Intr-aneurysmal hemodynamics such as wall shear stress and complex flow structures have been implicated as one of the important factors on the growth and rupture risk of the aneurysm. In this study, the sensitivity of intra-aneurysmal blood flow dynamics to the shear-thinning rheological model was investigated by employing the idealized geometries of basilar tip aneurysm with two representative anterior-posterior(AP) tilting anbles(2° and 30°).
Time-averged hemodynamic factors such as time-averaged wall shear stress, oscillatory shear index and relative residence time exhibited only minor effects by choice of different rhelogical models. However, highly unstable flow present in idealized aneurysm model with 2° AP tilting angle created noticeable chang in the instantaneous flow dynamics with significant increase of effctive viscosity. Nevertheless, the distinct hemodynamic phenotype characterizing gross intra-aneurysmal flow pattern was independent of the choice of rheological model.
This suggests that shear thinning viscous effct is of secondary importance in gross hemodynamics in the basilar tip aneurysm, but significantly enhanced on the instantaneous hemodynamics with unstable complex flow structures.