Document Detail


PIV-measured versus CFD-predicted flow dynamics in anatomically realistic cerebral aneurysm models.
MedLine Citation:
PMID:  18412502     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
Matthew D Ford; Hristo N Nikolov; Jaques S Milner; Stephen P Lownie; Edwin M Demont; Wojciech Kalata; Francis Loth; David W Holdsworth; David A Steinman
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of biomechanical engineering     Volume:  130     ISSN:  0148-0731     ISO Abbreviation:  J Biomech Eng     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-04-16     Completed Date:  2008-08-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7909584     Medline TA:  J Biomech Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  021015     Citation Subset:  IM    
Affiliation:
Imaging Research Laboratories, Robarts Research Institute, London, Canada N6A 5K8.
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MeSH Terms
Descriptor/Qualifier:
Blood Flow Velocity
Cerebral Angiography
Cerebrovascular Circulation*
Computer Simulation
Humans
Imaging, Three-Dimensional / methods
Intracranial Aneurysm / physiopathology*
Models, Cardiovascular*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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