Interaction between stents and flow inside a sidewall aneurysm model was investigated using Particle Image Velocimetry (PIV). Three spring-like stents having the same porosity but different filament diameter were placed inside the parent vessel that harbored the aneurysm traversing the aneurysmal neck. The flow field inside the aneurysm was investigated before and after placement of the stents. The flow through model was pulsatile and the hemodynamic conditions were representative for those found in human intracranial and extracranial cerebral arteries. Flow patterns inside the aneurysm were significantly altered after stent placement. To facilitate comparison among all cases, the circulation inside the aneurysm was obtained as the surface integral of the distributed vorticity. The results show that the strength of the circulation is substantially diminished for all stented cases. However, the temporal distribution of the circulation through the cardiac cycle is similar for the three stents considered. Further, the mean circulation over one cardiac cycle was obtained for each case as the integral of the absolute value of the temporal distribution. The mean circulation reveals that noteworthy differences in intraaneurysmal hemodynamics do exist among the filament diameters considered.