Contrast-enhanced ultrasound-guided high intensity focused ultrasound treatment of grade 4 liver lacerations in a swine model.

Abstract

We aimed to demonstrate the feasibility of using contrast-enhanced ultrasound (CEUS)-guided high intensity focused ultrasound (HIFU) for the rapid identification and treatment of active bleeding from liver lacerations in a swine model. A two-element HIFU transducer was coupled to a probe and scanner for coregistered diagnostic imaging and ablation. Contrast imaging was performed for vessel targeting and bleeding identification. Eight swine received a 2 × 2 cm laceration across a superficial hepatic vein to induce active hemorrhage. Animals were then randomized to receive either CEUS imaging alone or CEUS-guided HIFU treatment. Subsequently, lacerations were created in an additional eight swine, treated with CEUS-guided HIFU, and followed for 24 hours. Control animals did not achieve hemostasis, while all swine treated with CEUS-guided HIFU achieved hemostasis within 60 seconds of treatment and had less blood loss (60 mL; interquartile range [IQR], 40-125 mL vs. 725 mL; IQR, 410-925 mL; p = 0.016). For the survival studies, hemostasis was achieved after 2 to 6, 45-second treatment cycles (median, 2.5 treatments). The average total blood loss in the survival cohort was 105 mL (IQR, 41-325 mL). There were no changes in vital signs between the pre- and postlaceration control ( p > 0.10). No changes were observed in blood cell counts prelaceration and 24 hours posthemostasis ( p > 0.25). Importantly, all animals survived for the full 24-hour monitoring period. On gross pathologic examination, no apparent damage was detected in the adjacent organs or liver ducts. This preclinical study suggests that CEUS-guided HIFU is a promising tool for the noninvasive rapid identification and subsequent treatment of active bleeding from liver lacerations.