Use Of ICG In Liver - Diagnostic Green AM

With primary liver cancer and colorectal liver metastases amongst the most common leading causes of cancer-related deaths worldwide, surgery represents one of the main treatments to
obtain the best results in overall and disease free survival.¹

ICG in recent years has experienced increased interest in use for its clearance parameters as a dynamic
assessment of liver function both in medical and surgical settings.²

ICG is used routinely to evaluate hepatic function and liver blood flow.³ It is one of the most common and easy-to-use tests for the perioperative dynamic assessment of liver function in cases of major liver surgery (resective surgery and liver transplantation) and in the intensive care unit.

Use of ICG in Liver Function Diagnostics include:

- Measurement of excretory function of the liver Measurement of liver blood flow
- ICG is a tricarbocyanine dye with both hydrophilic and lipophilic properties.

While numerous clinical parameters are used to assess a patient’s liver function, the ICG test is the gold standard and is the only established test for estimating true global liver function.⁴

Assessment of dynamic liver function is crucial in the pre-operative preparation of those who require extensive liver resections, liver transplants and also to monitor liver function in a post-operative setting.

The ICG clearance or the elimination test is the most widely used quantitative liver function test. Following the administration of ICG I.V., serial blood samples are collected at 5, 15, 20, 25 & 30 mins. The ICG blood levels fall exponentially for about 20mins, by which time approximately 97% of the ICG is excreted. After processing the samples, the ICG-R15 (at 15 mins) is determined as a percentage.

QUANTITATIVE MEASUREMENT

ICG Retention 15mins (ICG-R15) (Normal <10%)
Pulse Dye Densitometry – LiMON device
ICG Plasma Disappearance Rate (ICG-PDR) (Normal > 18%/min)⁵

ICG CLEARANCE TESTS

Pre and post Liver Resections
Pre and post Liver Transplant Surgery
Acute Liver Failure (ICU setting)

LAPAROSCOPIC LIVER RESECTION (LLR)

Since the first Laparoscopic Liver Resection (LLR) was first preformed in 1991, the number of LLR’s has increased with the advancements of surgical techniques and technology. LLR for Hepatocellular Carcinoma (HCC) is now considered standard treatment for minor liver resection.⁶ Laparoscopic surgery and robotic surgery have solved the issue of large incisional wounds, a major drawback of open liver surgery.⁷

While there are significant advantages associated with a laparoscopic technique (less bleeding, shorter length of hospital stay, decreased morbidity and possibly lower
mortality), adoption by a surgeon does mean that the ability to touch and palpate the organ is eliminated. By using ICG in these circumstances, increasing the visualisation of the anatomy adds enormously to procedure success.

ICG USE IN TREATMENT FOR HEPATOCELLULAR
CARCINOMA (HCC)

Over the last few decades, imaging technologies in hepatobiliary (HPB) surgery have become indispensable tools for liver surgeons. The ICG fluorescence imaging (FI) technique helps to guide the hepatic surgical procedures and provides the surgeon with real-time visualisation of the fluorescent structures of interest that would be invisible under conventional white light.

The extrahepatic bile duct anatomy and liver tumours can be emphasised, and hepatic segments highlighted, based on the fluorescence property of ICG and its biliary excretion.

COLORECTAL LIVER METASTASES AND LIVER TRANSPLANT USE OF ICG

Additionally, a recent retrospective multi-center analysis of 174 patients showed that the use of ICG identifies significantly more and smaller tumours during colorectal liver metastases (CRLM) resection.⁸ For liver transplantation, use of ICG has shown to be the best curative treatment of chronic liver diseases/HCC/acute liver failure. Increasing the use of marginal grafts can lead to increased incidence of primary non-function (PNF) after transplantation with few early predictors available for PNF. By undertaking quantitative assessment of intra-operative ICG fluorescence on the graft, a 2020 study has shown that it was feasible to predict graft survival at three months with good sensitivity and specificity.⁹

Italy snapshot of LLR surgeries in practice

LLR represents 10.3% of all Liver Resections (1677 cases)
Malignant lesions 72.5% (1085 cases)
56% – Hepatocellular Carcinoma (HCC)
28% – Colorectal Liver Metastases (CRLM)
Overall mortality 0.2%
Mean length of stay is five days

SUMMARY OF ICG IN LIVER SETTING

Liver Function Assessment – Pre & Post Op
Intra-operative identification of anatomic
liver segments
After reconstruction of hepatic vessels –
assessment of liver inflow and outflow of
blood
Useful for real-time detection of bile leaks
during liver resection
Visualization of Liver Tumors (HCC & CRLM)

ICG USE – BENEFITS TO THE SURGEON

Real time visualization of anatomical
structures
Simple method to evaluate hepatic
function
Allows for safe use of marginal liver grafts
Easy to use test for dynamic assessment of
liver blood flow
Helps identify more and smaller colorectal
tumors
Quantitative liver function test

Note: All references are available in our brochure download

Use of IC-Green® (indocyanine green injection) In Liver