Qualitative meta-synthesis comparing non-Newtonian, non-Kolmogorov, and modified Krieger computational fluid dynamics models exploring the intracranial aneurysm dynamics: state of the art

Background: Computational fluid dynamics (CFD) models are crucial for examining blood flow and the morphology of brain aneurysms. These models are used to enhance the understanding of the formation, rupture, and post-treatment behavior of aneurysms. The three principal models are non-Newtonian, non-Kolmogorov, and modified Krieger. However, the extent to which these models differ in their ability to predict changes in blood flow within aneurysms remains unclear. This study aimed to compare these models to identify their differences and similarities and to determine which model is most effective for intracranial aneurysm geometry appraisal. Methods: We conducted a qualitative systematic review according to the ENTREQ guidelines. Our search encompassed the MEDLINE/PubMed and American Mathematical Society/MathSciNet databases, from their inception until January 2025. We utilized terms such as “intracranial aneurysm” and “cerebral aneurysm,” along with keywords like non-Newtonian, non-Kolmogorov, modified Krieger CFD models, and IA dynamics. Results: Seventy-four articles were included in this study. Conclusion: CFD simulation accuracy depends on blood vessel mapping, boundary conditions, and fluid model assumptions. Non-Newtonian models, which consider blood shear-thinning behavior, provide better flow depictions compared to Newtonian models. Advanced models, such as non-Kolmogorov and modified Krieger, enhance understanding by capturing turbulence and predicting wall shear stress. Despite these advances, debate continues regarding optimal aneurysm blood flow modeling. The field requires standardized protocols, validation procedures, and uncertainty quantification methods for effective treatment planning.