3,716 research outputs found

    3D MODELLING AND RAPID PROTOTYPING FOR CARDIOVASCULAR SURGICAL PLANNING – TWO CASE STUDIES

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    In the last years, cardiovascular diagnosis, surgical planning and intervention have taken advantages from 3D modelling and rapid prototyping techniques. The starting data for the whole process is represented by medical imagery, in particular, but not exclusively, computed tomography (CT) or multi-slice CT (MCT) and magnetic resonance imaging (MRI). On the medical imagery, regions of interest, i.e. heart chambers, valves, aorta, coronary vessels, etc., are segmented and converted into 3D models, which can be finally converted in physical replicas through 3D printing procedure. In this work, an overview on modern approaches for automatic and semiautomatic segmentation of medical imagery for 3D surface model generation is provided. The issue of accuracy check of surface models is also addressed, together with the critical aspects of converting digital models into physical replicas through 3D printing techniques. A patient-specific 3D modelling and printing procedure (Figure 1), for surgical planning in case of complex heart diseases was developed. The procedure was applied to two case studies, for which MCT scans of the chest are available. In the article, a detailed description on the implemented patient-specific modelling procedure is provided, along with a general discussion on the potentiality and future developments of personalized 3D modelling and printing for surgical planning and surgeons practice

    3D Printing and Engineering Tools Relevant to Plan a Transcatheter Procedure

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    Advance cardiac imaging techniques such as three-dimensional (3D) printing technology and engineering tools have experienced a rapid development over the last decade in many surgical and interventional settings. In presence of complex cardiac and extra-cardiac anatomies, the creation of a physical, patient-specific model is useful to better understand the anatomical spatial relationships and formulate the best surgical or interventional plan. Although many case reports and small series have been published over this topic, at the present time, there is still a lack of strong scientific evidence of the benefit of 3D models and advance engineering tools, including virtual and augmented reality, in clinical practice and only qualitative evaluation of the models has been used to investigate their clinical use. Patient-specific 3D models can be printed in many different materials including rigid, flexible and transparent materials, depending on their application. To plan interventional procedure, transparent materials may be preferred in order to better evaluate the device or stent landing zone. 3D models can also be used as an input for augmented and virtual reality application and advance fluido-dynamic simulation, which aim to support the interventional cardiologist before entering the cath lab. The aim of this chapter is to present an overview on how 3D printing, extended reality platforms and the most common computational engineering methodologies"finite element and computational fluid dynamics"are currently used to support percutaneous procedures in congenital heart disease (CHD), with examples from the scientific literature

    A process modelling method for care pathways

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    Abdominal aortic aneurysm: Treatment options, image visualizations and follow-up procedures

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    Abdominal aortic aneurysm is a common vascular disease that affects elderly population. Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm, however, endovascular aneurysm repair has rapidly expanded since its first introduction in 1990s. As a less invasive technique, endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair, especially in patients with co-morbid conditions. Computed tomography (CT) angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up. 2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair. CT has the disadvantage of high cummulative radiation dose, of particular concern in younger patients, since patients require regular imaging follow-ups after endovascular repair, thus, exposing patients to repeated radiation exposure for life. There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair. Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts, but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta. This article reviews the treatment options of abdominal aortic aneurysm, various image visualization tools, and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods. Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined

    Investigation and Validation of Imaging Techniques for Mitral Valve Disease Diagnosis and Intervention

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    Mitral Valve Disease (MVD) describes a variety of pathologies that result in regurgitation of blood during the systolic phase of the cardiac cycle. Decisions in valvular disease management rely heavily on non-invasive imaging. Transesophageal echocardiography (TEE) is widely recognized as the key evaluation technique where backflow of high velocity blood can be visualized under Doppler. In most cases, TEE imaging is adequate for identifying mitral valve pathology, though the modality is often limited from signal dropout, artifacts and a restricted field of view. Quantitative analysis is an integral part of the overall assessment of valve morphology and gives objective evidence for both classification and guiding intervention of regurgitation. In addition, patient-specific models derived from diagnostic TEE images allow clinicians to gain insight into uniquely intricate anatomy prior to surgery. However, the heavy reliance on TEE segmentation for diagnosis and modelling has necessitated an evaluation of the accuracy of the oft-used mitral valve imaging modality. Dynamic cardiac 4D-Computed Tomography (4D-CT) is emerging as a valuable tool for diagnosis, quantification and assessment of cardiac diseases. This modality has the potential to provide a high quality rendering of the mitral valve and subvalvular apparatus, to provide a more complete picture of the underlying morphology. However, application of dynamic CT to mitral valve imaging is especially challenging due to the large and rapid motion of the valve leaflets. It is therefore necessary to investigate the accuracy and level of precision by which dynamic CT captures mitral valve motion throughout the cardiac cycle. To do this, we design and construct a silicone and bovine quasi-static mitral valve phantom which can simulate a range of ECG-gated heart rates and reproduce physiologic valve motion over the cardiac cycle. In this study, we discovered that the dynamic CT accurately captures the underlying valve movement, but with a higher prevalence of image artifacts as leaflet and chordae motion increases due to elevated heart rates. In a subsequent study, we acquire simultaneous CT and TEE images of both a silicone mitral valve phantom and an iodine-stained bovine mitral valve. We propose a pipeline to use CT as the ground truth to study the relationship between TEE intensities and the underlying valve morphology. Preliminary results demonstrate that with an optimized threshold selection based solely on TEE pixel intensities, only 40\% of pixels are correctly classified as part of the valve. In addition, we have shown that emphasizing the centre-line rather than the boundaries of high intensity TEE image regions provides a better representation and segmentation of the valve morphology. This work has the potential to inform and augment the use of TEE for diagnosis and modelling of the mitral valve in the clinical workflow for MVD

