Purpose: Particle image velocimetry (PIV), an in vitro experimentation technique that optically measures velocity components to analyze fluid velocity fields, has become increasingly popular to study flow dynamics in various vascular territories. However, it can be difficult and expensive to create patient-specific clear models for PIV due to the importance of refractive index matching of the model and the fluid. We aim to implement and test the use of poly-vinyl alcohol (PVA) in a lost-core casting technique to create low-cost, patient-specific models for PIV.
Methods: Anonymized patient vascular anatomies were segmented and processed in Mimics/3Matic to create patient-specific cores from 3D digital subtraction angiographies. The cores were 3D-printed with PVA and post-processed with a 80:20 water:glue mixture to smooth the surface. Two silicones, Sylgard 184 and Solaris, were used to encapsulate the model and the PVA core was dissolved using warm water. Computed tomography scans were used to evaluate geometric accuracy using circumferences and surface differences in the model.
Results: Mean geometric differences in circumference along the inlet centerline and the mean surface difference in the aneurysm between the final Silicone Model and the desired STL Print geometry were statistically insignificant (0.6 mm, 95% CI [- 1.4, 2.8] and 0.3 mm 95% CI [- 0.1, 0.7], respectively). Particle illumination within each model was successful. The cost of one 10 cm × 10 cm × 5 cm model was $69.
Conclusion: This technique was successful to implement and test the use of PVA in a lost-core casting technique to create low-cost, patient-specific in vitro models for PIV experimentation.
Keywords: 3D printing; Compliant vascular model; Particle image velocimetry; Patient-specific.