Quantification of near-infrared fluorescence imaging with indocyanine green in free flap breast reconstruction

Background: One of the complications of free flap breast reconstruction is the oc-currence of skin and fat necrosis. Intra-operative use of near-infrared (NIR) fluorescence imag-ing with Indocyanine Green (ICG) has the potential to predict these complications. In this study, the quantification of the fluorescence intensity measured in free flap breast reconstruction was performed to gain insight into the perfusion patterns observed with ICG NIR fluorescence imag-ing.Methods: ICG NIR fluorescence imaging was performed in patients undergoing free flap breast reconstruction following mastectomy. After completion of the arterial and venous anastomosis, 7.5 mg ICG was administered intravenously. The fluorescence intensity over time was recorded using the Quest Spectrum Platform (R). Four regions of interest (ROI) were selected based on location and interpretation of the NIR fluorescence signal: (1) The perforator, (2) normal per -fusion, (3) questionable perfusion, and (4) low perfusion. Time-intensity curves were analyzed, and two parameters were extracted: Tmax and Tmax slopes.Results: Successful ICG NIR fluorescence imaging was performed in 13 patients undergoing 17 free flap procedures. Region selection included 16 perforators, 17 normal perfusions, 8 ques-tionable perfusions, and 5 low perfusion ROIs. Time-intensity curves of the perforator ROIs were comparable to the ROIs of normal perfusion and demonstrated a fast inflow. No outflow was observed for the ROIs with questionable and low perfusion.Conclusion: This study provides insight into the perfusion patterns observed with ICG NIR flu-orescence imaging in free flap breast reconstruction. Future studies should correlate quantita-tive parameters with clinical perfusion assessment and outcome.(c) 2022 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Pub-lished by Elsevier Ltd. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )