## 5 Conclusions  
CFD has been used as a powerful tool to study the effects of flow-diverters on aneurysm treatment and blood flow behavior in aneurysms before and after treatment. Because of the complicated nature of the intra-aneurysmal flow, the visualization of CFD data in the VR environment would be an efficient method to explore the performance of treatment devices and their positioning strategies. Therefore, we developed a straightforward method to visualize the CFD results in the VR environment. The blood flow in cerebral aneurysms without and with flow diverter stents was simulated numerically and visualized in the virtual reality environment using the proposed method. Several flow elements, including velocity vectors, contours, streamlines, particle tracers, and point clouds, were rendered and animated in the VR environment colored by node values. It was found from the CFD results that the flow diverters are thoroughly efficient devices to redirect the flow from aneurysms, but their efficiency completely depends on the placement of the stent. Additionally, the inflow and outflow locations and flow patterns changed due to stenting. The high-speed inflow jet impinging on the sac wall causes the untreated aneurysm to have high wall shear stresses on the distal neck and wall. The results also indicated that a small gap between the artery wall and stent can reduce the stent efficiency and even lead to higher kinetic energy inside the stented aneurysm in comparison to the untreated one.  
All CFD results need to be visualized on several slices through the parent artery and aneurysm from different viewpoints; however, the animated CFD data in the VR environment reduce the high volume of data as needed to be displayed in traditional postprocessing methods because of the high degree of freedom of VR headsets. The VR-visualized results showed that, fully immersed in the 3D flow elements field, a viewer without any specific CFD knowledge is able to recognize the high-risk regions inside the vessel and evaluate the performance of FD stents in flow stagnation, as a consequence, facilitating thrombosis.  
The findings of this research would provide surgeons with new insights into the applicability of treatment methods and also the proper placement of flow-diverter stents to obtain maximum efficacy.  
In conclusion, the visualization in the VR environment offers nonexperts in CFD a fully immersive environment to interact with three-dimensional computer-generated objects productively without the issues of traditional postprocessing methods. Additionally considering the VR benefits and limitations, the advantages of using the proposed visualization method outweigh the disadvantages.  
The following are available online at [[https://www.mdpi.com/article/10.3390/app11178082/s1](https://www.mdpi.com/article/10.3390/app11178082/s1)]([https://www.mdpi.com/article/10.3390/app11178082/s1](https://www.mdpi.com/article/10.3390/app11178082/s1)), Video S1: The animation of streamlines for Without-stent, Video S2: The animation of particle tracers for With-stent2, Video S3: The animation of velocity vectors for Without-stent, Video S4: The animation of velocity vectors for With-stent1.  
Conceptualization, S.B.I. and X.C.; data curation, S.B.I.; formal analysis, S.B.I.; funding acquisition, M.W. and X.C.; methodology, S.B.I.; project administration, X.C.; resources, M.W., W.R. and X.C.; software, S.B.I. and W.R.; supervision, X.C.; validation, S.B.I.; visualization, S.B.I., M.W. and W.R.; writing--original draft, S.B.I.; writing--review and editing, X.C. All authors have read and agreed to the published version of the manuscript.  
The authors declare no conflict of interest.