title: Variability of hemodynamic parameters using the common viscosity assumption in a computational fluid dynamics analysis of intracranial aneurysms.
abstract: BACKGROUND
  In most simulations of intracranial aneurysm hemodynamics, blood is assumed to be a Newtonian fluid. However, it is a non-Newtonian fluid, and its viscosity profile differs among individuals. Therefore, the common viscosity assumption may not be valid for all patients.
  
  
  OBJECTIVE
  This study aims to test the suitability of the common viscosity assumption.
  
  
  METHODS
  Blood viscosity datasets were obtained from two healthy volunteers. Three simulations were performed for three different-sized aneurysms, two using measured value-based non-Newtonian models and one using a Newtonian model. The parameters proposed to predict an aneurysmal rupture obtained using the non-Newtonian models were compared with those obtained using the Newtonian model.
  
  
  RESULTS
  The largest difference (25%) in the normalized wall shear stress (NWSS) was observed in the smallest aneurysm. Comparing the difference ratio to the NWSS with the Newtonian model between the two Non-Newtonian models, the difference of the ratio was 17.3%.
  
  
  CONCLUSIONS
  Irrespective of the aneurysmal size, computational fluid dynamics simulations with either the common Newtonian or non-Newtonian viscosity assumption could lead to values different from those of the patient-specific viscosity model for hemodynamic parameters such as NWSS.
authors: Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors: Takashi
authors: T
authors: Suzuki
authors: Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.|Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.|Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan.
authors: Hiroyuki
authors: H
authors: Takao
authors: Department of Chemical, Energy and Environment Engineering, Kansai University, Osaka, Japan.
authors: Takamasa
authors: T
authors: Suzuki
authors: Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.
authors: Tomoaki
authors: T
authors: Suzuki
authors: Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.
authors: Shunsuke
authors: S
authors: Masuda
authors: Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.|Siemens Japan K.K., Shinagawa-ku, Tokyo, Japan.
authors: Chihebeddine
authors: C
authors: Dahmani
authors: Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.
authors: Mitsuyoshi
authors: M
authors: Watanabe
authors: Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors: Hiroya
authors: H
authors: Mamori
authors: Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.
authors: Toshihiro
authors: T
authors: Ishibashi
authors: Department of Chemical, Energy and Environment Engineering, Kansai University, Osaka, Japan.
authors: Hideki
authors: H
authors: Yamamoto
authors: Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors: Makoto
authors: M
authors: Yamamoto
authors: Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.
authors: Yuichi
authors: Y
authors: Murayama
mesh_terms: D002340:Carotid Artery Diseases / Q000503:physiopathology*; D003198:Computer Simulation; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000503:physiopathology*; D008955:Models, Cardiovascular; D014783:Viscosity
keywords: Casson model; Computational fluid dynamics; intracranial aneurysm; non-Newtonian viscosity; viscosity; wall shear stress