Application of contrast ultrasound in ablation treatment of liver cancer

Abstract

Objective To investigate the effectiveness of contrast ultrasound (CEUS) in patient selection, efficacy verification and guidance during ablation treatment of liver cancer. Methods A to-tal of 168 focal liver lesions in 137 patients with liver cancer (131 with HCC, 6 with metastasis liver cancer-MLC) were examined using CEUS before and after ablation treatment. As for the CEUS, the low MI real time imaging technique-CPS and 2.4 ml SonoVue-the 2nd generation of ultrasound con-trast agent by bolus injection through the elbow vein were used. The effectiveness of ablation treat-ment was evaluated by CEUS after the ablation treatment. The results of CECT/CEMRI or biopsy ob-tained at the same stage with CEUS examination were adopted as gold standard. The biopsy diagnosis was obtained for all cases before ablation. Results Completed ablation was achieved in 91.1 % of 137 recruited cases (80 cases received microwave ablation, 57 multi-probe Ethanol ablation-QRA), un-completed ablation was observed in 8. 9 % cases, local recurrence was found in 8.3 % cases. Before ab-lation treatment, significant difference of tumor size pre and post contrast administration were ob-served in 4 patients(2.9%). More tumors were found for 16 cases, less tumor were found for 5 cases with CEUS comparing with un-enhanced US examination. Eight lesions were confirmed by CEUS but cannot be determined by un-enhanced US. There were 29 cases (21.2%) whose observed tumor num-ber was changed after SonoVue administration and the treatment protocol was changed for 12 cases (8.8%)due to the modification of tumor number after CEUS examination. After the ablation treat-ment, residue tumor tissue in 15 cases and local recurrence in 11 cases were confirmed by CEUS, which cannot he observed by no-enhanced US, and the re-ablations were performed under the guidance of CEUS. Meanwhile, there was one local recurrence lesion, and one lesion with residual tumor tissue hadn't been detected by CECT, but were confirmed by CEUS, and verified by biopsy later. Comparing with CECT/or CEMRI, the accuracy of diagnosis of the local recurrence lesion and residual tumor tis-sue after ablation treatment were 98.8 %. Conclusion Before the ablation treatment, CEUS can be helpful for selecting appropriate patients, making reasonable treatment protocol and detecting the tumor which cannot be seen under un-enhanced US. After the ablation treatment, CEUS can define ablation margin, provide accurate judgment for ablation result, sensitively detect the small residual tumor tissue and focal recurrence which cannot be detected by US. Meanwhile, CEUS can be used for guiding the needle when re-treatment is performed for residual tumor or focal recurrence. Key words: Liver neopeasms; Ultrasonography; Ablation treatment