Comparing Deposition Characteristics of Various Embolic Particles Using an In Vitro Prostate Microvasculature Model.

Purpose: To compare spatial distributions of radiopaque glass (RG) microspheres, tris-acryl gelatin (TAG) microspheres, and polyvinyl alcohol (PVA) nonspherical foam particles within a planar in vitro microvascular model of the hyperplastic hemiprostate.

Materials And Methods: A microvascular model simulating hyperplastic hemiprostate was perfused with a water-glycerin mixture. A microcatheter was positioned distal to the model's prostatic artery origin, and embolic particles (RG, 50 μm, 100 μm, and 150 μm; TAG, 100-300 μm and 300-500 μm; and PVA, 90-180 μm and 180-300 μm) were administered using a syringe pump. Microscopic imaging and subsequent semantic segmentation were performed to quantify particle distributions within the models. Distal penetrations were quantified statistically via modal analysis of the particle distributions.

Results: Maximum distal penetration was observed for RG microspheres of 50 μm, followed by RG microspheres of 100 μm and then TAG microspheres of 100-300 μm and RG microspheres of 150 μm. TAG microspheres of 300-500 μm, PVA particles of 90-180 μm, and PVA particles of 180-300 μm exhibited the lowest distal penetrations. The distal penetration metrics between groups were significantly different (P < .05) except between TAG microspheres of 100-300 μm and RG microspheres of 150 μm and between PVA particles of 90-180 and 180-300 μm.

Conclusions: Comparing the spatial distributions of embolic particles in an in vitro microvascular model simulating the hyperplastic hemiprostate revealed that noncompressible particles and those with narrower size calibrations and smaller relative diameters exhibited higher degrees of distal packing. The embolization front was less distinct for particles with wider size calibrations, which resulted in smaller, more distal emboli along with larger, more proximal emboli. Both PVA particles and TAG microspheres of 300-500 μm exhibited relatively low overall distal penetration.