Quantitative Contrast-enhanced Ultrasound Evaluation of Hepatocellular Carcinoma Radioembolization

Abstract

Objective: Contrast-enhanced ultrasound (CEUS) can be used to effectively monitor hepatocellular carcinoma (HCC) treatment response to percutaneous ablation and transarterial chemoembolization. Here, we performed a supplementary analysis of a prospective study to evaluate HCC participants treated with yttrium-90 transarterial radioembolization (Y90-TARE). We evaluated the utility of quantifiable parameters obtained from CEUS up to 2 weeks posttreatment for predicting treatment response compared with the standard of care cross-sectional imaging performed 2 to 6 months posttreatment (reference standard). Materials and Methods: In this IRB-approved, prospective clinical trial, participants with HCC scheduled for Y90-TARE underwent 3 CEUS sessions. These sessions occurred 1 to 4 hours post-Y90-TARE, 1 week, and 2 weeks posttreatment. Each CEUS examination involved a 10-minute infusion of Optison (GE HealthCare) using an Acuson Sequoia 2.0 or a HELX S3000 scanner (Siemens Healthineers) with 6C1 transducer. During each CEUS examination, flash-replenishment sequences were performed at the tumor midline for CEUS replenishment imaging. Changes between baseline and 1 or 2 weeks were used for quantitative analyses. Fractional tumor vascularity (FTV in %), perfusion (in mL/s*mg), peak enhancement (au), and time to peak (TTP in seconds) were calculated offline using Matlab (MathWorks) to quantitatively evaluate TARE response. Two abdominal radiologists read the reference standard MRI or CT obtained post-Y90-TARE and characterized the tumor as nonviable (complete response) or viable (partial response/stable disease). Unpaired t tests were performed to evaluate differences in nonviable versus viable disease. ROC analysis and logistic regression were evaluated to determine diagnostic performance and disease prediction. Results: Final analysis included 38 participants. Of these, 22 had nonviable disease (58%, 22/38) and 16 had viable disease (42%, 16/38). FTV showed a difference between nonviable and viable tumors at 2 weeks post-Y90-TARE (38% ± 24% vs 62% ± 28%, P = 0.008). In addition, there was a statistically significant difference in the change in FTV from immediately post-Y90-TARE to 2 weeks after treatment between participants with viable and nonviable disease (41% ± 31% vs 11% ± 26%, P = 0.006). No significant difference was found between viable and nonviable disease across examinations for any of the other variables ( P > 0.13). Conclusions: Quantitative CEUS appears to provide an early indicator of treatment response ∼2 weeks post-Y90-TARE.