A novel <i>in vitro</i> dye-based flow visualization method for quantifying the neointimal healing response of aneurysm devices in endothelialized silicone models

PurposeTo develop and implement a novel tool for evaluating neointimal healing over flow diverting aneurysm devices <i>in vitro</i> using a biocompatible, dye-based flow visualization method.MethodsBiocompatibility of Brilliant Blue FCF (BB FCF) dye was established using an alamarBlue metabolic viability assay. Next, a custom MATLAB image analysis script to quantify three intra-aneurysmal dye transport parameters (fill time, washout time, and max intensity) was evaluated through benchtop testing. Video recordings of BB FCF injections in four silicone aneurysm models with increasing levels of device-facilitated occlusion (0-100%) were used to quantify corresponding changes in dye transport parameters. Finally, the method was applied in a 14-day endothelialized silicone blood vessel mimic (BVM) study to assess the impact of repeated BB FCF injections on vessel construct morphology.ResultsBB FCF was noncytotoxic at concentrations ≤500 µM. Dye transport parameters differed as expected between occlusion models; fill and washout times were prolonged in partially occluded models compared to the patent control (<i>p</i> < .01), and maximum dye intensity decreased across all models as a function of occlusion (<i>p</i> < .0001). Repeated BB FCF injections in BVMs showed no morphological differences between endothelial linings in injection-treated vessels vs. no-injection controls.ConclusionThe methods and results documented in this study demonstrate that a non-angiographic dye-based flow visualization method has potential to provide a repeatable, non-destructive way to assess gradual healing-mediated occlusion performance of flow diverter devices <i>in vitro</i>, complementing traditional imaging techniques. This method lays the groundwork for correlating flow-based transport metrics with endothelial coverage to better understand healing-based aneurysm occlusion.