scholarly journals Multi-Scale, Patient-Specific Computational Flow Dynamics Models Predict Formation of Neointimal Hyperplasia in Saphenous Vein Grafts

2019 ◽  
Author(s):  
Francesca Donadoni ◽  
Cesar Pichardo-Almarza ◽  
Shervanthi Homer-Vanniasinkam ◽  
Alan Dardik ◽  
Vanessa Díaz-Zuccarini
Keyword(s):  
Neointimal Hyperplasia ◽  
Flow Dynamics ◽  
Patient Specific ◽  
Growth Mechanisms ◽  
Cfd Simulations ◽  
Vein Grafts ◽  
Multi Scale ◽  
Computational Flow Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamics Models

AbstractBypass occlusion due to neointimal hyperplasia (NIH) is among the major causes of peripheral graft failure. Its link to abnormal hemodynamics in the graft is complex, and isolated use of hemodynamic markers insufficient to fully capture its progression. Here, a computational model of NIH growth is presented, establishing a link between computational fluid dynamics (CFD) simulations of flow in the lumen, with a biochemical model representing NIH growth mechanisms inside the vessel wall. For all 3 patients analyzed, NIH at proximal and distal anastomoses was simulated by the model, with values of stenosis comparable to the computed tomography (CT) scans.

scholarly journals Multiscale, patient-specific computational fluid dynamics models predict formation of neointimal hyperplasia in saphenous vein grafts

2020 ◽  
Vol 6 (2) ◽  
pp. 292-306
Author(s):  
Francesca Donadoni ◽  
Cesar Pichardo-Almarza ◽  
Shervanthi Homer-Vanniasinkam ◽  
Alan Dardik ◽  
Vanessa Díaz-Zuccarini
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Saphenous Vein ◽  
Neointimal Hyperplasia ◽  
Patient Specific ◽  
Vein Grafts ◽  
Saphenous Vein Grafts ◽  
Dynamics Models

scholarly journals Patient-Specific, Multi-Scale Modeling of Neointimal Hyperplasia in Vein Grafts

2017 ◽  
Vol 8 ◽  
Author(s):  
Francesca Donadoni ◽  
Cesar Pichardo-Almarza ◽  
Matthew Bartlett ◽  
Alan Dardik ◽  
Shervanthi Homer-Vanniasinkam ◽  
...  
Keyword(s):  
Neointimal Hyperplasia ◽  
Patient Specific ◽  
Vein Grafts ◽  
Multi Scale ◽  
Scale Modeling ◽  
Multi Scale Modeling

Experimental and Numerical Flow Visualization in Patient Specific Pre Operative Human Airway Geometry

2011 ◽  
Author(s):  
Mathias Vermeulen ◽  
Cedric Van Holsbeke ◽  
Tom Claessens ◽  
Jan De Backer ◽  
Peter Van Ransbeeck ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Particle Image ◽  
Patient Specific ◽  
Lung Volume Reduction ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Specific Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
Human Airways

An experimental and numerical platform was developed to investigate the fluidodynamics in human airways. A pre operative patient specific geometry was used to create an identical experimental and numerical model. The experimental results obtained from Particle Image Velocimetry (PIV) measurements were compared to Computational Fluid Dynamics (CFD) simulations under stationary and pulsatile flow regimes. Together these results constitute the first step in predicting the clinical outcome of patients after lung surgeries such as Lung Volume Reduction.

Computational flow dynamics in patient specific model of cardiovascular system using CT and MRI

2006 ◽  
Author(s):  
S. Yamamoto ◽  
H. Bartsch ◽  
S. Maruyama ◽  
S. Yoneyama ◽  
S. Wada ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Specific Model ◽  
Flow Dynamics ◽  
Patient Specific ◽  
Computational Flow Dynamics ◽  
Ct And Mri

scholarly journals Vortex Analysis of Intra-Aneurismal Flow in Cerebral Aneurysms

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Kevin Sunderland ◽  
Christopher Haferman ◽  
Gouthami Chintalapani ◽  
Jingfeng Jiang
Keyword(s):  
Vortex Core ◽  
Cardiac Cycle ◽  
Temporal Stability ◽  
Cerebral Aneurysms ◽  
Patient Specific ◽  
Cfd Simulations ◽  
Hemodynamic Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
Marching Cube Algorithm ◽  
Core Characteristics

This study aims to develop an alternative vortex analysis method by measuring structure ofIntracranial aneurysm (IA) flow vortexes across the cardiac cycle, to quantify temporal stability of aneurismal flow. Hemodynamics were modeled in “patient-specific” geometries, using computational fluid dynamics (CFD) simulations. Modified versions of knownλ2andQ-criterion methods identified vortex regions; then regions were segmented out using the classical marching cube algorithm. Temporal stability was measured by the degree of vortex overlap (DVO) at each step of a cardiac cycle against a cycle-averaged vortex and by the change in number of cores over the cycle. No statistical differences exist in DVO or number of vortex cores between 5 terminal IAs and 5 sidewall IAs. No strong correlation exists between vortex core characteristics and geometric or hemodynamic characteristics of IAs. Statistical independence suggests this proposed method may provide novel IA information. However, threshold values used to determine the vortex core regions and resolution of velocity data influenced analysis outcomes and have to be addressed in future studies. In conclusions, preliminary results show that the proposed methodology may help give novel insight toward aneurismal flow characteristic and help in future risk assessment given more developments.

