The effect of downstream resistance on flow diverter treatment of a cerebral aneurysm at a bifurcation: A joint computational-experimental study
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Intracranial aneurysm can lead to hemorrhagic stroke upon rupture. Deployment of flow diverters can restrict the blood flow into aneurysm and mitigate the rupture risk. Computational fluid dynamics (CFD) and ultrasonography with pulse-wave and color Doppler ultrasound measurements were employed jointly to investigate the complex flow pattern in cerebral aneurysms, both before and after the deployment of flow diverters. Patient-specific configurations of both bifurcation and side-wall aneurysms were selected. The effect of downstream flow resistance was investigated by adjusting the volume flow rate and pressure at the outlet vessels computationally and experimentally. Velocity profiles in the aneurysm measured from ultrasonography showed good agreement with those from computer simulations. The discrepancy in velocity between the computational and experimental sets of data is less than 10%. The downstream resistance can alter the volume flux into a bifurcation aneurysm with a flow diverter deployed by 236%, while the corresponding value of a side-wall aneurysm is negligible. The vorticity of the aneurysmal flow was reduced by more than 80% in both cases after stenting. This study demonstrated that careful investigation of downstream flow resistance of a bifurcation aneurysm is essential to provide an accurate assessment of the aneurysmal flow dynamics after flow diverter deployment.
Key wordsIntracranial aneurysms computational fluid dynamics (CFD) doppler ultrasound
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Partial financial support has been provided by the Seed Funding Program for Basic Research of The University of Hong Kong, and Innovation and Technology Fund (ITS/150/15) of the Government of the Hong Kong Special Administrative Region. We thank Synapse Therapeutic Limited (Hong Kong) for donating the Pipeline Embolization Device used in this study.
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