Aim: To investigate the shape and the volume of ablation zones obtained with microwave ablation (MWA) performed with multiple antennas in liver tumours.
Materials and methods: Tumour volume, number of antennas, size (long diameter (Dl), along the antenna axis; short diameter (Ds), perpendicular to the antenna axis; vertical diameter (Dv), vertical to both Dl and Ds) and shape (roundness index (RI); 1 corresponds to a sphere) of the ablation zone, ablation volume, and complications were evaluated.
Results: Mean Dl, Ds, and Dv were 4.7 ± 1.4 cm, 3.9 ± 1.4 cm, and 3.8 ± 1.0 cm, respectively. Mean RIs (Ds/Dl, Dv/Dl, and Dv/Ds) were 0.83 ± 0.13, 0.83 ± 0.17, and 1.02 ± 0.23, respectively, without any difference between the mean RI obtained with the double (0.84 ± 0.01) and that with the triple-antenna (0.93 ± 0.13) approach (p = 0.25). Mean ablation volume was 41 ± 32 cm3 (vs. mean tumour volume 13 ± 10 cm3; range 1-40; p < 0.001). No complications were noted.
Conclusions: Simultaneous multi-antenna MWA of liver tumours results in large nearly spherical ablation zones.
Key points: • Simultaneous multi-antenna microwave ablation of liver tumours results in nearly spherical ablation zones. • The multi-antenna approach generates oversized ablation volumes compared with the target tumour volume. • The multi-antenna approach is safe.
Keywords: Liver; Microwaves; Neoplasms.