Hemodynamics and bio-mechanics are the major pathogenic factors in the initiation and evolution of human aneurysms. The current clinical practice of determining ruptures risk and treatment modalities based on the size parameter, maximum diameter (D_max), is very crude and ignores the associated stresses. Research reports that the geometric shape of the aneurysms, greatly influences their hemodynamic and bio-mechanic behaviour. Mathematical modelling route would be an apt tool for understanding the shape dependence of these stresses, since it is medically and ethically not possible to follow the patients till final stage. To this end, fluid structure interaction (FSI) studies were carried out using idealized fusiform (abdominal aortic aneurysm) and saccular (intracranial) aneurysm models, having a range of shape indices, under pulsatile flow, with linear elastic vessel wall, and parameters of clinical relevance such as, maximum wall shear stress (MWSS), time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), peak wall stress (PWS) etc are reported and correlated with growth, rupture risk/location, intraluminous thrombus (ILT) deposition etc. A critical shape index is identified and detailed visualizations of the re-circulation regions and vortex cycle is reported which is expected to serve the clinical community in pre-operative planning. The study further progresses to clinically appreciable numerical simulations, using a patient-specific posterior communicating artery (Pcom) aneurysm model, generated from CT scan images, under pulsatile inlet velocity profile, obtained from Transcranial Doppler (TCD) measurements, which is expected to form the basis for future hi-fidelity numerical studies for objective and scientific
aneurysm rupture risk prediction.