title: Computational fluid dynamics of cerebral aneurysm coiling using high-resolution and high-energy synchrotron X-ray microtomography: comparison with the homogeneous porous medium approach.
abstract: BACKGROUND
  Computational modeling of intracranial aneurysms provides insights into the influence of hemodynamics on aneurysm growth, rupture, and treatment outcome. Standard modeling of coiled aneurysms simplifies the complex geometry of the coil mass into a homogeneous porous medium that fills the aneurysmal sac. We compare hemodynamics of coiled aneurysms modeled from high-resolution imaging with those from the same aneurysms modeled following the standard technique, in an effort to characterize sources of error from the simplified model.
  
  
  METHODS
  Physical models of two unruptured aneurysms were created using three-dimensional printing. The models were treated with coil embolization using the same coils as those used in actual patient treatment and then scanned by synchrotron X-ray microtomography to obtain high-resolution imaging of the coil mass. Computational modeling of each aneurysm was performed using patient-specific boundary conditions. The coils were modeled using the simplified porous medium or by incorporating the X-ray imaged coil surface, and the differences in hemodynamic variables were assessed.
  
  
  RESULTS
  X-ray microtomographic imaging of coils and incorporation into computational models were successful for both aneurysms. Porous medium calculations of coiled aneurysm hemodynamics overestimated intra-aneurysmal flow, underestimated oscillatory shear index and viscous dissipation, and over- or underpredicted wall shear stress (WSS) and WSS gradient compared with X-ray-based coiled computational fluid dynamics models.
  
  
  CONCLUSIONS
  Computational modeling of coiled intracranial aneurysms using the porous medium approach may inaccurately estimate key hemodynamic variables compared with models incorporating high-resolution synchrotron X-ray microtomographic imaging of complex aneurysm coil geometry.
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington, USA.|Department of Radiology, University of Washington, Seattle, Washington, USA.|Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Levitt
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Barbour
authors.affiliation: Laboratoire 3SR, UMR 5521, CNRS, Université Grenoble Alpes, Grenoble INP, Grenoble, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Rolland du Roscoat
authors.affiliation: Laboratoire 3SR, UMR 5521, CNRS, Université Grenoble Alpes, Grenoble INP, Grenoble, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Geindreau
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA.
authors.forename: Venkat K
authors.identifier: http://orcid.org/0000-0002-8457-8509
authors.initials: VK
authors.lastname: Chivukula
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: McGah
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Nerva
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Morton
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington, USA.|Department of Radiology, University of Washington, Seattle, Washington, USA.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Kim
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington, USA.|Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA.
authors.forename: Alberto
authors.initials: A
authors.lastname: Aliseda
mesh_terms: D001807:Blood Vessel Prosthesis / Q000706:statistics & numerical data; D003198:Computer Simulation / Q000706:statistics & numerical data; D057510:Endovascular Procedures / Q000379:methods / Q000706:statistics & numerical data; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery / Q000628:therapy; D016062:Porosity; D066330:Printing, Three-Dimensional / Q000706:statistics & numerical data; D017356:Synchrotrons / Q000706:statistics & numerical data; D055114:X-Ray Microtomography / Q000379:methods* / Q000706:statistics & numerical data
keywords: Aneurysm; Blood Flow; CT; Coil; Material