Background: Intraoperative liver segmentation can be obtained by means of percutaneous intra-portal injection of a fluorophore and illumination with a near-infrared light source. However, the percutaneous approach is challenging in the minimally invasive setting. We aimed to evaluate the feasibility of fluorescence liver segmentation by superselective intra-hepatic arterial injection of indocyanine green (ICG).
Materials and methods: Eight pigs (mean weight: 26.01 ± 5.21 kg) were involved. Procedures were performed in a hybrid experimental operative suite equipped with the Artis Zeego®, multiaxis robotic angiography system. A pneumoperitoneum was established and four laparoscopic ports were introduced. The celiac trunk was catheterized, and a microcatheter was advanced into different segmental hepatic artery branches. A near-infrared laparoscope (D-Light P, Karl Storz) was used to detect the fluorescent signal. To assess the correspondence between arterial-based fluorescence demarcation and liver volume, metallic markers were placed along the fluorescent border, followed by a 3D CT-scanning, after injecting intra-arterial radiological contrast (n = 3). To assess the correspondence between arterial and portal supplies, percutaneous intra-portal angiography and intra-arterial angiography were performed simultaneously (n = 1).
Results: Bright fluorescence signal enhancing the demarcation of target segments was obtained from 0.1 mg/mL, in matter of seconds. Correspondence between the volume of hepatic segments and arterial territories was confirmed by CT angiography. Higher background fluorescence noise was found after positive staining by intra-portal ICG injection, due to parenchymal accumulation and porto-systemic shunting.
Conclusions: Intra-hepatic arterial ICG injection, rapidly highlights hepatic target segment borders, with a better signal-to-background ratio as compared to portal vein injection, in the experimental setting.
Keywords: Fluorescence-guided surgery; Hepatic segmentation; Image-guided surgery; Indocyanine green (ICG); Intra-arterial ICG injection; Laparoscopic liver surgery; Positive staining.