title: Particle imaging velocimetry evaluation of intracranial stents in sidewall aneurysm: hemodynamic transition related to the stent design.
abstract: We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantation using particle imaging velocimetry (PIV). The use of the recently developed multi-time-lag method has allowed for uniform and precise measurements of both high and low velocities at IA neck and dome, respectively. Flow modification analysis of both regular (RSs) and flow diverter stents (FDSs) was subsequently correlated with relevant geometrical stent parameters. Flow reduction was found to be highly sensitive to stent porosity variations for regular stents RSs and moderately sensitive for FDSs. Consequently, two distinct IA flow change trends, with velocity reductions up to 50% and 90%, were identified for high-porosity RS and low-porosity FDS, respectively. The intermediate porosity (88%) regular braided stent provided the limit at which the transition in flow change trend occurred with a flow reduction of 84%. This transition occurred with decreasing stent porosity, as the driving force in IA neck changed from shear stress to differential pressure. Therefore, these results suggest that stents with intermediate porosities could possibly provide similar flow change patterns to FDS, favourable to curative thrombogenesis in IAs.
authors.affiliation: Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva, Genève, Switzerland; Laboratory for Hydraulic Machines, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Pierre
authors.initials: P
authors.lastname: Bouillot
authors.affiliation: Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva, Genève, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Brina
authors.affiliation: Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva, Genève, Switzerland.
authors.forename: Rafik
authors.initials: R
authors.lastname: Ouared
authors.affiliation: Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva, Genève, Switzerland.
authors.forename: Karl-Olof
authors.initials: KO
authors.lastname: Lovblad
authors.affiliation: Laboratory for Hydraulic Machines, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Farhat
authors.affiliation: Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva, Genève, Switzerland; Division of Neuroradiology, Department of Medical Imaging, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Vitor Mendes
authors.initials: VM
authors.lastname: Pereira
mesh_terms: D000465:Algorithms; D002560:Cerebrovascular Circulation; D006439:Hemodynamics; D006801:Humans; D002532:Intracranial Aneurysm / Q000503:physiopathology* / Q000628:therapy*; D008955:Models, Cardiovascular; D016062:Porosity; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods*; D015607:Stents