Multimodal Visibility of a Modified Polyzene-F-coated Spherical Embolic Agent for Liver Embolization: Feasibility Study in a Porcine Model

Purpose: To evaluate multimodal visibility of modified currently available mierospheres on radiography, magnetic resonance (MR) imaging, and computed tomography (CT) in a porcine liver model. Materials and Methods: Livers of four pigs were embolized with two sizes (100 mu m +/- 25 and 700 mu m +/- 50) of modified Embozene Microspheres embedded with different densities of barium sulfate and iodine as radiopaque materials (intensity groups A-C, with increasing intensity from A to C for 100 mu m and intensities A and C for 700 mu m) and iron oxide as magnetic substance for MR imaging visibility. Pigs embolized with currently available Embozene Microspheres served as control groups. Pre- and postinterventional MR imaging (T1- and T2-weighted) and CT were performed. Qualitative and quantitative (ie, determination of signal-to-noise ratio [SNR]) particle visibility was evaluated on radiography, MR imaging, and CT. Results: Modified particles of both sizes were visible on radiography, MR imaging, and CT. Particles in the control group were not visible. For modified particles of both sizes, SNRs measured on MR imaging decreased significantly after embolization (eg, cluster analysis of group A, 100 mu m +/- 50 particles, T1-weighted, -74.6% +/- 3.4; P = .03). For modified particles of both sizes, SNR measured on CT increased significantly after embolization (eg, cluster analysis of group A, 700 mu m +/- 25 particles, +54.3% +/- 13.5; P = .03). Conclusions: Modification of currently available Embozene Microspheres was successful, with multimodal visibility on radiography, MR imaging, and CT in porcine liver. In the future, this might improve procedure accuracy and allow monitoring, control, and improvement of embolotherapy during and after the procedure.