Simple simulator of gastrointestinal endoscopy with incorporation of real video images

En el siguiente artículo se expone un modelo simple del procedimiento de endoscopia gástrica y un modelo plástico del estómago y de la distensión estomacal. El uso correcto de imágenes ayuda al desarrollo de sistemas de realidad virtual, y presenta más realismo a la simulación. El objetivo del trabajo consiste en experimentar la posibilidad de construir sistemas simuladores de pacientes en Colombia, utilizando la tecnología localmente disponible, a bajo costo y destinados para la formación de estudiantes de medicina.The following paper deals with a simple model of a gastric endoscopy procedure and a plastic model of the stomach and its distension. The correct use of imaging helps in the development of virtual reality systems, and provides a greater realism to the simulation itself. The goal is to experience the possibility of building patient simulator systems in Colombia, using locally available technology, at low costs and intended for the training of medical students

An Accurate and Dynamic Computer Graphics Muscle Model

A computer based musculo-skeletal model was developed at the University in the departments of Mechanical and Biomedical Engineering. This model accurately represents human shoulder kinematics. The result of this model is the graphical display of bones moving through an appropriate range of motion based on inputs of EMGs and external forces. The need existed to incorporate a geometric muscle model in the larger musculo-skeletal model. Previous muscle models did not accurately represent muscle geometries, nor did they account for the kinematics of tendons. This thesis covers the creation of a new muscle model for use in the above musculo-skeletal model. This muscle model was based on anatomical data from the Visible Human Project (VHP) cadaver study. Two-dimensional digital images from the VHP were analyzed and reconstructed to recreate the three-dimensional muscle geometries. The recreated geometries were smoothed, reduced, and sliced to form data files defining the surfaces of each muscle. The muscle modeling function opened these files during run-time and recreated the muscle surface. The modeling function applied constant volume limitations to the muscle and constant geometry limitations to the tendons

A Scheme for Automatically Building 3D Morphometric Anatomical Atlases: application to a Skull Atlas

International audienceWe present a general scheme for automatically building a morphometric anatomical atlas. We detail each stage of the method, including the non-rigid registration algorithm, three-dimensional line averaging and statistical processes. We apply the method to obtain a quantitative atlas of skull crest lines. Finally, we use the resulting atlas to study a craniofacial disease; we show how we can obtain qualitative and quantitative results by contrasting a skull affected by a mandible deformation with the atlas

Three-dimensional anatomical atlas of the human body

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor in Information Management, specialization in Geographic Information SystemsAnatomical atlases allow mapping the anatomical structures of the human body. Early versions of these systems consisted of analogic representations with informative text and labelled images of the human body. With the advent of computer systems, digital versions emerged and the third dimension was introduced. Consequently, these systems increased their efficiency, allowing more realistic visualizations with improved interactivity. The development of anatomical atlases in geographic information systems (GIS) environments allows the development of platforms with a high degree of interactivity and with tools to explore and analyze the human body. In this thesis, a prototype for the human body representation is developed. The system includes a 3D GIS topological model, a graphical user interface and functions to explore and analyze the interior and the surface of the anatomical structures of the human body. The GIS approach relies essentially on the topological characteristics of the model and on the kind of available functions, which include measurement, identification, selection and analysis. With the incorporation of these functions, the final system has the ability to replicate the kind of information provided by the conventional anatomical atlases and also provides a higher level of functionality, since some of the atlases limitations are precisely features offered by GIS, namely, interactive capabilities, multilayer management, measurement tools, edition mode, allowing the expansion of the information contained in the system, and spatial analyzes

