Discussion
With the clinical application of novel technologies in recent years, many standard procedures should be updated accordingly. In this study, a clinical trial was designed to investigate the optimal ICG dose suitable for use with a 4K fluorescent system for real‐time fluorescent cholangiography in LC. The data showed that, with a 4K fluorescent system, an ICG dose ranging from 10 to 25 µg by intravenous administration within 30 min preoperatively was appropriate for real‐time fluorescent cholangiography during LC. Compared to the dose of ICG used with 2D high-definition fluorescent systems [Dose, time interval, and the administration route of ICG are the three key factors that affect the cholangiographic effect during LC [Because of the high sensitivity of the 4K system, a lower dose of ICG than used with the HD system was proposed. The verified ICG dose (0.1 mg of ICG) used with the HD system was found unsatisfactory in the 4K system, as it showed a high background in the liver. Therefore, four different ICG doses (1, 10, 25, and 100 µg) were evaluated in this study. The data demonstrated that an ICG dose ranging from 10 to 25 µg was appropriate for real‐time fluorescent cholangiography in LC. The very-low dosage of ICG in our trail was extremely different from the previously reported studies. Most of those studies utilized dosage of 2.5 mg [According to the data of our trial, the FIs in the liver background and bile duct were ICG dose-independent, consistent with previously reported research [This study has several limitations. One of the limitations was that no follow-up data were analyzed. However, it is acceptable for this study, because we focused on fluorescent cholangiography during the surgery for navigational purposes. Furthermore, the enrolled sample size is small. We did not take the body weight factor into account in this single-center study for no significant differences of the body mass index among the four groups (Table 