Radioembolization (RE) is a treatment for patients with liver cancer, one of the leading cause of cancer-related deaths worldwide. RE consists of the transcatheter intraarterial infusion of radioactive microspheres, which are injected at the hepatic artery level and are transported in the bloodstream, aiming to target tumors and spare healthy liver parenchyma. In paving the way towards a computer platform that allows for a treatment planning based on computational fluid dynamics (CFD) simulations, the current simulation (model preprocess, model solving, model postprocess) times (of the order of days) make the CFD-based assessment non-viable. One of the approaches to reduce the simulation time includes the reduction in size of the simulated truncated hepatic artery. In this study, we analyze for three patient-specific hepatic arteries the impact of reducing the geometry of the hepatic artery on the simulation time. Results show that geometries can be efficiently shortened without impacting greatly on the microsphere distribution.

Objective: While microballoon interventions (MBIs) have emerged as a safe treatment for hepatocellular carcinoma, they also lead to blood flow alterations that are not well understood and could decrease the treatment's effectiveness. In this study, we developed patient-inspired in vitro and in silico models (IVM and ISM). The IVM was used to study the influence of using a microballoon vs. a standard catheter on the tumor targeting and to validate the ISM; the ISM was used to study the influence of the size of a communicating arcade on the tumor targeting. Methods: Two IVM (with a literature-based collateral artery and without collateral artery), two catheter modes (a microballoon catheter with inflated and deflated balloon), and three occlusion locations were combined to conduct an experimental, parametric analysis. Furthermore, the ISM was validated and used to study four collateral artery diameters. Results: The IVM generated realistic hemodynamic alterations, and the ISM replicated the experimental results with an average difference of 4 percent points on the flow distribution per outlet. The designed collateral artery did not affect the simulated intervention negatively. Conclusion: Patient-inspired IVMs and ISMs can be used to better understand the complex hemodynamic phenomena after balloon occlusion and help determine collateral artery sizes that generate successful MBIs. Significance: Combined patient-inspired IVM and ISM of the hepatic artery hemodynamics during MBIs were developed for the first time. This modeling approach could potentially lead to a better assessment of patients with liver cancer not eligible for standard chemoembolization or radioembolization.

Computational fluid dynamics techniques are increasingly used to computer simulate radioembolization, a transcatheter intraarterial treatment for patients with inoperable tumors, and analyze the influence of treatment parameters on the microsphere distribution. Ongoing clinical research studies are exploring the influence of the microsphere density in tumors on the treatment outcome. In this preliminary study, we computationally analyzed the influence of the microsphere concentration in the vial on the microsphere concentration in the blood. A patient-specific case was used to simulate the blood flow and the microsphere transport during three radioembolization procedures in which the only parameter varied was the concentration of microspheres in the vial and the span of injection, resulting in three simulations with the same number of microspheres injected. Results showed that a time-varying microsphere concentration in the blood at the outlets of the computational domain can be analyzed using CFD, and also showed that there was a direct relationship between the variation of microsphere concentration in the vial and the variation of microsphere concentration in the blood. Future research will focus on elucidating the relationship between the microsphere concentration in the vial, the microsphere concentration in the blood, and the final microsphere distribution in the tissue.

Mikroesfera-kontzentrazioaren analisia gibeleko erradioenbolizazioan "computational fluid dynamics" simulazioak erabiliz produkzioaren informazio-fitxa