Projects
CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts
The EU-funded project Cupido, started in February 2017, proposes an innovative solution: the application of nanotechnologies to the cardiovascular field. Cupido aims to hit the core of the cardiovascular disease, developing inhalable nanoparticles that can deliver a therapy directly to the diseased heart. Nanoparticles are extremely tiny, almost 1 million times smaller than a grain of sand in size and far too small to see with conventional microscopes. Exploiting such a tiny system as a route of administration can revolutionize the cardiovascular field, becoming the first non-invasive and heart-specific therapy. To achieve the goal, the Cupido consortium is working to develop biocompatible and biodegradable nanoparticles that can self-assemble and encapsulate drugs (novel or available) for cardiovascular disease. The nanoparticles, once inhaled, will first reach the lungs and later will translocate to the heart, where the drug will be finally released on the site of interest. The heart-specificity will be ensured thanks to chemical and magnetic guidance, reducing the chances of adverse side effects. Simula's role is to develop novel numerical methods for simulating nanoparticle deposition to enhance efficacy and to accelerate deposition in studies from small to large animals, but ultimately also humans. For more information, see the projects homepage.
Publications for CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts
Journal Article
Time-Lapsing Perfusion: Proof of Concept of a Novel Method to Study Drug Delivery in Whole Organs
Biophysical Journal 117, no. 12 (2019): 2316-2323.Status: Published
Time-Lapsing Perfusion: Proof of Concept of a Novel Method to Study Drug Delivery in Whole Organs
Perfusion is one of the most important processes maintaining organ health. From a computational perspective, however, perfusion is amongst the least studied physiological processes of the heart. The recent development of novel nanoparticle-based targeted cardiac therapy calls for novel simulation methods that can provide insights into the distribution patterns of therapeutic agents within the heart tissue. Additionally, resolving the distribution patterns of perfusion is crucial for gaining a full understanding of the long-term impacts of cardiovascular diseases that can lead to adverse remodelling, such as myocardial ischemia and heart failure. In this study we have developed and used a novel particle tracking-based method to simulate the perfusion-mediated distribution of nanoparticles or other solutes. To model blood flow through perfused tissue we follow the approach of others and treat the tissue as a porous medium in a continuum model. Classically, solutes are modelled
using reaction-advection-diffusion kinetics. However, due to the discrepancy between advection and diffusion in blood vessels, this method becomes numerically unstable. Instead, we track a bolus of solutes or nanoparticles using particle tracking based purely on advection in arteries. In capillaries we employ diffusion kinetics, using an effective diffusion coefficient to mimic capillary blood flow. We first demonstrate the numerical validity and computational efficiency of this method on a 2D benchmark problem. Finally, we demonstrate how the method is used to visualise perfusion patterns of a human left ventricle geometry. The efficiency of the method allows for nanoparticle tracking over multiple cardiac cycles using a conventional laptop, providing a framework for the simulation of experimentally relevant time frames to advance pre-clinical research.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Journal Article |
| Year of Publication | 2019 |
| Journal | Biophysical Journal |
| Volume | 117 |
| Issue | 12 |
| Pagination | 2316-2323 |
| Publisher | Cell Press |
Poster
Porous modelling of cardiac perfusion to optimise targeted drug delivery
Computing in Cardiology, Singapore, 2019.Status: Published
Porous modelling of cardiac perfusion to optimise targeted drug delivery
Delivery of therapy-loaded nanoparticles (NP) via inhalation is an innovative technology shown to successfully reduce heart failure in mice, improving the efficiency of drug delivery, and reducing adverse side effects. However, how exactly therapeutic NP are distributed and absorbed by heart tissue remains poorly understood, and accelerating this technology to humans is a major challenge. To overcome this problem we developed an open-source finite element model of myocardial perfusion based on porous media, where perfused tissue is treated as a sponge-like continuum material, driven by a continuum model of cardiac contraction to simulate perfusion patterns. We use our novel particle-tracking based method that remains numerically stable under high Peclet number flow to study NP distribution.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Poster |
| Year of Publication | 2019 |
| Date Published | 09/2019 |
| Place Published | Computing in Cardiology, Singapore |
Proceedings, refereed
Porous Modelling of Cardiac Perfusion under Contraction to Demonstrate the Distribution of Therapeutic Nanoparticles
In International Conference in Computing in Cardiology, Singapore, 2019. IEEE, 2019.Status: Published
Porous Modelling of Cardiac Perfusion under Contraction to Demonstrate the Distribution of Therapeutic Nanoparticles
Delivery of therapy-loaded nanoparticles (NP) via inhalation is an innovative technology shown to successfully reduce heart failure in mice, improving the efficiency of
drug delivery, and reducing adverse side effects. However, how exactly therapeutic NP are distributed and absorbed by heart tissue remains poorly understood, and accelerating this technology to humans is a major challenge. Working towards overcoming this problem we developed an open-source finite element model of myocardial per-
fusion based on porous media, where perfused tissue is treated as a sponge-like continuum material, driven by a continuum model of cardiac contraction to simulate perfusion patterns. We use our novel particle-tracking based method that remains numerically stable under high Peclet number flow to enable the study of NP distribution.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2019 |
| Conference Name | International Conference in Computing in Cardiology, Singapore, 2019 |
| Publisher | IEEE |
Talks, contributed
Autonomic Modelling of Interaction between Coronary Perfusion Flow and Myocardium Mechanics using Computational Poroelasticity
In International Society of Autonomic Neuroscience, Los Angeles, CA, USA. International Society of Autonomic Neuroscience, 2019, 2019.Status: Published
Autonomic Modelling of Interaction between Coronary Perfusion Flow and Myocardium Mechanics using Computational Poroelasticity
Autonomic control and modelling the cross-talk between blood flow in coronary vessels and ventricular wall mechanical deformations are central problems in mechanocardiac physiology. In this study, we use a multi-scale approach that includes multi-physics modules of the heart with autonomic control, to accurately model this complex interaction between coronary perfusion and myocardium mechanics. In particular, we implement a 3D finite element numerical scheme to account for this coupling using a reconstructed and geometrically-accurate anatomical model of a porcine subject, Figure 1(A). A mathematical model using statistical measurements and space filling topology is used to specify the coronary tree networks in the finite element computational model, Figure 1(B). A multi-compartment poroelastic governing equations of the blood-soft tissue interactions are derived. The evolution equations for both blood and soft tissue phases are described in the Lagrangian frame of reference. The complex network of blood vessel that surround the myocardium tissue are integrated using a reduced order modelling of Darcy law with a heterogeneous permeability tensor along with the finite deformation elasticity of the myocardium. The derived methodology approach is tested on simplified 2D and 3D myocardium poroelastic geometries with customized modules and well-posed prescribed traction boundary conditions at a finite set of coronary compartments, Figure 1(C-D). Results are given for the perfusion of the left ventricle deformation under passive inflation that show in particular wall compliance remodelling associated with perfusion dysfunction.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Talks, contributed |
| Year of Publication | 2019 |
| Location of Talk | International Society of Autonomic Neuroscience, Los Angeles, CA, USA |
| Publisher | International Society of Autonomic Neuroscience, 2019. |
Journal Article
Artery.FE: An implementation of the 1D blood flow equations in FEniCS
Journal of Open Source Software 3, no. 32 (2018).Status: Published
Artery.FE: An implementation of the 1D blood flow equations in FEniCS
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Journal | Journal of Open Source Software |
| Volume | 3 |
| Issue | 32 |
| Number | 1107 |
| Publisher | The Journal of Open Source Software, Open Source Initiative |
| Keywords | blood flow, FEniCS, Numerical models, PDE, Software |
| URL | http://joss.theoj.org/papers/10.21105/joss.01107 |
| DOI | 10.21105/joss.01107 |
Poster
Modelling drug delivery via nanoparticle deposition in the myocardium of the left ventricle
Berlin: The Heart by Numbers: Integrating Theory, Computation, and Experiment to Advance Cardiology, 2018.Status: Published
Modelling drug delivery via nanoparticle deposition in the myocardium of the left ventricle
The use of nanoparticles (NP) target drug delivery directly to the heart for treatment of diseases via nanoparticles (NP) has been a major goal of cardiovascular research since the early 2000s. The benefits of such a NP drug delivery system would include the reduction of side effects by the administration of smaller dosages, cost reduction and reducing the need for invasive treatments. However, the development of a NP-based drug delivery system also poses a number of challenges, such as the optimisation of physico-chemical parameters of the NP, in order to achieve efficient distribution throughout the tissue. We address this challenge by presenting a finite-element model of NP delivery via perfusion through the myocardium in the left ventricle (LV). Perfusion is represented by the three compartment porous media equations based on Darcy's law. A 0D lumped parameter model is used to represent the inflow boundary condition to the perfusing blood vessels. NP transport is modelled via the scalar transport equations based on reaction-advection-diffusion kinetics, where deposition via endocytosis follows zero order reaction kinetics. The model is solved on a human LV geometry with randomly set arterial entry points throughout the outer surface of the myocardium. Efficiency of NP endocytosis is tested based on varied kinetic rates, initial NP concentration, NP inflow rate, chemical properties of NP, and perfusion pressure. These simulations provide a framework to virtually prototype physico-chemical properties of the NP and predict their distribution within the tissue.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Poster |
| Year of Publication | 2018 |
| Publisher | The Heart by Numbers: Integrating Theory, Computation, and Experiment to Advance Cardiology |
| Place Published | Berlin |
| Keywords | blood flow, cardiac perfusion, darcy flow, nanoparticles |
PersonalizeAF
Atrial Fibrillation (AF) is the most common cardiac arrhythmia affecting more than 6 million Europeans with a cost exceeding 1% of the EU health care system budget (13.5 billion annually). New treatment strategies and the progress achieved in research on AF mechanisms and substrate evaluation methods to date have not been commensurate with an equivalent development of the knowledge and technologies required to individually characterize each patient in search of the most efficient therapy. PersonalizeAF addresses this challenge by delivering an innovative multinational, multi-sectorial, and multidisciplinary research and training program in new technologies and novel strategies for individualized characterization of AF substrate to and increase treatments’ efficiency. From the research point of view, PersonalizeAF will integrate data and knowledge from in-vitro, in silico, ex vivo and in vivo animal and human models to:
1) generate an individual description of the state of the atrial muscle identifying the disease mechanisms and characteristics;
2) understanding the potential effect that different therapies have on different atrial substrates; and
3) combining this information to generate a specific profile of the patient and the best therapy for each patient.
With this purpose, PersonalizeAF partnership aggregates relevant scientific staff from the academic and clinical world with highly specialized biomedical companies which will be involved in a high-level personalized training program that will train a new generation of highly skilled professionals and guarantee ESRs and future PhD students outstanding career opportunities in the biomedical engineering, cardiology services, and medical devices sectors. PersonalizeAF will disseminate results in a wide spectrum of stakeholders, create awareness in the general public about atrial fibrillation and encourage vocational careers among young students.
Coordinator
Universitat Politecnica de Valenica
Funding Scheme
MSCA-ITN-ETN - European Training Networks
Publications for PersonalizeAF
Talks, invited
Computational Fluid Dynamics Approaches to Predict Flow Physics of Left Atrium
In Universitat Pompeu Fabra - Barcelona, 2022.Status: Published
Computational Fluid Dynamics Approaches to Predict Flow Physics of Left Atrium
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, PARIS, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest), PersonalizeAF |
| Publication Type | Talks, invited |
| Year of Publication | 2022 |
| Location of Talk | Universitat Pompeu Fabra - Barcelona |
PARIS
Atrial Fibrillation (AF) is a complex cardiac disease that can lead to blood clots and increase the risk of stroke. AF is gaining epidemic proportions and the majority of AF patients are prescribed anticoagulants, but at the cost of increased risk of severe bleedings. Individualized anticoagulation management, therefore, remains a major challenge but routinely available patient-specific clinical data are under-utilized. Computational models based on patient-specific medical images of the atria have reached a high level of sophistication, but remain insufficiently validated and tested to be used for individualized clinical predictions. PARIS will utilize existing medical records of AF patients with known clinical outcome, to validate computer models and predictive machine learning methods in an iterative process. The ambition is to identify biomarkers that correlate with stroke and to prospectively outperform the current risk score to reduce individual bleeds by optimizing personalized treatment and clinical follow-up.
Funding
ERA-Net on Systems Medicine under the EU Framework Programme Horizon2020.
Partners
Inria Epione (France)
University Heart Center Hamburg (Germany)
Publications for PARIS
Poster
Impact of Rigid Versus Dynamic Boundaries on Computational Fluid Dynamics Predictor of Left Atrial Appendage Thrombus Formation
Computing in Cardiology, 2022.Status: Published
Impact of Rigid Versus Dynamic Boundaries on Computational Fluid Dynamics Predictor of Left Atrial Appendage Thrombus Formation
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, PARIS, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Poster |
| Year of Publication | 2022 |
| Place Published | Computing in Cardiology |
Talks, invited
A mechanistic approach towards personalized treatment in patients with atrial fibrillation
In University Heart & Vascular Center Hamburg - UKE, 2022.Status: Published
A mechanistic approach towards personalized treatment in patients with atrial fibrillation
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, PARIS |
| Publication Type | Talks, invited |
| Year of Publication | 2022 |
| Location of Talk | University Heart & Vascular Center Hamburg - UKE |
Computational Fluid Dynamics Approaches to Predict Flow Physics of Left Atrium
In Universitat Pompeu Fabra - Barcelona, 2022.Status: Published
Computational Fluid Dynamics Approaches to Predict Flow Physics of Left Atrium
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, PARIS, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest), PersonalizeAF |
| Publication Type | Talks, invited |
| Year of Publication | 2022 |
| Location of Talk | Universitat Pompeu Fabra - Barcelona |
Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest)
Despite massive investment in healthcare, huge R&D cost increase and regulatory pathway complexity hamper tremendously commercialisation of new devices & medicines, putting patient populations at risk of not receiving adequate therapy. At the same time, outside healthcare, computer modelling and simulation (CM&S) is precisely recognised to increase speed & agility while reducing costs of development. CM&S can create scientific evidence based on controlled investigations including variability, uncertainty quantification, and satisfying demands for safety, efficacy & improved access. Cardiac modelling has dramatically gained maturity over the last decades, with personalisation to clinical data enabling validation. We selected a number of cardiac devices and medicines where CM&S is mature enough and that represent the most common cardiac pathologies, to demonstrate a standardised and rigorous approach for in-silico clinical trials. SimCardioTest will bring a disruptive innovation by creating an integrated and secure platform standardising & bridging model simulations, in-silico trials, and certification support. This environment will go beyond the state-of-the-art in computational multi-physics & multi-scale personalised cardiac models. Diseased conditions and gender/age differences will be considered to overcome clinical trials limitations such as under-representation of groups (e.g. women, children, low socio- economic status). Advanced big data, visual analytics & artificial intelligence tools will extract the most relevant information. It is critical that Europe demonstrates its capacity to leverage in-silico technology in order to be competitive in healthcare innovation. SimCardioTest exploitation aims at delivering a major economic impact on the European pharmaceutical and cardiac devices industry. It will accelerate development, certification and commercialisation, and will produce a strong societal impact contributing to personalised healthcare.
Funding Source:
- Horizon2020
Partners:
- INRIA (coordinator)
- University de Bordeaux
- Universidad Pompeu Fabra
- University Politecnica de Valencia
- InSilicoTrials Technologies SRL
- Sorin CRM SAS
- ExacCure SAS
- Boston Scientific Scimed Inc.
