Indocyanine Green Tissue Angiography Can Reduce Extended Bowel Resections in Acute Mesenteric Ischemia

Knowledge, attitudes and practices of using Indocyanine Green (ICG) fluorescence in emergency surgery: an international web-based survey in the ARtificial Intelligence in Emergency and trauma Surgery (ARIES)-WSES project

Fluorescence imaging is a real-time intraoperative navigation modality to enhance surgical vision and it can guide emergency surgeons while performing difficult, high-risk surgical procedures. The aim of this study is to assess current knowledge, attitudes, and practices of emergency surgeons in the use of indocyanine green (ICG) in emergency settings. Between March 08, 2023 and April 10, 2023, a questionnaire composed of 27 multiple choice and open-ended questions was sent to 200 emergency surgeons who had previously joined the ARtificial Intelligence in Emergency and trauma Surgery (ARIES) project promoted by the WSES. The questionnaire was developed by an emergency surgeon with an interest in advanced technologies and artificial intelligence. The response rate was 96% (192/200). Responders affirmed that ICG fluorescence can support the performance of difficult surgical procedures in the emergency setting, particularly in the presence of severe inflammation and in evaluating bowel viability. Nevertheless, there were concerns regarding accessibility and availability of fluorescence imaging in emergency settings. Eighty-seven out of 192 (45.3%) respondents have a fluorescence imaging system of vision for both elective and emergency surgical procedures; 32.3% of respondents have this system solely for elective procedures; 21.4% of respondents do not have this system, 15% do not have experience with it, and 38% do not use this imaging in emergency surgery. Less than 1% (2/192) affirmed that ICG fluorescence changed always their intraoperative decision-making. Precision surgery effectively tailors surgical interventions to individual patient characteristics using advanced technology, data analysis and artificial intelligence. ICG fluorescence can serve as a valid and safe tool to guide emergency surgery in different scenarios, such as intestinal ischemia and severe acute cholecystitis. Due to the lack of high-level evidence within this field, a consensus of expert emergency surgeons is needed to encourage stakeholders to increase the availability of fluorescence imaging systems and to support emergency surgeons in implementing ICG fluorescence in their daily practice.

High Rates of Discordant Ureteral Perfusion During Open Ureteral Reconstruction with Indocyanine Green: Does Near-Infrared Fluorescence Imaging Change Management or Stricture Outcomes?

OBJECTIVE

To determine the role of near-infrared fluorescence imaging (NIFI) combined with indocyanine green (ICG) to assess ureteral tissue perfusion in a benign genitourinary reconstruction cohort with a high prevalence of prior abdominopelvic radiation and surgery.

MATERIALS AND METHODS

A prospective, single-surgeon series, between June 2018 and April 2022, of patients who underwent open genitourinary reconstructive surgeries in which NIFI/ICG was utilized to intraoperatively assess ureteral tissue perfusion prior to ureteral anastomosis. Primary outcome was ureteroanastomotic stricture (UAS). Secondary outcomes included impact of NIFI/ICG on surgical decision-making and ureter resection length.

RESULTS

39 patients, median age 66, underwent 40 multimodality reconstructive surgeries during which NIFI/ICG was utilized in the open setting. Radiation-induced etiology was present in 32 of 40 (80%) patients. UAS occurred in 1 of 57 (1.8%) anastomoses with median follow-up 23.4 months. Use of NIFI/ICG changed intraoperative decision-making in 63% of cases. Change in intraoperative decision-making was more common in patients with prior abdominopelvic radiation (66%) compared to non-radiated patients (13%), p=0.007. Discordance between subjective (white-light) and objective (NIFI/ICG) ureteral perfusion (white-light) occurred in 61% of ureters. Mean length of resected ureter was higher following objective assessment with NIFI/ICG (3.6 cm) versus subjective assessment (white light) conditions (1.8 cm), p=0.001.

CONCLUSIONS

Use of NIFI/ICG was associated with low rates of UAS at 2 years follow-up in a cohort with high prevalence of prior radiation. NIFI/ICG was associated with longer lengths of ureter resection and ureteral perfusion assessment discordance compared to subjective surgeon assessment under white-light conditions.

[Indications and surgical strategy for bowel resection in mesenteric ischemia : Resection margins considering current guidelines and literature as well as the influence of new technical possibilities]

Acute mesenteric ischemia (AMI) is still a time-critical and life-threatening clinical picture. If exploration of the abdominal cavity is necessary during treatment, an intraoperative assessment of which segments of the intestines have a sufficient potential for recovery must be made. These decisions are mostly based on purely clinical parameters, which are subject to high level of uncertainty. This review article provides an overview of how this decision-making process and the determination of resection margins can be improved using technical aids, such as laser Doppler flowmetry (LDF), indocyanine green (ICG) fluorescence angiography or hyperspectral imaging (HSI). Furthermore, this article compiles guideline recommendations on the role of laparoscopy and the value of a planned second-look laparotomy. In addition, an overview of strategies for preventing short bowel syndrome is given and other aspects, such as the timing and technical aspects of placement of a preternatural anus and an anastomosis are highlighted.

