Predicting Long-Term Hepatocellular Carcinoma Response to Transarterial Radioembolization Using Contrast-Enhanced Ultrasound: Initial Experiences

Conventional cross-sectional imaging done shortly after radioembolization of hepatocellular carcinoma (HCC) does not reliably predict long-term response to treatment. This study evaluated whether quantitative contrast-enhanced ultrasound (CEUS) can predict the long-term response of HCC to yttrium-90 (Y-90) treatment. Fifteen patients underwent CEUS at three time points: immediately following treatment and 1 and 2 wk post-treatment. Response 3-6 mo after treatment was categorized on contrast-enhanced magnetic resonance imaging by two experienced radiologists using the Modified Response Evaluation Criteria in Solid Tumors. CEUS data were analyzed by quantifying tumor perfusion and residual fractional vascularity using time-intensity curves. Patients with stable disease on magnetic resonance imaging had significantly greater fractional vascularity 2 wk post-treatment (65.15%) than those with partial or complete response (13.8 ± 9.9%, p = 0.007, and 14.9 ± 15.4%, p = 0.009, respectively). Complete responders had lower tumor vascularity at 2 wk than at post-operative examination (-38.3 ± 15.4%, p = 0.045). Thus, this pilot study suggests CEUS may provide an earlier indication of Y-90 treatment response than cross-sectional imaging.