- Virtual Physiological Human Institute
Publications for Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest)
Journal Article
simcardems: A FEniCS-based cardiac electro-mechanicssolver
Journal of Open Source Software 88442954520810717, no. 81411347316 (2023): 4753.Status: Published
simcardems: A FEniCS-based cardiac electro-mechanicssolver
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Department of Numerical Analysis and Scientific Computing, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Journal Article |
| Year of Publication | 2023 |
| Journal | Journal of Open Source Software |
| Volume | 88442954520810717 |
| Issue | 81411347316 |
| Pagination | 4753 |
| Date Published | Jan-01-2023 |
| Publisher | JOSS |
| URL | https://joss.theoj.org/papers/10.21105/joss.04753 |
| DOI | 10.21105/joss.04753 |
On The Strategies for Prediction of Atrial Hemodynamics and Stresses; Application of Verification and Validation Guidelines to Modelling of Atrial Flows
International journal of numerical methods in biomedical engineering (2023).Status: Submitted
On The Strategies for Prediction of Atrial Hemodynamics and Stresses; Application of Verification and Validation Guidelines to Modelling of Atrial Flows
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Journal Article |
| Year of Publication | 2023 |
| Journal | International journal of numerical methods in biomedical engineering |
| Publisher | John Wiley & Sons |
Poster
Impact of Rigid Versus Dynamic Boundaries on Computational Fluid Dynamics Predictor of Left Atrial Appendage Thrombus Formation
Computing in Cardiology, 2022.Status: Published
Impact of Rigid Versus Dynamic Boundaries on Computational Fluid Dynamics Predictor of Left Atrial Appendage Thrombus Formation
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, PARIS, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Poster |
| Year of Publication | 2022 |
| Place Published | Computing in Cardiology |
Proceedings, refereed
A Comparative Study of Normal and High-Fidelity Approaches to Predict Flow Physics of Left Atrium
In Computing in Cardiology, CinC 2022. Computing in Cardiology, 2022.Status: Published
A Comparative Study of Normal and High-Fidelity Approaches to Predict Flow Physics of Left Atrium
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2022 |
| Conference Name | Computing in Cardiology, CinC 2022 |
| Publisher | Computing in Cardiology |
| URL | https://cinc.org/2022/Program/accepted/28.pdf |
Population of Computational Cell and Tissue Cardiac Electromechanical Models for functional analysis
In World Congress of Biomechanics. 9th ed, 2022.Status: Accepted
Population of Computational Cell and Tissue Cardiac Electromechanical Models for functional analysis
Introduction
Cardiac computational models can fill important gaps in understanding the cardiomyocyte or cardiac tissue properties. Recent maturity in cardiac mechanical modelling enables quantitative predictive power across a range of applications. One challenge however is the tight coupling of cardiac mechanics with the underlying electrophysiological properties of the tissue, which makes modelling clinical mechanical phenomena such as drug effects difficult. More robust predictions can be achieved by modelling populations of models, which incorporate stochastic parameter variability to represent biological variation. For cardiac computational models to live up to their potential in developing safe and efficient treatments for increasingly prevalent cardiac disease, such populations of fully coupled electromechanics models will provide greater predictive power on mechanics and physiology of the heart.
Methods
A fully coupled electromechanics model of ventricular tissue is developed by coupling the O’Hara-Rudy[1] electrophysiology model and the Land[2] mechanics model. A population of models was created by varying 16 electrophysiological and 11 mechanical parameters at the cell level. The population was calibrated from 1000 to 187 models based on biomarkers derived from the action potential shape, calcium transient and active tension. The electromechanics solver is implemented by combining existing solvers for electrophysiology[3] and mechanics[4], which are both based on the open-source framework FEniCS[5]. A geometry of 20x7x3 mm is simulated with 1.0 or 0.5 mm spatial resolution for mechanics or electrophysiology respectively, with free movement in the fibre direction on one side.
Results
Traces from all population models were extracted at the center of the tissue in all directions (green star in top left panel) for further analysis (see figure). Electrophysiological biomarkers, such as action potential duration and systolic calcium concentration remain within calibrated and cell population model range. The maximum active tension in tissue is reduced by 65% compared to cell simulations. This reduction can be attributed to the free contraction in tissue versus fixed stretch in calibration and cell simulations. The magnitude and especially the recovery duration of active stretch varies widely across the population (see table for average±SD). This range of timing and force of contraction reinforce the need to assess cardiac function and drug effects in populations of electromechanical models.
Discussion
We present a pipeline for creating populations of strongly coupled 3D excitation-contraction models for ventricular tissue. The tissue model includes bidirectional coupling and biological variation, facilitating further investigation into the multifactorial effect of variation and drugs on the in silico human heart. This enables simulation of both mechanical and physiological function of the heart to aid development of safe and efficient treatment based on population statistics.
References
O’Hara, T. et al.; PLoS Comput Biol 2011 [doi:10.1371/journal.pcbi.1002061]
Land, S. et al.; J. Mol. Cell. Cardiol. 2017 [doi:10.1016/J.YJMCC.2017.03.008]
Logg, A. et al.; Springer 2012 [doi:10.1007/978-3-642-23099-8]
Rognes, M. E. et al.; Journal of Open Source Software, 2017 [doi:10.21105/joss.00224]
Finsberg, H. N. T.; Journal of Open Source Software, 2019 [doi:10.21105/joss.01539]
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2022 |
| Conference Name | World Congress of Biomechanics |
| Edition | 9th |
Talk, keynote
SIMCARDIOTEST OPEN SOURCE SOFTWARE – DEMO on OASIS: Computational fluid dynamics solver & SOFA: Simulation Open Framework Architecture
In Porto, Portugal. VPH2022 Porto, 2022.Status: Published
SIMCARDIOTEST OPEN SOURCE SOFTWARE – DEMO on OASIS: Computational fluid dynamics solver & SOFA: Simulation Open Framework Architecture
SimCardioTest is a collaborative project between 10 organizations from 6 European countries and United States funded by the European Commission (EU H2020). The aim of the project is to provide new insight into designing predictive tools in cardiac pathologies and to accelerate the uptake of computer simulations for testing medicines and medical devices.
The aim of the workshop is hands on/demonstration of the open source OASIS and SOFA software.
| Afilliation | Scientific Computing |
| Project(s) | Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest), Department of Computational Physiology |
| Publication Type | Talk, keynote |
| Year of Publication | 2022 |
| Location of Talk | Porto, Portugal |
| Publisher | VPH2022 Porto |
| URL | https://vph-conference.org/call-for-proposals/ |
Talks, contributed
Omecamtiv Mecarbil Improves Contraction Behaviour in a 3D Electromechanical Tissue Model of Heart Failure
In 49th Computing in Cardiology Conference, 2022.Status: Published
Omecamtiv Mecarbil Improves Contraction Behaviour in a 3D Electromechanical Tissue Model of Heart Failure
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Talks, contributed |
| Year of Publication | 2022 |
| Location of Talk | 49th Computing in Cardiology Conference |
Computational 3D cardiac electromechanical models for functional and pharmacological analysis
In 9th International Workshop on Cardiac Mechano-Electric Coupling and Arrhythmias, 2022.Status: Published
Computational 3D cardiac electromechanical models for functional and pharmacological analysis
| Afilliation | Scientific Computing |
| Project(s) | Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest), Department of Computational Physiology |
| Publication Type | Talks, contributed |
| Year of Publication | 2022 |
| Location of Talk | 9th International Workshop on Cardiac Mechano-Electric Coupling and Arrhythmias |
Functional Analysis of Healthy and Heart Failure Tissue Populations using 3D Cardiac Electromechanical Models
In 15th World Congress on Computational Mechanics (virtual), 2022.Status: Accepted
Functional Analysis of Healthy and Heart Failure Tissue Populations using 3D Cardiac Electromechanical Models
Computer modelling and simulation of the beating heart must reflect on electrical activation of cells and tissue, mechanical properties of tissue, and their interaction. Electrophysiological properties of the heart have been simulated abundantly and applied to increase mechanistic understanding of disease and improve treatment development. Recent maturity in cardiac mechanical modelling increased quantitative predictive power. However, tight coupling of cardiac mechanics with the underlying electrophysiological properties of the tissue makes modelling clinical mechanical phenomena such as cardiac disease and drug effects difficult. A combination of uncertainty quantification through populations of models and fully coupled electromechanics models provide greater predictive power on cardiac mechanisms and aid treatment development for cardiac diseases.
A fully coupled electromechanics model of ventricular tissue is developed by coupling the O’Hara-Rudy[1] electrophysiology model and the Land[2] mechanics model. A population of models was created by varying 16 electrophysiological and 11 mechanical parameters at the cell level. The population was calibrated from 1000 to 187 models based on biomarkers derived from the action potential shape, calcium transient and active tension. This calibrated population was altered in 11 parameters of the cell model to represent heart failure (based on [3]). A geometry of 20x7x3 mm is simulated with 1.0 or 0.5 mm spatial resolution for mechanics or electrophysiology respectively, with free movement in the fibre direction on one side. Results are extracted at the centre of the tissue, as well as tissue shortening on the free-contracting side.
Relative to the healthy population, heart failure manifests in both electrophysiological and mechanics biomarkers. The action potential takes ~20% longer to recover from activation and peak calcium concentration in the cell is reduced by 50.9%. In a similar trend, mechanical biomarkers show 42.2% reduction in peak active force, slower contraction and more variation in recovery times across the heart failure tissue population. The peak tissue shortening in the fibre direction as a result of free contraction is reduced from 0.68±0.07mm to 0.45±0.07mm (-33.2%) and its peak is delayed by 112ms (38.6%) in heart failure.
These simulations indicate strong effects on electrophysiological and mechanical heart function by population variation and disease such as heart failure. Therefore, strongly coupled 3D models are necessary to assess the impact of biological variation, cardiac vulnerability as well as safe and effective treatment development.
REFERENCES
[1] O’Hara, T. et al.; PLoS Comput. Biol. 2011 [doi:10.1371/journal.pcbi.1002061]
[2] Land, S. et al.; J. Mol. Cell. Cardiol. 2017 [doi:10.1016/J.YJMCC.2017.03.008]
[3] Gomez, J. et al; PLoS ONE 2014 [doi:10.1371/journal.pone.0106602]
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest) |
| Publication Type | Talks, contributed |
| Year of Publication | 2022 |
| Location of Talk | 15th World Congress on Computational Mechanics (virtual) |
| Keywords | Cardiac biomechanics, Cardiac disease, Uncertainty quantification |
Talks, invited
Computational Fluid Dynamics Approaches to Predict Flow Physics of Left Atrium
In Universitat Pompeu Fabra - Barcelona, 2022.Status: Published
Computational Fluid Dynamics Approaches to Predict Flow Physics of Left Atrium
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, PARIS, Simulation of Cardiac Devices and Drugs for In-Silico Testing and Certification (SimCardioTest), PersonalizeAF |
| Publication Type | Talks, invited |
| Year of Publication | 2022 |
| Location of Talk | Universitat Pompeu Fabra - Barcelona |
Publications
Journal Article
High-Fidelity Fluid Structure Interaction Simulations of Turbulent-Like Aneurysm Flows Reveals High-Frequency Narrowband Wall Vibrations: A Stimulus of Mechanobiological Relevance?
Journal of Biomechanics (2022).Status: Published
High-Fidelity Fluid Structure Interaction Simulations of Turbulent-Like Aneurysm Flows Reveals High-Frequency Narrowband Wall Vibrations: A Stimulus of Mechanobiological Relevance?
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2022 |
| Journal | Journal of Biomechanics |
| Publisher | Elsevier |
Proceedings, refereed
Impact of Flow Rate on Wall Vibration in Intracranial Aneurysms
In 8th European Congress on Computational Methods in Applied Sciences and Engineer- ing. Oslo, Norway, 2022.Status: Submitted
Impact of Flow Rate on Wall Vibration in Intracranial Aneurysms
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2022 |
| Conference Name | 8th European Congress on Computational Methods in Applied Sciences and Engineer- ing |
| Place Published | Oslo, Norway |
Turbulent-like arteriovenous fistula flows cause wall vibrations: a specific stimulus for stenosis formation?
In 9th World Congress of Biomechanics,, 2022.Status: Accepted
Turbulent-like arteriovenous fistula flows cause wall vibrations: a specific stimulus for stenosis formation?
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2022 |
| Conference Name | 9th World Congress of Biomechanics, |
Proceedings, refereed
ARTERIOVENOUS FISTULA FOR HEMODIALYSIS: CAN TURBULENT-LIKE FLOW PHENOTYPE INDUCE WALL VIBRATIONS?
In 21st CONGRESS OF THE VASCULAR ACCESS SOCIETY, 2021.Status: Submitted
ARTERIOVENOUS FISTULA FOR HEMODIALYSIS: CAN TURBULENT-LIKE FLOW PHENOTYPE INDUCE WALL VIBRATIONS?
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2021 |
| Conference Name | 21st CONGRESS OF THE VASCULAR ACCESS SOCIETY |
IMPACT OF FLOW RATE ON HIGH FREQUENCY FLOW INSTABILITIES IN INTRACRANIAL ANEURYSMS, WITH IMPLICATIONS FOR WALL VIBRATION
In SB3C2021 Summer Biomechanics, Bioengineering and Biotransport Conference, 2021.Status: Submitted
IMPACT OF FLOW RATE ON HIGH FREQUENCY FLOW INSTABILITIES IN INTRACRANIAL ANEURYSMS, WITH IMPLICATIONS FOR WALL VIBRATION
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2021 |
| Conference Name | SB3C2021 Summer Biomechanics, Bioengineering and Biotransport Conference |
Turbulent-like arteriovenous fistula flows cause wall vibrations: a specific stimulus for stenosis formation?
In 47th Congress of the European Society of Artificial Organs. London, England: European Society for Artificial Organs, 2021.Status: Published
Turbulent-like arteriovenous fistula flows cause wall vibrations: a specific stimulus for stenosis formation?
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2021 |
| Conference Name | 47th Congress of the European Society of Artificial Organs |
| Publisher | European Society for Artificial Organs |
| Place Published | London, England |
Journal Article
Automated landmarking of bends in vascular structures: a comparative study with application to the internal carotid artery
BioMedical Engineering OnLine 20, no. 1 (2021): 120.Status: Published
Automated landmarking of bends in vascular structures: a comparative study with application to the internal carotid artery
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2021 |
| Journal | BioMedical Engineering OnLine |
| Volume | 20 |
| Issue | 1 |
| Pagination | 120 |
| Date Published | 11/2021 |
| Publisher | Springer Nature BMC |
| URL | https://biomedical-engineering-online.biomedcentral.com/articles/10.1186... |
| DOI | 10.1186/s12938-021-00957-6 |
On delayed transition to turbulence in an eccentric stenosis model for clean vs. noisy high-fidelity CFD
Journal of Biomechanics 125 (2021): 110588.Status: Published
On delayed transition to turbulence in an eccentric stenosis model for clean vs. noisy high-fidelity CFD
Recent comparisons between experiments and computational fluid dynamics (CFD) simulations of flow in the Food and Drug Administration (FDA) standardized nozzle geometry have highlighted the potential sensitivity of axisymmetric CFD models to small perturbations induced by mesh and inlet velocity, particularly for Reynolds numbers (Re) in the transitional regime. This evokes the classic experiment of Reynolds on transition to turbulence in a straight pipe, which can be delayed, apparently indefinitely, if special care is taken to control for external influences. Such idealized experiments are, however, extremely difficult to perform and, in the context of cardiovascular modeling, belie the "noise" inherent in typical experimental and physiological systems. Previous high-fidelity CFD of a canonical eccentric (i.e., non-axisymmetric) stenosis model showed transition occurring for steady flow at Re ~ 700-800, with modest delay caused by the introduction of shear-thinning rheology. On the other hand, recent experimental measurements of steady flowing blood and blood-mimicking fluids in this same stenosis model report transition for Re ~ 400-500. Taking a cue from the FDA nozzle controversy, the present study demonstrates that the addition of small-magnitude random noise at the inlet brings the eccentric-stenosis CFD results more in-line with experiments, and reveals a more gradual transition towards turbulence. This highlights that, even in non-axisymmetric idealized geometries, unnaturally "clean" high-fidelity CFD may impede not only good agreement with experiments, but also understanding of the onset and character of blood flow instabilities as they may exist, naturally, in the vasculature.
