Predicting Long Term HCC Response to Radioembolization Using Contrast-Enhanced Ultrasound 1-2 Weeks Post Treatment

This study evaluated whether quantitative contrast-enhanced ultrasound (CEUS) can predict long term response of hepatocellular carcinoma (HCC) to Yttrium-90 (Y-90) radioembolization therapy. Twelve patients scheduled for Y-90 radioembolization therapy of a previously untreated HCC underwent CEUS at 3 time points: immediately following treatment, and 7 and 14 days post-treatment. Ultrasound imaging was performed using a Siemens S3000 Helx scanner with a C6-1 probe in dual 2D B-mode/contrast mode. Treatment response was evaluated with MRI 3-4 months post-treatment using modified response evaluation criteria in solid tumors (mRECIST) by two experienced radiologists in consensus. CEUS data was analyzed by quantifying tumor perfusion and residual fractional vascularity, using contrast time intensity curves that were created off-line. At 7 days post-treatment, the patient with stable disease exhibited significantly greater tumor vascularity (70.96 ± 7.63%) than patients with partial response (30.88 ± 20.56%, p < 0.0001) and complete response (13.64 ± 10.97%, p < 0.0001). Additionally, patients with stable disease exhibited significantly greater tumor perfusion 14 days post-treatment (2.33 ± 0.22 ml/s*mg) than both partial response (0.05 ± 0.05 ml/s*mg, p < 0.0001) and complete response patients (0.47 ± 0.46 ml/s*mg, p < 0.0001). Although larger sample sizes and longer follow up are needed to fully evaluate the clinical impact of CEUS, it appears to provide an earlier indicator of Y-90 treatment response than MRI.