A Case of Successful Hybrid Treatment of Dual Arterial Bypass Using Indocyanine Green Fluorescence Angiography and Endovascular Treatment for Recurrent Superior Mesenteric Artery Aneurysm

A 54-year-old woman with a mycotic superior mesenteric artery (SMA) aneurysm underwent emergent aneurysm resection with a great saphenous vein bypass. Follow-up computed tomography revealed a rapidly growing recurrent SMA aneurysm at the stump. Under the diagnosis of recurrent pseudoaneurysm of SMA with a fragile stump, we performed an open dual arterial bypass using indocyanine green fluorescence angiography and endovascular coil embolization. Subsequently, the patient's recurrent mycotic SMA aneurysm was successfully managed without mesenteric ischemic complications. This method may help prevent fatal mesenteric ischemia during SMA aneurysm surgery.

Utility of indocyanine green fluorescent dye in emergency general surgery: a review of the contemporary literature

For decades, indocyanine green (ICG) has been available for medical and surgical use. The indications for ICG use in surgery have expanded where guided surgery directed by fluorescence and near-infrared fluorescent imaging offers numerous advantages. Recently, surgeons have reported using ICG operative navigation in the emergency setting, with fluorescent cholangiography being the most common procedure. The utility of ICG also involves real-time perfusion assessment, such as ischemic organs and limbs. The rising use of ICG in surgery can be explained by the ICG's rapid technological evolution, accuracy, ease of use, and great potential to guide precision surgical diagnosis and management. The review aims to summarize the current literature on the uses of ICG in emergency general surgery. It provides a comprehensive and practical summary of the use of ICG, including indication, route of administration, and dosages. To simplify the application of ICG, we subdivided its use into anatomical mapping and perfusion assessment. Anatomical mapping includes the biliary tree, ureters, and bowel. Perfusion assessment includes bowel, pancreas, skin and soft tissue, and gonads. This review provides a reference to emergency general surgeons to aid in implementing ICG in the emergency setting for more enhanced and safer patient care.

Cesena guidelines: WSES consensus statement on laparoscopic-first approach to general surgery emergencies and abdominal trauma

BACKGROUND

Laparoscopy is widely adopted across nearly all surgical subspecialties in the elective setting. Initially finding indication in minor abdominal emergencies, it has gradually become the standard approach in the majority of elective general surgery procedures. Despite many technological advances and increasing acceptance, the laparoscopic approach remains underutilized in emergency general surgery and in abdominal trauma. Emergency laparotomy continues to carry a high morbidity and mortality. In recent years, there has been a growing interest from emergency and trauma surgeons in adopting minimally invasive surgery approaches in the acute surgical setting. The present position paper, supported by the World Society of Emergency Surgery (WSES), aims to provide a review of the literature to reach a consensus on the indications and benefits of a laparoscopic-first approach in patients requiring emergency abdominal surgery for general surgery emergencies or abdominal trauma.

METHODS

This position paper was developed according to the WSES methodology. A steering committee performed the literature review and drafted the position paper. An international panel of 54 experts then critically revised the manuscript and discussed it in detail, to develop a consensus on a position statement.

RESULTS

A total of 323 studies (systematic review and meta-analysis, randomized clinical trial, retrospective comparative cohort studies, case series) have been selected from an initial pool of 7409 studies. Evidence demonstrates several benefits of the laparoscopic approach in stable patients undergoing emergency abdominal surgery for general surgical emergencies or abdominal trauma. The selection of a stable patient seems to be of paramount importance for a safe adoption of a laparoscopic approach. In hemodynamically stable patients, the laparoscopic approach was found to be safe, feasible and effective as a therapeutic tool or helpful to identify further management steps and needs, resulting in improved outcomes, regardless of conversion. Appropriate patient selection, surgeon experience and rigorous minimally invasive surgical training, remain crucial factors to increase the adoption of laparoscopy in emergency general surgery and abdominal trauma.

CONCLUSIONS

The WSES expert panel suggests laparoscopy as the first approach for stable patients undergoing emergency abdominal surgery for general surgery emergencies and abdominal trauma.

ICG-augmented hyperspectral imaging for visualization of intestinal perfusion compared to conventional ICG fluorescence imaging: an experimental study

BACKGROUND

Small bowel malperfusion (SBM) can cause high morbidity and severe surgical consequences. However, there is no standardized objective measuring tool for the quantification of SBM. Indocyanine green (ICG) imaging can be used for visualization, but lacks standardization and objectivity. Hyperspectral imaging (HSI) as a newly emerging technology in medicine might present advantages over conventional ICG fluorescence or in combination with it.

METHODS

HSI baseline data from physiological small bowel, avascular small bowel and small bowel after intravenous application of ICG was recorded in a total number of 54 in-vivo pig models. Visualizations of avascular small bowel after mesotomy were compared between HSI only (1), ICG-augmented HSI (IA-HSI) (2), clinical evaluation through the eyes of the surgeon (3) and conventional ICG imaging (4). The primary research focus was the localization of resection borders as suggested by each of the four methods. Distances between these borders were measured and histological samples were obtained from the regions in between in order to quantify necrotic changes 6 h after mesotomy for every region.

