Vascular Modelling of Complex Flow in Aneurysms and Endovascular Devices

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Vascular flow models and measurement platforms provide a critical tool for exploring complex flow in vascular geometries such as brain aneurysms, including the effects of interventional devices. Typical endovascular interventions for aneurysms include insertion of coils, stents, or flow diverters, which aim to achieve flow stagnation and thrombosis within the aneurysm. The outcome of a particular device implementation is dependent upon in vivo flow conditions namely flow rates, pressure gradients, and downstream impedances that critically determine device impact and potential complications. ******It is also increasingly recognized that disturbed and turbulent-like flow conditions play a fundamental role in vascular pathology, particularly through low and multidirectional oscillations in wall shear stress. Particle image velocimetry (PIV) is an essential benchmarking tool that provides instantaneous velocity vector measurements in a cross-section of flow via analysis of images of fluorescent micro-particles excited by laser illumination. PIV offers high temporal and spatial resolution mapping of 3D velocity vectors, and it is thus uniquely able to capture 3D flow disturbances, such as vortex shedding, high-frequency oscillations, and transition to turbulent-like flow, such as in vascular models. ******We aim to develop an integrated cerebrovascular flow simulation platform including our high-resolution PIV system that will enable the rapid testing of endovascular devices in patient-specific aneurysm geometries. We will develop methodology for the rapid 3D-printing of transparent patient-specific aneurysm geometries. These models will be incorporated into a cerebrovascular flow system with the capacity to vary downstream impedances in a predictive fashion as necessary to reproduce patient-specific pressure and flow waveforms. The proposed system will include the highest level of physiological realism to date, with patient-specific geometries and waveforms, compliant vessels, non-Newtonian fluid, and high temporal and spatial resolution to capture flow instabilities.