    Scar conducting channel wall thickness characterization to predict arrhythmogenicity during ventricular tachycardia ablation

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    Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2020-2021. Tutora: Paz Garre Anguera de Sojo.The obtention of cardiac images before the surgery ablation of ventricular tachycardia is widely used to obtain more and better information from the patient than the information obtained during the procedure. This technique is commonly performed using cardiac magnetic resonance since it allows to study and characterise the tissue, which is crucial to detect quantify scarred tissue and the particular region that triggers the tachycardia. In this project, the arrhythmogenicity of different conducting channels from patients subjected to ventricular tachycardia ablation has been studied along with their wall thickness in order to assess a correlation using late gadolinium enhancement cardiac magnetic resonance imaging. In addition, the correlation between the left ventricle wall thickness of the conducting channels and the outcome of the cardiac catheter ablation performed from the endocardial region of the heart has also been studied. This project emerges from a previous study performed in the Hospital Clínic de Barcelona that characterized several features of the main conducting channel that triggers the ventricular tachycardia. To perform this study, the images used and the information regarding the arrhythmogenic conducting channel of every patient were obtained from the previous research, using 26 patients for the main objective of this project and using 10 of them for the study of the outcome of the ventricular tachycardia ablation The study of the wall thickness and the visualization of the conducting channels were performed using ADAS 3D software. Results showed that there was not a significative difference between the wall thickness from arrhythmogenic conducting channels and from the non-arrhythmogenic conducting channels within the patients studied but it is important to highlight that the p-value obtained was too large, which might have been caused by the lack of patients to include to this study. However, an interesting distribution of the arrhythmogenic conducting channel was noticed in the inferior-septum region of the heart, which is interesting to study further in the future using more patients and, hence, more conducting channels to study. To conclude, it is important to highlight the role of technology and biomedical engineering in this field to achieve better image acquisition to improve therapeutical techniques for the patient and this project has contributed to the awareness and the comprehension of the role of a biomedical engineer in a clinical environment

    Scenario-based system architecting : a systematic approach to developing future-proof system architectures

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    This thesis summarizes the research results of Mugurel T. Ionita, based on the work conducted in the context of the STW15 - AIMES16 project. The work presented in this thesis was conducted at Philips Research and coordinated by Eindhoven University of Technology. It resulted in six external available publications, and ten internal reports which are company confidential. The research regarded the methodology of developing system architectures, focusing in particular on two aspects of the early architecting phases. These were, first the generation of multiple architectural options, to consider the most likely changes to appear in the business environment, and second the quantitative assessment of these options with respect to how well they contribute to the overall quality attributes of the future system, including cost and risk analysis. The main reasons for looking at these two aspects of the architecting process was because architectures usually have to live for long periods of time, up to 5 years, which requires that they are able to deal successfully with the uncertainty associated with the future business environment. A second reason was because the quality attributes, the costs and the risks of a future system are usually dictated by its architecture, and therefore an early quantitative estimate about these attributes could prevent the system redesign. The research results of this project were two methods, namely a method for designing architecture options that are more future-proof, meaning more resilient to future changes, (SODA method), and within SODA a method for the quantitative assessment of the proposed architectural options (SQUASH method). The validation of the two methods has been performed in the area of professional systems, where they were applied in a concrete case study from the medical domain. The SODA method is an innovative solution to the problem of developing system architectures that are designed to survive the most likely changes to be foreseen in the future business environment of the system. The method enables on one hand the business stakeholders of a system to provide the architects with their knowledge and insight about the future when new systems are created. And on the other hand, the method enables the architects to take a long view and think strategically in terms of different plausible futures and unexpected surprises, when designing the high level structure of their systems. The SQUASH method is a systematic way of assessing in a quantitative manner, the proposed architectural options, with respect to how well they deal with quality aspects, costs and risks, before the architecture is actually implemented. The method enables the architects to reason about the most relevant attributes of the future system, and to make more informed decisions about their design, based on the quantitative data. Both methods, SODA and SQUASH, are descriptive in nature, rooted in the best industrial practices, and hence proposing better ways of developing system architectures

    Clinical Application of Three-dimensional Printing and Extended Reality in Congenital Heart Disease

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    This PhD study investigates the clinical role of the two emerging techniques, which are 3D printing and virtual reality, to improve the visualisation and surgical planning of congenital heart disease. This research findings show that both of these technologies can enhance the users’ perception on the spatial relationship of the heart structures and defects, and therefore improving the management of congenital heart disease
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