## 3 Results and Discussion
Furthermore, it is possible to appreciate the complex changes in the OSI distribution on aneurysm surface, such as, for example, in the location where the maximum OSI occurred in the normal condition (0.48), as it turned to be lower in ISH (0.12) and in hypertension (0.25). Moreover, in Figure 12 the RRT magnitude is shown, and it is possible to observe that a decrease occurred when passing to an ISH condition and hypertension, with differences of up to almost 52% in ISH. These results aim to determine in future studies what is the implication of this parameter decrease and its effects on the remodeling of the endothelial wall. It should be noted that, for the normal condition, the A-1 model (ruptured) clearly presents the highest RRT of all models. Analyzing this in more detail, Figure 13 showed the magnitude and distribution of the RRT at normal condition for A-1. Here, it can be observed that, in general, the model presents low RRT, concentrating the greater magnitudes in a  
Figure 9: WSS at systole (SWSS) in A-1 model, for each pressure condition. The reason for these interesting behaviors could be explained by the fact that the ISH condition, despite not being the highest pressure condition, is the condition that presents the greatest pressure range between diastole and systole of the cardiac cycle (range approximately 90 mmHg). As a result, it is also the condition with the greatest range of displacements and deformations of the arterial wall, which implies a bigger expansion in the fluid domain that would promote more and smoother movement of the blood flow with less deceleration. Having higher velocities inside the domain and, thus, higher shear stresses, is reflected in the WSS, TAWSS, OSI and RRT, which could result in adverse changes from a hemodynamic point of view and its interaction with the endothelium wall. This should not be treated as a general behavior, but it does lead to question at which point this expansion causes this effect and not the opposite, i.e., that too much increase in area due to arterial expansion would actually lead to a decrease in blood flow velocity. It should be noted that in this study a high intracranial pressure (IICP) was used. Therefore, in conditions with lower intracranial pressure, greater displacements could be expected, and, therefore, even more adverse changes. On the other hand, this study has some limitations and considerations. Only six aneurysm models were studied and, as noted before, in order to validate the behavior exhibited here, a higher number of cases will be needed for future studies. In regard to the conditions, we used the same boundary conditions for all models and a constant external pressure. For the aneurysm thickness we considered it as a constant value at the entire geometry, being this an important simplification because is known that thickness is variable, with thin-walled regions at the aneurysm location. This thickness consideration was used for two reasons: the challenge that implies modelling a variable thickness, and the lack of enough patient data from bibliography and measurements. Concerning the mechanical boundary conditions, the fixed support at inlet and outlets faces is an important consideration that might influence the results, but there is no alternative condition to be imposed. In regard to the results validation, computational modeling of an intracranial aneurysm can determine its hemodynamic parameters by means of declaring subject-specific boundary conditions, geometry-image reconstruction, the accuracy of spatial and temporal discretization and flow parameters. An important stage in the numerical simulations is the validation of them with either in vitro or in vivo measurements techniques. [PERSON] et al. establishes that, in general, a good agreement between well-conducted numerical study and experimental measurements can be achieved, but quantitative discrepancies still remain [30]. Many validation studies are limited to the restricted flow conditions of a single case [31; 32; 33; 34].