Investigation of Patient-Specific Cerebral Aneurysm using Volumetric PIV, CFD, and \textit{In Vitro} PC-MRI

4D PC-MRI is a modality capable of providing time-resolved velocity fields in cerebral aneurysms \textit{in vivo}. The MRI-measured velocities and subsequent hemodynamic parameters such as wall shear stress, and oscillatory shear index, can help neurosurgeons decide a course of treatment for a patient, e.g. whether to treat or monitor the aneurysm. However, low spatiotemporal resolution, limited velocity dynamic range, and inherent noise of PC-MRI velocity fields can have a notable effect on subsequent calculations, and should be investigated. In this work, we compare velocity fields obtained with 4D PC-MRI, computational fluid dynamics (CFD) and volumetric particle image velocimetry (PIV), using a patient-specific model of a basilar tip aneurysm. The same \textit{in vitro} model is used for all three modalities and flow input parameters are controlled. \textit{In vivo}, PC-MRI data was also acquired for this patient and used for comparison. Specifically, we investigate differences in the resulting velocity fields and biases in subsequent calculations. Further, we explore the effect these errors may have on assessment of the aneurysm progression and seek to develop corrective algorithms and other methodologies that can be used to improve the accuracy of hemodynamic analysis in clinical setting.