RESULTS

StO2 images (1) were capable of visualizing areas of physiological perfusion and areas of clearly impaired perfusion. However, exact borders where physiological perfusion started to decrease could not be clearly identified. Instead, IA-HSI (2) suggested a sharp-resection line where StO2 values started to decrease. Clinical evaluation (3) suggested a resection line 23 mm (±7 mm) and conventional ICG imaging (4) even suggested a resection line 53 mm (±13 mm) closer towards the malperfused region. Histopathological evaluation of the region that was sufficiently perfused only according to conventional ICG (R3) already revealed a significant increase in pre-necrotic changes in 27% (±9%) of surface area. Therefore, conventional ICG seems less sensitive than IA-HSI with regards to detection of insufficient tissue perfusion.

CONCLUSIONS

In this experimental animal study, IA-HSI (2) was superior for the visualization of segmental SBM compared to conventional HSI imaging (1), clinical evaluation (3) or conventional ICG imaging (4) regarding histopathological safety. ICG application caused visual artifacts in the StO2 values of the HSI camera as values significantly increase. This is caused by optical properties of systemic ICG and does not resemble a true increase in oxygenation levels. However, this empirical finding can be used to visualize segmental SBM utilizing ICG as contrast agent in an approach for IA-HSI. Clinical applicability and relevance will have to be explored in clinical trials.

LEVEL OF EVIDENCE

Not applicable. Translational animal science. Original article.

Indocyanine green dye and its application in gastrointestinal surgery: The future is bright green

Indocyanine green (ICG) is a water-soluble fluorescent dye that is minimally toxic and widely used in gastrointestinal surgery. ICG facilitates anatomical identification of structures (e.g., ureters), assessment of lymph nodes, biliary mapping, organ perfusion and anastomosis assessment, and aids in determining the adequacy of oncological margins. In addition, ICG can be conjugated to artificially created antibodies for tumour markers, such as carcinoembryonic antigen for colorectal, breast, lung, and gastric cancer, prostate-specific antigen for prostate cancer, and cancer antigen 125 for ovarian cancer. Although ICG has shown promising results, the optimization of patient factors, dye factors, equipment, and the method of assessing fluorescence intensity could further enhance its utility. This review summarizes the clinical application of ICG in gastrointestinal surgery and discusses the emergence of novel dyes such as ZW-800 and VM678 that have demonstrated appropriate pharmacokinetic properties and improved target-to-background ratios in animal studies. With the emergence of robotic technology and the increasing reporting of ICG utility, a comprehensive review of clinical application of ICG in gastrointestinal surgery is timely and this review serves that aim.

Application of fluorescence-guided surgery in the acute care setting: a systematic literature review

PURPOSE

Fluorescence-based imaging has found application in several fields of elective surgery, but there is still a lack of evidence in the literature about its use in emergency setting. The present review critically summarizes currently available applications and limitations of indocyanine green (ICG) fluorescence in abdominal emergencies including acute cholecystitis, mesenteric ischemia, and trauma surgery.

METHODS

A systematic review was performed according to the PRISMA statement identifying articles about the use of ICG fluorescence in the management of the most common general surgery emergency. Only studies focusing on the use of ICG fluorescence for the management of acute surgical conditions in adults were included.

RESULTS

Thirty-six articles were considered for qualitative analysis. The most frequent disease was occlusive or non-occlusive mesenteric ischemia followed by acute cholecystitis. Benefits from using ICG for acute cholecystitis were reported in 48% of cases (clear identification of biliary structures and a safer surgical procedure). In one hundred and twenty cases that concerned the use of ICG for occlusive or non-occlusive mesenteric ischemia, ICG injection led to a modification of the surgical decision in 44 patients (36.6%). Three studies evaluated the use of ICG in trauma patients to assess the viability of bowel or parenchymatous organs in abdominal trauma, to evaluate the perfusion-related tissue impairment in extremity or craniofacial trauma, and to reassess the efficacy of surgical procedures performed in terms of vascularization. ICG injection led to a modification of the surgical decision in 50 patients (23.9%).

CONCLUSION

ICG fluorescence is a safe and feasible tool also in an emergency setting. There is increasing evidence that the use of ICG fluorescence during abdominal surgery could facilitate intra-operative decision-making and improve patient outcomes, even in the field of emergency surgery.

Management of Anastomotic Leakage after Colorectal Resection: Survey among the German CHIR-Net Centers

(1) Background: A widely accepted algorithm for the management of colorectal anastomotic leakage (CAL) is difficult to establish. The present study aimed to evaluate the current clinical practice on the management of CAL among the German CHIR-Net centers. (2) Methods: An online survey of 38 questions was prepared using the International Study Group of Rectal Cancer (ISREC) grading score of CAL combined with both patient- and surgery-related factors. All CHIR-Net centers received a link to the online questionary in February 2020. (3) Results: Most of the answering centers (55%) were academic hospitals (41%). Only half of them use the ISREC definition and grading for the management of CAL. A preference towards grade B management (no surgical intervention) of CAL was observed in both young and fit as well as elderly and/or frail patients with deviating ostomy and non-ischemic anastomosis. Elderly and/or frail patients without fecal diversion are generally treated as grade C leakage (surgical intervention). A grade C management of CAL is preferred in case of ischemic bowel, irrespective of the presence of an ostomy. Within grade C management, the intestinal continuity is preserved in a subgroup of patients with non-ischemic bowel, with or without ostomy, or young and fit patients with ischemic bowel under ostomy protection. (4) Conclusions: There is no generally accepted therapy algorithm for CAL management within CHIR-Net Centers in Germany. Further effort should be made to increase the application of the ISREC definition and grading of CAL in clinical practice.

