Purpose To investigate the performance of two microwave ablation (MWA) systems regarding ablation volume, ablation shape and variability. Materials and Methods In this ex vivo study, the Emprint... Show morePurpose To investigate the performance of two microwave ablation (MWA) systems regarding ablation volume, ablation shape and variability. Materials and Methods In this ex vivo study, the Emprint and Amica MWA systems were used to ablate porcine livers at 4 different settings of time and power (3 and 5 minutes at 60 and 80 Watt). In total, 48 ablations were analysed for ablation size and shape using Vitrea Advanced Visualization software after acquisition of a 7T MRI scan. Results Emprint ablations were smaller (11,1 vs. 21,1 mL p < 0.001), more spherical (sphericity index of 0.89 vs. 0.59 p < 0.001) and showed less variability than Amica ablations. In both systems, longer ablation time and higher power resulted in significantly larger ablation volumes. Conclusion Emprint ablations were more spherical, and the results showed a lower variability than those of Amica ablations. This comes at the price of smaller ablation volumes. Show less