Background: Endovascular treatment of intracranial aneurysms (IAs) by flow diverter
(FD) stents depends on flow modification. Patient-specific modeling of FD deployment and
computational fluid dynamics (CFD) could enable a priori endovascular strategy optimization. We
developed a fast, simplistic, expansion-free balls-weeping algorithm to model FDs in patientspecific
aneurysm geometry. However, since such strong simplification could result in less accurate
simulations, we also developed a fast virtual stenting workflow (VSW) that explicitly models
stent expansion using pseudo-physical forces.
Methods: To test which of these two fast algorithms more accurately simulates real FDs, we
applied them to virtually treat three representative patient-specific IAs. We deployed Pipeline
Embolization Device into 3 patient-specific silicone aneurysm phantoms and simulated the treatments
using both balls-weeping and VSW algorithms in computational aneurysm models. We then
compared the virtually deployed FD stents against experimental results in terms of geometry and
post-treatment flow fields. For stent geometry, we evaluated gross configurations and porosity. For
post-treatment aneurysmal flow, we compared CFD results against experimental measurements by
particle image velocimetry.
Results: We found that VSW created more realistic FD deployments than balls-weeping in terms
of stent geometry, porosity and pore density. In particular, balls-weeping produced unrealistic FD
bulging at the aneurysm neck, and this artifact drastically increased with neck size. Both FD
deployment methods resulted in similar flow patterns, but the VSW had less error in flow velocity
and inflow rate.
Conclusion: In conclusion, modeling stent expansion is critical for preventing unrealistic bulging
effects and thus should be considered in virtual FD deployment algorithms. Also endowed with its
high computational efficiency and superior accuracy, the VSW algorithm is a better candidate for
implementation into a bedside clinical tool for FD deployment simulation.