Quantitative Assessment of the Blood Perfusion of the Gastric Conduit by Indocyanine Green Imaging

Background: Indocyanine green (ICG) fluorescence imaging has been used to assess the blood perfusion of the gastrointestinal tract in surgery. Especially, it was used to determine the best anastomotic site. However, in previous studies, ICG fluorescence was judged subjectively based on the visual appearance. This study evaluated the usefulness of our novel method to quantitatively assess the blood perfusion of the gastric conduit in esophagectomy based on ICG fluorescence. Materials and methods: Twenty patients who underwent esophagectomy with gastric conduit reconstruction were prospectively investigated. Using a camera in contact with the surface of the stomach, ICG images were quantitatively evaluated using ROIs, a software program that quantified the fluorescence intensity and created a time-fluorescence intensity curve to assess the blood perfusion three times intraoperatively. Results: No postoperative esophago-gastrostomy leakage developed. However, after preparing the gastric conduit and just before anastomosis, the maximum increase in fluorescence intensity (Flmax) significantly decreased (48.8 +/- 26.0 and 31.5 +/- 14.9 versus 84.9 +/- 28.2; P < 0.001 and P < 0.001, respectively), and the time to reach Flmax was significantly extended (60 +/- 35.4 and 58.3 +/- 34.9 versus 18.9 +/- 6.5; P < 0.001 and P < 0.002, respectively), in comparison to the control value. Just before anastomosis, 18 cases (90%) showed an identical pattern characterized by an obtuse and low arterial inflow peak and a slow rise of fluorescence intensity over time, indicating a decreased blood flow. Conclusions: The quantitative analysis of ICG fluorescence imaging could objectively prove a decrease in blood perfusion-which could not be determined macroscopically-in the gastric conduit before esophageal reconstruction. The results from the present and further studies may indicate its clinical value. (C) 2018 Elsevier Inc. All rights reserved.