Intraoperative ICG fluorescence contrast imaging of the main artery watershed area in colorectal cancer surgery: Report of a case. Int J Surg Case Rep. 2016;26:176-178. [PMID: 27497042 PMCID: PMC4976611 DOI: 10.1016/j.ijscr.2016.06.009]

Quantitative evaluation of anastomotic perfusion during colorectal surgery via indocyanine green fluorescence angiography: a narrative review

Background and Objective

Quantitative studies of indocyanine green (ICG) are needed to optimize its evaluative potential in anastomotic perfusion during colorectal surgery. However, some limitations still existed in current studies about qualitative evaluations such as small-scale studies, the inconsistent concentration of the drug, the method of injection, etc. Therefore, this review summarized the primary quantitative parameters, image, method, and so on, during ICG fluorescence angiography aiming to further provide a theoretical basis for the application of ICG in laparoscopic colorectal surgery.

Methods

The following keywords "indocyanine green or ICG", "anastomotic perfusion", and "colorectal surgery" were applied to search for literature published from 2002 to 2022 in the PubMed, Web of Science, and Medline databases. Then, the information about ICG fluorescence angiography in quantitative evaluation of anastomotic perfusion during colorectal surgery was summarized. Through integrating the experiences derived from the literature and our research center, the crucial quantitative parameters [such as T0, Tmax, Fmax, and S (Fmax/Tmax)], image characteristics, and standard operational process for ICG fluorescence angiography were summarized.

Key Content and Findings

Firstly, quantitative parameters, including T0, Tmax, Fmax, and S (Fmax/Tmax) during the ICG fluorescence angiography could predict anastomotic leakage, and thus should be recorded. Secondly, the image curve generated by the software might differ among patients, which included a filling period, reducing period, and platform period; some patients even presented a second fluorescence intensity peak. Finally, present studies presented great heterogeneity regarding the injection dose of ICG, observation distance from the laparoscope to the anastomotic site, software, and so on, during ICG fluorescence angiography in quantitatively evaluating the intestinal blood perfusion.

Conclusions

This review points out the challenges of ICG fluorescence angiography in quantitative evaluation of anastomotic perfusion and gives some advice. However, some difficulties and issues are non-neglectable during the clinical implications of the quantitative evaluation of ICG, such as standardizing the specific cut-off value about the quantitative parameters, injection dose of ICG, observation distance from the laparoscope to the anastomotic site, software, and so on, during ICG fluorescence angiography in quantitatively evaluating the intestinal blood perfusion to eliminate heterogeneity.

Minimally Invasive Management of Diverticular Disease

Traditionally, management of complicated diverticular disease has involved open damage control operations with large definitive resections and colostomies. Studies are now showing that in a subset of patients who would typically have undergone an open Hartmann's procedure for Hinchey III/IV diverticulitis, a laparoscopic approach is equally safe, and has better outcomes. Similar patients may be good candidates for primary anastomosis to avoid the morbidity and subsequent reversal of a colostomy. While most operations for diverticulitis across the country are still performed open, there has been an incremental shift in practice toward minimally invasive approaches in the elective setting. The most recent data from large trials, most notably the SIGMA trial, found laparoscopic sigmoid colectomy is associated with fewer short-term and long-term complications, decreased pain, improvement in length of stay, and maintains better cost-effectiveness than open resections. Some studies even demonstrate that robotic sigmoid resections can maintain a similar if not more reduction in morbidity as the laparoscopic approach while still remaining cost-effective. Intraoperative approaches also factor into improving outcomes. One of the most feared complications in colorectal surgery is anastomotic leak, and many studies have sought to find ways to minimize this risk. Factors to consider to minimize incidence of leak are the creation of tension-free anastomoses, amount of contamination, adequacy of blood supply, and a patient's use of steroids. Techniques supported by data that decrease anastomotic leaks include preoperative oral antibiotic and mechanical bowel prep, intraoperative splenic flexure mobilization, low-tie ligation of the inferior mesenteric artery, and use of indocyanine green immunofluorescence to assess perfusion. In summary, the management of benign diverticular disease is shifting from open, morbid operations for a very common disease to a minimally invasive approach. In this article, we review those approaches shown to have better outcomes, greater patient satisfaction, and fewer complications.

Artificial intelligence based real-time microcirculation analysis system for laparoscopic colorectal surgery

BACKGROUND

Colonic perfusion status can be assessed easily by indocyanine green (ICG) angiography to predict ischemia related anastomotic complications during laparoscopic colorectal surgery. Recently, various parameter-based perfusion analysis have been studied for quantitative evaluation, but the analysis results differ depending on the use of quantitative parameters due to differences in vascular anatomical structure. Therefore, it can help improve the accuracy and consistency by artificial intelligence (AI) based real-time analysis microperfusion (AIRAM).

