Do we need to shift from dye injection to fluorescence in respective liver surgery?

Anatomical hepatectomy for hepatocellular carcinoma (HCC) has been a standard procedure for hepatic surgeons by guaranteeing curability and hepatic parenchymal preservation. Recently, indocyanine green (ICG) fluorescent imaging has been applied for hepatobiliary surgery, in substitution for cholangiography, to detect hepatic tumors, and the anatomical hepatectomy. This technique can reveal the hepatic segmental border line on the hepatic surface and its boundary plane during hepatic parenchymal resection. Initially, dye staining with indigo-carmine has been used for anatomical hepatectomy, and recently, ICG fluorescent imaging is applied to this technique. The conventional dye staining method is an innovative method for indicate the hepatic segmental border on the hepatic surface that can otherwise never be visualized. However, the intensity of staining is inconsistent or skill-dependent and disappears quickly with dilution because it is not taken up by the liver. The advantages of ICG fluorescent segmental staining are its high reproducibility and sensitivity. It stays in the injected segment for a few hours because ICG is taken up by hepatocytes. The segmental border inside the liver can also be visualized by this technique, thus providing intraoperative navigation. The limitation of ICG fluorescent staining may be whole liver staining because of recirculation of over dose of ICG, which is difficult to cancel the fluorescence once ICG is injected. With further improvement of the imaging system and standardization of the ICG usage (dose and timing), ICG fluorescent imaging might replace the conventional dye staining method in its role in anatomical hepatectomy.