Quantitative ICG Fluorescence Angiography in Colorectal Surgery (QUANTICO): a Protocol for a Prospective, Standardized, Observational, Surgeon-blinded Multi-center Trial

Fluorescence angiography with indocyanine green (ICG-FA) has gained increased popularity in colorectal surgery to check perfusion to the newly-formed anastomotic area and decrease the rate of postoperative anastomotic leakage.

While qualitative ICG assessment has the advantage to be used instantly during the operative procedure, it does bear drawbacks (subjective assessment, dependent on factors like camera distance, ICG dose and white-light contamination).

The alternative is quantitative ICG assessment, which is performed by evaluating the time-intensity curve of the ICG-FA with an external analyzing software. The procedure is showing promising results, but the methodology is still reported very heterogeneously.

This study is a multi-center, prospective, standardized, surgeon-blinded observational trial. The key aspect of this study is the non-interventional design with blinding of both the qualitative and quantitative results from the ICG perfusion measurement, providing no chance of influencing the course of the operation. Assessment of perfusion will be performed postoperatively blinded to the outcome. Assessment of the pre-anastomotic area is intraoperatively performed by an image analysis software that then calculates a perfusion score based on an algorithm integrating relevant perfusion metrics. The primary outcome is the combined rate of early and late anastomotic complications within 90 days postoperatively.