Intraoperative Multimodal Bowel Perfusion Quantification Combining Hyperspectral Imaging and Indocyanine Green

Background/Objectives: Intraoperative perfusion imaging can support determining the anastomosis site to avoid leakages after colorectal surgery. Indocyanine green–fluorescence angiography (ICG-FA) and hyperspectral imaging (HSI) have been used recently but suffering from different drawbacks. A comparison of quantitative perfusion parameters from both modalities should substantiate the relevance of HSI next to ICG-FA. A computational framework combining ICG-FA and HSI should be developed to overcome system-specific disadvantages. Methods: ICG-FA and HSI were performed in 26 non-consecutive patients undergoing any colorectal surgery at the University Hospital of Leipzig between November 2022 and December 2023 to compare the position of the transition between well- and poorly perfused areas in both imaging modalities, as well as to compare quantitative perfusion parameters. Hyperspectral data was acquired before, during, and after ICG-FA to reconstruct an ICG-mimicking image from HSI data for future combined applications. This approach was further tested by investigating the influence of ICG on HSI-derived tissue parameters. Results: Anastomotic leakage occurred in one case. Compared to the clinical assessment, the median position of the transection margin was 0.1 cm more proximal, 0.15 cm more proximal, and 0.36 cm more distal for ICG, reconstructed ICG, and HSI, respectively. The reconstructed ICG image resembled the ground truth in 21 cases. ICG did not show any relevant influence on HSI parameters. Conclusions: The results indicated subtle differences between ICG-based blood flow and HSI-derived tissue oxygenation visualisation, which can be combined for comprehensive intraoperative perfusion analyses using one HSI system only and an ICG-related signal reconstruction framework. Further studies need to address dose and the time dependencies of the combined usage of HSI and ICG.