Research About Pathology And Computational Fluid Dynamics Of Intracranial Aneurysms

Text：Intracranial aneurysms (IAs) are pathologic expansion of the frail arterial wallwhose can not resist the pressure and dilatation of hemodynamics, and are the result ofdynamic effect of geometry, morphology, hemodynamics and pathology.Hemodynamics plays an important role in the initialization, progression and rupture ofcerebral aneurysms, but there are still full of controversy about the diversity of growthand rupture mechanisms because of the inherent complexity and heterogeneity of IAs.The method of computational fluid dynamics (CFD) was introduced andcombined with pathology to research the mechanisms of pathology and hemodynamics,using some specimens and DSA data from clinical patients suffering from IAs,furthermore, the dynamic course of origin and progress of IAs were simulated bydigitization eliminating technology, for researching the hemodynamic characteristicsand mechanism. All the exploration above could contribute to understand the naturecharacteristics of IAs, and supply more reliable evidence for introducing CFD tools intoclinical assessment, treatment decision, new therapies development and improving thedevices of interventional therapy.Part1: Research about the classified characteristics and distribution of thepathologic phenotypes of IAs. We classified them to two kinds of phenotypes, whichwere the thin wall type with degeneration and devastating, and the thick wall type withhyperplasia and remodeling. The destiny of stabilize or rupture of IAs may be decidedby the different pathological phenotypes.Part2: Construction the3D digitalization models and analysis the hemodynamicscharacteristics of IAs. Using Mimics, Ansys and CFX tool of CFD, we researched somehemodynamics parameters and characteristics of different IAs. We found the differentrepresentation of hemodynamics parameters and characteristics because of different geometry and morphology of IAs. We summarized the distribution regularity andcharacteristics for different parts from different parameters about pressure, wall shearstress (WSS), pressure gradient, WSS gradient, the vectors, turbulent dynamics energy,et al. The origin, progress and rupture of IAs may be the result of combined action ofseveral hemodynamics parameters at definite domain.Part3: Research of pathology phenotypes and hemodynamics characteristics ofIAs. The relationship of hemodynamics characteristics and pathology phenotypes can beproved. The two phenotypes of the thin wall of degeneration and the thick wall ofhyperplasia can present different hemodynamics characteristics.Part4: Research of the hemodynamics characteristics and mechanisms of IAsgrowing by digitizing elimination technology and CFD simulation. The daughterbubbles and lobes were eliminated for restoring and simulating the situation before IAsgrowing. Growing was depended closely on the hemodynamics. The higher pressure,the high WSSG, and the right WSS vector maybe the mainly hemodynamics parameters.The different growing mechanisms were the different result of different hemodynamicsparameters at the different situation.Part5: Research of the hemodynamics characteristics and mechanisms of IAsorigin by digitizing elimination technology and CFD simulation. The aneurysms wereeliminated totally for restoring and simulating the situation before IAs initialization. Theorigin of IAs was located at the downstream transition zones near the hemodynamicsimpacting zones, or the transition marginal zone near the branch arteries. Higherpressure gradient, higher WSSG and the vector directing the origin zone may be the keyroles in the beginning of the IAs. The others parameters such as the higher pressure, thehigh WSS, the WSS or pressure vector, maybe play the synergetic action roles at theorigin of IAs.