M. Lu¹, X. Yu², A. Li¹, T. Jiang³, M.H. Chen², B. Zhao⁴, X. Zhou⁵, J.F. Wang²; ¹Guangzhou/CN, ²Beijing/CN, ³Hangzhou/CN, ⁴Shanghai/CN, ⁵Xian/CN

Purpose
To evaluate the ability of contrast enhanced ultrasound (CEUS) in the assessment of tumor vascularity and response to thermal ablation therapy of hepatocellular carcinoma (HCC) in comparison with contrast enhanced CT (CECT) and/or contrast enhanced MRI (CEMRI).

Material and methods
A total of 133 patients were evaluated both with CEUS and CECT/CEMRI as reference standard for assessment of tumor vascularity within 14 days before the radio-frequency (RF) or microwave ablation treatment. CEUS was performed using a sulphur hexafluoride-filled microbubble contrast agent (SonoVue®, Bracco, Italy) and real-time contrast-specific imaging techniques. Treatment response was assessed as presence of residual viable tumor tissue within the target lesion in 118 patients who presented 1 month after the ablation procedure. Diagnostic performance of CEUS in comparison with reference standards was evaluated.

Results
As compared to CECT/CEMRI, the sensitivity and accuracy of CEUS in detecting tumor vascularity before ablation was 97.0% and 94.2%, respectively. The specificity and accuracy of CEUS in detecting tumor vascularity in the 118 patients who presented at 1 month follow up were 98.2% and 96.6%, respectively. The diagnostic agreement of CEUS with CECT/CEMRI was 95.8%(113/118).

Conclusion
The sensitivity and accuracy of real time CEUS in detection of tumor vascularity and assessment of response to thermal ablation in HCC was comparable to those of CECT/CEMRI, suggesting that both contrast enhanced imaging modalities have comparable diagnostic efficacy. CEUS examination proved to be a safe procedure, easy to access, with possibility of cost saving and diagnostic impact in the clinical practice.