244 research outputs found
Hemodynamic on abdominal aortic aneurysm: Parametric study
Peer ReviewedPostprint (author's final draft
Study of angulations of visceral abdominals arteries in their abdominal aorta emergency
Postprint (author's final draft
Computational fluid dynamics indicators to improve cardiovascular pathologies
In recent years, the study of computational hemodynamics within anatomically complex vascular regions has generated great interest among clinicians.
The progress in computational fluid dynamics, image processing and high-performance computing haveallowed us to identify the candidate vascular regions for the appearance of cardiovascular diseases and to predict how this disease may evolve.
Medicine currently uses a paradigm called diagnosis. In this thesis we attempt to introduce into medicine the predictive paradigm that has been used in engineering for many years. The objective of this thesis is therefore to develop predictive models based on diagnostic indicators for cardiovascular pathologies.
We try to predict the evolution of aortic abdominal aneurysm, aortic coarctation and coronary artery disease in a personalized way for each patient. To understand how the cardiovascular pathology will evolve and when it will become a health risk, it is necessary to develop new technologies by merging medical imaging and computational science. We propose diagnostic indicators that can improve the diagnosis and predict the evolution of the disease more efficiently than the methods used until now. In particular, a new methodology for computing diagnostic indicators based on computational hemodynamics and medical imaging is proposed. We have worked with data of anonymous patients to create real predictive technology that will allow us to continue advancing in personalized medicine and generate more sustainable health systems. However, our final aim is to achieve an impact at a clinical level. Several groups have tried to create predictive models for cardiovascular pathologies, but they have not yet begun to use them in clinical practice. Our objective is to go further and obtain predictive variables to be used practically in the clinical field.
It is to be hoped that in the future extremely precise databases of all of our anatomy and physiology will be available to doctors. These data can be used for predictive models to improve diagnosis or to improve therapies or personalized treatments.En els Ăşltims anys, l'estudi de l'hemodinĂ mica computacional en regions vasculars anatòmicament complexes ha generat un gran interès entre els clĂnics. El progrĂ©s obtingut en la dinĂ mica de fluids computacional, en el processament d'imatges i en la computaciĂł d'alt rendiment ha permès identificar regions vasculars on poden aparèixer malalties cardiovasculars, aixĂ com predir-ne l'evoluciĂł. Actualment, la medicina utilitza un paradigma anomenat diagnòstic. En aquesta tesi s'intenta introduir en la medicina el paradigma predictiu utilitzat des de fa molts anys en l'enginyeria. Per tant, aquesta tesi tĂ© com a objectiu desenvolupar models predictius basats en indicadors de diagnòstic de patologies cardiovasculars. Tractem de predir l'evoluciĂł de l'aneurisma d'aorta abdominal, la coartaciĂł aòrtica i la malaltia coronĂ ria de forma personalitzada per a cada pacient. Per entendre com la patologia cardiovascular evolucionarĂ i quan suposarĂ un risc per a la salut, cal desenvolupar noves tecnologies mitjançant la combinaciĂł de les imatges mèdiques i la ciència computacional. Proposem uns indicadors que poden millorar el diagnòstic i predir l'evoluciĂł de la malaltia de manera mĂ©s eficient que els mètodes utilitzats fins ara. En particular, es proposa una nova metodologia per al cĂ lcul dels indicadors de diagnòstic basada en l'hemodinĂ mica computacional i les imatges mèdiques. Hem treballat amb dades de pacients anònims per crear una tecnologia predictiva real que ens permetrĂ seguir avançant en la medicina personalitzada i generar sistemes de salut mĂ©s sostenibles. Però el nostre objectiu final Ă©s aconseguir un impacte en l¿à mbit clĂnic. Diversos grups han tractat de crear models predictius per a les patologies cardiovasculars, però encara no han començat a utilitzar-les en la prĂ ctica clĂnica. El nostre objectiu Ă©s anar mĂ©s enllĂ i obtenir variables predictives que es puguin utilitzar de forma prĂ ctica en el camp clĂnic. Es pot preveure que en el futur tots els metges disposaran de bases de dades molt precises de tota la nostra anatomia i fisiologia. Aquestes dades es poden utilitzar en els models predictius per millorar el diagnòstic o per millorar terĂ pies o tractaments personalitzats.Postprint (published version
Computational modeling of the fluid flow in type B aortic dissection using a modified finite element embedded formulation
