Coupled CFD-Particle Approaches to Predict Particle Transport and Reflux in Embolization

Embolization treatment is a process where particles block the arteries that supply diseased tissues, such as tumors. It is essential to accurately simulate how these particles interact with blood flow to improve treatment outcomes. In this study, we compare the one-way and four-way coupling of fluid and particles.

We evaluate a one-way coupled Lagrangian particle tracking approach based on the Maxey-Riley equation, implemented using in-house software (FlowVC) that uses blood flow fields obtained from SimVascular. This method neglects particle-fluid feedback and inter-particle collisions. We then examine a four-way coupled Eulerian-Lagrangian approach that solves the Navier-Stokes equations for blood flow and tracks particle motion with momentum exchange and collision modeling using a parcel-based method (via the Multi-Phase Particle-in-Cell formulation in OpenFOAM). In addition, we evaluate an unresolved Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) approach that couples the fluid solver with DEM to explicitly resolve particle-particle and particle-wall contacts.

These strategies are compared regarding their physical assumptions and ability to capture particle distribution in a benchmark case of an idealized bifurcation network. Flow solutions are validated against experimental data, and particle transport outcomes are analyzed across models. Finally, we present a new modeling approach that extends the parcel-based Eulerian-Lagrangian method to simulate particle and contrast agent ejection from a catheter using miscible liquid mixtures. This framework enables the study of the reflux phenomena during embolization and provides insights that may inform the design of more effective catheter systems for targeted therapy.