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2021 |
| Journal | Journal of Biomechanics |
| Volume | 125 |
| Pagination | 110588 |
| Date Published | Jan-08-2021 |
| Publisher | Elsevier |
| ISSN | 00219290 |
| URL | https://www.sciencedirect.com/science/article/abs/pii/S0021929021003675?... |
| DOI | 10.1016/j.jbiomech.2021.110588 |
On the prevalence of flow instabilities from high-fidelity computational fluid dynamics of intracranial bifurcation aneurysms
Journal of Biomechanics 127 (2021): 110683.Status: Published
On the prevalence of flow instabilities from high-fidelity computational fluid dynamics of intracranial bifurcation aneurysms
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2021 |
| Journal | Journal of Biomechanics |
| Volume | 127 |
| Pagination | 110683 |
| Date Published | Jan-10-2021 |
| Publisher | Elsevier |
| ISSN | 00219290 |
| URL | https://www.sciencedirect.com/science/article/abs/pii/S0021929021004528?... |
| DOI | 10.1016/j.jbiomech.2021.110683 |
Journal Article
A framework for automated and objective modification of tubular structures: Application to the internal carotid artery
International journal for numerical methods in biomedical engineering 36 (2020): e3330.Status: Published
A framework for automated and objective modification of tubular structures: Application to the internal carotid artery
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2020 |
| Journal | International journal for numerical methods in biomedical engineering |
| Volume | 36 |
| Number | 5 |
| Pagination | e3330 |
| Publisher | Wiley Online Library |
Computed Post-Stenotic Flow Instabilities Correlate Phenotypically with Vibrations Measured Using Laser Doppler Vibrometry: Perspectives for a Promising In-Vivo Device for Early Detection of Moderate and Severe Carotid Stenosis
Journal of Biomechanical Engineering 142, no. 9 (2020): 091007.Status: Published
Computed Post-Stenotic Flow Instabilities Correlate Phenotypically with Vibrations Measured Using Laser Doppler Vibrometry: Perspectives for a Promising In-Vivo Device for Early Detection of Moderate and Severe Carotid Stenosis
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology, Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2020 |
| Journal | Journal of Biomechanical Engineering |
| Volume | 142 |
| Issue | 9 |
| Pagination | 091007 |
| Date Published | 04/2020 |
| Publisher | American Society of Mechanical Engineers Digital Collection |
turtleFSI: A Robust and Monolithic FEniCS-based Fluid-Structure Interaction Solver
Journal of Open Source Software 5, no. 50 (2020): 2089.Status: Published
turtleFSI: A Robust and Monolithic FEniCS-based Fluid-Structure Interaction Solver
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2020 |
| Journal | Journal of Open Source Software |
| Volume | 5 |
| Issue | 50 |
| Pagination | 2089 |
| Date Published | Jan-06-2020 |
| Publisher | The Open Journal |
| URL | https://joss.theoj.orghttps://joss.theoj.org/papers/10.21105/joss.02089h... |
| DOI | 10.21105/joss10.21105/joss.02089 |
Proceedings, refereed
Turbulent-Like Aneurysm Flows Trigger Distinct Highfrequent Wall Vibrations
In 14th World Congress in Computational Mechanics (WCCM). Vol. Online. Paris, France: European Community on Computational Methods in Applied Sciences, 2020.Status: Published
Turbulent-Like Aneurysm Flows Trigger Distinct Highfrequent Wall Vibrations
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2020 |
| Conference Name | 14th World Congress in Computational Mechanics (WCCM) |
| Volume | Online |
| Date Published | 2020 |
| Publisher | European Community on Computational Methods in Applied Sciences |
| Place Published | Paris, France |
Talks, contributed
Are High-Frequency Aneurysm Wall Vibrations of Importance?
In 6th International Conference on Computational and Mathematical Biomedical Engineering – CMBE2019, Sendai, Japan , 2019.Status: Published
Are High-Frequency Aneurysm Wall Vibrations of Importance?
We present a preliminary study on aneurysm wall vibrations associated with turbulent-like hemodynamics in intracranial vascular sections. The specificity of our numerical model is to explore the fluid/structure coupling of the arterial flow and the wall mechanics to relatively high frequencies (100-500 Hz). Despite the computational cost of the couple FSI problem and its direct impact on the resolutions of the model presented here, our findings highlight an important mechanical interplay resulting in a complex, but characteristic, deformation of the arterial wall. We hope to stimulate discussions and further work towards this physiological process, which can potentially have important implications for cell signaling mechanisms.
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Talks, contributed |
| Year of Publication | 2019 |
| Location of Talk | 6th International Conference on Computational and Mathematical Biomedical Engineering – CMBE2019, Sendai, Japan |
| Keywords | fluid-structure interaction, Intracranial aneurysm, wall vibrations |
Autonomic Modelling of Interaction between Coronary Perfusion Flow and Myocardium Mechanics using Computational Poroelasticity
In International Society of Autonomic Neuroscience, Los Angeles, CA, USA. International Society of Autonomic Neuroscience, 2019, 2019.Status: Published
Autonomic Modelling of Interaction between Coronary Perfusion Flow and Myocardium Mechanics using Computational Poroelasticity
Autonomic control and modelling the cross-talk between blood flow in coronary vessels and ventricular wall mechanical deformations are central problems in mechanocardiac physiology. In this study, we use a multi-scale approach that includes multi-physics modules of the heart with autonomic control, to accurately model this complex interaction between coronary perfusion and myocardium mechanics. In particular, we implement a 3D finite element numerical scheme to account for this coupling using a reconstructed and geometrically-accurate anatomical model of a porcine subject, Figure 1(A). A mathematical model using statistical measurements and space filling topology is used to specify the coronary tree networks in the finite element computational model, Figure 1(B). A multi-compartment poroelastic governing equations of the blood-soft tissue interactions are derived. The evolution equations for both blood and soft tissue phases are described in the Lagrangian frame of reference. The complex network of blood vessel that surround the myocardium tissue are integrated using a reduced order modelling of Darcy law with a heterogeneous permeability tensor along with the finite deformation elasticity of the myocardium. The derived methodology approach is tested on simplified 2D and 3D myocardium poroelastic geometries with customized modules and well-posed prescribed traction boundary conditions at a finite set of coronary compartments, Figure 1(C-D). Results are given for the perfusion of the left ventricle deformation under passive inflation that show in particular wall compliance remodelling associated with perfusion dysfunction.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Talks, contributed |
| Year of Publication | 2019 |
| Location of Talk | International Society of Autonomic Neuroscience, Los Angeles, CA, USA |
| Publisher | International Society of Autonomic Neuroscience, 2019. |
Journal Article
Automated and Objective Removal of Bifurcation Aneurysms: Incremental Improvements, and Validation Against Healthy Controls
Journal of Biomechanics 96 (2019): 109342.Status: Published
Automated and Objective Removal of Bifurcation Aneurysms: Incremental Improvements, and Validation Against Healthy Controls
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2019 |
| Journal | Journal of Biomechanics |
| Volume | 96 |
| Pagination | 109342 |
| Publisher | Elsevier |
| URL | https://www.sciencedirect.com/science/article/abs/pii/S0021929019305640 |
| DOI | 10.1016/j.jbiomech.2019.109342 |
High-Frequency Fluctuations in Post-Stenotic Patient Specific Carotid Stenosis Fluid Dynamics: a Computational Fluid Dynamics Strategy Study
Cardiovascular Engineering and Technology 10 (2019): 277-298.Status: Published
High-Frequency Fluctuations in Post-Stenotic Patient Specific Carotid Stenosis Fluid Dynamics: a Computational Fluid Dynamics Strategy Study
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2019 |
| Journal | Cardiovascular Engineering and Technology |
| Volume | 10 |
| Pagination | 277-298 |
| Publisher | Springer |
| DOI | 10.1007/s13239-019-00410-9 |
morphMan: Automated manipulation of vascular geometries
Journal of Open Source Software 35, no. 4 (2019): 1065.Status: Published
morphMan: Automated manipulation of vascular geometries
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2019 |
| Journal | Journal of Open Source Software |
| Volume | 35 |
| Issue | 4 |
| Pagination | 1065 |
| Publisher | JOSS |
| DOI | 10.21105/joss.01065 |
Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH) - Phase II: Rupture Risk Assessment
International Journal of Computer Assisted Radiology and Surgery 14 (2019): 1795-1804.Status: Published
Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH) - Phase II: Rupture Risk Assessment
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2019 |
| Journal | International Journal of Computer Assisted Radiology and Surgery |
| Volume | 14 |
| Number | 10 |
| Pagination | 1795-1804 |
| Date Published | 05/2019 |
| Publisher | British Medical Journal Publishing Group |
| URL | https://link.springer.com/article/10.1007/s11548-019-01986-2 |
| DOI | 10.1007/s11548-019-01986-2 |
Time-Lapsing Perfusion: Proof of Concept of a Novel Method to Study Drug Delivery in Whole Organs
Biophysical Journal 117, no. 12 (2019): 2316-2323.Status: Published
Time-Lapsing Perfusion: Proof of Concept of a Novel Method to Study Drug Delivery in Whole Organs
Perfusion is one of the most important processes maintaining organ health. From a computational perspective, however, perfusion is amongst the least studied physiological processes of the heart. The recent development of novel nanoparticle-based targeted cardiac therapy calls for novel simulation methods that can provide insights into the distribution patterns of therapeutic agents within the heart tissue. Additionally, resolving the distribution patterns of perfusion is crucial for gaining a full understanding of the long-term impacts of cardiovascular diseases that can lead to adverse remodelling, such as myocardial ischemia and heart failure. In this study we have developed and used a novel particle tracking-based method to simulate the perfusion-mediated distribution of nanoparticles or other solutes. To model blood flow through perfused tissue we follow the approach of others and treat the tissue as a porous medium in a continuum model. Classically, solutes are modelled
using reaction-advection-diffusion kinetics. However, due to the discrepancy between advection and diffusion in blood vessels, this method becomes numerically unstable. Instead, we track a bolus of solutes or nanoparticles using particle tracking based purely on advection in arteries. In capillaries we employ diffusion kinetics, using an effective diffusion coefficient to mimic capillary blood flow. We first demonstrate the numerical validity and computational efficiency of this method on a 2D benchmark problem. Finally, we demonstrate how the method is used to visualise perfusion patterns of a human left ventricle geometry. The efficiency of the method allows for nanoparticle tracking over multiple cardiac cycles using a conventional laptop, providing a framework for the simulation of experimentally relevant time frames to advance pre-clinical research.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Journal Article |
| Year of Publication | 2019 |
| Journal | Biophysical Journal |
| Volume | 117 |
| Issue | 12 |
| Pagination | 2316-2323 |
| Publisher | Cell Press |
Proceedings, refereed
Automated and objective segmentation of medical image using machine learning techniques: all models are wrong, but some are useful
In Computational and Mathematical Biomedical Engineering. Sendai, Japan: CMBE, 2019.Status: Published
Automated and objective segmentation of medical image using machine learning techniques: all models are wrong, but some are useful
Medical images are the basis of ”patient-specific” simulations but come with severe limitations, most notably through operator dependencies like image segmentation. The aim was to develop an open- source pipeline for automated and objective segmentation. Combining latest advances from machine learning and signal processing, we demonstrate that the pipeline preserve all major characteristic features of a test image and identify minor branches, which can be further modified by the user. In conclusion, the default pipeline will in the majority of cases offer labor free automated and objective segmentation, or at worst provide an optimal starting point for manual segmentation.
| Afilliation | Scientific Computing, Machine Learning |
| Project(s) | Simula Metropolitan Center for Digital Engineering, Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2019 |
| Conference Name | Computational and Mathematical Biomedical Engineering |
| Publisher | CMBE |
| Place Published | Sendai, Japan |
Comparing apples to oranges; Measured skin vibrations correlate phenotypically with computed post-stenotic flow instabilities. A pragmatic but robust tool for early detection of carotid stenoses?
In Computer Methods in Biomechanics and Biomedical Engineering. Sendai, Japan: Computer Methods in Biomechanics and Biomedical Engineering, 2019.Status: Published
Comparing apples to oranges; Measured skin vibrations correlate phenotypically with computed post-stenotic flow instabilities. A pragmatic but robust tool for early detection of carotid stenoses?
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2019 |
| Conference Name | Computer Methods in Biomechanics and Biomedical Engineering |
| Publisher | Computer Methods in Biomechanics and Biomedical Engineering |
| Place Published | Sendai, Japan |
Intensity of Stenosis-Indused Flow Instabilities of the Internal Carotid Artery: A Computational Approach
In Summer Biomechanics, Bioengineering, and Biotransport Conference. Seven Springs, PA: SB3C Foundation, 2019.Status: Published
Intensity of Stenosis-Indused Flow Instabilities of the Internal Carotid Artery: A Computational Approach
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2019 |
| Conference Name | Summer Biomechanics, Bioengineering, and Biotransport Conference |
| Publisher | SB3C Foundation |
| Place Published | Seven Springs, PA |
Porous Modelling of Cardiac Perfusion under Contraction to Demonstrate the Distribution of Therapeutic Nanoparticles
In International Conference in Computing in Cardiology, Singapore, 2019. IEEE, 2019.Status: Published
Porous Modelling of Cardiac Perfusion under Contraction to Demonstrate the Distribution of Therapeutic Nanoparticles
Delivery of therapy-loaded nanoparticles (NP) via inhalation is an innovative technology shown to successfully reduce heart failure in mice, improving the efficiency of
drug delivery, and reducing adverse side effects. However, how exactly therapeutic NP are distributed and absorbed by heart tissue remains poorly understood, and accelerating this technology to humans is a major challenge. Working towards overcoming this problem we developed an open-source finite element model of myocardial per-
fusion based on porous media, where perfused tissue is treated as a sponge-like continuum material, driven by a continuum model of cardiac contraction to simulate perfusion patterns. We use our novel particle-tracking based method that remains numerically stable under high Peclet number flow to enable the study of NP distribution.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2019 |
| Conference Name | International Conference in Computing in Cardiology, Singapore, 2019 |
| Publisher | IEEE |
Poster
Can turbulent-like flow cause high frequency vibrations of intracranial aneurysm walls ?
Biomechanics in Vascular Biology and Cardiovascular Disease (14th international symposium), London, United Kingdom, 2019.Status: Published
Can turbulent-like flow cause high frequency vibrations of intracranial aneurysm walls ?
The presence of wall vibrations of relatively high frequencies (several hundreds of Hz) on the top of intracranial aneurysms have been reported in the 70’s from open brain surgery measurements [1]. Later study [2], based on non-invasive recordings, provided additional evidences for charateristic high frequencie intracranial blood flow sounds associated with the presence of aneurysms. It is only recently that computational and experimental in-vitro studies modelled turbulent-like blood flow environments within intracranial vasculature, with characteristic fluctuations in the order of 100-300 Hz ([3, 4]). However, the link between unstable blood flow and arterial wall vibrations within intracranial aneurysms still remains speculative and is the focus of the present work.
