Abstract T MP25: Development of Patient Specific Computational Fluid Dynamics Model of Intracranial Arterial Stenosis

Abstract

Introduction: Intracranial atherosclerotic steno-occlusive disease (ICASD) is a significant cause of stroke worldwide. A better understanding of the role of hemodynamic factors in the progression of ICASD is fundamental for the development of future treatment strategies. Prior studies have been limited to estimations of wall shear stress (WSS), turbulent kinetic energy (TKE), and flow velocity (FV) at single physiological states. We present a modeling technique for measuring hemodynamic parameters across a cardiac cycle using patient-specific vessel geometry and boundary conditions. Methods: The geometry was obtained from a rotational angiogram of the symptomatic lesion. Transcranial Doppler (TCD) was used to digitally record the cerebral blood flow velocity (CBFV). The MOCAIP algorithm was used to calculate dominant, artifact-free CBFV waveforms for each vessel. The mesh and boundary conditions were imported into the ANSYS: Simulation Technology software as a non-deformable mesh containing a Newtonian fluid with molar mass 64500g/mol, density 1.06g/cc, and viscosity 0.035 centipoise. A dynamic state (DS) simulation of one full cardiac cycle with 25ms timesteps and steady state (SS) simulations using the velocities at the systolic peak were performed. WSS, TKE, and FV within the stenosis were measured and compared between DS and SS simulations. Results: When compared with the DS simulation, the mean WSS of the SS simulation was significantly higher (SS 30.6Pa DS 30.0Pa, p<0.0005). There were no significant differences between TKE (SS 0.074m2/s2 DS 0.073m2/s2) or FV (SS 2.68m/s DS 2.71m/s). Conclusion: Incorporating individual-specific boundary conditions based on CBFV TCD measurements with patient-specific geometry intracranial arterial modeling is feasible and adds a spectrum of dynamic data that can significantly differ from SS simulations.