Histotripsy for Liver Tumor Ablation and Beyond: AJR Expert Panel Narrative Review

Histotripsy was cleared by the FDA for liver tumor ablation in October 2023. The technology uses short-duration high-amplitude low-duty-cycle ultrasound waves, converging these focally to cause tissue cavitation. This process results in liquification of a defined treatment volume into a lysate while sparing surrounding tissues. The technology is noninvasive (i.e., no skin puncture) and nonthermal and does not produce ionizing radiation. These procedural characteristics and early direct-to-patient marketing contributed to growth in patient interest and clinical adoption of histotripsy for liver tumor ablation despite lagging clinical evidence. Specifically, although histotripsy is supported by substantial preclinical porcine data, the published clinical evidence on histotripsy for liver tumor ablation in humans has focused on technical performance, safety, and early response (i.e., within 3 months postprocedure), in small highly selected populations, and level 1 evidence incorporating long-term oncologic outcomes remains lacking. This AJR Expert Panel Narrative Review explores the current status of histotripsy for liver tumor ablation, addressing the technology's preclinical background, supporting clinical evidence, technical considerations for implementation including patient selection, the potential for immunomodulation, and emerging extrahepatic applications.