Abstract 2460: Assessing the effectiveness of transarterial chemoembolization using super-resolution ultrasound imaging and a rat model of hepatocellular carcinoma

Abstract

Abstract Introduction: Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related deaths worldwide. Transarterial chemoembolization (TACE) treatment of HCC restricts the blood supply to the tumor. Conventional assessment of tumor response is performed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) or computed tomography (DCE-CT) at 4 to 6 weeks after the TACE procedure. An earlier indication of treatment effectiveness would improve patient management and prognosis. Super-resolution ultrasound (SR-US) imaging allows a ten-fold improvement in spatial resolution compared to traditional ultrasound (US) and allows visualization of microvascular networks. The goal of this preclinical research study was to use SR-US imaging to assess the effectiveness of TACE treatment in a relatively brief time frame. Methods: Eight male Sprague Dawley rats weighing around 300 g were injected with 5 million N1S1 cells in the upper left liver lobe and the tumors were allowed to grow for 14 days. The TACE procedure consisted of transhepatic arterial delivery of a mixture of 25 µL Lipiodol and 25 µL Doxorubicin (10 mg/kg) via a polyethylene microcatheter. After intravenous injection of a microbubble (MB) contrast agent, contrast-enhanced US images were acquired (N = 3000) with a preclinical system (Vevo 3100, FUJIFILM VisualSonics Inc) equipped with an MX201 linear array transducer. US images were processed to remove high motion frames, followed by tissue suppression filtering, and then MB localization and accumulation. Morphological filtering was used to enhance the vessel structures. In vivo US, MRI, and CT imaging were performed at baseline before TACE and again at 1 and 2 wk. After euthanasia, tumor tissue was removed for ex vivo analysis. Results: A rat model of HCC for assessing TACE treatment was introduced. Based on tumor size changes and residual perfusion after the TACE procedure, treatments were determined to be a complete responder, partial responder, or non-responder. Initial results demonstrate that SR-US imaging can sensitively detect any reduction in HCC perfusion as measured by a microvascular density (MVD) metric within 2 wk after a single TACE procedure. MVD measurements from the SR-US images were consistence with tumor volume data from MRI and CT imaging. Conclusions: In vivo SR-US images of tumor microvascular networks provided insight into treatment efficacy. Citation Format: Junjie Li, Katherine Brown, Megan Yociss, John Eisenbrey, Kenneth Hoyt. Assessing the effectiveness of transarterial chemoembolization using super-resolution ultrasound imaging and a rat model of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2460.