The impact of nitroglycerine and volume on gastric tube microperfusion assessed by indocyanine green fluorescence imaging

The influence of hypervolemia and intraoperative administration of nitroglycerine on gastric tube microperfusion remains unclear The present study aimed to investigate the impact of different hemodynamic settings on gastric tube microperfusion quantified by fluorescence imaging with Indocyanine green (ICG-FI) as a promising tool for perfusion evaluation. Three groups with seven pigs each were formed using noradrenaline, nitroglycerin, and hypervolemia for hemodynamic management, respectively. ICG-FI, hemodynamic parameters, and transit-time flow measurement (TTFM) in the right gastroepiploic artery were continuously assessed. Fluorescent microspheres (FM) were administered, and the partial pressure of tissue oxygen was quantified. The administration of nitroglycerine and hypervolemia were both associated with significantly impaired microperfusion compared to the noradrenaline group quantified by ICG-FI. Even the most minor differences in microperfusion could be sufficiently predicted which, however, could not be represented by the mean arterial pressure measurement. Histopathological findings supported these results with a higher degree of epithelial damage in areas with impaired perfusion. The values measured by ICG-FI significantly correlated with the FM measurement. Using tissue oxygenation and TTFM for perfusion measurement, changes in microperfusion could not be comprehended. Our results support current clinical practice with restrictive volume and catecholamine administration in major surgery. Hypervolemia and continuous administration of nitroglycerine should be avoided.

Operative management of acute abdomen after bariatric surgery in the emergency setting: the OBA guidelines

BACKGROUND

Patients presenting with acute abdominal pain that occurs after months or years following bariatric surgery may present for assessment and management in the local emergency units. Due to the large variety of surgical bariatric techniques, emergency surgeons have to be aware of the main functional outcomes and long-term surgical complications following the most performed bariatric surgical procedures. The purpose of these evidence-based guidelines is to present a consensus position from members of the WSES in collaboration with IFSO bariatric experienced surgeons, on the management of acute abdomen after bariatric surgery focusing on long-term complications in patients who have undergone laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass.

METHOD

A working group of experienced general, acute care, and bariatric surgeons was created to carry out a systematic review of the literature following the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) and to answer the PICO questions formulated after the Operative management in bariatric acute abdomen survey. The literature search was limited to late/long-term complications following laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass.

CONCLUSIONS

The acute abdomen after bariatric surgery is a common cause of admission in emergency departments. Knowledge of the most common late/long-term complications (> 4 weeks after surgical procedure) following sleeve gastrectomy and Roux-en-Y gastric bypass and their anatomy leads to a focused management in the emergency setting with good outcomes and decreased morbidity and mortality rates. A close collaboration between emergency surgeons, radiologists, endoscopists, and anesthesiologists is mandatory in the management of this group of patients in the emergency setting.

Indocyanine green (ICG) fluorescence guide for the use and indications in general surgery: recommendations based on the descriptive review of the literature and the analysis of experience

Indocyanine Green is a fluorescent substance visible in near-infrared light. It is useful for the identification of anatomical structures (biliary tract, ureters, parathyroid, thoracic duct), the tissues vascularization (anastomosis in colorectal, esophageal, gastric, bariatric surgery, for plasties and flaps in abdominal wall surgery, liver resection, in strangulated hernias and in intestinal ischemia), for tumor identification (liver, pancreas, adrenal glands, implants of peritoneal carcinomatosis, retroperitoneal tumors and lymphomas) and sentinel node identification and lymphatic mapping in malignant tumors (stomach, breast, colon, rectum, esophagus and skin cancer). The evidence is very encouraging, although standardization of its use and randomized studies with higher number of patients are required to obtain definitive conclusions on its use in general surgery. The aim of this literature review is to provide a guide for the use of ICG fluorescence in general surgery procedures.

Acute Mesenteric Ischemia

The surgical treatment of occlusive acute mesenteric ischemia (AMI) without revascularization is associated with an 80% overall mortality. Early diagnosis is crucial, and revascularization may reduce overall mortality in AMI by up to 50%. A diagnosis of AMI requires a high index of clinical suspicion and the collaborative effort of emergency department physicians, general and vascular surgeons, and radiologists. This article provides an overview of the etiology, physiology, evaluation, and management of acute mesenteric ischemia.

