Influencing Factors Of Indocyanine Green Fluorescence Imaging In Hepatobiliary Surgery

BackgroundIndocyanine green(ICG)is a widely used near-infrared fluorescent dye,mainly applied to visualization of liver tumors,liver segment and biliary tract in hepatobiliary surgery,so that surgeons can more easily and accurately identify liver tumors and more precisely perform hepatectomy.However,the application experience of ICG is still lacking in hepatobiliary surgery and problems still exist.For example,it is not uniform of the time and dose of preoperative ICG administration,and the impact stays unsure of patients’ liver cirrhosis grade and different hepatobiliary diseases on ICG clearance,which deserves further research.Therefore,there still lacks agreement of norms and standards for ICG administration before laparoscopic hepatobiliary surgery at home and abroad.In order to explore the factors that affect the fluorescent imaging characteristics of liver and tumors,we designed this prospective clinical study to detect the influencing factors of the fluorescence effect,so as to reduce the failure probability of fluorescence staining.So that the indocyanine green fluorescence imaging technology can maximize its advantage and value in hepatobiliary surgery.MethodsThis study prospectively included patients who were scheduled to undergo laparoscopic surgery due to liver tumors or cholelithiasis.Laboratory examinations were performed within one week before surgery,including liver and kidney function,coagulation indicators,tumor indicators,hepatitis indicators,etc.For every participant,ICG was injected intravenously at a dose of 5 mg the day before surgery.Based on surgical images,the fluorescence intensity(FI)of liver,gallbladder,tumor,and peri-tumor tissue were measured by specific software.Multiple linear regression was used to analyze the correlation between FI and preoperative indicators and regression equations were established for predicting the fluorescence intensity.Statistical analysis was carried out using SPSS 26 and the P value less than 0.05 was considered statistically significant.ResultsA total of 112 patients were enrolled in this study from May 2020 to January 2021,all of whom underwent hepatobiliary surgery guided by intraoperative ICG fluorescence imaging.Among them,67 patients(59.8%)were diagnosed with liver tumors and 45(40.2%)with cholelithiasis.The ICG clearance effect of liver in 91 cases(81.3%)was good,and in 21 cases(18.7%)was poor.Correlation analysis showed a strong correlation between the subjective fluorescence effect and the objective fluorescence intensity of liver(FI-L)and the optimal cut-off value of FI-L equaling 27 could serve as a boundary value for equivalent evaluation to subjective liver fluorescence effect.Correlation analysis results indicated that the factors showing strong correlation with FI-L were mainly hepatic function injury indicators and biliary obstruction indicators.The result of multiple linear regression analysis showed that the factors for predicting FI-L were direct bilirubin(DBil),prothrombin activity(PTA)and carbohydrate antigen 199(CA199).The obtained linear regression equation was written as FI-L=-46.473+1.367×DBil+0.587×PTA+0.055×CA199,which could be used to predict FI-L and showed statistical significance(P<0.001).Similar predictive linear models were also established in the subgroups of liver tumor and cholelithiasis,both of which were statistically significant.T test was performed to compare FI-L of two groups of patients with different dosing time interval less or more than 20 h.The result showed that the average liver fluorescence intensity of patients in the long time interval group was lower than that in the other group(19.2 vs 35.2),indicating that prolonging the preoperative ICG injection time might conduce to obtain a better liver fluorescence effect,but the difference was not statistically significant(t=1.494,P=0.146).In addition,a rare phenomenon of fluorescent staining was unexpectedly observed during laparoscopic hepatectomy guided by ICG fluorescence imaging.We reported these four cases with local cholestasis manifesting the unusual fluorescent staining phenomenon in the current study.ConclusionsThe current study explored the influencing factors of intraoperative ICG fluorescence effect,and established a prediction model of the fluorescent intensity of liver.According to the predicted liver fluorescence effect before surgery,the dosage or medication time of ICG can be adjusted appropriately in advance to reduce the failure rate of intraoperative fluorescent staining.In addition,we observed a rare fluorescent phenomenon duing the research process,which manifested a large-area fluorescence of the liver segment or sub-segment where the tumor was located.This phenomenon can be caused by local cholestasis which is related to tumor infiltration or compression,stone obstruction,local inflammation or bile duct thrombus.Complete removal of the lesion and cholestatic liver parenchyma may conduce to radical excision and reduce the recurrence rate after surgery.