Computergestützte Visualisierung eines human-embryonalen Gehirns

In der vorliegenden Arbeit wurde das 3-D-Modell des Gehirns eines frühen humanen Embryos angefertigt, des Weiteren eine 3-D-Software entwickelt, die es erlaubt, das Modell in Echtzeit manipulierbar darzustellen und es schließlich vollwertig stereoskopisch betrachten zu können. Diese Software wird Studierenden auf dem Server des Leibniz-Rechenzentrums zur Verfügung gestellt. Damit können sie am eigenen Rechner virtuelle 3-D-Modelle, die am Lehrstuhl III der Anatomischen Anstalt erarbeitet und bereit gestellt werden, plastisch (auch stereoskopisch) studieren. So besteht in Zukunft die Möglichkeit, die embryonale Entwicklung mit zeitgemäßen Methoden leicht verständlich zu veranschaulichen. Dem 3-D-Modell diente als Quellmaterial eine Schnittserie aus 574 Schichten eines menschlichen Embryos im Carnegie-Stadium 18. Die Schichten wurden über ein Mikroskop digitalisiert und am Computer wieder räumlich zueinander ausgerichtet. Um die ursprünglichen anatomischen Verhältnisse trotz der verzerrten Schnitte mit dem kommerziell verfügbaren Programm AmiraDev 3.0 möglichst korrekt herzustellen, wurde dieser elementare aber komplizierte Schritt durch selbst entwickelte Techniken unterstützt und sichtbar verbessert. Im so entstandenen Bilderstapel wurde das Gehirn markiert und dann zum virtuellen Modell trianguliert. Die hier entwickelte 3-D-Software erlaubt es, das willkürlich drehbare 3-D-Modell sowie andere Rekonstruktionen am Rechner anzuzeigen. Eine frei wählbare Schnittebene und die Transparenzfunktion geben Aufschluss über den inneren Aufbau des 3-D-Modells, z. B. über das Ventrikelsystem. In der Programmiersprache C++ wurden hocheffiziente, handoptimierte Bibliotheken für lineare Algebra und Computergrafik entwickelt, die eine ruckfreie Betrachtung ermöglichen. Im Hinblick auf Effizienz, Erweiterbarkeit und Fehlervermeidung wurde auf ein wohl überlegtes Software-Design mit sicherer Semantik Wert gelegt. Auch wenn ein virtuelles 3-D-Modell bereits einen besseren räumlichen Eindruck als eine plane Abbildung verschafft, kommt eine echte Tiefenwirkung erst durch stereoskopische Darstellung zustande. Diese wurde lege artis als asymmetrische perspektivische Projektion so implementiert, dass sie unkompliziert auf Tastendruck genutzt werden kann. Die ausgereifte Software beherrscht das Anaglyphenverfahren (Rot-Grün-Brille) genauso wie auch aufwendigere Projektionsverfahren. Die Arbeit stellt darüber hinaus in kurzer Form die für die Programmentwicklung relevanten mathematischen Grundlagen dar. Ferner wird ein Überblick über die im Internet verfügbaren, teils kommerziell vertriebenen Datensätze – speziell zur Embryologie – gegeben und das selbst entwickelte Darstellungsmodell mit seinen Vorteilen und den (selbst auferlegten) Beschränkungen in dieses Bezugssystem eingeordnet

A robust framework for medical image segmentation through adaptable class-specific representation

Medical image segmentation is an increasingly important component in virtual pathology, diagnostic imaging and computer-assisted surgery. Better hardware for image acquisition and a variety of advanced visualisation methods have paved the way for the development of computer based tools for medical image analysis and interpretation. The routine use of medical imaging scans of multiple modalities has been growing over the last decades and data sets such as the Visible Human Project have introduced a new modality in the form of colour cryo section data. These developments have given rise to an increasing need for better automatic and semiautomatic segmentation methods. The work presented in this thesis concerns the development of a new framework for robust semi-automatic segmentation of medical imaging data of multiple modalities. Following the specification of a set of conceptual and technical requirements, the framework known as ACSR (Adaptable Class-Specific Representation) is developed in the first case for 2D colour cryo section segmentation. This is achieved through the development of a novel algorithm for adaptable class-specific sampling of point neighbourhoods, known as the PGA (Path Growing Algorithm), combined with Learning Vector Quantization. The framework is extended to accommodate 3D volume segmentation of cryo section data and subsequently segmentation of single and multi-channel greyscale MRl data. For the latter the issues of inhomogeneity and noise are specifically addressed. Evaluation is based on comparison with previously published results on standard simulated and real data sets, using visual presentation, ground truth comparison and human observer experiments. ACSR provides the user with a simple and intuitive visual initialisation process followed by a fully automatic segmentation. Results on both cryo section and MRI data compare favourably to existing methods, demonstrating robustness both to common artefacts and multiple user initialisations. Further developments into specific clinical applications are discussed in the future work section

