Quantitative Analysis of Colonic Perfusion Using ICG Fluorescence Angiography and Its Consequences for Anastomotic Healing in a Rat Model

Simple Summary Although indocyanine green (ICG) fluorescence angiography has been widely used to prevent anastomotic leakage (AL) in recent years, its usefulness remains unclear. The purpose of this study was to investigate whether quantitative analysis of colonic perfusion using ICG angiography could predict AL in a rat AL model. In the quantitative assessment, the following five parameters were calculated: Fmax (fluorescence difference between maximum and baseline), Tmax (time from onset to maximum), T-1/2 (time from onset to half of maximum), Slope (Fmax/Tmax), and TR (T-1/2/Tmax). Using a rat AL model, we found that there was a significant difference between the AL group and non-AL group in terms of Fmax, Tmax, T-1/2, and Slope. In particular, Slope could be useful to predict AL. Forty-three rats were randomly assigned to the following four groups: non-ischemic group (Control Group), 1 cm-long ischemic group (Group 1), 2 cm-long ischemic group (Group 2), and 3 cm-long ischemic group (Group 3). The rates of AL were 0% (0/10) in the Control Group, 22.2% (2/9) in Group 1, 25% (2/8) in Group 2, and 50% (4/8) in Group 3. The bursting pressure of the Control Group was significantly higher than that of the other groups (p < 0.01). Regarding the pathological findings, the granulation thickness and the number of blood vessels at the anastomosed site were significantly higher in the Control Group than in Group 3 (p < 0.05). Receiver operating characteristics analysis revealed that Slope was the most significant predictor of AL, with an area under the curve of 0.861. When the cutoff value of Slope was 0.4, the sensitivity and specificity for the prediction of AL were 75% and 81.4%, respectively. Quantitative analysis of ICG fluorescence angiography could predict AL in a rat model.