Shifting surgical archetypes of ICG fluorescent-angiography for bowel perfusion assessment in cardiogenic shock under ECMO support

Extracorporeal membrane oxygenation (ECMO) has been adopted to support patients with acute severe cardiac or pulmonary failure that is potentially reversible and unresponsive to conventional management. Mesenteric ischemia (MI) can present as a life-threatening complication in patients receiving veno-arterial echocardiogram (ECHO) support. Due to the nature and acuity of these conditions, determining adequate perfusion upon surgical intervention is challenging for the operating surgeon, especially in cardiogenic shock (CS) patients on ECMO support persenting low arterial pulsatility. Indocyanine green fluorescent angiography (ICG-FA) has proven to be useful for real-time assessment of vascular perfusion, which may help determine the extent of bowel ischemia in patients receiving ECMO support. The case report here-in presented, breaks the paradigm of performing non-cardiac surgical procedures on ECMO support via a pioneering visual aid technique. LEARNING OBJECTIVE: ICG-FA is a promising visual intraoperatory technique providing real-time feedback for the adequate identification and assessment of target tissue/organs. The high morbidity and mortality rates associated to MI and CS-particularly when concomitantly present-hinders salvage surgical therapy. The use of ECMO provides hemodynamic stability This case report highlights the importance of adequate surgical intervention under extracorporeal life support in the presence of both CS and MI. To the authors' knowledge, this is the first report of application of ICG-FA to evaluate mesenteric perfusion in a patient receiving ECMO support.

Intestinal perfusion assessed by quantitative fluorescence angiography in piglets with necrotizing enterocolitis

BACKGROUND

Reduced intestinal perfusion is thought to be a part of the pathogenesis in necrotizing enterocolitis (NEC). This study aims to evaluate the intestinal perfusion assessment in NEC-lesions by quantitative fluorescence angiography with indocyanine green (q-ICG) during laparoscopy and open surgery.

METHODS

Thirty-four premature piglets were delivered by cesarean section and fed with parenteral nutrition and increasing infant formula volumes to induce NEC. During surgery, macroscopic NEC-lesions were evaluated using a validated macroscopic scoring system (1-6 for increasing NEC severity). The intestinal perfusion was assessed by q-ICG and quantified with a validated pixel intensity computer algorithm.

RESULTS

Significantly higher perfusion values were found in healthy areas of the colon (score 1) compared to those with NEC scores of 4, 5, and 6 (p < 0.05). Similarly, in the small intestine, perfusion was higher in the intestine with areas scored 1 compared to scores of 3 and 4 (p < 0.05). A cut-off value was found between NEC score of 1-2 vs. 3-4 for the small intestine at 117 and for colon at 107 between NEC scores 12 vs. scores of 36 with an area less than the curve value at 0.9 (p < 0.05).

CONCLUSIONS

q-ICG seems to be a feasible and valuable technique to evaluate the perfusion of tissue with NEC-lesions. We found a cut-off between intestine with scores 1-2 and intestine with NEC scores 3-6 in colon, and NEC score 3-4 in the small intestine.

LEVEL OF EVIDENCE

II.

Time limit to rescue intestine with viability at risk caused by blood flow disruption in patients presenting with acute abdomen

Purpose

Early management is crucial for acute intestinal blood flow disorders; however, no published study has identified criteria for the time limit for blood flow resumption. This study specifically examines the time factors for avoiding intestinal resection.

Methods

The subjects of this retrospective cohort study were 125 consecutive patients who underwent emergency surgery for a confirmed diagnosis of intestinal strangulation (n = 86), incarceration (n = 27), or volvulus (n = 12), between January 2015 and March 2021. Intestinal resection was performed when intestinal irreversible changes had occurred even after ischemia was relieved surgically. We analyzed the relationship between the time from computed tomography (CT) imaging to the start of surgery (C-S time) and intestinal resection using the Kaplan–Meier method and calculated the estimated intestinal rescue rate. Patient background factors affecting intestinal resection were also examined.

Results

The time limit for achieving 80% intestinal rescue rate was 200 min in C-S time, and when this exceeded 300 min, the intestinal rescue rate dropped to less than 50%. Multivariate analysis identified the APACHE II score as a significant influencing factor.

Conclusion

A rapid transition from early diagnosis to early surgery is critical for patients with acute abdomen originating from intestinal blood flow disorders. The times from presentation at the hospital to surgery should be reduced further, especially for severe cases.

The use of fluorescence angiography to assess bowel viability in the acute setting: an international, multi-centre case series

Introduction

Assessing bowel viability can be challenging during acute surgical procedures, especially regarding mesenteric ischaemia. Intraoperative fluorescence angiography (FA) may be a valuable tool for the surgeon to determine whether bowel resection is necessary and to define the most appropriate resection margins. The aim of this study is to report on FA use in the acute setting and to judge its impact on intraoperative decision making.

Materials and methods

This is a multi-centre, retrospective case series of patients undergoing emergency abdominal surgery between February 2016 and 2021 in three general/colorectal units where intraoperative FA was performed to assess bowel viability. Primary endpoint was change of management after the FA assessment.

Results

A total of 93 patients (50 males, 66.6 ± 19.2 years, ASA score ≥ III in 85%) were identified and studied. Initial surgical approach was laparotomy in 66 (71%) patients and laparoscopy in 27 (29% and seven, 26% conversions). The most common aetiologies were mesenteric ischaemia (n = 42, 45%) and adhesional/herniae-related strangulation (n = 41, 44%). In 50 patients a bowel resection was performed. Overall rates of anastomosis after resection, reoperation and 30-day mortality were 48% (n = 24/50, one leak), 12% and 18%, respectively. FA changed management in 27 (29%) patients. In four patients (4% overall), resection was avoided and in 21 (23%) extra bowel length was preserved (median 50 cm of bowel saved, IQR 28–98) although three patients developed further ischaemia. FA prompted extended resection (median of 20 cm, IQR 10–50 extra bowel) in six (6%) patients.