scholarly journals CFD Simulations of Radioembolization: A Proof-of-Concept Study on the Impact of the Hepatic Artery Tree Truncation

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 839
Author(s):  
Unai Lertxundi ◽  
Jorge Aramburu ◽  
Julio Ortega ◽  
Macarena Rodríguez-Fraile ◽  
Bruno Sangro ◽  
...  
Keyword(s):  
Hepatic Artery ◽  
Liver Parenchyma ◽  
Patient Specific ◽  
Proof Of Concept ◽  
Cfd Simulations ◽  
Intraarterial Infusion ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
Healthy Liver ◽  
Simulation Time

Radioembolization (RE) is a treatment for patients with liver cancer, one of the leading cause of cancer-related deaths worldwide. RE consists of the transcatheter intraarterial infusion of radioactive microspheres, which are injected at the hepatic artery level and are transported in the bloodstream, aiming to target tumors and spare healthy liver parenchyma. In paving the way towards a computer platform that allows for a treatment planning based on computational fluid dynamics (CFD) simulations, the current simulation (model preprocess, model solving, model postprocess) times (of the order of days) make the CFD-based assessment non-viable. One of the approaches to reduce the simulation time includes the reduction in size of the simulated truncated hepatic artery. In this study, we analyze for three patient-specific hepatic arteries the impact of reducing the geometry of the hepatic artery on the simulation time. Results show that geometries can be efficiently shortened without impacting greatly on the microsphere distribution.

PIV-Measured Versus CFD-Predicted Flow Dynamics in Anatomically Realistic Cerebral Aneurysm Models

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Matthew D. Ford ◽  
Hristo N. Nikolov ◽  
Jaques S. Milner ◽  
Stephen P. Lownie ◽  
Edwin M. DeMont ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Cardiac Cycle ◽  
Flow Dynamics ◽  
Cfd Modeling ◽  
Patient Specific ◽  
Flow Loop ◽  
Cfd Simulations ◽  
Flow Through

Computational fluid dynamics (CFD) modeling of nominally patient-specific cerebral aneurysms is increasingly being used as a research tool to further understand the development, prognosis, and treatment of brain aneurysms. We have previously developed virtual angiography to indirectly validate CFD-predicted gross flow dynamics against the routinely acquired digital subtraction angiograms. Toward a more direct validation, here we compare detailed, CFD-predicted velocity fields against those measured using particle imaging velocimetry (PIV). Two anatomically realistic flow-through phantoms, one a giant internal carotid artery (ICA) aneurysm and the other a basilar artery (BA) tip aneurysm, were constructed of a clear silicone elastomer. The phantoms were placed within a computer-controlled flow loop, programed with representative flow rate waveforms. PIV images were collected on several anterior-posterior (AP) and lateral (LAT) planes. CFD simulations were then carried out using a well-validated, in-house solver, based on micro-CT reconstructions of the geometries of the flow-through phantoms and inlet/outlet boundary conditions derived from flow rates measured during the PIV experiments. PIV and CFD results from the central AP plane of the ICA aneurysm showed a large stable vortex throughout the cardiac cycle. Complex vortex dynamics, captured by PIV and CFD, persisted throughout the cardiac cycle on the central LAT plane. Velocity vector fields showed good overall agreement. For the BA, aneurysm agreement was more compelling, with both PIV and CFD similarly resolving the dynamics of counter-rotating vortices on both AP and LAT planes. Despite the imposition of periodic flow boundary conditions for the CFD simulations, cycle-to-cycle fluctuations were evident in the BA aneurysm simulations, which agreed well, in terms of both amplitudes and spatial distributions, with cycle-to-cycle fluctuations measured by PIV in the same geometry. The overall good agreement between PIV and CFD suggests that CFD can reliably predict the details of the intra-aneurysmal flow dynamics observed in anatomically realistic in vitro models. Nevertheless, given the various modeling assumptions, this does not prove that they are mimicking the actual in vivo hemodynamics, and so validations against in vivo data are encouraged whenever possible.

Intra-Aneurysmal Flow Complexity Quantification Using Flowlines Geometry

2013 ◽  
Author(s):  
Simona Hodis ◽  
David F. Kallmes ◽  
Dan Dragomir-Daescu
Keyword(s):  
Intracranial Aneurysms ◽  
Flow Characteristics ◽  
Adaptive Grid ◽  
Patient Specific ◽  
Adaptive Grids ◽  
Cfd Simulations ◽  
Mathematical Formula ◽  
Element Size ◽  
Computational Fluid Dynamics Cfd ◽  
Topological Characteristics

We present a quantified description of the fluid flow and a novel flowline-based meshing technique to create adaptive grids for Computational Fluid Dynamics (CFD) simulations in patient-specific intracranial aneurysms. The adaptive grid density is obtained such that it captures the fine geometrical details of the flow with high grid density, while smoother flow characteristics are calculated with a coarser grid density. The correlation between the topological characteristics of the flow and the element size of the adaptive grid results in a practical mathematical formula for calculating the element size using only one uniform base mesh and a user defined implementation in CFD post processors.

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