Liver cancer is a leading cause of cancer related deaths, however primary treatment options such as surgical resection and liver transplants may not be viable for many patients. Minimally invasive image-guided microwave ablation (MWA) provides a locally effective treatment option for these patients with an impact comparable to surgery for both cancer specific and overall survival. MWA efficacy is correlated with accurate image guidance, however conventional modalities such as B-mode ultrasound and computed tomography (CT) have limitations. Alternatively, ultrasound elastography has been utilized to demarcate post-ablation zones yet has limitations for pre-ablation visualization due to variability in strain contrast between cancer types. This study attempts to characterize both pre-ablation tumors and post-ablation zones using electrode displacement elastography (EDE) for 13 patients with hepatocellular carcinoma or liver metastasis. Typically, MWA ablation margins of 0.5 – 1.0 cm are desired, which are strongly correlated with treatment efficacy. Our results demonstrate an average estimated ablation margin inner quartile range of 0.54 – 1.21 cm with a median value of 0.84 cm. These treatment margins lie within or above the targeted ablative margin indicating the potential for using EDE for differentiating index tumors and ablated zones for use during clinical ablations. We also obtained a high correlation between corresponding segmented cross-sectional areas from contrast-enhanced computed tomography (CECT), the current clinical gold standard, when compared to EDE strain images with r(2) values of 0.97 and 0.98 for pre- and post-ablation regions.