This work explores the use of an embedded computational fluid dynamics method to study the type B aortic dissection. The use of the proposed technique makes it possible to easily test different intimal flap configurations without any need of remeshing. To validate the presented methodology, we take as reference test case an in vitro experiment present in the literature. This experiment, which considers several intimal flap tear configurations (number, size and location), mimics the blood flow in a real type B aortic dissection. We prove the correctness and suitability of the presented approach by comparing the pressure values and waveform. The obtained results exhibit a remarkable similarity with the experimental reference data. Complementary, we present a feasible surgical application of the presented computer method. The aim is to help the clinicians in the decision making before the type B aortic dissection surgical fenestration. The capabilities of the proposed technique are exploited to efficiently create artificial reentry tear configurations. We highlight that only the radius and center of the reentry tear need to be specified by the clinicians, without any need to modify neither the model geometry nor the mesh. The obtained computational surgical fenestration results are in line with the medical observations in similar clinical studies
Mechanistic and pathological study of the genesis, growth, and rupture of abdominal aortic aneurysms
Postprint (published version
Estimation of wall shear stress using 4D flow cardiovascular MRI and computational fluid dynamics
Electronic version of an article published as Journal of mechanics in medicine and biology, 0, 1750046 (2016), 16 pages. DOI:10.1142/S0219519417500464
© World Scientific Publishing CompanyIn the last few years, wall shear stress (WSS) has arisen as a new diagnostic indicator in patients with arterial disease. There is a substantial evidence that the WSS plays a significant role, together with hemodynamic indicators, in initiation and progression of the vascular diseases. Estimation of WSS values, therefore, may be of clinical significance and the methods employed for its measurement are crucial for clinical community. Recently, four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has been widely used in a number of applications for visualization and quantification of blood flow, and although the sensitivity to blood flow measurement has increased, it is not yet able to provide an accurate three-dimensional (3D) WSS distribution. The aim of this work is to evaluate the aortic blood flow features and the associated WSS by the combination of 4D flow cardiovascular magnetic resonance (4D CMR) and computational fluid dynamics technique. In particular, in this work, we used the 4D CMR to obtain the spatial domain and the boundary conditions needed to estimate the WSS within the entire thoracic aorta using computational fluid dynamics. Similar WSS distributions were found for cases simulated. A sensitivity analysis was done to check the accuracy of the method. 4D CMR begins to be a reliable tool to estimate the WSS within the entire thoracic aorta using computational fluid dynamics. The combination of both techniques may provide the ideal tool to help tackle these and other problems related to wall shear estimation.Peer ReviewedPostprint (author's final draft
Decision support system for cardiovascular problems
The two main lines of medical research in this project are vascular anatomy (large vessels around
the heart, coronaries and peripheral arteries) and heart chambers. Geometric models will be
constructed to aid clinical diagnosis or multiphysical modelling and simulation. Two levels of
complexity will be considered. For heart modelling, the first level will concentrate on models of the
left and right ventricular cavities for robust and efficient extraction of simple clinical indexes of
geometry, volume, mass, and wall kinetics. The second level will aim at more complex, fourchambered
models, which will be important in developing comprehensive solid and fluid models to
assist the design of medical devices
Computational modeling of the fluid flow in type B aortic dissection using a modified finite element embedded formulation
The final publication is available at Springer via http://dx.doi.org/10.1007/s10237-020-01291-xThis work explores the use of an embedded computational fluid dynamics method to study the type B aortic dissection. The use of the proposed technique makes it possible to easily test different intimal flap configurations without any need of remeshing. To validate the presented methodology, we take as reference test case an in vitro experiment present in the literature. This experiment, which considers several intimal flap tear configurations (number, size and location), mimics the blood flow in a real type B aortic dissection. We prove the correctness and suitability of the presented approach by comparing the pressure values and waveform. The obtained results exhibit a remarkable similarity with the experimental reference data. Complementary, we present a feasible surgical application of the presented computer method. The aim is to help the clinicians in the decision making before the type B aortic dissection surgical fenestration. The capabilities of the proposed technique are exploited to efficiently create artificial reentry tear configurations. We highlight that only the radius and center of the reentry tear need to be specified by the clinicians, without any need to modify neither the model geometry nor the mesh. The obtained computational surgical fenestration results are in line with the medical observations in similar clinical studies.Peer ReviewedPostprint (author's final draft
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