Percutaneous microwave ablation of a transgenic large animal porcine liver tumor model after intra-arterial embolization

Abstract

Objectives: Percutaneous ablation with microwave ablation (MWA) successfully treats hepatic tumors (HTs) up to 3 cm in size when appropriate margins are achieved. MWA is limited when treating larger HT due to the disbursement of heat from adjacent tissue and vasculature. Embolization before MWA can achieve a larger ablation zone (AZ); however, no evaluation has been performed to assess the influence of proximal or distal embolization on AZ. Material and Methods: Using a transgenic porcine liver tumor model, angiography and embolization of HT were performed with lipiodol or different-sized particles, ranging from 40 to 1200 µm to complete vascular occlusion followed by MWA for 4 min at 65 watts with subsequent ex vivo assessment of AZ. Results: AZ volume using 40 µm, 100 µm, and 300–500 µm microparticles were significantly larger than for the control, non-embolization group (mean ± standard deviation: 40 µm: 17.48 cm3 ± 1.22, P ≤ 0.001; 100 µm: 14.81 cm3 ± 0.43, P ≤ 0.001; and 300–500 µm: 12.16 cm3 ± 0.8, P ≤ 0.001 compared to 6.06 cm3 ± 2.02 in the control group. Conclusion: Distal embolization with smaller particles produced significantly larger AZ in an in vivo liver tumor when compared to no embolization control, lipiodol, or proximal large particle embolization.