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Poster |
| Year of Publication | 2019 |
| Place Published | Biomechanics in Vascular Biology and Cardiovascular Disease (14th international symposium), London, United Kingdom |
Porous modelling of cardiac perfusion to optimise targeted drug delivery
Computing in Cardiology, Singapore, 2019.Status: Published
Porous modelling of cardiac perfusion to optimise targeted drug delivery
Delivery of therapy-loaded nanoparticles (NP) via inhalation is an innovative technology shown to successfully reduce heart failure in mice, improving the efficiency of drug delivery, and reducing adverse side effects. However, how exactly therapeutic NP are distributed and absorbed by heart tissue remains poorly understood, and accelerating this technology to humans is a major challenge. To overcome this problem we developed an open-source finite element model of myocardial perfusion based on porous media, where perfused tissue is treated as a sponge-like continuum material, driven by a continuum model of cardiac contraction to simulate perfusion patterns. We use our novel particle-tracking based method that remains numerically stable under high Peclet number flow to study NP distribution.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Poster |
| Year of Publication | 2019 |
| Date Published | 09/2019 |
| Place Published | Computing in Cardiology, Singapore |
Talks, invited
Modeling of ‘patient-specific’ blood flow in the brain: Are we there yet?
In American Physical Society, Seattle, WA, USA, 2019.Status: Published
Modeling of ‘patient-specific’ blood flow in the brain: Are we there yet?
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Talks, invited |
| Year of Publication | 2019 |
| Location of Talk | American Physical Society, Seattle, WA, USA |
| Type of Talk | Invited |
Journal Article
Artery.FE: An implementation of the 1D blood flow equations in FEniCS
Journal of Open Source Software 3, no. 32 (2018).Status: Published
Artery.FE: An implementation of the 1D blood flow equations in FEniCS
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Journal | Journal of Open Source Software |
| Volume | 3 |
| Issue | 32 |
| Number | 1107 |
| Publisher | The Journal of Open Source Software, Open Source Initiative |
| Keywords | blood flow, FEniCS, Numerical models, PDE, Software |
| URL | http://joss.theoj.org/papers/10.21105/joss.01107 |
| DOI | 10.21105/joss.01107 |
Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH): Phase I: Segmentation
Cardiovascular Engineering and Technology 9, no. 4 (2018): 565-581.Status: Published
Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH): Phase I: Segmentation
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Journal | Cardiovascular Engineering and Technology |
| Volume | 9 |
| Issue | 4 |
| Pagination | 565–581 |
| Date Published | 09/2018 |
| Publisher | Springer US |
| ISSN | 1869-408X |
| URL | http://link.springer.com/10.1007/s13239-018-00376-0 |
| DOI | 10.1007/s13239-018-00376-0 |
Real-World Variability in the Prediction of Intracranial Aneurysm Wall Shear Stress: The 2015 International Aneurysm CFD Challenge
Cardiovascular Engineering and Technology 9, no. 4 (2018): 544-564.Status: Published
Real-World Variability in the Prediction of Intracranial Aneurysm Wall Shear Stress: The 2015 International Aneurysm CFD Challenge
Purpose
Image-based computational fluid dynamics (CFD) is widely used to predict intracranial aneurysm wall shear stress (WSS), particularly with the goal of improving rupture risk assessment. Nevertheless, concern has been expressed over the variability of predicted WSS and inconsistent associations with rupture. Previous challenges, and studies from individual groups, have focused on individual aspects of the image-based CFD pipeline. The aim of this Challenge was to quantify the total variability of the whole pipeline.
Methods
3D rotational angiography image volumes of five middle cerebral artery aneurysms were provided to participants, who were free to choose their segmentation methods, boundary conditions, and CFD solver and settings. Participants were asked to fill out a questionnaire about their solution strategies and experience with aneurysm CFD, and provide surface distributions of WSS magnitude, from which we objectively derived a variety of hemodynamic parameters.
Results
A total of 28 datasets were submitted, from 26 teams with varying levels of self-assessed experience. Wide variability of segmentations, CFD model extents, and inflow rates resulted in interquartile ranges of sac average WSS up to 56%, which reduced to < 30% after normalizing by parent artery WSS. Sac-maximum WSS and low shear area were more variable, while rank-ordering of cases by low or high shear showed only modest consensus among teams. Experience was not a significant predictor of variability.
Conclusions
Wide variability exists in the prediction of intracranial aneurysm WSS. While segmentation and CFD solver techniques may be difficult to standardize across groups, our findings suggest that some of the variability in image-based CFD could be reduced by establishing guidelines for model extents, inflow rates, and blood properties, and by encouraging the reporting of normalized hemodynamic parameters.
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Journal | Cardiovascular Engineering and Technology |
| Volume | 9 |
| Issue | 4 |
| Pagination | 544–564 |
| Date Published | 10/2018 |
| Publisher | Springer |
| Place Published | US |
| ISSN | 1869-408X |
| Keywords | Intracranial aneurysm, Patient-specific modeling, Rupture risk, Uncertainty quantification, Wall shear stress |
| URL | https://goo.gl/mG9u9t |
| DOI | 10.1007/s13239-018-00374-2 |
The FDA nozzle benchmark: “In theory there is no difference between theory and practice, but in practice there is”
International Journal for Numerical Methods in Biomedical Engineering 35, no. 1 (2018): e3150.Status: Published
The FDA nozzle benchmark: “In theory there is no difference between theory and practice, but in practice there is”
The utility of flow simulations relies on the robustness of computational fluid dynamics (CFD) solvers and reproducibility of results. The aim of this study was to validate the Oasis CFD solver against in vitro experimental measurements of jet breakdown location from the FDA nozzle benchmark at Reynolds number 3500, which is in the particularly challenging transitional regime. Simulations were performed on meshes consisting of 5, 10, 17, and 28 million (M) tetrahedra, with Δt = 10−5 seconds. The 5M and 10M simulation jets broke down in reasonable agreement with the experiments. However, the 17M and 28M simulation jets broke down further downstream. But which of our simulations are “correct”? From a theoretical point of view, they are all wrong because the jet should not break down in the absence of disturbances. The geometry is axisymmetric with no geometrical features that can generate angular velocities. A stable flow was supported by linear stability analysis. From a physical point of view, a finite amount of “noise” will always be present in experiments, which lowers transition point. To replicate noise numerically, we prescribed minor random angular velocities (approximately 0.31%), much smaller than the reported flow asymmetry (approximately 3%) and model accuracy (approximately 1%), at the inlet of the 17M simulation, which shifted the jet breakdown location closer to the measurements. Hence, the high‐resolution simulations and “noise” experiment can potentially explain discrepancies in transition between sometimes “sterile” CFD and inherently noisy “ground truth” experiments. Thus, we have shown that numerical simulations can agree with experiments, but for the wrong reasons.
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Journal | International Journal for Numerical Methods in Biomedical Engineering |
| Volume | 35 |
| Issue | 1 |
| Pagination | e3150 |
| Date Published | 09/2019 |
| Publisher | Wiley |
| URL | http://doi.wiley.com/10.1002/cnm.3150http://onlinelibrary.wiley.com/wol1... |
| DOI | 10.1002/cnm.3150 |
Proceedings, refereed
Can We Detect Carotid Artery Stenosis From Skin Vibrations: A Computational Investigation of High-Frequent Flow Under Physiological Varying Flow Conditions.
In 8th World Congress of Biomechanics, 2018.Status: Published
Can We Detect Carotid Artery Stenosis From Skin Vibrations: A Computational Investigation of High-Frequent Flow Under Physiological Varying Flow Conditions.
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2018 |
| Conference Name | 8th World Congress of Biomechanics |
| Date Published | 06/2018 |
Miscellaneous
Data for "High-Frequency Fluctuations in Post-Stenotic Patient Specific Carotid Stenosis Fluid Dynamics: A Computational Fluid Dynamics Strategy Study"
FigShare: FigShare, 2018.Status: Published
Data for "High-Frequency Fluctuations in Post-Stenotic Patient Specific Carotid Stenosis Fluid Dynamics: A Computational Fluid Dynamics Strategy Study"
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Miscellaneous |
| Year of Publication | 2018 |
| Publisher | FigShare |
| Place Published | FigShare |
| URL | https://doi.org/10.6084/m9.figshare.7300496.v2 |
| DOI | 10.6084/m9.figshare.7300496.v2 |
Data for "The 2015 International Aneurysm CFD Challenge"
FigShare: FigShare, 2018.Status: Published
Data for "The 2015 International Aneurysm CFD Challenge"
| Afilliation | Scientific Computing |
| Project(s) | Department of Computational Physiology |
| Publication Type | Miscellaneous |
| Year of Publication | 2018 |
| Publisher | FigShare |
| Place Published | FigShare |
| URL | 10.6084/m9.figshare.6383516.v2 |
| DOI | 10.6084/m9.figshare.6383516.v2 |
Poster
Modelling drug delivery via nanoparticle deposition in the myocardium of the left ventricle
Berlin: The Heart by Numbers: Integrating Theory, Computation, and Experiment to Advance Cardiology, 2018.Status: Published
Modelling drug delivery via nanoparticle deposition in the myocardium of the left ventricle
The use of nanoparticles (NP) target drug delivery directly to the heart for treatment of diseases via nanoparticles (NP) has been a major goal of cardiovascular research since the early 2000s. The benefits of such a NP drug delivery system would include the reduction of side effects by the administration of smaller dosages, cost reduction and reducing the need for invasive treatments. However, the development of a NP-based drug delivery system also poses a number of challenges, such as the optimisation of physico-chemical parameters of the NP, in order to achieve efficient distribution throughout the tissue. We address this challenge by presenting a finite-element model of NP delivery via perfusion through the myocardium in the left ventricle (LV). Perfusion is represented by the three compartment porous media equations based on Darcy's law. A 0D lumped parameter model is used to represent the inflow boundary condition to the perfusing blood vessels. NP transport is modelled via the scalar transport equations based on reaction-advection-diffusion kinetics, where deposition via endocytosis follows zero order reaction kinetics. The model is solved on a human LV geometry with randomly set arterial entry points throughout the outer surface of the myocardium. Efficiency of NP endocytosis is tested based on varied kinetic rates, initial NP concentration, NP inflow rate, chemical properties of NP, and perfusion pressure. These simulations provide a framework to virtually prototype physico-chemical properties of the NP and predict their distribution within the tissue.
| Afilliation | Scientific Computing |
| Project(s) | CUPIDO: Cardio Ultraefficient nanoParticles for Inhalation of Drug prOducts |
| Publication Type | Poster |
| Year of Publication | 2018 |
| Publisher | The Heart by Numbers: Integrating Theory, Computation, and Experiment to Advance Cardiology |
| Place Published | Berlin |
| Keywords | blood flow, cardiac perfusion, darcy flow, nanoparticles |
Proceedings, refereed
A Virtual Inter Laboratory Comparison of Predicted Hemodynamic Indices in Intracranial Aneurysms: Consistent or Not?
In Summer Biomechanics, Bioengineering, and Biotransport Conference, 2017.Status: Published
A Virtual Inter Laboratory Comparison of Predicted Hemodynamic Indices in Intracranial Aneurysms: Consistent or Not?
| Afilliation | Scientific Computing |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2017 |
| Conference Name | Summer Biomechanics, Bioengineering, and Biotransport Conference |
Investigating the Numerical Parameter Space for a Stenosed Patient-Specific Internal Carotid Artery Model
In Progress in Applied CFD. Selected papers from 10th International Conference on Computational Fluid Dynamics in the Oil & Gas, Metallurgical and Process Industries. SINTEF Academic Press, 2017.Status: Published
Investigating the Numerical Parameter Space for a Stenosed Patient-Specific Internal Carotid Artery Model
| Afilliation | Scientific Computing |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2017 |
| Conference Name | Progress in Applied CFD. Selected papers from 10th International Conference on Computational Fluid Dynamics in the Oil & Gas, Metallurgical and Process Industries |
| Publisher | SINTEF Academic Press |
| ISBN Number | 978-82-536-1544-8 |
| ISSN Number | 2387-4295 |
Prediction of Post Stenotic Flow Instabilities in a Patient Specific Common Carotid Artery Model?
In Summer Biomechanics, Bioengineering, and Biotransport Conference, 2017.Status: Published
Prediction of Post Stenotic Flow Instabilities in a Patient Specific Common Carotid Artery Model?
| Afilliation | Scientific Computing |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2017 |
| Conference Name | Summer Biomechanics, Bioengineering, and Biotransport Conference |
Journal Article
Cerebral aneurysm blood flow simulations: There’s solver settings and then there’s solver settings
Journal of Biomechanics 61 (2017): 280.Status: Published
Cerebral aneurysm blood flow simulations: There’s solver settings and then there’s solver settings
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2017 |
| Journal | Journal of Biomechanics |
| Volume | 61 |
| Pagination | 280-280 |
| Publisher | Journal of Biomechanics |
| DOI | 10.1016/j.jbiomech.2017.04.039 |
Talks, contributed
Verification and Validation in Image-Based Biomedical Computing
In International Conference on Computational Science and Engineering, Oslo, Norway, 2017.Status: Published
Verification and Validation in Image-Based Biomedical Computing
| Afilliation | Scientific Computing |
| Publication Type | Talks, contributed |
| Year of Publication | 2017 |
| Location of Talk | International Conference on Computational Science and Engineering, Oslo, Norway |
Proceedings, refereed
A Benchmark Standard Model of a Generic Medical Device; All Models Are Wrong, but Some Are Useful.
In 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, 2016.Status: Published
A Benchmark Standard Model of a Generic Medical Device; All Models Are Wrong, but Some Are Useful.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease |
A Simple and Rational Approach to Outflow Conditions in Cerebrovascular CFD Models.
In American Society of Mechanical Engineers Summer Biomechanics, Bioengineering and Biotransport Conference, 2016.Status: Published
A Simple and Rational Approach to Outflow Conditions in Cerebrovascular CFD Models.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | American Society of Mechanical Engineers Summer Biomechanics, Bioengineering and Biotransport Conference |
An Objective Framework for Digital Removal of Bifurcation Aneurysms - Incremental Improvements?
In 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, 2016.Status: Published
An Objective Framework for Digital Removal of Bifurcation Aneurysms - Incremental Improvements?
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease |
Can Manipulation of Arterial Morphology Shed Light on the Mechanobiological Stimuli Behind Aneurysm Initiation?
In 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, 2016.Status: Published
Can Manipulation of Arterial Morphology Shed Light on the Mechanobiological Stimuli Behind Aneurysm Initiation?
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease |
Freezing Turbulence in Brain Aneurysm Flow Visualizations: An Applied Art-Science Collaboration.
In Special Interest Group on GRAPHics and Interactive Techniques, 2016.Status: Published
Freezing Turbulence in Brain Aneurysm Flow Visualizations: An Applied Art-Science Collaboration.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | Special Interest Group on GRAPHics and Interactive Techniques |
Impact of Outflow Boundary Conditions on Flow Rates in Cerebrovascular CFD Models.
In 22nd Congress of the European Society of Biomechanics, 2016.Status: Published
Impact of Outflow Boundary Conditions on Flow Rates in Cerebrovascular CFD Models.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | 22nd Congress of the European Society of Biomechanics |
Inconsistency Is the Only Thing in Which Men Are Consistent: Can Subtle Flow Rate Assumptions Have Large Implications?
In 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, 2016.Status: Published
Inconsistency Is the Only Thing in Which Men Are Consistent: Can Subtle Flow Rate Assumptions Have Large Implications?
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | 11th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease |
Non-Newtonian versus Numerical Rheology: Practical Impact Of Shear-thinning On The Prediction Of Stable And Unstable Flows In Intracranial Aneurysms.
