Evaluation of Liver Ablation Using Two-Dimensional Shear-Wave Elastography in the Rabbit Liver Model

Abstract

To explore the Shear Wave Elastography (SWE) cut-off value of the radiofrequency (RF) ablations and the optimal scale of SWE to delineate the ablation zone. The Institutional Animal Care and Use Committee approved this study. The livers of 30 healthy rabbits were radio-frequency ablated. Conventional ultrasound, contrast enhanced ultrasound (CEUS) and two-dimensional SWE were performed to depict the ablation zone 1h, 2h, 3h, 1d, 7d and 28d after ablation (six groups, five rabbits for each group). Then the livers were harvested for NADH staining. SWE parameters, elasticity distribution, SWE min of the ablation zone and SWE max of the liver tissue beside the ablation boundary were measured. The Receiver Operating Characteristic Curve was obtained to calculate the SWE cut-off value of the ablation zone. Reset the scale of SWE image according to the cut-off value. The overlap percent between elasticity maturation region of SWE image and non-enhanced region of CEUS image was assessed. Highest SWE value was found in the center and that decreased gradually to the peripheral. Non-enhanced regions in CEUS images overlapped well with the ablative tissue in NADH images in 96% specimens. The SWE cut-off value of ablative tissue was 49 kPa – 50 kPa. The elasticity maturation region in SWE image with scale of 50 kPa well delineated the non-enhanced region of the CEUS image in 88% specimens. There was regular elasticity distribution in the ablation area. The SWE cut-off value of ablative tissue is 49 kPa – 50 kPa. The optimal scale for SWE to delineate the ablation zone is 50 kPa.