Intraoperative fluorescence image-guided pulmonary segmentectomy

Background The intraoperative color and fluorescence-merged imaging system (ICFIS) is a new technology that may aid the demarcation of intersegmental borders during pulmonary segmentectomy. This study was performed to validate, for the first time, image-guided segmentectomy using ICFIS and to find the optimal dosage of fluorescent dye to ensure safe and sustained imaging during surgery. Methods Nine rabbits were subjected to pulmonary segmentectomy. These constituted three groups of three rabbits each. After ligation of the segmental pulmonary artery supplying the targeted segment, the rabbits were injected intravenously with indocyanine green (ICG) at a concentration of 0.3, 0.6, or 3.0 mg/kg, depending on their group assignment. The optimal dose was determined from the rabbit study and then used to guide ICFIS during pulmonary segmentectomy in five pigs. Results The fluorescent signal contrast ratios of the targeted area to the normal lung using ICG concentrations of 0.3, 0.6, or 3.0 mg/kg were 1.9 ± 0.25, 2.0 ± 0.17, and 2.1 ± 0.06, respectively. The mean ICG washout times were 1, 3, and 6 min, respectively. Proceeding with an ICG concentration of 0.6 mg/kg, the mean washout time was found to be longer in pigs (15 min). This provided adequate time for successful ICFIS-guided segmentectomy in all five pigs, without the requirement for additional procedures for intersegmental plane demarcation. Conclusions ICG image-guided segmentectomy using ICFIS enabled immediate visualization of the intersegmental planes. The washout time using the ICG dose determined in this study was long enough to ensure that visualization was sustained throughout the surgery.