In American Society of Mechanical Engineers Summer Biomechanics, Bioengineering and Biotransport Conference, 2016.Status: Published
Non-Newtonian versus Numerical Rheology: Practical Impact Of Shear-thinning On The Prediction Of Stable And Unstable Flows In Intracranial Aneurysms.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | American Society of Mechanical Engineers Summer Biomechanics, Bioengineering and Biotransport Conference |
Proper Orthogonal Decomposition Analyses of High-Frequency Transient Flow Instabilities in Intracranial Aneurysms
In American Physical Society Division of Fluid Dynamics, 2016.Status: Published
Proper Orthogonal Decomposition Analyses of High-Frequency Transient Flow Instabilities in Intracranial Aneurysms
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | American Physical Society Division of Fluid Dynamics |
The FDA Nozzle Benchmark: In Theory There Is No Difference Between Theory and Practice, but in Practice There Is.
In American Society of Mechanical Engineers Summer Biomechanics, Bioengineering and Biotransport Conference, 2016.Status: Published
The FDA Nozzle Benchmark: In Theory There Is No Difference Between Theory and Practice, but in Practice There Is.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | American Society of Mechanical Engineers Summer Biomechanics, Bioengineering and Biotransport Conference |
The Oasis Navier-Stokes Solver: Theory, Accuracy, Applications, and High-Performance Computing Capabilities.
In FEniCS 16, 2016.Status: Published
The Oasis Navier-Stokes Solver: Theory, Accuracy, Applications, and High-Performance Computing Capabilities.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2016 |
| Conference Name | FEniCS 16 |
Journal Article
Improved Reduced-Order Modelling of Cerebrovascular Flow Distribution by Accounting for Arterial Bifurcation Pressure Drops.
Journal of Biomechanics 51 (2016): 83-88.Status: Published
Improved Reduced-Order Modelling of Cerebrovascular Flow Distribution by Accounting for Arterial Bifurcation Pressure Drops.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2016 |
| Journal | Journal of Biomechanics |
| Volume | 51 |
| Pagination | 83-88 |
| Publisher | Journal of Biomechanics |
Non-Newtonian versus Numerical Rheology: Practical Impact Of Shear-thinning On The Prediction Of Stable And Unstable Flows In Intracranial Aneurysms.
International Journal for Numerical Methods in Biomedical Engineering 33 (2016).Status: Published
Non-Newtonian versus Numerical Rheology: Practical Impact Of Shear-thinning On The Prediction Of Stable And Unstable Flows In Intracranial Aneurysms.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2016 |
| Journal | International Journal for Numerical Methods in Biomedical Engineering |
| Volume | 33 |
| Number | 7 |
| Date Published | 10/16 |
| Publisher | Int J Numer Method Biomed Eng |
On the Quantification and Visualization of Transient Periodic Instabilities in Pulsatile Flows
Journal of Biomechanics (2016): 179-182.Status: Published
On the Quantification and Visualization of Transient Periodic Instabilities in Pulsatile Flows
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2016 |
| Journal | Journal of Biomechanics |
| Number | 52 |
| Pagination | 179-182 |
| Date Published | 12/2016 |
| Publisher | Journal of Biomechanics |
Journal Article
A unified method for estimating pressure losses at vascular junctions
International Journal for Numerical Methods in Biomedical Engineering Jul;31(7):e02717 (2015).Status: Published
A unified method for estimating pressure losses at vascular junctions
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2015 |
| Journal | International Journal for Numerical Methods in Biomedical Engineering |
| Volume | Jul;31(7):e02717 |
| Date Published | 2015 |
| Publisher | Wiley Online Library |
Estimation of Inlet Flow Rates for Image-Based Aneurysm CFD Models: Where and How to Begin?
Annals of Biomedical Engineering 43, no. 6 (2015): 1422-1431.Status: Published
Estimation of Inlet Flow Rates for Image-Based Aneurysm CFD Models: Where and How to Begin?
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2015 |
| Journal | Annals of Biomedical Engineering |
| Volume | 43 |
| Issue | 6 |
| Pagination | 1422-1431 |
| Publisher | Springer |
Narrowing the Expertise Gap for Predicting Intracranial Aneurysm Hemodynamics: Impact of Solver Numerics versus Mesh and Time-Step Resolution
American Journal of Neuroradiology 36 (2015).Status: Published
Narrowing the Expertise Gap for Predicting Intracranial Aneurysm Hemodynamics: Impact of Solver Numerics versus Mesh and Time-Step Resolution
BACKGROUND AND PURPOSE: Recent high-resolution computational fluid dynamics studies have uncovered the presence of laminar flow instabilities and possible transitional or turbulent flow in some intracranial aneurysms. The purpose of this study was to elucidate requirements for computational fluid dynamics to detect these complex flows, and, in particular, to discriminate the impact of solver numerics versus mesh and time-step resolution.
MATERIALS AND METHODS: We focused on 3 MCA aneurysms, exemplifying highly unstable, mildly unstable, or stable flow phenotypes, respectively. For each, the number of mesh elements was varied by 320× and the number of time-steps by 25×. Computational fluid dynamics simulations were performed by using an optimized second-order, minimally dissipative solver, and a more typical first-order, stabilized solver.
RESULTS: With the optimized solver and settings, qualitative differences in flow and wall shear stress patterns were negligible for models down to ∼800,000 tetrahedra and ∼5000 time-steps per cardiac cycle and could be solved within clinically acceptable timeframes. At the same model resolutions, however, the stabilized solver had poorer accuracy and completely suppressed flow instabilities for the 2 unstable flow cases. These findings were verified by using the popular commercial computational fluid dynamics solver, Fluent.
CONCLUSIONS: Solver numerics must be considered at least as important as mesh and time-step resolution in determining the quality of aneurysm computational fluid dynamics simulations. Proper computational fluid dynamics verification studies, and not just superficial grid refinements, are therefore required to avoid overlooking potentially clinically and biologically relevant flow features.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2015 |
| Journal | American Journal of Neuroradiology |
| Volume | 36 |
| Number | 7 |
| Publisher | American Society of Neuroradiology |
Oasis: A high-level/high-performance open source Navier–Stokes solver
Computer Physics Communications 188 (2015): 177-188.Status: Published
Oasis: A high-level/high-performance open source Navier–Stokes solver
Abstract Oasis is a high-level/high-performance finite element Navier–Stokes solver written from scratch in Python using building blocks from the \{FEniCS\} project (fenicsproject.org). The solver is unstructured and targets large-scale applications in complex geometries on massively parallel clusters. Oasis utilizes \{MPI\} and interfaces, through FEniCS, to the linear algebra backend PETSc. Oasis advocates a high-level, programmable user interface through the creation of highly flexible Python modules for new problems. Through the high-level Python interface the user is placed in complete control of every aspect of the solver. A version of the solver, that is using piecewise linear elements for both velocity and pressure, is shown to reproduce very well the classical, spectral, turbulent channel simulations of Moser et al. (1999). The computational speed is strongly dominated by the iterative solvers provided by the linear algebra backend, which is arguably the best performance any similar implicit solver using \{PETSc\} may hope for. Higher order accuracy is also demonstrated and new solvers may be easily added within the same framework. Program summary Program title: Oasis Catalogue identifier: AEUW_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEUW_v1_0.html Program obtainable from: \{CPC\} Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: \{GNU\} Lesser \{GPL\} version 3 or any later version No. of lines in distributed program, including test data, etc.: 3491 No. of bytes in distributed program, including test data, etc.: 266924 Distribution format: tar.gz Programming language: Python/C++. Computer: Any single laptop computer or cluster. Operating system: Any (Linux, OSX, Windows). RAM: a few Megabytes to several hundred Gigabytes Classification: 12. External routines: \{FEniCS\} 1.3.0 (www.fenicsproject.org, that in turn depends on a number of external libraries like MPI, PETSc, Epetra, Boost and ParMetis) Nature of problem: Incompressible, Newtonian fluid flow. Solution method: The finite element method. Unusual features: \{FEniCS\} automatically generates and compiles low-level C++ code based on high-level Python code. Running time: The example provided takes a couple of minutes on a single processor.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2015 |
| Journal | Computer Physics Communications |
| Volume | 188 |
| Pagination | 177 - 188 |
| Publisher | Elsevier |
| ISSN | 0010-4655 |
| Keywords | Navier–Stokes |
| URL | http://www.sciencedirect.com/science/article/pii/S0010465514003786 |
| DOI | 10.1016/j.cpc.2014.10.026 |
The Computational Fluid Dynamics Rupture Challenge 2013—Phase II: variability of hemodynamic simulations in two intracranial aneurysms
Journal of Biomechanical Engineering 137, no. 12 (2015): 121008/1-121008/13.Status: Published
The Computational Fluid Dynamics Rupture Challenge 2013—Phase II: variability of hemodynamic simulations in two intracranial aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2015 |
| Journal | Journal of Biomechanical Engineering |
| Volume | 137 |
| Issue | 12 |
| Pagination | 121008/1-121008/13 |
| Date Published | 2015 |
| Publisher | American Society of Mechanical Engineers |
Proceedings, refereed
Are computer simulations misleading us about the nature of blood flow in the brain?
In NSCM-28 - 28th Nordic Seminar on Computational Mechanics, 2015.Status: Published
Are computer simulations misleading us about the nature of blood flow in the brain?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | NSCM-28 - 28th Nordic Seminar on Computational Mechanics |
| Date Published | 10/2015 |
Can Highly Resolved Computational Fluid Dynam- ics Simulations Shed New Light on Aneurysm Initiation?
In 4th International Conference on Computational and Mathematical Biomedical Engineering, 2015.Status: Published
Can Highly Resolved Computational Fluid Dynam- ics Simulations Shed New Light on Aneurysm Initiation?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | 4th International Conference on Computational and Mathematical Biomedical Engineering |
| Date Published | 06/2015 |
CFD Simulation of Transition to Turbulence for Newtonian vs. Non-Newtonian Flow Through a Stenosis
In The Summer Biomechanics, Bioengineering & Biotransport Conference, 2015.Status: Published
CFD Simulation of Transition to Turbulence for Newtonian vs. Non-Newtonian Flow Through a Stenosis
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | The Summer Biomechanics, Bioengineering & Biotransport Conference |
| Date Published | 06/2015 |
| Notes | Winner of the Best PhD Student Paper competition |
Characterization of Transition to Turbulence for Blood in a S-Shaped Pipe Under Steady Flow Conditions
In The Summer Biomechanics, Bioengineering & Biotransport Conference, 2015.Status: Published
Characterization of Transition to Turbulence for Blood in a S-Shaped Pipe Under Steady Flow Conditions
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | The Summer Biomechanics, Bioengineering & Biotransport Conference |
| Date Published | 06/2015 |
Effects of non-Newtonian rheology on transition to turbulence
In The 2015 AMMCS-CAIMS Congress, 2015.Status: Published
Effects of non-Newtonian rheology on transition to turbulence
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | The 2015 AMMCS-CAIMS Congress |
| Date Published | 06/2015 |
Flow Instabilities in Volume-Matched Sidewall ICA Aneurysms: A Possible Association with Rupture Status?
In Congress of Neurological Surgeons, 2015.Status: Published
Flow Instabilities in Volume-Matched Sidewall ICA Aneurysms: A Possible Association with Rupture Status?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | Congress of Neurological Surgeons |
| Date Published | 09/2015 |
Impact of Non-Newtonian Rheology in Transition to Turbulence in Artery Models.
In 4th International Conference on Computational and Mathematical Biomedical Engineering, 2015.Status: Published
Impact of Non-Newtonian Rheology in Transition to Turbulence in Artery Models.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | 4th International Conference on Computational and Mathematical Biomedical Engineering |
| Date Published | 06/2015 |
Implementation, verification and validation of large eddy simulation models in Oasis
In MekIT'15 8th National Conference on Computational Mechanics. Barcelona, Spain: International Center for Numerical Methods in Engineering (CIMNE), 2015.Status: Published
Implementation, verification and validation of large eddy simulation models in Oasis
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | MekIT'15 8th National Conference on Computational Mechanics |
| Pagination | 99-122 |
| Date Published | 11/2015 |
| Publisher | International Center for Numerical Methods in Engineering (CIMNE) |
| Place Published | Barcelona, Spain |
| ISBN Number | 978-84-944244-9-6 |
Inlet Flow Rate Variation and Onset of Flow Instabilities in the Carotid Siphon
In The Summer Biomechanics, Bioengineering & Biotransport Conference, 2015.Status: Published
Inlet Flow Rate Variation and Onset of Flow Instabilities in the Carotid Siphon
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | The Summer Biomechanics, Bioengineering & Biotransport Conference |
| Date Published | 06/2015 |
On the assumption of laminar flow in the cerebrovasculature: Implications for CFD insights into aneurysm initiation and rupture?
In Computational Fluid Dynamics (CFD) in Medicine and Biology II, An Engineering Conferences International (ECI) Conference Series., 2015.Status: Published
On the assumption of laminar flow in the cerebrovasculature: Implications for CFD insights into aneurysm initiation and rupture?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2015 |
| Conference Name | Computational Fluid Dynamics (CFD) in Medicine and Biology II, An Engineering Conferences International (ECI) Conference Series. |
| Date Published | 09/2015 |
Talks, invited
Are computer simulations misleading us about the nature of blood flow in the brain?
In NSCM-28 - 28th Nordic Seminar on Computational Mechanics, 2015.Status: Published
Are computer simulations misleading us about the nature of blood flow in the brain?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2015 |
| Location of Talk | NSCM-28 - 28th Nordic Seminar on Computational Mechanics |
The 2015 Aneurysm CFD Challenge: Variability of Segmentations, Hemodynamics, and Hemodynamic Indices: Qualitative and Preliminary Results - Incremental updates
In Computational Fluid Dynamics (CFD) in Medicine and Biology II, An Engineering Conferences International (ECI) Conference series. Albufeira, Portugal, 2015.Status: Published
The 2015 Aneurysm CFD Challenge: Variability of Segmentations, Hemodynamics, and Hemodynamic Indices: Qualitative and Preliminary Results - Incremental updates
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2015 |
| Location of Talk | Computational Fluid Dynamics (CFD) in Medicine and Biology II, An Engineering Conferences International (ECI) Conference series. Albufeira, Portugal |
Talks, contributed
Can Highly Resolved Computational Fluid Dynamics Simulations Shed New Light on Aneurysm Initiation?
In Accounting for complexity in blood flow modelling, Uncertainty Quantification in Predictive Computational Vascular Mechanics, Computational and Mathematical Biomedical Engineering, Paris, France., 2015.Status: Published
Can Highly Resolved Computational Fluid Dynamics Simulations Shed New Light on Aneurysm Initiation?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2015 |
| Location of Talk | Accounting for complexity in blood flow modelling, Uncertainty Quantification in Predictive Computational Vascular Mechanics, Computational and Mathematical Biomedical Engineering, Paris, France. |
Implementation, verification and validation of large eddy simulation models in Oasis
In MekIT - Conference on Computational Mechanics - NTNU, Trondheim, Norway, 2015.Status: Published
Implementation, verification and validation of large eddy simulation models in Oasis
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2015 |
| Location of Talk | MekIT - Conference on Computational Mechanics - NTNU, Trondheim, Norway |
Lessons learned from simulating blood flow in the brain: Preaching to the converted?
In MPNS COST Action MP1404 Simulation and pharmaceutical technologies for advanced patient-tailored inhaled medicines, Parma, Italy, 2015.Status: Published
Lessons learned from simulating blood flow in the brain: Preaching to the converted?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2015 |
| Location of Talk | MPNS COST Action MP1404 Simulation and pharmaceutical technologies for advanced patient-tailored inhaled medicines, Parma, Italy |
The 2015 Aneurysm CFD Challenge: Are we there yet?
