Document Detail


Pulsatile flow effects on the hemodynamics of intracranial aneurysms.
MedLine Citation:
PMID:  21034150     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
High-resolution numerical simulations are carried out to systematically investigate the effect of the incoming flow waveform on the hemodynamics and wall shear stress patterns of an anatomic sidewall intracranial aneurysm model. Various wave forms are constructed by appropriately scaling a typical human waveform such that the waveform maximum and time-averaged Reynolds numbers, the Womersley number (α), and the pulsatility index (PI) are systematically varied within the human physiologic range. We show that the waveform PI is the key parameter that governs the vortex dynamics across the aneurysm neck and the flow patterns within the dome. At low PI, the flow in the dome is similar to a driven cavity flow and is characterized by a quasi-stationary shear layer that delineates the parent artery flow from the recirculating flow within the dome. At high PI, on the other hand, the flow is dominated by vortex ring formation, transport across the neck, and impingement and breakdown at the distal wall of the aneurysm dome. We further show that the spatial and temporal characteristics of the wall shear stress field on the aneurysm dome are strongly correlated with the vortex dynamics across the neck. We finally argue that the ratio between the characteristic time scale of transport by the mean flow across the neck and the time scale of vortex ring formation can be used to predict for a given sidewall aneurysm model the critical value of the waveform PI for which the hemodynamics will transition from the cavity mode to the vortex ring mode.
Authors:
Trung B Le; Iman Borazjani; Fotis Sotiropoulos
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of biomechanical engineering     Volume:  132     ISSN:  1528-8951     ISO Abbreviation:  J Biomech Eng     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-01     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7909584     Medline TA:  J Biomech Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  111009     Citation Subset:  IM    
Affiliation:
Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55414, USA.
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