Exploring the clinical applicability of quantitative near-infrared fluorescence imaging with indocyanine green: towards objective and standardized assessment of tissue perfusion

Abstract

Inadequate tissue perfusion contributes to major surgical complications, including non-healing wounds, anastomotic leakage, and flap necrosis. Near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) enables real-time visualization of tissue perfusion, but clinical interpretation remains largely subjective. This thesis investigated the feasibility, clinical applicability, and standardization of quantitative ICG-NIRF imaging across vascular, gastrointestinal, and reconstructive surgery.

In patients with lower extremity arterial disease, quantitative perfusion changes after revascularization were associated with clinical improvement, while analysis of directly and indirectly revascularized angiosomes questioned the clinical relevance of the angiosome concept. In colorectal and oesophageal surgery, quantitative imaging was feasible and identified reproducible perfusion patterns, whereas subjective fluorescence assessment showed considerable interobserver variability. A multicenter randomized trial protocol was developed to evaluate fluorescence-guided perfusion assessment in breast reconstruction. Finally, reference curves for ten vital tissue types demonstrated that normalized perfusion patterns can be compared despite differences in imaging protocols.

Overall, quantitative ICG-NIRF imaging provides objective and broadly applicable perfusion information. Further standardization, automated analysis, and large outcome-driven multicenter studies are required before routine clinical implementation.