Novel method of intraoperative liver tumour localisation with indocyanine green and near-infrared imaging

Abstract

Introduction: Fluorescence imaging (FI) with indocyanine green (ICG) is increasingly implemented as an intraoperative navigation tool in hepatobiliary surgery to identify hepatic tumours. This is useful in minimally invasive hepatectomy, where gross inspection and palpation are limited. This study aimed to evaluate the feasibility, safety and optimal timing of using ICG for tumour localisation in patients undergoing hepatic resection.

Methods: From 2015 to 2018, a prospective multicentre study was conducted to evaluate feasibility and safety of ICG in tumour localisation following preoperative administration of ICG either on Day 0-3 or Day 4-7.

Results: Among 32 patients, a total of 46 lesions were resected: 23 were hepatocellular carcinomas (HCCs), 12 were colorectal liver metastases (CRLM) and 11 were benign lesions. ICG FI identified 38 (82.6%) lesions prior to resection. The majority of HCCs were homogeneous fluorescing lesions (56.6%), while CLRM were homogeneous (41.7%) or rim-enhancing (33.3%). The majority (75.0%) of the lesions not detected by ICG FI were in cirrhotic livers. Most (84.1%) of ICG-positive lesions detected were < 1 cm deep, and half of the lesions ≥ 1 cm in depth were not detected. In cirrhotic patients with malignant lesions, those given ICG on preoperative Day 0-3 and Day 4-7 had detection rates of 66.7% and 91.7%, respectively. There were no adverse events.

Conclusion: ICG FI is a safe and feasible method to assist tumour localisation in liver surgery. Different tumours appear to display characteristic fluorescent patterns. There may be no disadvantage of administering ICG closer to the operative date if it is more convenient, except in patients with liver cirrhosis.

Keywords: hepatobiliary surgery; indocyanine green; near-infrared imaging; tumour localisation.

Copyright: © Singapore Medical Association.

Figures

Fig. 1

(a) Diagram shows the principle of fluorescence imaging in tumour localisation: radiation from the light source is filtered by a high-pass filter to remove the fluorescent wavelengths; the blood and ICG suspension under a tissue absorbs the excitation wavelengths and emits a fluorescent band; and the emitted light is received by the sensor through a low-pass filter to remove the excitation light reflected from the source.(35) Charts show the distribution of (b) pathological types in ICG-positive lesions; (c) fluorescence patterns in hepatocellular carcinomas; and (d) fluorescence patterns in colorectal liver metastases. CLRM: colorectal liver metastases; HCC: hepatocellular carcinoma; ICG: indocyanine green

Fig. 2

A hepatocellular carcinoma (HCC) located in segment 6 during open segment 6 wedge resection. Intraoperative (a) fusion fluorescence image and (b) NIR camera photograph show (a & b) the HCC visualised intraoperatively following a preoperative intravenous injection of indocyanine green. (c) Fluorescence image shows the resected specimen with a rim-enhancing pattern. (d) US image shows the HCC lesion intraoperatively.

Fig. 3

A patient with colorectal liver metastasis in segment 4/5 received a preoperative intravenous injection of indocyanine green. (a) Fusion fluorescence imaging shows a homogeneous pattern clearly delineating the metastatic liver lesion. (b) Monochromatic fluorescence image shows the resected liver specimen corresponding to the metastatic liver lesion. (c) Photograph shows the resected liver specimen consisting of segment 4/5 with the metastatic lesion on the liver surface. (d) US image shows the lesion intraoperatively.