Conclusion

Intraoperative use of FA impacts surgical decisions regarding bowel resection for intestinal ischaemia, potentially enabling bowel preservation in approximately one out of four patients. Prospective studies are needed to optimize the best use of this technology for this indication and to determine standards for the interpretation of FA images and the potential subsequent need for second-look surgeries.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00464-022-09136-7.

Effect of Surgical Technique on the Microstructure and Microcirculation of the Small Intestine Stump during Delayed Anastomosis: Multimodal OCT Data

The aim of the study was to use multimodal optical coherence tomography (MM OCT) to evaluate microstructure and microcirculation in the proximal and distal sections of the intestine relative to the resected area in acute mesenteric ischemia.

Role of near-infrared fluorescence in colorectal surgery

Near-infrared fluorescence (NIRF) is a technique of augmented reality that, when applied in the operating theatre, allows the colorectal surgeon to visualize and assess bowel vascularization, to identify lymph nodes draining a cancer site and to identify ureters. Herein, we review the literature regarding NIRF in colorectal surgery.

Management of post-traumatic ischaemic ileal stricture using intraoperative indocyanine green fluorescence-guided resection

Blunt abdominal trauma can affect mesenteric circulation which may lead to bowel strictures. Indocyanine green (ICG) angiography can be used to assess mesenteric blood flow and bowel perfusion as a guide to resect length intraoperatively. But this concept has not been applied to ischaemic bowel strictures. We present a case of ischaemic ileal stricture induced by blunt abdominal trauma which was managed by resection and anastomosis. Intraoperative near-infrared (NIR) ICG angiography was used as a guide to resect the bowel length. This case emphasises that ischaemic bowel strictures should be suspected in patients presenting with intestinal obstruction following trauma. Resection and anastomosis of the affected segment remains the primary treatment modality with excellent outcomes. NIR ICG angiography is a real-time objective and useful resource for assessing bowel perfusion and could be used to determine the length of the segment to be resected in patients with ischaemic bowel stricture.

The use of indocyanine green fluorescence to define bowel microcirculation during laparoscopic surgery for acute small bowel obstruction

AIM

Although there is growing evidence to support the feasibility of a minimally invasive approach for acute small bowel obstruction, the inability to adequately evaluate compromised bowel segments has been cited as a major limitation. The aim of this work is to report a novel application of extemporaneous indocyanine green (ICG) fluorescence to assess bowel viability where there is a concern for ischaemic damage.

METHOD

After the cause of obstruction has been identified and resolved, and where there are dubious signs of bowel ischaemia present, fluorescent selective angiography is undertaken. The segment of bowel in question is observed under both normal and fluorescent light to assess local microcirculation. The adequacy of both the arterial supply and the venous drainage is thus appraised to define bowel viability.

RESULTS

Among 71 patients who have undergone surgery for acute small bowel obstruction with a laparoscopic approach, seven received extemporaneous ICG fluorescence assessment of bowel viability. Different presentations with their relevant management are described.

CONCLUSIONS

Selective use of intraoperative fluorescent angiography may overcome some of the intrinsic limitations of laparoscopy in assessing bowel viability during surgery for acute small bowel obstruction.

The use of Indocyanine green fluorescent in patients with abdominal trauma for better intraoperative decision-making and less bowel anastomosis leak: case series

Despite technological advances in the management of blunt abdominal trauma, the rate of bowel anastomotic leakage (AL) remains high. The etiology of AL is multifactorial, but insufficient blood perfusion is considered to play a substantial role in the pathogenesis. In recent years, angiography with Indocyanine green (ICG), a fluorescent dye, has been introduced in the clinical practice to assess organ perfusion in several conditions. Given the scarcity of publications describing the use of ICG in trauma patients as a potentially useful strategy that may facilitate intraoperative decisions and limit the extent of bowel resection, we presented the utility of intraoperative ICG fluorescent in abdominal trauma patients in a level 1 trauma center. The use of ICG fluoroscopy in patients with abdominal trauma is feasible and useful; however, large prospective studies in trauma patients are warranted.

Fluorescence imaging in colorectal surgery

BACKGROUND

Fluorescent imaging is an emerging technological tool that can guide surgeons during surgery by highlighting anatomical structures and pathology, and help with intraoperative decision making.

METHODS

A comprehensive review of published literature was performed using the search terms "fluorescence", "imaging" and "colorectal surgery" in PubMed. Only clinical trials that were published in English were included in this review. Ex vivo and animal studies were excluded.

RESULTS

This review demonstrates the use of fluorescence imaging in colorectal surgery in four areas: (1) assessment of tissue perfusion and vasculature; (2) assessment of tumour; (3) lymphatic drainage and (4) identification of the urinary tract. The most commonly used fluorescent dyes are nonspecific, such as indocyanine green and methylene blue, but there is increasing interest in the development of specific fluorescently labelled molecular markers.

