Abstract No. 449 Shear wave elastography (SWE) as a quantitative biophysical assay to measure tumor stiffness changes after hepatic arterial embolization

Abstract

Real-time intraprocedural quantitative assays are sorely needed to measure tumor changes during hepatic arterial embolization (HAE). Current assays fail to depict tumor mechanical properties. Our purpose was to assess tumor stiffness changes in an orthotopic rat model of hepatocellular carcinoma (HCC) before and after HAE. This study was approved by the institutional Animal Care and Use Committee. Rat hepatoma McA-RH7777 cells were orthotopically implanted in the liver of 12 male Buffalo rats, and, after 3 weeks, the animals underwent HAE through a left common carotid approach. Bilobar bland embolization was performed using 70-150 μm LC beads until near-stasis. Normal liver and tumor stiffness was measured using ultrasound shear wave elastography (SWE) before and immediately after HAE. The overall mean tumor stiffness measured 15.2 kPa ± 7.6 (standard deviation) before HAE compared to 22.2 kPa ± 7.4 immediately after the procedure, P = .003. The peak tumor stiffness measured 18.2 kPa ± 9.7 (standard deviation) before HAE compared to 28.6 kPa ± 11.3 after the procedure, P = .006. Normal liver stiffness measured 4.8 kPa ± 2.1 before and 7.2 kPa after embolization, P = .008. Our findings demonstrate significant acute increase in tumor stiffness after hepatic embolization. SWE offers a new perspective in real-time assessment of tumor mechanical changes during embolization. Further studies may help determine if this technique can be used to improve HAE intraprocedural efficacy.