Ultrasonography-guided hepatic tumor resection using a real-time virtual sonography with indocyanine green navigation (with videos).

Purpose: For hepatic tumors that cannot be identified on routine ultrasonography (US), we marked the target area using real-time virtual sonography (RVS) with indocyanine green (ICG)-ethanol (1:100) during surgery, and performed hepatic resection while observing the fluorescence.

Experiment: An ICG-ethanol mixture locally injected into mouse liver was retained in the same area for more than 4 h. The same mixture locally injected into pig liver at a depth of 3 cm could be observed using an infrared camera.

Case: An ICG-ethanol mixture (500 μl) was locally injected under RVS guidance into a metastatic hepatic tumor that was visible only on magnetic resonance imaging (MRI), and hepatic resection was performed while Photodynamic Eye (PDE) images were being observed. The metastatic lesion (3 mm in diameter in a pathological specimen) could be successfully resected.

Conclusion: This method was useful for resecting US-invisible hepatic tumors.