Contrast-Enhanced B-Flow Ultrasound: A Novel Approach to Liver Trauma Imaging

Contrast-enhanced ultrasound (CEUS) shows promise in solid organ trauma by identifying areas of disrupted perfusion. In contrast, B-Flow ultrasound offers high fidelity imaging of larger vessels. We hypothesize that contrast-enhanced B-Flow (CEB-Flow) will improve accuracy of hepatic vessel injury delineation, as an adjunct tool to CEUS and future ultrasound-guided therapies. Imaging data was collected using our IACUC approved swine model for traumatic liver injury. All procedures were approved within this IACUC protocol. Sonography was performed using a Logiq E10 scanner with C1-6 probe (GE HealthCare). After ultrasound guided liver trauma, we performed open-abdomen B-Mode ultrasound, CEUS, and CEB-Flow of the injury during infusion of Definity (Lantheus Medical Imaging, N. Billerica, MA). CEUS was performed using coded harmonic imaging and CEB-Flow using a commercial package (GE Healthcare). Twelve swine were used for analysis. Three blinded interpreters were asked to identify injured liver parenchyma and lacerated vessels. Identification rates were compared using ultrasound-guided laceration images and pathology confirmation as a reference standard. Liver injury identification ranged from 88.3% to 100% on CEUS and 50% to 66.7% on CEB-Flow. Consensus identification rates in identifying parenchymal injury were not significantly different (91.7% CEUS vs. 66.7% CEB-Flow, p = .25). Lacerated vessel identification ranged from 41.7% to 58.3% for CEUS and 75.0% to 91.7% for CEB-Flow. Specifically, CEB-Flow demonstrated improved consensus in identifying lacerated vasculature (41.7% CEUS vs. 91.7% CEB-Flow, p = .041). In this swine model study, the combination of CEUS and CEB-Flow could accurately identify and localize traumatic hepatic injury. CEB-Flow may better characterize vessel injury, which in turn may direct and improve bedside management.