Objective:

To determine the electric field threshold in our numerical model that best fits the local response to irreversible electroporation (IRE) ablation of hepatic tumors as seen in 6 week follow-up MRI. To numerically evaluate the heat generating effect of IRE and demonstrate the potential of treatment planning to avoid thermal damage and shorten procedures in the future.


Methods:

In a retrospective study 18 cases of hepatic tumors treated with IRE ablation were numerically reconstructed and treatment outcome was computed with a numerical treatment planning framework. Simulated ablation volumes were compared to ablation volumes segmented from follow-up MRI. Two cases with a high thermal damage component were selected for numerical optimization.


Results:

The best fit between segmented and simulated ablation zones was obtained at 900 V/cm threshold with the average absolute error of 5.6 1.5 mm. Considerable heating was observed in the dataset. In 7/18 cases >50 % of tumor volume experienced heating likely to cause thermal damage. In the selected two cases thermal damage was eliminated with adjustment of applied voltages.


Conclusion:

Our results indicate that lesions visible on MRI 6 weeks post IRE represent areas that experienced an electric field of 900 V/cm or higher.


Significance:

We developed a sophisticated method for validation of the numerical treatment planning framework. A future prospective study can be effectively designed based on the findings of this study.



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