Desarrollo de un modelo tridimensional de ventrículos humanos anatómicamente detallado para simulación de electrofisiología cardíaca

[EN] First, an exhaustive revision of the state of art on 3D cardiac models has been carried out, focusing on material and methods used for their construction. As main goal of the work, a 3D cardiac model has also been developed based on in-vivo medical images, including a realistic representation of the two whole ventricles up to the cardiac valves' planes, the cardiac fiber orientation, the cardiac conduction system and an ischemic scar on the left ventricle due to a myocardial infarction. This model has been constructed to be used in 3D realistic cardiac electrophysiology simulations.[ES] En primer lugar, se ha realizado una exhaustiva revisión del estado del arte sobre los modelos cardíacos 3D, prestando especial atención al material y los métodos empleados en su construcción. Como objetivo principal del trabajo, también se ha desarrollado un modelo cardíaco 3D a partir de imagen médica in-vivo, incluyendo una representación realista de los dos ventrículos completos hasta los planos de las válvulas cardíacas, la orientación de las fibras cardíacas, el sistema de conducción cardíaco y una escara isquémica sobre el ventrículo izquierdo provocada por un infarto de miocardio. Este modelo se ha construido para su uso en simulaciones realistas de electrofisiología cardíaca en 3D.López Pérez, AD. (2013). Desarrollo de un modelo tridimensional de ventrículos humanos anatómicamente detallado para simulación de electrofisiología cardíaca. http://hdl.handle.net/10251/44340Archivo delegad

3D modeling of the human upper limb including the biomechanics of joints, muscles and soft tissues

The challenge in virtual human modeling is to achieve the representation of the main human characteristics with as much realism as possible. Such achievements would allow the simulation and/or analysis of many virtual situations involving humans. Simulation is especially useful to derive information from the models so as to predict and/or reproduce the behaviors that would be observed in real situations. Computer methods in visualization and simulation have thus great potential for advances in medicine. The processes of strength generation and motion coordination are some of these phenomena for which there is still much remaining to be understood. The human shoulder is also probably the articulation of the human body which deserves more than any other to be named "terra incognita". Investigations towards the biomechanical modeling and simulation of the human upper limb are therefore presented in this study. It includes thorough investigation into the musculoskeletal anatomy and biomechanics of the human upper limb, into the biomechanical constitutive modeling of muscles and soft tissues, and into the nonlinear continuum mechanics and numerical methods, especially the incremental finite element methods, necessary for their simulation. On this basis, a 3-D biomechanical musculoskeletal human upper limb model has been designed using the Visible Human Data provided by the U.S. National Library of Medicine, and applied to the dynamic musculoskeletal simulation of the human upper limb. This research has been achieved in the context of the EU ESPRIT Project CHARM, whose objective has been to develop a comprehensive human animation resource database and a set of software tools allowing the modeling of the human complex musculoskeletal system and the simulation of its dynamics, including the finite element simulation of soft tissue deformation and muscular contraction. An investigation towards the application of this knowledge for the realistic modeling and animation of the upper limb in computer animation is then presented. The anatomical and biomechanical modeling of the scapulo-thoracic constraint and the shoulder joint sinus cones are proposed and applied to the realistic animation, using inverse kinematics, of a virtual skeleton and an anatomic musculoskeletal body model