Contrast-enhanced ultrasound in the short-term evaluation of hepatocellular carcinoma after locoregional treatment

Abstract
BACKGROUND:
Contrast-enhanced ultrasound (CEUS) with second-generation contrast agents performed 1-month after HCC treatment is almost as sensitive as contrast-enhanced computed tomography (CECT) in depicting the residual tumor. However, the efficacy of CEUS performed early after the procedure is still debated.

AIM:
We evaluated the diagnostic accuracy of CEUS for the assessment of tumour response shortly after locoregional therapy in patients with unresectable HCC.

METHODS:
Ninety-four patients with 104 HCC lesions who were scheduled to receive PEI, RFA, TACE or combined treatment were enrolled in this study. With CECT at 1-month as the reference standard, the diagnostic accuracy of CEUS performed 48-hours after the procedure was evaluated. Patients were followed-up to look for tumor or disease progression.

RESULTS:
Based on CECT findings, 43/104 lesions were diagnosed as having residual viability after 1 month. CEUS performed 48-hours after treatment detected residual tumor in 34/43 nodules with treatment failure at CECT with a sensitivity, specificity, PPV, NPV and accuracy of 79.1%, 96.7%, 94.4%, 86.8% and 89% respectively. There was a high degree of concordance between CEUS and CECT (kappa coefficient=0.78). An hyperemic halo was detectable in 35 lesions without a statistically significant difference between concordant and discordant cases. In patients with uninodular disease responders according to 48 hours CEUS had a significantly longer mean overall survival and time to progression compared to non-responders.

CONCLUSION:
CEUS performed 48 hours after treatment can be considered a reliable modality for the evaluation of the real extent of necrosis and has prognostic value in the assessment of hepatocellular carcinoma.