Development of “Imageable” Beads for Transcatheter Embolotherapy

Abstract

Purpose-To develop and characterize radiopaque embolization microspheres capable of in vivo detection with intra-procedural fluoroscopy and CT imaging and to evaluate their spatial distribution inside target tissues during and following transcatheter embolization.Materials and Methods-PVA hydrogel microspheres were loaded with lipiodol and examined for iodine content, stability of loading, and conspicuity with fluoroscopy and CT in vitro. Transcatheter embolization of swine liver and kidney was performed with the radiopaque microspheres and spatial distribution was evaluated with intra-procedural fluoroscopy and CT. Ex vivo evaluation was performed using light microscopy and micro-CT.Results-In vitro analyses demonstrated that radiopaque microspheres could be loaded with sufficient iodine content to be detected with routine fluoroscopy and CT imaging and that such loading was relatively stable. Radiopaque microspheres were visible in vivo with fluoroscopy and CT during transcatheter embolization. CT imaging during embolization procedures demonstrated a dose dependent relationship in the number and size of visualized embolized arteries. Imaging features of radiopaque microsphere distribution inside target tissues correlated well with ex vivo light microscopic and micro-CT evaluation of microsphere distribution.Conclusions-Radiopaque embolization microspheres are visualized during transcatheter embolization with routine intra-procedural fluoroscopy and CT. These radiopaque microspheres provided the three dimensional spatial distribution of embolic material inside target organs during the procedure, and therefore can provide real-time, intra-procedural feedback for the interventional

Predicting the thermal responses and radiopacity of multicomponent zinc–silicate bioglasses: A focus on ZnO, La2O3, SiO2 and TiO2

“…Quantitative data was determined in Hounsfield Unit (HU) values with three measurements performed for each composition. PVA (Contour™) particles were used as a commercial control and mixed in a 50:50 strength contrast Isovue® 370 (Iopamidol; 370 mg of non-ionic iodine per mL, Bracco Diagnostics Inc.) agent in saline, as most commonly used in interventional radiology clinical settings [20][21][22].…”

Microfluidic one-step fabrication of radiopaque alginate microgels with in situ synthesized barium sulfate nanoparticles

“…Alginate, a natural biocompatible and highly stable sugar-based polymer, has been widely used as an effective embolic material in the experimental aneurysm model, 11,12 arteriovenous malformation 13 and local chemoembolization. 14 Nevertheless, the preparation of alginate based embolic materials is still rather complicated, involving premixing of an aqueous dispersion of alginate microgels and liquid imaging agents, such as iohexol 4,15 and Lipiodol, 16 or alginate, with encapsulation of heavy metal salt such as barium sulfate (BaSO 4 ) or bismuth sulfate. 17 In vitro studies indicated that the premixed liquid imaging agents with alginate microgels tend to rapidly dissociate from the alginate substrate in a period of minutes to hours, resulting in poor visualization under X-rays.…”

Holmium–lipiodol–alginate microspheres for fluoroscopy-guided embolotherapy and multimodality imaging

“…The novel microsphere formulation as presented here allows intra-procedural imaging of the embolization procedure as was demonstrated in a porcine kidney during an embolization procedure. This facilitates direct feedback of the microsphere administration and may therefore enable the possibility to modify the intervention and defining desirable embolization endpoints depending on observations made during the procedure (Sharma et al, 2010). Post-procedural imaging of the embolization procedure, which was shown with both (CB)CT and MRI, allows determination of microsphere distribution.…”