In American Society of Mechanical Engineers Validation and Verification meeting, New York, USA., 2015.Status: Published
The 2015 Aneurysm CFD Challenge: Are we there yet?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2015 |
| Location of Talk | American Society of Mechanical Engineers Validation and Verification meeting, New York, USA. |
The 2015 Aneurysm CFD Challenge: Variability of Segmentations, Hemodynamics, and Hemodynamic Indices: Qualitative and Preliminary Results
In Summer Biomechanics, Bioengineering \& Biotransport Conference, Utah, USA, 2015.Status: Published
The 2015 Aneurysm CFD Challenge: Variability of Segmentations, Hemodynamics, and Hemodynamic Indices: Qualitative and Preliminary Results
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2015 |
| Location of Talk | Summer Biomechanics, Bioengineering \& Biotransport Conference, Utah, USA |
Talk, keynote
On the assumption of laminar ow in the cerebrovas- culature: Implications for CFD insights into aneurysm initiation and rupture?
In Computational Fluid Dynamics (CFD) in Medicine and Biology II, An Engineering Conferences International (ECI) Conference series. Albufeira, Portugal, 2015.Status: Published
On the assumption of laminar ow in the cerebrovas- culature: Implications for CFD insights into aneurysm initiation and rupture?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talk, keynote |
| Year of Publication | 2015 |
| Location of Talk | Computational Fluid Dynamics (CFD) in Medicine and Biology II, An Engineering Conferences International (ECI) Conference series. Albufeira, Portugal |
Proceedings, refereed
A Novel Framework for Classifying Wall Shear Stress Phenotypes in Arterial Disturbed Blood Flow
In World Congress of Biomechanics Proceedings. JBioMech, 2014.Status: Published
A Novel Framework for Classifying Wall Shear Stress Phenotypes in Arterial Disturbed Blood Flow
Background and Purpose: Recent high-resolution (HR) computational fluid dynamics (CFD) simulations have revealed that flow instabilities with high-frequency fluctuations can occur at relatively low Reynolds numbers (Valen-Sendstad and Steinman, 2014). We have assumed that the highly disturbed wall shear stress (WSS) caused by such flow instabilities impact the (dys)functional nature of arterial endothelial cells, believed to initiate arterial diseases. Current indices designed to quantify the disturbed WSS, such as oscillatory shear index (OSI) and transverse wall shear stress (transWSS), however, sometimes fail to distinguish different types of highly disturbed WSS. We propose a method for quantifying and distinguishing the WSS disturbances adequately and demonstrate its capability. Materials and Methods: We used an anatomically realistic carotid siphon derived from the open-source Aneurisk data-set. The aneurysm was removed with previously developed and verified tools. Pulsatile flow was simulated using 30,000 time-steps per cycle and the equivalent of 24M linear tetrahedrons. Changes in instantaneous WSS were decomposed into magnitude and angle variations, respectively, with the angle defined relative to the cycle-averaged WSS vector direction. The proposed classification of WSS phenotypes therefore consists of a permutation (from low to high values) of WSS, WSS magnitude change, and WSS angle change; a total of 9. Results: The attached figure shows the distributions of OSI, transWSS, and the currently proposed phenotypes. Despite highly different stimuli at the wall (shown in the polar plots, where the WSS magnitude is plotted on a common logarithmic scale), both OSI and transWSS calculations return the same numerical value for large regions. E.g., the WSS phenotype in polar plots OSI=.211
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2014 |
| Conference Name | World Congress of Biomechanics Proceedings |
| Publisher | JBioMech |
Illustration-Inspired Visualization of Blood Flow Dynamics
In World Congress of Biomechanics Proceedings. JBioMech, 2014.Status: Published
Illustration-Inspired Visualization of Blood Flow Dynamics
Image-based computational fluid dynamics (CFD) has emerged as a central tool in the evaluation of hemodynamic factors in cardiovascular disease development and treatment planning, to the point where major vendors are now seeking to deploy CFD solvers on their medical imaging platforms. Detailed hemodynamic data available from CFD reveal complicated flows that are difficult to render clearly - and thus communicate to clinical stakeholders - using conventional engineering flow visualization techniques. This is especially challenging considering the four-dimensional nature of the flow patterns (i.e., varying in space and time), as well as the clinical need for generating static reports rather than cumbersome digital animations. Taking a cue from the rich history of biomedical illustration, the goal of our multi-disciplinary collaboration between the University of Toronto and the Ontario College of Art and Design University is to develop new data-driven paradigms for visualizing blood flow, based on the principles of illustration, sequential art and caricature, and informed by the visual vocabularies and conventions of radiology and vascular surgery. Our first investigations have involved the depiction of transitional flows in cerebral aneurysms. The top row of the included figure shows selected frames from an animation of vortex cores (i.e., positive and negative Q-criterion), created using the open-source scientific visualization package, Paraview. Note how difficult it is to infer the dynamics from these static images. For the bottom row, vortex cores were outlined in black to better discriminate them from each other. Surface shading was enhanced, and colouring was used to highlight selected cores, the dynamic motion of which can be followed easily across the individual frames. The original translucent lumen surface rendering was also replaced by a simple outline drawing that nevertheless retains, and perhaps even heightens, the impression of a 3D aneurysm. Although this example was composed by a professional biomedical illustrator (JH) using graphics editing tools applied to the individual static frames, we are presently working towards automating these steps in collaboration with Toronto-based Side Effects Software, developers of the Houdini 3D Animation suite widely used in the motion picture industry.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2014 |
| Conference Name | World Congress of Biomechanics Proceedings |
| Publisher | JBioMech |
| Keywords | Conference |
Inlet Flow Rates for Image-Based Aneurysm CFD Models: Where (and How) to Begin?
In World Congress of Biomechanics Proceedings. JBioMech, 2014.Status: Published
Inlet Flow Rates for Image-Based Aneurysm CFD Models: Where (and How) to Begin?
| Afilliation | , Scientific Computing |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2014 |
| Conference Name | World Congress of Biomechanics Proceedings |
| Publisher | JBioMech |
Numerical Resolution Requirements for Converging Wall Shear Stresses in Intracranial Aneurysms
In World Congress of Biomechanics Proceedings. JBioMech, 2014.Status: Published
Numerical Resolution Requirements for Converging Wall Shear Stresses in Intracranial Aneurysms
Abstract: Background: CFD can simulate the hemodynamics forces like wall shear stress (WSS) that are known to play an important role in rupture of intracranial aneurysms. Every stone has been turned striving for more {`}patient-specific' simulations, except for numerical accuracy itself. The purpose of this study is to quantify such errors, particularly for WSS. Methods: Five refinement levels were simulated for three previously reported cases based on flow phenotype (Valen-Sendstad and Steinman, 2014): stable-sidewall (case 8), quasi-unstable- bifurcation (case 9), and unstable-bifurcation (case 16). Pulsatile simulations were performed using second-order-accurate P2-P1 (Taylor-Hood) tetrahedral elements. Finest meshes had a sac resolution of 0.055mm, 0.061mm, and 0.10mm for cases 8, 9 and 16, respectively, resulting in 4-million elements (\~32M linear tetrahedra). These finest meshes were successively coarsened by a factor of sqrt(2) with respect to side length, resulting in coarsest meshes having \~100,000 elements (\~800,000 linear tetrahedra). All meshes had four boundary layers. We used 35,000 time- steps/cycle and second-order time-stepping scheme for three reasons: 1) to avoid adding artificial numerical viscosity to stabilize the solution, 2) to eliminate temporal discretization errors, and 3) to isolate and quantify spatial discretization errors alone. Results: In contrast to conventional mesh refinement studies, we show a 3-fold decrease in effective node spacing, not simply mesh size. As a consequence, mesh sizes grew cubically. In the figure, we show normalized L2 errors for domain-averaged velocity and dome-averaged WSS at peak systole relative to the finest mesh. Although the velocity errors, a standard metric for monitoring grid convergence, appear to be within 2% error for the second-finest mesh (equivalent to \~13M linear tetrahedra), the WSS errors are an order of magnitude away from convergence. Having said this, patterns of WSS were qualitatively similar. Conclusions: High spatial resolution is required to converge WSS, even when velocity appears to be well-converged: on average, an effective mesh resolution of \~0.05mm is needed to converge WSS below \~10%. Work to be presented will also include temporal refinement study with high spatial resolution to clarify the requirements on temporal resolution, as well as the impact on popular scalar hemodynamic indices.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2014 |
| Conference Name | World Congress of Biomechanics Proceedings |
| Publisher | JBioMech |
Talk, keynote
CFD Modelling of Cerebrovascular Hemodynamics: Breaking News
In 9th international symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, Montreal, Canada, April, 2014, 2014.Status: Published
CFD Modelling of Cerebrovascular Hemodynamics: Breaking News
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talk, keynote |
| Year of Publication | 2014 |
| Location of Talk | 9th international symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, Montreal, Canada, April, 2014 |
| Date Published | 04/2014 |
| Keywords | Conference |
It's not the size, but what you do with it: CFD solver settings trump model resolution.
In Zurich. Interdisciplinary Cerebrovascular Symposium / Intracranial Stent Meeting, 2014.Status: Published
It's not the size, but what you do with it: CFD solver settings trump model resolution.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talk, keynote |
| Year of Publication | 2014 |
| Location of Talk | Zurich |
| Publisher | Interdisciplinary Cerebrovascular Symposium / Intracranial Stent Meeting |
Talks, invited
Flow Instabilities in Sidewall Aneurysms: a Possible Association With Rupture Status?
In World Congress of Biomechanics, 2014.Status: Published
Flow Instabilities in Sidewall Aneurysms: a Possible Association With Rupture Status?
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2014 |
| Location of Talk | World Congress of Biomechanics |
On Numerical Methods for Transitional Flow - Application to Blood Flow in Aneurysms
In Quality and Validation of Computational Cardio-vascular Biomechanics, WCCM-ECCM-ECCOM, 2014.Status: Published
On Numerical Methods for Transitional Flow - Application to Blood Flow in Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2014 |
| Location of Talk | Quality and Validation of Computational Cardio-vascular Biomechanics, WCCM-ECCM-ECCOM |
Unstable Flow in the Carotid Siphon: Implications for Aneurysm Initiation and Rupture
In World Congress of Biomechanics, 2014.Status: Published
Unstable Flow in the Carotid Siphon: Implications for Aneurysm Initiation and Rupture
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2014 |
| Location of Talk | World Congress of Biomechanics |
| Keywords | Conference |
Journal Article
High-Resolution CFD Detects Flow Instabilities in the Carotid Siphon: Implications for Aneurysm Initiation and Rupture?
Journal of Biomechanics (2014): 3210-3216.Status: Published
High-Resolution CFD Detects Flow Instabilities in the Carotid Siphon: Implications for Aneurysm Initiation and Rupture?
| Afilliation | Scientific Computing, Scientific Computing |
| Publication Type | Journal Article |
| Year of Publication | 2014 |
| Journal | Journal of Biomechanics |
| Number | 47 |
| Pagination | 3210-3216 |
| Publisher | Elsevier |
Mind the Gap: Impact of Computational Fluid Dynamics Solution Strategy on Prediction of Intracranial Aneurysm Hemodynamics and Rupture Status Indicators
American Journal of Neuroradiology 35 (2014): 536-543.Status: Published
Mind the Gap: Impact of Computational Fluid Dynamics Solution Strategy on Prediction of Intracranial Aneurysm Hemodynamics and Rupture Status Indicators
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2014 |
| Journal | American Journal of Neuroradiology |
| Volume | 35 |
| Number | 3 |
| Pagination | 536-543 |
| Date Published | March |
| Publisher | American Journal of Neuroradiology |
| Notes | Commentary:AJNR, 2014 Mar;35(3):544-5 |
Proceedings, refereed
A Quasi-Analytical Method for Calculating Junction Pressure Losses in 1D Vascular Network Models: Validation With High-Resolution CFD
In 3rd International Conference on Computational and Mathematical Biomedical Engineering - CMBE2013. Proceedings, 2013.Status: Published
A Quasi-Analytical Method for Calculating Junction Pressure Losses in 1D Vascular Network Models: Validation With High-Resolution CFD
| Afilliation | , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2013 |
| Conference Name | 3rd International Conference on Computational and Mathematical Biomedical Engineering - CMBE2013 |
| Publisher | Proceedings |
Impact of CFD Solution Strategy on Predicted Aneurysm Hemodynamics: Good News and Bad News
In Proceedings of 8th international symposium on Biomechanics in Vascular Biology and Cardiovascular Disease. Proceedings, 2013.Status: Published
Impact of CFD Solution Strategy on Predicted Aneurysm Hemodynamics: Good News and Bad News
Last year at this meeting we demonstrated that high-resolution (HR) CFD simulations could detect a highly transient response to steady inflow conditions in 5 of 12 MCA aneurysm cases [1]. We also showed preliminary results suggesting that normal resolution (NR) simulations, representative of those from the clinical literature (e.g, [2,3]), might be misleading about the nature of aneurysm flow patterns and wall shear stress (WSS), and hence derived predictors of rupture risk. We now test this hypothesis in a controlled manner, by comparing NR vs. HR simulations of physiologically pulsatile flow in the 12 MCA aneurysm cases from [1].