CONCLUSION

Fluorescence imaging is a potentially useful tool for colorectal surgery. Early studies on fluorescence imaging have been promising but larger scale randomised controlled trials are warranted to demonstrate the effectiveness and benefits of using fluorescence imaging routinely. The development of molecular dyes that are specific to targets could significantly increase the potential use of fluorescence imaging during surgery.

Prospects of Intraoperative Multimodal OCT Application in Patients with Acute Mesenteric Ischemia

INTRODUCTION

Despite the introduction of increasingly multifaceted diagnostic techniques and the general advances in emergency abdominal and vascular surgery, the outcome of treatment of patients with acute impaired intestinal circulation remains unsatisfactory. The non-invasive and high-resolution technique of optical coherence tomography (OCT) can be used intraoperatively to assess intestine viability and associated conditions that frequently emerge under conditions of impaired blood circulation. This study aims to demonstrate the effectiveness of multimodal (MM) OCT for intraoperative diagnostics of both the microstructure (cross-polarization OCT mode) and microcirculation (OCT angiography mode) of the small intestine wall in patients with acute mesenteric ischemia (AMI).

METHODS AND PARTICIPANTS

A total of 18 patients were enrolled in the study. Nine of them suffered from AMI in segments II-III of the superior mesenteric artery (AMI group), whereby the ischemic segments of the intestine were examined. Nine others were operated on for adenocarcinoma of the colon (control group), thus allowing areas of their normal small intestine to be examined for comparison. Data on the microstructure and microcirculation in the walls of the small intestine were obtained intraoperatively from the side of the serous membrane using the MM OCT system (IAP RAS, Russia) before bowel resection. The MM OCT data were compared with the results of histological examination.

RESULTS

The study finds that MM OCT visualized the damage to serosa, muscularis externa, and blood vessels localized in these layers in 100% of AMI cases. It also visualized the submucosa in 33.3% of AMI cases. The MM OCT images of non-ischemic (control group), viable ischemic, and necrotic small intestines (AMI group) differed significantly across stratification of the distinguishable layers, the severity of intermuscular fluid accumulations, and the type and density of the vasculature.

CONCLUSION

The MM OCT diagnostic procedure optimally meets the requirements of emergency surgery. Data on the microstructure and microcirculation of the intestinal wall can be obtained simultaneously in real time without requiring contrast agent injections. The depth of visualization of the intestinal wall from the side of the serous membrane is sufficient to assess the volume of the affected tissues. However, the methodology for obtaining MM OCT data needs to be improved to minimize the motion artefacts generated in actual clinical conditions.

Hyperspectral imaging and indocyanine green fluorescence angiography in acute mesenteric ischemia: A case report on how to visualize intestinal perfusion

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First case of HSI and ICG in Acute mesenteric ischemia.

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Similar results of moth modalities with regard to well perfused intestine.

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ICG shows exact vascular blood supply and intestinal perfusion.

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Hyperspectral imaging can distinguish necrotic and vital intestinal segments in AMI.

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Combined use helps surgeons to evaluate intestinal perfusion intraoperatively in AMI.

Introduction and importance

Acute mesenteric ischemia is a challenging acute condition which is often caused by occlusion of an intestinal vessel. Therapeutic algorithms include revascularization of the occluded vessel and a surgical procedure to remove necrotic intestine. Sometimes necrotic intestine is hard to identify visually. Therefore, tools such as hyperspectral imaging (HSI) and indocyanine green fluorescence angiography (ICGFA) might be helpful for objective intraoperative evaluation of intestinal perfusion.

Case presentation

We present a case of an 80-year-old woman with an acute superior mesenteric artery occlusion and subsequent intestinal gangrene. After endovascular arterial revascularization, we performed an explorative laparotomy in which we assessed intestinal perfusion by HSI and ICGFA. Both HSI and ICGFA showed a sharp perfusion borderline in the proximal jejunum. The distal intestine showed low tissue oxygenation (HSI) and inhomogeneous perfusion (ICGFA).

Clinical discussion

Both methods showed reproducible results for tissue perfusion and, thus, could provide additional information on the extent of necrotic bowel with need for resection. Therefore, both modalities might be used in future image-guided surgery in cases of acute mesenteric ischemia where visual discrimination of intestinal perfusion is challenging in order to resect as much bowel as necessary to improve patient outcome. Both methods exert different strengths: i.e. ICGFA is real-time angiography, whereas HSI may expose intestinal necrosis in spectroscopy.

Conclusion

We show, for the first time, simultaneous imaging of HSI and ICGFA in a case of acute mesenteric ischemia. Both imaging modalities reveal similar results reliably concerning intestinal perfusion.

