Intraoperative Real-Time Assessment of Liver Function with Near-Infrared Fluorescence Imaging

Abstract

Background: Postoperative liver failure is a serious complication after major hepatectomy, and perioperative prediction of its incidence using current technology is still very difficult. Near-infrared (NIR) fluorescence imaging allows quantitative assessment of the fluorescent signal from indocyanine green (ICG) in regions of interest on the liver surface. This method might offer a new promising modality for evaluating regional liver reserve. However, data are lacking regarding the relationship between liver function and fluorescent signals on the liver surface after intravenous ICG injection. This study was conducted to obtain the data necessary to apply NIR fluorescence imaging as a modality for measuring liver function. Materials and Methods: This study included 16 patients who underwent open hepatopancreatobiliary surgery between March 2011 and March 2012. After laparotomy, ICG was injected intravenously at 2.5 mg/L of liver volume, then the fluorescence intensity (FI) and signal-to-background ratio (SBR) in the lateral segment of the liver were assessed for 15 min. Intraoperative blood samples were also obtained to measure the plasma clearance rate of ICG (ICGK). Correlations between ICGK, liver volume, and SBR, as well as between ICGK, liver volume, and rate of change of FI were analyzed. Results: The experimental procedure was performed in all 16 patients. The FI of the liver increased rapidly after ICG injection, then became more gradual, reaching a near-plateau after 15 min. A significant correlation was seen between ICGK and the rate of change of FI up to 15 min (|rS| = 0.5725, p < 0.05). Conclusion: This is the first report to show a relationship between liver function and fluorescent signals on the liver surface after intravenous ICG injection. Intraoperative NIR fluorescence imaging with ICG may be useful as a new method for assessing liver function.

Indocyanine Green Fluorescence Imaging to Predict Graft Survival After Orthotopic Liver Transplantation: A Pilot Study

“…Quantitative assessment of the global hepatic function using this imaging technique was only reported by Narasaki et al ( 13 ) They reported that the FI on the liver surface was not correlated with the global hepatic function measured by plasma clearance rate of indocyanine green (ICGK) at 15 minutes. This lack of correlation resulted from an interindividual variability in factors that can influence FI by absorption and scattering of NIR fluorescent light, such as the presence of liver steatosis or fibrosis.…”

“…First, this parameter was measured for only a few seconds during LT, and the consequence of some possible biases, such as hemodynamic instability or the possible effects of anesthetic agents during general anesthesia, are not yet known on the pharmacokinetics of ICG. ( 13 ) For this reason, all measurements were performed on hemodynamically stable patients (pressor amines permitted) because severe instability, being itself a risk factor for PNF, could bias ICG interpretation. Second, the indication for re‐LT is a serious decision with severe consequences for the patient with higher morbidity and mortality.…”

“…(4) The early intraoperative prediction of PNF was also clinically very relevant to quickly identify patients needing a retransplantation in emergency. (24) This exponential model has the advantage of fitting the measured FI curve with greater accuracy than the model of Narasaki et al (13) The restriction of recording to 150 seconds allowed the values obtained to be homogenized and gave the same weight to the beginning of the fluorescent curve for all videos. Moreover, a short acquisition duration was a minimal extra time compared with the operative time, making it more easily acceptable to the surgical team and safe for the patient.…”

“…This technique has also been reported to assess liver function, by a quantitative analysis of parenchymal fluorescence intensity (FI) before hepatic resection. (13)(14)(15) To the best of our knowledge, quantitative analysis of intraoperative ICG fluorescence imaging has never been used in the LT setting as a predictor of graft survival.…”

Near-infrared fluorescence laparoscopy of the ureter with three preclinical dyes in a pig model

“…The use of near-infrared fluorescence (NIRF) imaging might be able to meet this need. This technique is already used in hepatobiliary surgery to visualize the bile ducts [8] or the perfusion of the liver [9], and in colorectal surgery to assess the perfusion of the bowel anastomosis [10–15]. A few studies have also been published on the use of NIRF imaging to identify the ureters.…”