Comparison of microsphere penetration with LC Bead LUMI™ versus other commercial microspheres

The purpose of this study was to evaluate LC Bead LUMI™ (40–90 µm and 70–150 µm) in order to determine if their increased resistance to compression influences microsphere penetration and distribution compared to more compressible commercial microspheres. LC Bead LUMI™ 40–90 µm and 70–150 µm, LC BeadM1® 70–150 µm, Embozene™ 40 µm and Embozene™ 100 µm size and distributions were measured using optical microscopy. Penetration in vitro was evaluated using an established ‘plate model’, consisting of a calibrated tapered gap between a glass plate and plastic housing to allow visual observation of microsphere penetration depth. Behaviour in vivo was assessed using a rabbit renal embolization model with histopathologic confirmation of vessel penetration depth. Penetration behaviour in vitro was reproducible and commensurate with the measured microsphere size, the smaller the microsphere the deeper the penetration. Comparison of the microsphere diameter measured on the 2D plate model versus the corresponding average microsphere size measured by histopathology in the kidney showed no significant differences (p = > 0.05 Mann-Whitney, demonstrating good in vitro - in vivo predictive capabilities of the plate model) confirming predictable performance for LC Bead LUMI™ (40–90 µm and 70–150 µm) based on microsphere size, their increased rigidity having no bearing on their depth of penetration and distribution. An assessment of a LC Bead LUMI™ (40–90 µm and 70–150 µm) has shown that despite having greater resistance to compression, these microspheres behave in a predictable manner within in vitro and in vivo models comparable with more compressible microspheres of similar sizes.