P-L15 Fluorescence guided laparoscopic resection of Colorectal Liver Metastases: Same day administration of indocyanine green with use of SPY- Colour Segmented Fluorescence imaging to identify tumours intra-operatively

Abstract

Abstract Background Near-infrared fluorescent (NIRF) imaging using indocyanine green (ICG) has various applications in minimally invasive surgery. There are a number of techniques in timing and dose administration. Visually different fluorescent enhancement patterns correlate with different pathologies to aid identification of lesions intra-operatively. The aim of this study is to present our experience with utilisation of Colour Segmented Fluorescence ICG mode in laparoscopic liver surgery for colorectal liver metastases. Methods We present a single surgeon (SA) experience with the use of laparoscopic fluorescence guided imaging surgery (L-FGIS). Between November 2020 and July 20201, L-FGIS was used in seven patients with suspected CRLM. ICG was administered intravenously at a dose of 0.2 to 0.3 mg/kg IV 2-3 hours prior to liver surgery. Through use of the SPY Colour Segmented Fluorescence (CSF) imaging mode, the image is scaled as to NIRF fluorescence intensity to allow for the clear identification of the CRLM intra-operatively. Results A total of seven patients (Four males) with median age of 74.3 years (range: 30.5 -86) underwent L-FGIS during the study period. Two out of seven patients underwent re-do liver surgery. The median size of the tumour was 27mm (range: 10-65mm) and median number of tumours were one (range: 1-2). To visualise the tumour and to avoid interference of green background liver, ICG camera was switched to CSF mode. All lesions had signet ring appearance under CSF mode (see figure 1). Except in one patient (necrotic lesion), the histology of resected specimen contained a well to moderately differentiated colorectal adenocarcinoma metastasis. R0 resection was achieved in all patients and median clearance of the tumour was 3mm (range 0.4-10mm). Conclusions In our limited experience ICG administered at least 2-3 hours prior to surgery can identify superficially located colorectal metastases, provided ICG camera is switched to CSF mode. Superficially located lesions are easily identifiable under CSF mode. CSF mode helped us to identify the lesions and to mark the resection margin. The use of ICG is an important advancement in CRLM surgery and further research is needed to optimise image interpretation and correlate with clinical resection outcomes.