Intraoperative ICG-based imaging of liver neoplasms: a simple yet powerful tool. Preliminary results
Detecting small nodules that are grossly unidentifiable remains a major challenge in liver resection for cancer. Novel developments in navigation surgery, especially indocyanine green (ICG)-based fluorescence imaging, are making a clear breakthrough in addressing this issue. ICG is almost routinely administered during the preoperative stage in hepatobiliary surgery. However, its full potential has yet to be realized, partly because there are no precise guidelines regarding the optimal dose or timing of ICG injections before liver surgery. The main goal of this study was to design an algorithm for the management of ICG injections to achieve optimal liver staining results.
Twenty-seven consecutive, unselected patients undergoing liver resection for cancer were enrolled and underwent preoperative liver function assessment by the LiMON test. Extra ICG i.v. injections at different doses and timings were performed. In vivo intraoperative analysis of the stain detected by near-infrared fluorescence imaging of the liver and ex vivo analysis of each resected nodule was performed and compared to the pathological analysis.
(i) The success rate of ICG injections in terms of liver staining was 92.6%; (ii) in the absence of or with 7 or more days from a previous ICG injection, the best dose to inject before the operation was 0.2 mg/kg, and the best timing was between 24 and 48 h before the scheduled surgery; and (iii) the ICG fluorescence patterns observed in the tumors were total fluorescence staining (41% of the cases), partial fluorescence staining (15%), rim fluorescence staining surrounding the tumor (30%), and no staining (15%).
This study is a building block for the characterization of liver nodules and the search for additional surface lesions undetected by preoperative radiological work-up—a crucial task for the successful treatment of liver cancer at an early stage using a safe, minimally invasive, and inexpensive technique.
KeywordsFluorescence imaging Intraoperative imaging Indocyanine green Liver cancer Navigation surgery
This study was supported by the University Hospital of Brescia (Spedali Civili di Brescia), Italy, the University of Brescia, and RicerChiAmo onlus (http://www.ricerchiamobrescia.it). The equipment used in this study was made available by both Karl Storz and Stryker companies.
GLB developed the original idea and methodology of the project and made substantial contributions to the manuscript. MSA wrote the first draft of the paper and incorporated the conceptual feedback sent by the coauthors. SM, SB, BM, PP, and EA collected intraoperative images and performed the literature search and review. NP, FG, and MB made scientific contributions to the project and critically revised the manuscript.
Compliance with ethical standards
GL Baiocchi was the scientific organizer of the international workshop “Intraoperative ICG Fluorescence Imaging in Hepatobiliary and Visceral Surgery: State of the Art and New Frontiers,” (Brescia, Italy, October 21, 2017) partly funded (travel expenses) by Karl Storz and Stryker companies though he has no direct conflict of interest with the content discussed in this manuscript. Drs. MS Alfano, S Molfino, S Benedicenti, B Molteni, P Porsio, E Arici, F Gheza, Profs. M Botticini, and N Portolani have no conflicts of interest or financial ties to disclose.
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