| Afilliation | , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2013 |
| Conference Name | Proceedings of 8th international symposium on Biomechanics in Vascular Biology and Cardiovascular Disease |
| Publisher | Proceedings |
Journal Article
A Study of Wall Shear Stress in 12 Aneurysms With Respect to Different Viscosity Models and Flow Conditions
Journal of Biomechanics 46 (2013): 2802-2808.Status: Published
A Study of Wall Shear Stress in 12 Aneurysms With Respect to Different Viscosity Models and Flow Conditions
Recent computational fluid dynamics (CFD) studies relate abnormal blood flow to rupture of cerebral aneurysms. However, it is still debated how to model blood flow with sufficient accuracy. Common assumptions made include Newtonian behavior of blood, traction free outlet boundary conditions and inlet boundary conditions based on available literature. These assumptions are often required since the available patient specific data is usually restricted to the geometry of the aneurysm and the surrounding vasculature. However, the consequences of these assumptions have so far been inadequately addressed. This study investigates the effects of 4 different viscosity models, 2 different inflow conditions and 2 different outflow conditions in 12 middle cerebral artery aneurysms. The differences are quantified in terms of 3 different wall shear stress (WSS) metrics, involving maximal WSS, average WSS, and proportion of aneurysm sac area with low WSS. The results were compared with common geometrical metrics such as volume, aspect ratio, size ratio and parent vessel diameter and classifications in terms of sex and aneurysm type. The results demonstrate strong correlations between the different viscosity models and boundary conditions. The correlation between the different WSS metrics range from weak to medium. No strong correlations were found between the different WSS metrics and the geometrical metrics or classifications.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2013 |
| Journal | Journal of Biomechanics |
| Volume | 46 |
| Number | 16 |
| Pagination | 2802-2808 |
| Date Published | November |
High-Resolution Computational Fluid Dynamics Detects High-Frequency Velocity Fluctuations in Bifurcation, But Not Sidewall, Aneurysms of the Middle Cerebral Artery
Journal of Biomechanics 46, no. 2 (2013): 402-407.Status: Published
High-Resolution Computational Fluid Dynamics Detects High-Frequency Velocity Fluctuations in Bifurcation, But Not Sidewall, Aneurysms of the Middle Cerebral Artery
High-frequency flow fluctuations in intracranial aneurysms have previously been reported in vitro and in vivo. On the other hand, the vast majority of image-based computational fluid dynamics (CFD) studies of cerebral aneurysms report periodic, laminar flow. We have previously demonstrated that transitional flow, consistent with in vivo reports, can occur in a middle cerebral artery (MCA) bifurcation aneurysm when ultra-high-resolution direct numerical simulation methods are applied. The object of the present study was to investigate if such high-frequency flow fluctuations might be more widespread in adequately-resolved CFD models. A sample of N=12 anatomically realistic MCA aneurysms (five unruptured, seven ruptured), was digitally segmented from CT angiograms. Four were classified as sidewall aneurysms, the other eight as bifurcation aneurysms. Transient CFD simulations were carried out assuming a steady inflow velocity of 0.5 m/s, corresponding to typical peak systolic conditions at the MCA. To allow for detection of clinically-reported high-frequency flow fluctuations and resulting flow structures, temporal and spatial resolutions of the CFD simulations were in the order of 0.1 ms and 0.1 mm, respectively. A transient flow response to the stationary inflow conditions was found in five of the 12 aneurysms, with energetic fluctuations up to 100 Hz, and in one case up to 900 Hz. Incidentally, all five were ruptured bifurcation aneurysms, whereas all four sidewall aneurysms, including one ruptured case, quickly reached a stable, steady state solution. Energetic, rapid fluctuations may be overlooked in CFD models of bifurcation aneurysms unless adequate temporal and spatial resolutions are used. Such fluctuations may be relevant to the mechanobiology of aneurysm rupture, and to a recently reported dichotomy between predictors of rupture likelihood for bifurcation vs. sidewall aneurysms.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2013 |
| Journal | Journal of Biomechanics |
| Volume | 46 |
| Issue | 2 |
| Pagination | 402-407 |
| Publisher | Elsevier |
Variability of Computational Fluid Dynamics Solutions for Pressure and Flow in a Giant Aneurysm: the ASME 2012 Summer Bioengineering Conference CFD Challenge
Journal of Biomedical Engineering 135 (2013).Status: Published
Variability of Computational Fluid Dynamics Solutions for Pressure and Flow in a Giant Aneurysm: the ASME 2012 Summer Bioengineering Conference CFD Challenge
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2013 |
| Journal | Journal of Biomedical Engineering |
| Volume | 135 |
| Number | 2 |
| Publisher | J Biomech Eng |
Talks, contributed
Impact of CFD Solution Strategy on Predicted Aneurysm Hemodynamics: Good News and Bad News
In 8th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, Rotterdam, 2013.Status: Published
Impact of CFD Solution Strategy on Predicted Aneurysm Hemodynamics: Good News and Bad News
| Afilliation | , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2013 |
| Location of Talk | 8th International Symposium on Biomechanics in Vascular Biology and Cardiovascular Disease, Rotterdam |
| Keywords | Conference |
Impact of CFD Solution Strategy on Predicted Aneurysm Hemodynamics: Good News and Bad News
In CBC seminar series, 2013.Status: Published
Impact of CFD Solution Strategy on Predicted Aneurysm Hemodynamics: Good News and Bad News
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2013 |
| Location of Talk | CBC seminar series |
Poster
{`}Freezing Time' to Show 4D Evolution of Transitional Vortex Cores in an Aneurysm That Is Undergoing Highly Unstable Flow
2013.Status: Submitted
{`}Freezing Time' to Show 4D Evolution of Transitional Vortex Cores in an Aneurysm That Is Undergoing Highly Unstable Flow
| Afilliation | , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Poster |
| Year of Publication | 2013 |
Book Chapter
A Comparison of Some Common Finite Element Schemes for the Incompressible Navier-Stokes Equations
In Automated Solution of Differential Equations by the Finite Element Method, 395-418. Vol. 84. Lecture Notes in Computational Science and Engineering 84. Springer, 2012.Status: Published
A Comparison of Some Common Finite Element Schemes for the Incompressible Navier-Stokes Equations
| Afilliation | Scientific Computing, , Scientific Computing, Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Book Chapter |
| Year of Publication | 2012 |
| Book Title | Automated Solution of Differential Equations by the Finite Element Method |
| Secondary Title | Lecture Notes in Computational Science and Engineering |
| Volume | 84 |
| Chapter | 21 |
| Pagination | 395-418 |
| Publisher | Springer |
| ISBN Number | 978-3-642-23098-1 |
Computational Hemodynamics
In Automated Solution of Differential Equations by the Finite Element Method, 439-454. Vol. 84. Lecture Notes in Computational Science and Engineering 84. Springer, 2012.Status: Published
Computational Hemodynamics
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Book Chapter |
| Year of Publication | 2012 |
| Book Title | Automated Solution of Differential Equations by the Finite Element Method |
| Secondary Title | Lecture Notes in Computational Science and Engineering |
| Volume | 84 |
| Chapter | 23 |
| Pagination | 439-454 |
| Publisher | Springer |
| ISBN Number | 978-3-642-23098-1 |
Proceedings, refereed
CFD CHALLENGE: SOLUTIONS USING an IN-HOUSE FINITE ELEMENT METHOD FLOW SOLVER IMPLEMENTED in FEniCS
In ASME 2012 Summer Bioengineering Conference, Fajardo, Puerto Rico, 2012.Status: Published
CFD CHALLENGE: SOLUTIONS USING an IN-HOUSE FINITE ELEMENT METHOD FLOW SOLVER IMPLEMENTED in FEniCS
FEniCS is a finite element library for {`}automated, efficient solution of differential equations' (www.fenicsproject.org). The focus has been to develop high level software interface that allows the user to type in the equations nearly as they are read. Recent development has involved extensions for parallell computing and building efficient pipeline for patient specific geometries based on Vascular Modelling Toolkit (VMTK, www.vmtk.org) meshes. The aim is therefore to evaluate the accuracy and efficiency of one of the developed computational fluid mechanics (CFD) solvers. The simulations were perfored according to the given instructions and information is not repeated. This abstract is therefore not complete and must be seen in the light of the Challenge.
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2012 |
| Conference Name | ASME 2012 Summer Bioengineering Conference, Fajardo, Puerto Rico |
Is CFD Misleading Us About the Nature of Wall Shear Stresses in Cerebral Aneurysms?
In The 7th International Symposium on Biomechanics in Vascular Biology & Cardiovascular Disease, Atlanta, Georgia, USA. Internal, 2012.Status: Published
Is CFD Misleading Us About the Nature of Wall Shear Stresses in Cerebral Aneurysms?
Computational fluid dynamics (CFD) simulations are increasingly being used to model cerebral aneurysm hemodynamics and wall shear stress (WSS) in order to infer aneurysm wall strength and therefore risk of rupture. Numerous recent computational studies have been successful in retrospectively classifying aneurysms according to their rupture status, but the link between the proposed hemodynamic indices and the precise mechanisms leading to rupture remains unclear. One presumption common to virtually all of these CFD studies is that blood flow inside an aneurysm is laminar and stable, even though it is well known that many aneurysms produce sounds or bruits with energy peaks at hundreds of Hz. Clinicians have reported this invasively and non-invasively, and turbulence has been shown to occur in intracranial aneurysms in several experiments. These phenomena seem have raised little interest in the computational biomechanics community, and there is therefore a gap between the clinically reported frequencies and the resolution at which the simulations are performed. We have previously shown, using direct numerical simulation of pulsatile flow in two patient-specific middle cerebral artery (MCA) aneurysms, that transitional flow was present, leading to strong wall shear stress gradients. More recently, we have demonstrated the presence of unstable flow patterns in 5 of 12 MCA aneurysm cases simulated under high resolution, transient steady flow conditions. These findings would suggest that in many cases the aneurysmal wall may be subject to more violent forces than have been predicted by the vast majority of CFD model studies. To illustrate this, we carried out transient steady flow simulations for the two MCA cases we had previously simulated with DNS, using a first order accurate solver with roughly 600,000 linear tetrahedral and boundary layer elements and 10 msec temporal resolution, and a second order solver with the same number of elements (i.e. more than double the spatial resolution) and 0.03 msec temporal resolution. The latter simulations exhibited strong velocity and WSS fluctuations, as anticipated from the previous DNS studies, whereas the first order simulations stabilized quickly. These preliminary head-to-head comparisons are currently being extended to more cases, and under pulsatile flow conditions. In summary, the presumption of laminar, stable flow underlying most CFD models of cerebral aneurysms may be a self-fulfilling prophecy that leads to a misinterpretation of the biomechanical forces at play in aneurysm progression and rupture.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2012 |
| Conference Name | The 7th International Symposium on Biomechanics in Vascular Biology & Cardiovascular Disease, Atlanta, Georgia, USA |
| Publisher | Internal |
Talks, contributed
Is CFD Misleading Us About the Nature of Wall Shear Stresses in Cerebral Aneurysms?
In The 7th International Symposium on Biomechanics in Vascular Biology & Cardiovascular Disease, Atlanta, Georgia, USA, 2012.Status: Published
Is CFD Misleading Us About the Nature of Wall Shear Stresses in Cerebral Aneurysms?
Computational fluid dynamics (CFD) simulations are increasingly being used to model cerebral aneurysm hemodynamics and wall shear stress (WSS) in order to infer aneurysm wall strength and therefore risk of rupture. Numerous recent computational studies have been successful in retrospectively classifying aneurysms according to their rupture status, but the link between the proposed hemodynamic indices and the precise mechanisms leading to rupture remains unclear. One presumption common to virtually all of these CFD studies is that blood flow inside an aneurysm is laminar and stable, even though it is well known that many aneurysms produce sounds or bruits with energy peaks at hundreds of Hz. Clinicians have reported this invasively and non-invasively, and turbulence has been shown to occur in intracranial aneurysms in several experiments. These phenomena seem have raised little interest in the computational biomechanics community, and there is therefore a gap between the clinically reported frequencies and the resolution at which the simulations are performed. We have previously shown, using direct numerical simulation of pulsatile flow in two patient-specific middle cerebral artery (MCA) aneurysms, that transitional flow was present, leading to strong wall shear stress gradients. More recently, we have demonstrated the presence of unstable flow patterns in 5 of 12 MCA aneurysm cases simulated under high resolution, transient steady flow conditions. These findings would suggest that in many cases the aneurysmal wall may be subject to more violent forces than have been predicted by the vast majority of CFD model studies. To illustrate this, we carried out transient steady flow simulations for the two MCA cases we had previously simulated with DNS, using a first order accurate solver with roughly 600,000 linear tetrahedral and boundary layer elements and 10 msec temporal resolution, and a second order solver with the same number of elements (i.e. more than double the spatial resolution) and 0.03 msec temporal resolution. The latter simulations exhibited strong velocity and WSS fluctuations, as anticipated from the previous DNS studies, whereas the first order simulations stabilized quickly. These preliminary head-to-head comparisons are currently being extended to more cases, and under pulsatile flow conditions. In summary, the presumption of laminar, stable flow underlying most CFD models of cerebral aneurysms may be a self-fulfilling prophecy that leads to a misinterpretation of the biomechanical forces at play in aneurysm progression and rupture.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2012 |
| Location of Talk | The 7th International Symposium on Biomechanics in Vascular Biology & Cardiovascular Disease, Atlanta, Georgia, USA |
Non-Newtonian Effects in Cerebral Aneurysms. a Computational Study on 12 Patient Specific Aneurysms
In ICS '12, 2012.Status: Published
Non-Newtonian Effects in Cerebral Aneurysms. a Computational Study on 12 Patient Specific Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2012 |
| Location of Talk | ICS '12 |
Poster
On Non-Newtonian Effects in Cerebral Aneurysms: a Computational Study on 12 Patient Specific Aneurysms
2012.Status: Published
On Non-Newtonian Effects in Cerebral Aneurysms: a Computational Study on 12 Patient Specific Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Poster |
| Year of Publication | 2012 |
Revisiting 'Turbulence' in Cerebral Aneurysms
2012.Status: Published
Revisiting 'Turbulence' in Cerebral Aneurysms
One of the commonly made assumptions in Computational Fluid Dynamics (CFD) is that cerebral blood flow is laminar, i.e., viscous forces are dominating and the flow is smooth. The numerical methods that are used, are chosen or tailored accordingly, i.e., to converge to such a laminar flow solution with the minimal amount of work1-2. The flow is modeled with a temporal resolution far below the clinically reported frequencies3 and thus any potential flow disturbances, if physically present, are being numerically suppressed. Since no potential disturbances are resolved, no disturbances are observed and the assumption of laminar flow is therefore a self-fulfilling prophecy. Even though recent laminar CFD studies can discriminate between ruptured and unruptured aneurysms better than, e.g. aneurysm size, the link between the proposed hemodynamic agonists and the mechanisms of rupture is unclear. However, the literature contains much evidence which supports that certain aneurysms exhibit energetic high frequency flow fluctuations. For example, high frequency flow fluctuations are known to produce sound, and clinicians have reported such sound or 'bruits' from aneurysms during craniotomy.3 The predominant frequencies were at 460 Hz, which is consistent with the energy peaks at higher frequencies recorded acoustically on the eyes in patients with aneurysms.4 Unstable flow has also been reported in glass model studies of aneurysms.5 This evidence seems to have been ignored, or at least has not received much attention in computational modeling studies. The goal of the present study was to investigate if such high-frequency flow fluctuations in intracranial aneurysms might be a common occurrence, by using thousands of time steps in contrast to, e.g., one hundred2.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Poster |
| Year of Publication | 2012 |
| Keywords | Conference |
Talks, contributed
'Turbulence' in Cerebral Aneurysms
In CBC Workshop on Biomechanics, 17-18 November, 2011.Status: Published
'Turbulence' in Cerebral Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2011 |
| Location of Talk | CBC Workshop on Biomechanics, 17-18 November |
Computational Cerebral Hemodynamics
In The Norwegian Defence Research Establishment, 2011.Status: Published
Computational Cerebral Hemodynamics
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2011 |
| Location of Talk | The Norwegian Defence Research Establishment |
Direct Numerical Simulation of Transitional Flow in Patient-Specific Intracranial Aneurysms
In ASME 2011 Summer Bioengineering Conference, 2011.Status: Published
Direct Numerical Simulation of Transitional Flow in Patient-Specific Intracranial Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2011 |
| Location of Talk | ASME 2011 Summer Bioengineering Conference |
Simulation Methodology for Cerebral Blood Flow
In Biomedical Simulation Lab, Institute of Biomaterials and Biomedical Engineering at the University of Toronto, 2011.Status: Published
