Tissue shrinkage in microwave ablation of liver: an ex vivo predictive model

Measurements of specimen dimensions, carbonised and coagulated regions were performed using a ruler with an accuracy of 1 mm. Based on the results of the first two experiments a predictive model for the contraction of liver tissue from microwave ablation was constructed and compared to the result of the third experiment. Results: For carbonised tissue, a linear contraction of 31 ± 6% was obtained independently of the heating source, power and operation time.

Radiofrequency experiments determined that the average percentage linear contraction of white coagulated tissue was 12 ± 5%. The average accuracy of our model was determined to be 3 mm (5%). Conclusions: The proposed model allows the prediction of the shrinkage of liver tissues upon microwave ablation given the extension of the carbonised and coagulated zones.

This may be useful in helping to predict whether sufficient tissue volume is ablated in clinical practice.