"Imageable" Zinc-Silicate Glass Microspheres For Transarterial Embolization: A Renal Artery Embolization Study.

Abstract Intrinsically radiopaque (imageable) microspheres for transarterial embolization (TAE) are required to enable real-time intraprocedural feedback and definition of spatial distribution patterns of embolic materials in target tissues. This pilot study evaluates acute and sub-chronic safety and efficacy of imageable zinc-silicate (Zn-Si) glass microspheres in a swine renal artery embolization (RAE) model. Eight swine were divided into two cohorts. Clinical determinants of embolization effectiveness, including imageability, deliverability and temporal/ spatial distribution of microspheres in target tissues were assessed. Subsequently, cohort I and II were used to evaluate the acute and subchronic host response against the Zn-Si microspheres versus a clinical control. The developed microspheres provide for direct intraprocedural feedback using standard diagnostic imaging techniques. Fluoroscopy correlated with ex-vivo high-resolution radiography, CT and micro-CT, demonstrating high imageability, excellent spatial distribution and packing of the Zn- Si microspheres. At follow-up, infarction of the embolized kidneys was noted without any major adverse tissue reaction. Mild recanalization was observed microscopically for both experimental and control microspheres. Zn-Si microspheres permit the definition of spatial distribution in a target tissue, consequently permitting the optimization, personalization and improvement of TAE techniques.