Applications of fusion-fluorescence imaging using indocyanine green in laparoscopic hepatectomy

Indocyanine green (ICG)-fluorescence imaging has been developed for real-time identification of hepatic tumors and segmental boundaries during hepatectomy. Fusion ICG-fluorescence imaging (real-time visualization of pseudocolor-fluorescence signals on white-light color images) may serve as a reliable navigation tool especially in laparoscopic hepatectomy, in which gross inspection and palpation are limited.

The study population consisted of 41 patients undergoing laparoscopic hepatectomy. Hepatic tumors were identified by fluorescence imaging following the preoperative intravenous administration of ICG (0.5 mg/kg body weight). To visualize hepatic perfusion and segmental boundaries, ICG (1.25 mg) was injected intravenously during surgery, following closure of the proximal portal pedicle. A laparoscopic imaging system, which enabled superimposition of the pseudocolor-fluorescence images on white color images, was used for the fusion ICG-fluorescence imaging.

Among the 53 malignant tumors resected, fusion ICG-fluorescence imaging revealed 45 nodules (85%), including three nodules of colorectal liver metastasis unidentifiable by white-light color images or intraoperative ultrasonography. It also delineated the segmental boundaries on the hepatic raw surfaces as well as on the phrenic/visceral surfaces in all 12 patients evaluated using this technique.

Fusion imaging enhances the feasibility of intraoperative ICG-fluorescence imaging in the identification of hepatic tumors and segmental boundaries. It may therefore help surgeons in the safe and accurate completion of laparoscopic hepatectomies.