HPB P35 Fluorescence guided resection of Liver Tumours: Same day administration of indocyanine green with SPY- Colour Segmented Fluorescence imaging to identify tumours intra-operatively

Abstract

Indocyanine green (ICG) fluorescence imaging is a real-time navigation tool that has shown promising liver surgery results. Several regimes have been described regarding optimum timing and dose of ICG administration. Visually different fluorescent enhancement patterns correlate with different pathologies to aid the identification of lesions intra-operatively. This study aims to present our experience with using the Colour Segmented Fluorescence (CSF) model and same-day administration of low dose ICG in the resection of liver tumours. We present a single surgeon (SA) experience using indocyanine green fluorescence image-guided surgery (I-FIGS) at University Hospitals Plymouth, UK. I-FIGS was used between November 2020 and March 2022 in 15 patients with suspected liver tumours. ICG was administered intravenously at a dose of 0.02 to 0.03 mg/kg IV 2–3 hours prior to liver surgery. Using the SPY CSF mode, the image is scaled to NIRF fluorescence intensity to identify the liver tumours and their margins intra-operatively. A total of fifteen patients (eight males) with a median age of 71 years (36–86) underwent I-FIGS during the study period. Of these, 67% underwent laparoscopic liver surgery, 78% underwent non-anatomical resections, and 33% underwent re-do liver surgery. The average size of the tumour was 40.6 mm, and median number of tumours was one. All lesions were visible in CSF mode, and all had a signet ring appearance. The histology of the tumours confirmed a well to moderately differentiated colorectal metastasis in 13 (86%) patients and hepatoma in two patients. R0 resection was achieved in 11 (76%) of patients. In two patients with R1 resection, the tumour was right on the right hepatic vein, and R0 would not have been possible. The resection margins were clear in two other patients but <1mm. The overall false positive rate in our experience with I-FIGS was 3%. In our limited experience, low-dose ICG administered at least 2–3 hours prior to surgery can accurately identify liver tumours and their margins in CSF mode. Superficially located lesions are easily identifiable under CSF mode, and CSF mode helped us identify the lesions and mark the resection margin. The use of ICG is an important advancement in liver surgery, and further research is needed to optimise image interpretation and correlate with clinical resection outcomes.