title: Intra-aneurysmal flow rates are reduced by two flow diverters: an experiment using tomographic particle image velocimetry in an aneurysm model.
abstract: BACKGROUND
  Limitations on treating large, giant, and wide-necked aneurysms with coiling have made flow diverters a promising alternative to current practice by supporting reconstruction of the parent artery.
  
  
  OBJECTIVE
  To assess the changes to fluid dynamics within an aneurysm by studying two different endoluminal flow diverters on a simple aneurysm model, using tomographic particle image velocimetry to determine which device would better minimize fluid flow into an aneurysm and observe any significant changes in aneurysm fluid structures.
  
  
  METHODS
  Steady velocity fields of the model's aneurysm dome and neck were measured at three inlet velocities (18, 39, and 59 cm/s) for two flow diverter diameters with different porosities and compared against a baseline case with no flow diverter.
  
  
  RESULTS
  In the baseline case a large vortex was present inside the dome for all flow rates. However, both devices eliminated this main vortex at all flow rates and reduced the peak aneurysmal velocities by about 90%. A strong correlation between flow diverter porosity and flow reduction was found. In each case the inflow to the aneurysm shifted from the distal neck to the mid- or proximal neck after flow diverter placement.
  
  
  CONCLUSIONS
  Even with this relatively simple experimental setup, we were able to observe the major flow field changes, which occurred immediately after the deployment of each flow diverter. Limitations of the study included a simplified geometry and steady-state flow. Constraints included model making and limited availability of flow diverters.
authors.affiliation: Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Kendall D
authors.initials: KD
authors.lastname: Dennis
authors.affiliation: Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Rossman
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: David F
authors.initials: DF
authors.lastname: Kallmes
authors.affiliation: Division of Engineering, Mayo Clinic, Rochester, Minnesota, USA Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Dragomir-Daescu
mesh_terms: D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D003198:Computer Simulation; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000503:physiopathology*; D012212:Rheology / Q000295:instrumentation / Q000379:methods*; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
keywords: Aneurysm; Blood Flow; Flow Diverter; Stent