Performance of two clinical fluorescence imaging systems with different targeted and non-targeted near-infrared fluorophores: a cadaveric explorative study

Lavinia E Chiti; Benjamin Husi; Brian Park; Patricia Beer; Faustine D'Orchymont; Jason P Holland; Mirja C Nolff

doi:10.3389/fvets.2023.1091842

Performance of two clinical fluorescence imaging systems with different targeted and non-targeted near-infrared fluorophores: a cadaveric explorative study

Front Vet Sci. 2023 Apr 17:10:1091842. doi: 10.3389/fvets.2023.1091842. eCollection 2023.

Authors

Lavinia E Chiti¹, Benjamin Husi¹, Brian Park¹, Patricia Beer¹, Faustine D'Orchymont², Jason P Holland², Mirja C Nolff¹

Affiliations

¹ Klinik für Kleintierchirurgie, Vetsuisse-Fakultät, University of Zurich, Zurich, Switzerland.
² Department of Chemistry, University of Zurich, Zurich, Switzerland.

Abstract

Introduction: Near-infrared (NIR) fluorescence-guided surgery is increasingly utilized in humans and pets. As clinical imaging systems are optimized for Indocyanine green (ICG) detection, the usage of targeted dyes necessitates the validation of these systems for each dye. We investigated the impact of skin pigmentation and tissue overlay on the sensitivity of two NIR cameras (IC-Flow^TM, Visionsense^TM VS3 Iridum) for the detection of non-targeted (ICG, IRDye800) and targeted (Angiostamp^TM, FAP-Cyan) NIR fluorophores in an ex vivo big animal model.

Methods: We quantitatively measured the limit of detection (LOD) and signal-to-background ratio (SBR) and implemented a semi-quantitative visual score to account for subjective interpretation of images by the surgeon.

Results: Visionsense^TM VS3 Iridum outperformed IC-Flow^TM in terms of LOD and SBR for the detection of all dyes except FAP-Cyan. Median SBR was negatively affected by skin pigmentation and tissue overlay with both camera systems. Level of agreement between quantitative and semi-quantitative visual score and interobserver agreement were better with Visionsense^TM VS3 Iridum.

Conclusion: The overlay of different tissue types and skin pigmentation may negatively affect the ability of the two tested camera systems to identify nanomolar concentrations of targeted-fluorescent dyes and should be considered when planning surgical applications.

Keywords: cat; dog; imaging system assessment; molecular probe; near infrared; surgical oncology.

Grants and funding

JH thanks the European Union's Horizon 2020 research and innovation programme/from the European Research Council (grant no. 101001734, ERC-CoG-2020, PhotoPHARMA) for financial support.