Comparison of Shear Wave Elastography and Contrast-Enhanced Ultrasonography for Microwave Ablation Assessment in Rabbit Liver

Background/Objectives: To evaluate the feasibility and diagnostic performance of shear wave elastography (SWE) compared to contrast-enhanced ultrasonography (CEUS) in real-time assessment of microwave ablation (MWA) zones in rabbit liver, and to deter-mine the SWE stiffness threshold indicative of coagulative necrosis. Methods: Microwave ablation was performed on 90 liver lesions in 30 rabbits using two power/time settings. SWE was performed immediately post-ablation to measure stiffness at the lesion center, edge, and surrounding liver. CEUS was subsequently used to assess lesion size. Meas-urements from SWE and CEUS were compared with gross pathology. Receiver operating characteristic (ROC) analysis was conducted to define the SWE threshold for ablation boundary detection. Results: SWE-mean values increased significantly at the ablation center and edge (P < 0.001), with a decreasing gradient from center to periphery. ROC analysis identified 22.31 kPa as the optimal stiffness threshold for coagulative necrosis at the ablation margin (AUC = 0.828, sensitivity = 81.6%, specificity = 78.9%). Lesion di-mensions measured by SWE and CEUS were comparable to those of gross specimens, with no significant differences. Conclusions: SWE provides accurate and reproducible as-sessment of microwave ablation zones and may serve as a contrast-free alternative to CEUS for intraoperative monitoring. These findings support the potential clinical utility of SWE in real-time, non-invasive evaluation of ablation efficacy.