## 3 Results and Discussion  
Results are presented in both the traditional post-processing and virtual reality environment to show the interactive accessibility of VR visualization in this section. The velocity magnitude contours with streaking patterns (that follow vector field tangents) are illustrated in Figure 14 on Slice 1 at \(t=t_{2}\), the peak of systolic flow, for the cases of Without-stent, With-stent1, and With-sent2. The flow pattern for the untreated aneurysm shows that the flow starts to enter the sac after the proximal edge of the neck and continues toward the distal edge. The inflow impinges to the sac wall close to the distal neck, rotates inside the sac, and exits the aneurysm at the proximal neck; therefore, a single large vortex is created within the sac (Figure 14a). Due to the placement of the stent across the aneurysm neck, the whole inlet flow enters from the proximal neck for stented cases and then the flow breaks up to the flow swirling around the sac (Figure 14c, Zone1), and the flow is restricted to the neck region and leaves the sac from the distal neck region directly (Figure 14c, Zone2). The size of Zone2 is smaller for the With-stent2 case because of the lower inflow rate into the aneurysm. Figure 14b shows the effect of a small gap between the stent and the artery wall. An inflow jet in the proximal neck edge is created due to the presence of the gap, so this aneurysm feeding increases the flow into the sac and slows down the thrombosis process. The effects of inflow/outflow locations into/out of the aneurysm, and the wall-stent gap can be observed in more detail in the 3D space of the VR environment. If the user selects one of the flow elements using the menu, illustrated in Figure 13, the animation of the associated element starts playing. Figure 15 shows a screenshot of the velocity vector animation at \(t=t2\). The vessel wall has been deactivated here to show the vectors more clearly. In addition to the vectors, the legend, hemodynamic parameters table, and the associated time of the cardiac cycle are displayed. The user is free to walk inside the fluid domain, zoom, grab, or move the domain to explore the flow behavior while the animation is playing or paused. A distinguishing feature of VR visualization can be explored if the user zooms in to the wall-stent gap for the With-stent1 case and find out the high-speed jet flow into the sac through the gap, as displayed in Figure 15-right. In addition, the time variation in the jet flow velocity is traceable via the velocity vectors animation in the VR environment. Figure 14: Velocity magnitude (m/s) contours on Slice1, \(t=t2\): (**a**) Without-stent; (**b**) With-stent1; (**c**) With-stent2. Three-dimensional streamlines provide the viewer with the advantages of simultaneously displaying all recirculating zones that are considerably different for treated and untreated aneurysms. The interactive accessibility of blood flow behavior in the vessel would be experienced by exploring the streamlines, as shown in the screenshots of Figure 16. Zone1 and Zone 2 can be seen in Figure 16b-top,16c-top, respectively. Two white arrows demonstrate the different paths of flow after entering the sac through the proximal neck edge. In addition, vortex flows from View 1 (shown in Figure 2) are accessible to be explored, as shown in Figure 16b-bottom and 16c-bottom. The particle tracer is another proper method to follow the fluid path through the vessel. The Videos S1 and S2 in Supplementary Materials show the animation of streamlines (Without-stent) and particle tracers (With-stent2), respectively. In these animations, the viewer is mostly located on View 1 and View 2 viewpoints. The contours of wall shear stress magnitude at time t2 are shown in Figure 17 and it can be found out that the locations of high wall shear stress have changed due to stenting.