Patient-specific hemodynamic analysis of the anterior communicating artery: comparative evaluation of unilateral and bilateral vascular models using MRI-based computational simulations

The anterior communicating artery (AComA) is a key collateral pathway in the Circle of Willis. This study investigated the effects of bilateral inflows and vascular geometry on hemodynamics using computational fluid dynamics (CFD) simulations derived from magnetic resonance angiography (MRA) data in four subjects. Flow rates were measured using phase-contrast MRA (1.5T Siemens) at major anterior circulation segments. CFD models incorporated rigid walls, pulsatile flow, and MRA-derived inlet waveform curves under laminar, incompressible assumptions. Simulated internal carotid artery velocities correlated strongly (>90%) with measurements. While inlet phase lags had limited impact on time-averaged wll shear stress (TAWSS), significant TAWSS differences (>90%) were observed in a subject with marked anterior cerebral artery (ACA) asymmetry (92% diameter ratio). Bilateral ACA inflows are critical for accurate TAWSS estimation, especially in symmetric anatomies. These findings support incorporting patient-specific bilateral inflows in CFD models for improved AComA hemodynamic evaluation and treatment planning.