Simulation Methodology for Cerebral Blood Flow
In experiments turbulence has previously been shown to occur in intracranial aneurysms, but the turbulent effects on the arterial wall have not been investigated. The effects of turbulence induced oscillatory wall stresses could be of great importance in understanding aneurysm rupture due to the local arterial wall response to such hemodynamical forces. To investigate the effects of turbulence on blood flow in an intracranial aneurysm, we performed a high resolution computational fluid dynamics (CFD) simulations in a patient specific middle cerebral artery (MCA) aneurysm using a realistic, pulsatile inflow velocity. The flow showed transition to turbulence just after peak systole, and the turbulent fluctuations increased in intensity until mid deceleration, before relaminarization occurred during diastole. The flow impinged with an angle nearly normal onto the aneurysm dome, and the turbulence structures greatly affected both the frequency of change of wall shear stress (WSS) direction and WSS magnitude, which reached a maximum value of 41.5 Pa. The recorded frequencies were predominantly in the range of 1-500 Hz. The current study confirms, through properly resolved CFD simulations, that turbulence can occur in intracranial aneurysms. Because of the local arterial wall response to hemodynamical forces, the effects of oscillatory WSS caused by turbulence, could be correlated with aneurysm rupture, and should be investigated experimentally.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2011 |
| Location of Talk | Biomedical Simulation Lab, Institute of Biomaterials and Biomedical Engineering at the University of Toronto |
Why Blood Flow in the Vicinity of Aneurysms Is Difficult to Compute
In Talk at CBC Workshop on CBC Key Topics, 2011.Status: Submitted
Why Blood Flow in the Vicinity of Aneurysms Is Difficult to Compute
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2011 |
| Location of Talk | Talk at CBC Workshop on CBC Key Topics |
Journal Article
A Quantitative Characterization of Differences in Flow Patterns in Ruptured Versus Unruptured MCA Aneurysms
journal (2011).Status: Submitted
A Quantitative Characterization of Differences in Flow Patterns in Ruptured Versus Unruptured MCA Aneurysms
The rupture of an intracranial aneurysm is often associated with death or severe neurological deficits. When detected, the physician has to evaluate the risk of rupture and determine the optimal treatment. Risk estimation based on computational fluid dynamics (CFD) and wall shear stress (WSS) has recently been the focus of many studies. Here, we introduce new indicators for assessing risk of aneurysm rupture based on fluid mechanical properties such as the kinetic energy, vorticity and pressure drop over the aneurysm.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Journal | journal |
Direct Numerical Simulation of Transitional Flow in a Patient-Specific Intracranial Aneurysm
Journal of Biomechanics 44 (2011): 2826-2832.Status: Published
Direct Numerical Simulation of Transitional Flow in a Patient-Specific Intracranial Aneurysm
In experiments turbulence has previously been shown to occur in intracranial aneurysms, but the turbulent effects on the arterial wall have not been investigated. The effects of turbulence induced oscillatory wall stresses could be of great importance in understanding aneurysm rupture due to the local arterial wall response to such hemodynamical forces. To investigate the effects of turbulence on blood flow in an intracranial aneurysm, we performed a high resolution computational fluid dynamics (CFD) simulations in a patient specific middle cerebral artery (MCA) aneurysm using a realistic, pulsatile inflow velocity. The flow showed transition to turbulence just after peak systole, and the turbulent fluctuations increased in intensity until mid deceleration, before relaminarization occurred during diastole. The flow impinged with an angle nearly normal onto the aneurysm dome, and the turbulence structures greatly affected both the frequency of change of wall shear stress (WSS) direction and WSS magnitude, which reached a maximum value of 41.5 Pa. The recorded frequencies were predominantly in the range of 1-500 Hz. The current study confirms, through properly resolved CFD simulations, that turbulence can occur in intracranial aneurysms. Because of the local arterial wall response to hemodynamical forces, the effects of oscillatory WSS caused by turbulence, could be correlated with aneurysm rupture, and should be investigated experimentally. Keywords: Computational fluid dynamics, Blood flow, Direct Numerical Simulation, Turbulence, Middle cerebral artery aneurysm
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Journal | Journal of Biomechanics |
| Volume | 44 |
| Number | 16 |
| Pagination | 2826-2832 |
| DOI | 10.1016/j.jbiomech.2011.08.015 |
Flow Characteristics in a Canine Aneurysm Model: A Comparison of 4-D Accelerated Phase-Contrast MR Measurements and Computational Fluid Dynamics Simulations
Medical Physics 38 (2011): 6300-6313.Status: Published
Flow Characteristics in a Canine Aneurysm Model: A Comparison of 4-D Accelerated Phase-Contrast MR Measurements and Computational Fluid Dynamics Simulations
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Journal | Medical Physics |
| Volume | 38 |
| Number | 11 |
| Pagination | 6300-6313 |
| Publisher | Med Phys |
PhD Thesis
Computational Cerebral Hemodynamics
University of Oslo, 2011.Status: Published
Computational Cerebral Hemodynamics
Stroke is the third most common reason for death in the Western world. One type of stroke is caused by the rupture of an out-pouch of a blood vessel, called an aneurysm. As much as six per cent of us can develop aneurysms during our life time, and the number of incidences of stroke is on the rise. Understanding the underlying processes of initiation, growth and rupture of aneurysms is of great importance to both a patient and society in general. Therefore, one has to gain detailed knowledge of blood flow and its effects on the blood vessel wall. Blood flow inside aneurysms has previously been believed to be stable and smooth. However, in Valen-Sendstad's thesis, it is proven through very high-resolution computational fluid dynamics that the flow can be complex and turbulent. This means that the cells inside the blood vessels, or aneurysms, might experience forces much stronger than previously assumed.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | PhD Thesis |
| Year of Publication | 2011 |
| Date Published | May |
| Publisher | University of Oslo |
| Thesis Type | phd |
| ISBN Number | ISSN 1501-7710 No. 1067 |
Proceedings, refereed
Investigations of Transistional Flows Using Image Based Hemodynamics
In 8th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries, 2011.Status: Published
Investigations of Transistional Flows Using Image Based Hemodynamics
We investigated the complexity of blood flow in intracranial aneurysms in terms of the frequency spectrum of pointwise velocity and pressure fluctuations. The investigations were performed using high-resolution computational fluid dynamics (CFD) simulations for patient-specific middle cerebral artery (MCA) aneurysms, using realistic inflow profile. Through these simulations, the study confirmed that complex transitional flow can occur in intracranial aneurysms. In particular, we found fluctuations of the order of 500- 1000 Hz.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2011 |
| Conference Name | 8th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries |
| Date Published | June |
On the Complexity of Stationary Flow in Patient-Specific Aneurysms
In MekIT'11 Sixth national conference on Computational Mechanics. tapir academic press, 2011.Status: Published
On the Complexity of Stationary Flow in Patient-Specific Aneurysms
Summary Sound or bruits in the vasculatory system at the range of 1Hz-1kHz is known to occur, and frequency peaks at high frequencies are associated with sick blood vessels. The exact reason for these sounds are not known, but the sound may be generated by turbulence. Turbulence generated sound is typically associated with high frequencies but also with low energy levels. Unfortunately, most blood flow simulations are performed with space and time resolutions where rapid fluctuations typ- ically associated with non-laminar flow cannot be captured. Complex non-laminar flow and the subsequent oscillatory wall stresses can po- tentially be of importance in understanding aneurysm rupture through the local arterial wall response. To investigate the possible presence of complex non-laminar blood flow in intracranial aneurysms, we per- formed high resolution computational fluid dynamics (CFD) simulations for patient specific middle cerebral artery (MCA) aneurysms with sta- tionary inflow conditions. The current study confirms, through high resolution simulations, that complex oscillatory flow may occur in in- tracranial aneurysms. CFD practitioners should therefore be aware of the potentially strong demands to space-time computational resolution in blood flow simulations.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2011 |
| Conference Name | MekIT'11 Sixth national conference on Computational Mechanics |
| Pagination | 379-392 |
| Publisher | tapir academic press |
| ISBN Number | 978-82-519-2798-7 |
Talks, invited
Simulating Blood Flow in Cerebral Aneurysm
In Minisymposium Numerical Methods for Biomedical Problems on Enumath, 2011.Status: Published
Simulating Blood Flow in Cerebral Aneurysm
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2011 |
| Location of Talk | Minisymposium Numerical Methods for Biomedical Problems on Enumath |
The Finite Element Library FEniCS and Simulation of Blood Flow in Cerebral Aneurysms
In Talk at CSB Seminar, University of Stuttgart, 2011.Status: Published
The Finite Element Library FEniCS and Simulation of Blood Flow in Cerebral Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, invited |
| Year of Publication | 2011 |
| Location of Talk | Talk at CSB Seminar, University of Stuttgart |
Talks, contributed
A Note on the Efficiency and Accuracy of Some Common Finite Element Schemes for the Incompressible Navier-Stokes Equations
In AC/DC seminar series, 2010.Status: Published
A Note on the Efficiency and Accuracy of Some Common Finite Element Schemes for the Incompressible Navier-Stokes Equations
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2010 |
| Location of Talk | AC/DC seminar series |
Presence of Turbulence in Intracranial MCA Aneurysms
In CBC Workshop on Aerosols: Dispersion, Transport and Effects, Simula, November 10, 2010.Status: Published
Presence of Turbulence in Intracranial MCA Aneurysms
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2010 |
| Location of Talk | CBC Workshop on Aerosols: Dispersion, Transport and Effects, Simula, November 10 |
Proceedings, refereed
Comparison of Aneurismal Hemodynamics Between 4D Accelerated Phase-Contrast MR Angiography and Computational Fluid Dynamics Simulations: Initial Experience in a Canine Aneurysm Model
In Proceedings of the ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010.Status: Published
Comparison of Aneurismal Hemodynamics Between 4D Accelerated Phase-Contrast MR Angiography and Computational Fluid Dynamics Simulations: Initial Experience in a Canine Aneurysm Model
| Afilliation | Scientific Computing, Scientific Computing |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2010 |
| Conference Name | Proceedings of the ASME 2010 Summer Bioengineering Conference |
| Pagination | SBC2010-19455 223 |
| Date Published | June |
| Publisher | American Society of Mechanical Engineers |
Journal Article
Sex Differences in Intracranial Arterial Bifurcations
Gender Medicine 7 (2010).Status: Published
Sex Differences in Intracranial Arterial Bifurcations
Background: Subarachnoid hemorrhage (SAH) is a serious condition, occurring 50-70% more frequently in females than males. SAH is mainly caused by rupture of an intracranial aneurysm. An intracranial aneurysm is formed by localized dilation of the intracranial arterial vessel wall, usually at the apex of the arterial bifurcation. The female preponderance is usually explained by systemical factors (hormonal influences and intrinsic wall weakness). Objective: To explore any sex variation in the bifurcation anatomy of the MCA and ICA, and the subsequent hemodynamic impact. Methods: We measured vessel radii and bifurcation angles in 47 middle cerebral artery (MCA) and 52 internal carotid artery (ICA) bifurcations in 49 patients (32 females and 17 males). The measurements were used to create idealized, averaged bifurcations of the MCA and ICA for females and males. Computational fluid dynamics simulations were performed to calculate hemodynamic forces in the models. Results: The measurements showed statistically significant sex differences in vessel diameter (men larger than females), but not in bifurcation angles. Computational fluid dynamics simulations showed higher wall shear stress in the female MCA bifurcation (19 %) and ICA bifurcation (50 %) compared with the male bifurcations. Conclusions: The present study suggests that sex differences in vessel size and blood flow velocity result in higher hemodynamic forces acting upon the female vessel wall. This is a new hypothesis that may partially explain why intracranial aneurysms and SAH are more likely to occur in females than males.
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2010 |
| Journal | Gender Medicine |
| Volume | 7 |
| Number | 2 |
| Publisher | Gend Med |
Talks, contributed
Cerebral Blood Flow
In Invited talk at Telemark College, Engineering Faculty, Porsgrunn, Norway, 2009, 2009.Status: Published
Cerebral Blood Flow
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Invited talk at Telemark College, Engineering Faculty, Porsgrunn, Norway, 2009 |
CSF Flow Modelling
In Invited talk at CSR Flow Research Conference at University of Wisconsin, Nov 9, 2009.Status: Published
CSF Flow Modelling
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Invited talk at CSR Flow Research Conference at University of Wisconsin, Nov 9 |
Implementing a K-E Turbulence Model in the FEniCS Finite Element Programming Environment
In Talk at MekIT'09: Fifth National Conference on Computational Mechanics, Trondheim, May 26-27, 2009.Status: Published
Implementing a K-E Turbulence Model in the FEniCS Finite Element Programming Environment
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Talk at MekIT'09: Fifth National Conference on Computational Mechanics, Trondheim, May 26-27 |
Patient-Specific Hemodynamics in FEniCS
In Invited talk at the minisymposium on Computational Vascular and Cardiovascular Mechanics at USNCCM 2009, 2009.Status: Published
Patient-Specific Hemodynamics in FEniCS
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Invited talk at the minisymposium on Computational Vascular and Cardiovascular Mechanics at USNCCM 2009 |
Patient-Specific Hemodynamics in FEniCS
In Presentation at the FEniCS 09 Workshop, 2009.Status: Published
Patient-Specific Hemodynamics in FEniCS
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Presentation at the FEniCS 09 Workshop |
Patient-Specific Simulations of Stroke and Syringomyelia
In Talk : Advisory commitee meeting FFI project P1112 Aerosols: Dispersion, Transport and Consequences, Nov 03, 2009.Status: Published
Patient-Specific Simulations of Stroke and Syringomyelia
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Talk : Advisory commitee meeting FFI project P1112 Aerosols: Dispersion, Transport and Consequences, Nov 03 |
Sex Differences in Intracranial Bifurcation Geometry and Blood Flow Velocity Result in Stronger Hemodynamic Forces Upon the Female Vessel Wall
In Talk: Received award for best young presenter at the Nordic Society of Neuroradiology Meeting in 2009, 2009.Status: Published
Sex Differences in Intracranial Bifurcation Geometry and Blood Flow Velocity Result in Stronger Hemodynamic Forces Upon the Female Vessel Wall
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Talk: Received award for best young presenter at the Nordic Society of Neuroradiology Meeting in 2009 |
Simulation Methodology for Bioflows
In Talk : Advisory commitee meeting FFI project P1112 Aerosols: Dispersion, Transport and Consequences, May 05, 2009.Status: Published
Simulation Methodology for Bioflows
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Talk : Advisory commitee meeting FFI project P1112 Aerosols: Dispersion, Transport and Consequences, May 05 |
Some Biomedical Applications at Simula
In Talk at the CBC Workshop on Computational Biology with UMB, 2009.Status: Published
Some Biomedical Applications at Simula
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2009 |
| Location of Talk | Talk at the CBC Workshop on Computational Biology with UMB |
Proceedings, refereed
Implementing a K-E Turbulence Model in the FEniCS Finite Element Programming Environment
In MekIT'09. Fifth national conference on Computational Mechanics. Tapir, 2009.Status: Published
Implementing a K-E Turbulence Model in the FEniCS Finite Element Programming Environment
| Afilliation | Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Proceedings, refereed |
| Year of Publication | 2009 |
| Conference Name | MekIT'09. Fifth national conference on Computational Mechanics |
| Publisher | Tapir |
| ISBN Number | 9788251924214 |
Talks, contributed
Blood Flow Computations at Simula
In Invited talk at Medical Physics, University of Wisconsin, March 11., 2008.Status: Published
Blood Flow Computations at Simula
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2008 |
| Location of Talk | Invited talk at Medical Physics, University of Wisconsin, March 11. |
Developing Flow Solver Methodology for Patientspecific Simulation of Hemodynamics
In Talk at Workshop on Finite Element Methods for Fluids and Fluid-Structure Interaction, June 5, 2008.Status: Published
Developing Flow Solver Methodology for Patientspecific Simulation of Hemodynamics
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2008 |
| Location of Talk | Talk at Workshop on Finite Element Methods for Fluids and Fluid-Structure Interaction, June 5 |
Scientific Computing at Simula
In Invited Talk at Workshop on Cerebral Aneurysms and Subarachnoidal Hemorrhage, Tromsø Jan 24-26, 2008.Status: Published
Scientific Computing at Simula
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Talks, contributed |
| Year of Publication | 2008 |
| Location of Talk | Invited Talk at Workshop on Cerebral Aneurysms and Subarachnoidal Hemorrhage, Tromsø Jan 24-26 |
Journal Article
Simulation of Hemodynamics in the Aneurysm Neck After Coiling
Neuroradiology (2008).Status: Submitted
Simulation of Hemodynamics in the Aneurysm Neck After Coiling
| Afilliation | Scientific Computing, , Scientific Computing |
| Project(s) | Center for Biomedical Computing (SFF) |
| Publication Type | Journal Article |
| Year of Publication | 2008 |
| Journal | Neuroradiology |