A Non-Newtonian Model for Blood Flow behind a Flow Diverting Stent

G. Mach [1], C. Sherif [2], U. Windberger [3], A. Gruber [3],
[1] Vienna University of Technology, Cerebrovascular Research Group Vienna, Vienna, Austria
[2] Hospital Rudolfstiftung, Cerebrovascular Research Group Vienna, Vienna, Austria
[3] Medical University Vienna, Cerebrovascular Research Group Vienna, Vienna, Austria

Usually, when calculating the blood flow in cerebral arteries and intracranial aneurysms, blood is modeled as a Newtonian fluid, neglecting its shear-thinning behavior. Since flow diverting devices slow down the blood flow in the aneurysm sack, the accuracy of this assumption had to be reviewed. A Carreau Yasuda model is introduced as a non-Newtonian model for blood viscosity. CFD simulations of an intracranial sidewall aneurysm treated with an endovascular device using a Newtonian and the non-Newtonian model have been performed and the results of the comparison between the blood viscosity models are presented. Our example found the Newtonian model overestimating the effect of the flow diverting stent by up to 6%, thus, it seems not to be sufficient for calculations past endovascular devices.