AIM

To evaluate the feasibility of AIRAM to predict the risk of anastomotic complication in the patient with laparoscopic colorectal cancer surgery.

METHODS

The ICG curve was extracted from the region of interest (ROI) set in the ICG fluorescence video of the laparoscopic colorectal surgery. Pre-processing was performed to reduce AI performance degradation caused by external environment such as background, light source reflection, and camera shaking using MATLAB 2019 on an I7-8700k Intel central processing unit (CPU) PC. AI learning and evaluation were performed by dividing into a training patient group (n = 50) and a test patient group (n = 15). Training ICG curve data sets were classified and machine learned into 25 ICG curve patterns using a self-organizing map (SOM) network. The predictive reliability of anastomotic complications in a trained SOM network is verified using test set.

RESULTS

AI-based risk and the conventional quantitative parameters including T_1/2max, time ratio (TR), and rising slope (RS) were consistent when colonic perfusion was favorable as steep increasing ICG curve pattern. When the ICG graph pattern showed stepped rise, the accuracy of conventional quantitative parameters decreased, but the AI-based classification maintained accuracy consistently. The receiver operating characteristic curves for conventional parameters and AI-based classification were comparable for predicting the anastomotic complication risks. Statistical performance verifications were improved in the AI-based analysis. AI analysis was evaluated as the most accurate parameter to predict the risk of anastomotic complications. The F1 score of the AI-based method increased by 31% for T_1/2max, 8% for TR, and 8% for RS. The processing time of AIRAM was measured as 48.03 s, which was suitable for real-time processing.

CONCLUSION

In conclusion, AI-based real-time microcirculation analysis had more accurate and consistent performance than the conventional parameter-based method.

Intraarterial indocyanine green (ICG) fluorescence augmentation by marking embryonal resection areas in colorectal surgery: a feasibility study in a porcine model

Aim: In this pilot animal study we examined whether it is possible to visualize the embryonal resection layers by using intraarterial indocyanine green (ICG) staining when performing total mesorectal excision (TME) for carcinoma of the rectum. Material and methods: We injected ICG into the inferior mesenteric artery (AMI) of four swines to see whether the watershed area of the arterial supply zone can be sufficiently visualized by fluorescence imaging in order to mark the right dissection area along the fascia parietalis before and during resection. Results: We observed a fluorescence signal in all the supplied areas of AMI but not in other parts of the abdominal cavity or other organs. Additionally, the mesorectum also showed a sharp border between colored and non-colored tissue. Conclusion: In this study we present that resection borders may be determined before resection based on ICG-perfusion and we showed that intraoperative exclusive coloring of the rectum including the mesorectum is possible. Visualizing resection borders based on ICG-perfusion before settling the first cut may be a new approach in oncological surgery.

Quantitative analysis of colon perfusion pattern using indocyanine green (ICG) angiography in laparoscopic colorectal surgery

Purpose

This study aimed to quantitatively evaluate colon perfusion patterns using indocyanine green (ICG) angiography to find the most reliable predictive factor of anastomotic complications after laparoscopic colorectal surgery.

Methods

Laparoscopic fluorescence imaging was applied to colorectal cancer patients (n = 86) from July 2015 to December 2017. ICG (0.25 mg/kg) was slowly injected into peripheral blood vessels, and the fluorescence intensity of colonic flow was measured sequentially, producing perfusion graphs using a video analysis and modeling tool. Colon perfusion patterns were categorized as either fast, moderate, or slow based on their fluorescence slope, T_1/2MAX and time ratio (TR = T_1/2MAX/T_MAX). Clinical factors and quantitative perfusion factors were analyzed to identify predictors for anastomotic complications.

Results

The mean age of patients was 65.4 years, and the male-to-female ratio was 63:23. Their operations were laparoscopic low anterior resection (55 cases) and anterior resection (31 cases). The incidence of anastomotic complication was 7%, including colonic necrosis (n = 1), anastomotic leak (n = 3), delayed pelvic abscess (n = 1), and delayed anastomotic dehiscence (n = 1). Based on quantitative analysis, the fluorescence slope, T_1/2MAX, and TR were related with anastomotic complications. The cut-off value of TR to categorize the perfusion pattern was determined to be 0.6, as shown by ROC curve analysis (AUC 0.929, P < 0.001). Slow perfusion (TR > 0.6) was independent factor for anastomotic complications in a logistic regression model (OR 130.84; 95% CI 6.45–2654.75; P = 0.002). Anastomotic complications were significantly correlated with the novel factor TR (> 0.6) as the most reliable predictor of perfusion and anastomotic complications.

Conclusions

Quantitative analysis of ICG perfusion patterns using T_1/2MAX and TR can be applied to detect segments with poor perfusion, thereby reducing anastomotic complications during laparoscopic colorectal surgery.