Quantitative three-dimensional evaluation of ablation margins for the prediction of local tumor progression

Abstract

Introduction The objective of this research is to assess whether there is a correlation between quantitatively assessed ablation margins and the occurrence of local tumor progression (LTP) using dedicated image processing software.
Methods 28 patients with 45 de novo HCCs treated with percutaneous thermal ablation, e.g. radiofrequency ablation (RFA) and microwave ablation (MWA) between January 2014 and March 2019 were retrospectively included. Semi-automated segmentation of the liver and the ablation zone, manual segmentation of the tumor, and semi-automated registration of pre- and postprocedural contrast enhanced computed tomography (CECT) and magnetic resonance imaging (MRI) images was performed using in-house developed software deLIVERed. The image processing results were used for quantitative analysis of the minimal ablation margin (MAM) and the ablation margin surface area. The outcome of the quantitative analysis was compared to LTP occurence.
Results Image processing of the scans of 39 of the 45 tumors was feasible. 5/39 tumors developed LTP. Based on quantitative analysis, thermal ablation was insufficient in 29/39 tumors. Of these 29 tumors, 4 developed LTP. The median MAM for the LTP group and no LTP group was -4.6 and -1.7 mm, respectively. There was no clear correlation between the MAM and LTP occurrence.
The median tumor surface area exposed to insufficient margins was 28.9% and 7.7.% with and without development of LTP, respectively.
Conclusion Quantitative analysis of postablation images can provide insight in ablation margins and the development of LTP. The ablation margin surface area provides additional information to the MAM. However, additional research is needed in order to further investigate the implications of ablation margin surface area.