a whole heart MRI scan (150 slices, SSFP). Furthermore, two dots indicating the points where the left and right-ventricular myocardial connect are added. A thin slab perpendicular to the long axis within the cylinder can be selected for exclusive rendering, providing a method of visualizing only epicardial or endocardial viability. To investigate scar transmurality, the user can select a wedge-shaped region of interest. Figure 1c shows the transmurality of that region by projecting it from its side. The unfolding method is modified for this projection to compensate for distortions due to the shape of the selected region. Since the wall thickness may vary within the region of interest, lines indicating the minimum and maximum wall thickness in the selected region are displayed. Results: The long-axis projection provides a smooth overview of the viability due to the unfolding method that preserves the continuous, volumetric nature of the myocardium. This also causes the resolution of the diagram to increase when more slices are acquired. The additional context information (i.e., coronary arteries) allows for easier interpretation of the location of any scar. Due to the close relation to the bull's eye plot, we believe that clinical adoption will be easy. The transmurality view provides detailed information on the distribution of scar within the myocardium. The preservation of wall thickness allows for judgment of the location and extent of the scar in relation to healthy tissue. Conclusion: Our novel volumetric bull's eye plot allows for a comprehensive assessment of viability and scar transmurality thanks to its continuous nature and the additional context information provided. ", month = feb, journal = "Journal of Cardiovascular Magnetic Resonance", volume = "11", series = "1", location = "Los Angeles, California", event = "SCMR 2008", booktitle = "Abstracts of the 11th Annual SCMR Scientific Sessions – 2008", Conference date = "Poster presented at SCMR 2008 (2008-02-08--2008-02-10)", note = "199--200", pages = "199 – 200", keywords = "Viability, Bulls Eye Plot, Cardiac MRI", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/termeer-2008-scmr/", } @article{termeer-2007-covicad, title = "CoViCAD: Comprehensive Visualization of Coronary Artery Disease", author = "Maurice Termeer and Javier Oliv\'{a}n Besc\'{o}s and Marcel Breeuwer and Anna Vilanova i Bartroli and Frans Gerritsen and Eduard Gr\"{o}ller", year = "2007", abstract = "We present novel, comprehensive visualization techniques for the diagnosis of patients with Coronary Artery Disease using segmented cardiac MRI data. We extent an accepted medical visualization technique called the bull’s eye plot by removing discontinuities, preserving the volumetric nature of the left ventricular wall and adding anatomical context. The resulting volumetric bull’s eye plot can be used for the assessment of transmurality. We link these visualizations to a 3D view that presents viability information in a detailed anatomical context. We combine multiple MRI scans (whole heart anatomical data, late enhancement data) and multiple segmentations (polygonal heart model, late enhancement contours, coronary artery tree). By selectively combining different rendering techniques we obtain comprehensive yet intuitive visualizations of the various data sources.", month = oct, journal = "IEEE Transactions on Visualization and Computer Graphics (accepted for publication)", volume = "13", number = "6", keywords = "VBEP, viability, late enhancement, Cardiac MRI, bull", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/termeer-2007-covicad/", } @inproceedings{termeer-2006-000, title = "Preserving Sharp Edges with Volume Clipping", author = "Maurice Termeer and Javier Oliv\'{a}n Besc\'{o}s and Alexandru Telea", year = "2006", abstract = "Volume clipping is a useful aid for exploring volumetric datasets. To maximize the effectiveness of this technique, the clipping geometry should be flexibly specified and the resulting images should not contain artifacts due to the clipping techniques. We present an improvement to an existing illumination model for volume clipping to allow sharp edges in the data to stay visible. These sharp edges often originate from material transitions in the volume or structures being partially cut by the clipping geometry. The focus is on high, industrial image quality and flexibility of the algorithm; techniques for using high-resolution polygonal meshes as clipping algorithms and removal of artifacts are presented. Features of the latest consumer graphics hardware are exploited to provide the visualization at an interactive framerate without the need for multipassing. We have validated the techniques presented here by implementing them in the context of a professional volume rendering application at Philips Medical Systems, and comparing our results with current results produced by existing solutions.", month = nov, location = "Aachen, Germany", booktitle = "Proceedings Vision, Modeling and Visualization 2006", keywords = "volume clipping, sharp edges", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/termeer-2006-000/", }