• 3D printing
• aneurysm
• cfd
• computational fluid dynamics
• echo piv
• particle image velocimetry

The objective of this work is to develop a workflow to refine the blood flow study in cerebral arteries affected by aneurysms, utilizing Echo-Particle Imaging Velocimetry (ECHO-PIV) in vitro and Computational Fluid Dynamics (CFD). An integration between the mentioned tools is hereby carried out.
Commercially available Doppler-based ultrasound scanners demonstrate limitations for complex flow analyses in the deepest cerebral vessels, e.g. signal attenuation (low SNR), angle dependency, one velocity component estimation, while PC-MRI is affected by a low temporal resolution and high costs. These reasons led to the suggestion of methods with less significant downsides, aiming to measure the velocity components, that is to say, the Vector Flow Imaging techniques, which include ECHO-PIV. The advantage of this method resides on performing an echocardiography in vitro on the 3D printed patient's artery, in order to overcome the drawbacks mentioned above, for a more detailed study.
Firstly, the artery of interest is segmented and 3D printed. At this point, the in vitro ECHO-PIV functions with the acquisition of closely timed ultrasound B-mode images of microbubbles, special scatterers, flowing in the printed artery, by means of a contrast-enhanced ultrasound imaging. The 2D cross-correlation between consecutive frames provides the targets displacements, therefore, given the frame rate, the velocity components.
Secondly, CFD performs blood flow simulations in silico of the artery under exam, validating the ECHO-PIV and producing useful insights for blood flow assessments.
The accomplished results indicate the potentiality of this workflow, conceived as a promising path to follow for a patient-specific intervention.