Scientific Basis and Clinical Application of ICG Fluorescence Imaging: Hepatobiliary Cancer

ABSTRACT

Despite recent advances in imaging modalities, the intraoperative diagnosis of small liver cancers remains unsatisfactory. Although fluorescent imaging using indocyanine green (ICG) has just been applied to hepatobiliary surgeries, this technique has the potential to delineate small liver cancers during surgery, through allowing visualization of the disordered biliary excretion of ICG in the hepatocellular carcinoma (HCC) tissues and non-cancerous liver tissues surrounding metastasis of colorectal cancer (CRC). In this technique, ICG is administered intravenously for routine liver function testing before surgery, at the dose of 0.5 mg per kg body weight. The liver surfaces prior to resection, and the cut surfaces of the resected specimen, are examined by the fluorescent imaging system. In our previous series, ICGfluorescent imaging prior to resection delineated more than 90% of liver cancers that were located within 10 mm of the liver surface. On examination of the cut surfaces of the resected specimens, this technique identified all of the microscopically confirmed HCCs and metastases of CRC. Furthermore, ICG-fluorescent imaging was useful to detect small HCCs that were not evident grossly unless visualized by this technique, as reported by Gotoh et al. These results suggest that ICG-fluorescent imaging enables the highly sensitive identification of small liver cancers in real time during liver resection and the subsequent macroscopic examination, enhancing the accuracy of surgery and operative cancer staging.

Keywords:

ICG fluorescence imaging, cancer detection, hepatocellular carcinoma, liver metastasis of colorectal cancer, disordered bile excretion.