| Abstract: |
Purpose: To determine the technical feasibility of discriminating discontiguous from contiguous ablation zones between a pair of microwave ablation (MWA) applicators using broadband microwave transmission signal measurements in an in vivo porcine liver model. Materials and Methods: Dual applicator 2.45 GHz MWA was performed using 1 directional and 1 omnidirectional applicator, spaced 3 cm apart, under imaging guidance. The study involved 15 hepatic MWAs across 4 swine, with ablation durations of 200 seconds (n = 8) for discontiguous ablation and 600 seconds (n = 7) for contiguous ablation, each at 60 W; these ablation durations and applied power combinations were selected with the intent of creating discontiguous (200 s) and contiguous (600 s) ablation zones. A custom software periodically measured transmission signals between the applicators at 46-second intervals. Contrast-enhanced computed tomography (CT), gross pathology, and histopathologic analyses were used to assess the processed transmission signal (PTS). Results: Statistical analyses revealed significant differences between contiguous and discontiguous ablation zones on contrast-enhanced CT imaging (volume, 16.9 cm3 [SD ± 5.2] vs 3.9 cm3 [SD ± 1.5]; P = .0002) and gross tissue sections and histology (area, 10 cm3 [SD ± 3.3] and 6.5 cm3 [SD ± 1.3]; P = .001), and PTS datasets showed values of 85.1% (SD ± 11) and 37.3% (SD ± 12.9; P = .02). PTS values functioned well as predictors of complete versus incomplete ablation (area under the receiver operating characteristic curve, 0.90), with a PTS threshold of 53% being optimal for indicating ablation zone contiguity. Ablation zone contiguity was strongly correlated with PTS (Spearman correlation coefficient, 0.86; P < .0001). Conclusions: This study demonstrated that PTS between dual MWA applicators can distinguish between contiguous and discontiguous ablation zones. © 2025 SIR |
