Can tumor coverage evaluated 24h post-radiofrequency ablation predict local tumor progression of liver metastases?

摘要

PurposeTo assess the predictive value for local tumor progression (LTP) of geometrical tumor coverage using the contrast-enhanced (ce-)CT images acquired before and within 24h after radiofrequency (RF) ablation.MethodsTwenty patients (6 male and 14 female, median age 62years) with 45 focal hypovascular liver metastases (16 colorectal carcinoma, 3 melanoma and 1 breast carcinoma) underwent RF ablation under CT-guidance and received a ce-PET/CT scan within 24h post-procedure. Pre- and post-ablation ce-CT-images were aligned using an interactive procedure and used to verify the tumor coverage of the RF ablation. Results were correlated to LTP as recorded during follow-up performed every 2-3months after the intervention (mean follow-up of 110weeks) and compared to standard reading performed by three readers of the ce-CT images.ResultsEleven tumors (25%) showed LTP during the follow-up period. One lesion, which did not show LTP, was excluded from analysis due to the poor quality of the alignment. For the remaining, 29 (66%) tumors were completely covered by the ablation zone, 9 (20%) were not, and for 6 (14%) tumors the edges coincided with the edge of the ablation zone. The sensitivity, specificity, PPV and NPV for LTP of having incomplete tumor coverage or no apparent ablative margin versus standard reading of ce-CT were 100, 88, 73 and 100% versus 42, 88, 58 and 82%, respectively.ConclusionsVerifying the tumor coverage of liver metastases by an ablation zone through alignment of pre- and early post-ablation ce-CT images has a high predictive value for LTP.