1045 SEVERAL PATHOLOGICAL LESIONS INFLUENCE NON-INVASIVE TESTS OF LIVER FIBROSIS

Methods: Ten patients with unresectable multinodular unilobar HCC and and a target main lesion larger than 3 cm underwent CEUS before, 2 days after, and 30 to 40 days after combined single step therapy. The schedule consisted of percutaneous RFA of the target lesion followed by lobar TACE. The percentage of necrosis was calculated at the sonographic section that depicted the largest diameter of the tumor. Differences in the extent of early (2 days after treatment) and delayed (30 to 40 days after treatment) necrosis were quantitatively and subjectively assessed. Results: Early post-treatment tumor necrosis ranged from 50% to 96% (mean 82.8±11%) and was significantly higher than delayed tumor necrosis which ranged (p < 0.001). Concordance between early and delayed CEUS on the presence of residual vascularization was obtained in four patients. In the remaining six patients the results were discordant: in four cases tumor necrosis was complete in the early evaluation and disappeared on the follow-up, whereas a better rate of delayed response was found in 2 patients. Conclusion: Short term CEUS cannot be considered a reliable modality for the evaluation of the real extent of necrosis. In particular, the absence of enhancement two days after procedure does not always indicate a complete ablation and cannot exclude the presence of viable tumoral tissue.