Fluorescence-Based Quantification of Gastrointestinal Perfusion: A Step Towards an Automated Approach

Background: Qualitative fluorescence angiography (FA) provides insights into intestinal tissue perfusion, but today it is not yet accurate in predicting anastomotic leakage. To improve peroperative detection of impaired perfusion, quantified parameters should be investigated using a standardized method. The aim of this study was to develop a (semi)automated algorithm for comprehensive and convenient analysis of FA parameters. Materials and Methods: An analysis tool was developed for the extraction of quantified FA parameters. The start- and endpoint of intensity increase (T₀ and Tmax) were automatically detected in the intensity-time curves. Algorithm performance was measured against manual assignment of T₀ and Tmax by 9 independent observers in 18 in vivo generated test signals, using the intraclass correlation coefficient (ICC). Characteristics of parameter T1∕2 (time to 50% of maximal intensity) were analyzed in normally perfused small intestine of 32 subjects who underwent robotic laparoscopic surgery. Since ethical approval was not required under the Dutch law, the need for informed consent was waived. Results: Automated detection of T₀ and Tmax was successful in all subjects. Output of the algorithm had an excellent agreement with the median of the human observations: ICC = 0.95 (95% confidence interval: 0.86-0.96). Overall, T1∕2 had a median value of 5.1 (interquartile range = 2.4) seconds and a minimal and maximal value of 1.3 and 9.9 seconds, respectively. Conclusions: The presented method provided convenient data analysis in the search for effective FA quantification. Future research should expand the data to find adequate threshold values for peroperatively identifying insufficient perfusion and investigate the influence of physiological conditions.

Quantitative fluorescence angiography detects dynamic changes in gastric perfusion

INTRODUCTION

The use of Indocyanine green (ICG) fluorescence angiography (ICG-FA) is an applied method to assess visceral perfusion during surgical procedures worldwide. Further development has entailed quantification of the fluorescence signal; however, whether quantified ICG-FA can detect intraoperative changes in perfusion after hemorrhage has not been investigated previously. In this study, we investigated whether a quantification method, developed and validated in our department (q-ICG), could detect changes in gastric perfusion induced by hemorrhage and resuscitation.

METHODS

Ten pigs were included in the study. Specific regions of interest of the stomach were chosen, and three q-ICG measurements of gastric perfusion obtained: 20 min after completion of the laparoscopic setup (baseline), after reducing the circulating blood volume by 30%, and after reinfusion of the withdrawn blood volume. Hemodynamic variables were recorded, and blood samples were collected every 10 min during the procedure.

RESULTS

The reduction in blood volume generated decreased gastric perfusion (q-ICG) from baseline (p = 0.023), and gastric perfusion subsequently increased (p < 0.001) after the reintroduction of the withdrawn blood volume. Cardiac output (CO) and mean arterial blood pressure (MAP) shifted correspondingly and the gastric perfusion correlated to CO (r = 0.575, p = 0.001) and MAP (r = 0.436, p = 0.018).

CONCLUSION

We present a novel study showing that the q-ICG method can detect dynamic changes in local tissue perfusion induced by hemorrhage and resuscitation. As regional gastrointestinal perfusion may be significantly reduced, while hemodynamic variables such as MAP or heart rate remain stable, q-ICG may provide an objective, non-invasive method for detecting regional early ischemia, strengthening surgical decision making.

Validation of quantitative assessment of indocyanine green fluorescent imaging in a one-vessel model

Objectives

Evaluation of intestinal perfusion remains subjective and depends on the surgeon´s individual experience. Intraoperative quality assessment of tissue perfusion with indocyanine green (ICG) fluorescence using a near-infrared camera system has been described in different ways and for different indications. The aim of the present study was to evaluate fluorescent imaging (FI) in the quantitative assessment of intestinal perfusion in a gastric tube model in pigs and to compare the results to results obtained with florescent microspheres (FM), the gold standard for tissue perfusion.

Methods

Seven pigs (56.0±3.0 kg), both males and females, underwent gastric tube formation after transection and ligation of the gastric arteries, except the right gastroepiploic artery, to avoid collateral blood flow.

After baseline assessment (T0), hypotension (T1) was induced by propofol (Karampinis et al 2017) (< 60 mmHg). Then, propofol was paused to obtain normotension (T2, Mean arterial pressure (MAP) 60–90 mmHg). Finally, hypertension (T3, MAP>90 mmHg) was induced by norepinephrine.

Measurements were performed in three regions of interest (ROIs) under standardized conditions: the fundus (D1), corpus (D2), and prepyloric area (D3). Hemodynamic parameters and transit-time flow measurement (TTFM) in the right gastroepiploic artery were continuously assessed. FI, FM and the partial pressure of tissue oxygen (TpO₂) were quantified in each ROI.

Results

The study protocol could successfully be performed during stable hemodynamics. Flow in the gastroepiploic artery measured by transit time flow measurement (TTFM) was related to hemodynamic changes between the measurements, indicating improved blood flow with increasing MAP. The distal part of the gastric tube (D1) showed significantly (p<0.05) impaired perfusion compared to the proximal parts D3 and D2 using FM. ICG-FI also showed the highest values in D3 and the lowest values in D1 at all hemodynamic levels (T1-T3; p<0,05).

Conclusion

Visual and quantitative assessment of gastric tube perfusion is feasible in an experimental setting using ICG-FI. This might be a promising tool for intraoperative assessment during visceral surgery in the future.

Non-occlusive Mesenteric Ischemia as a Fatal Complication in Acute Pancreatitis: A Case Series

BACKGROUND

Vascular complications of severe acute pancreatitis are well known and largely described unlike non-occlusive mesenteric ischemia, which is a rare and potentially fatal complication. Non-occlusive mesenteric ischemia is an acute mesenteric ischemia without thrombotic occlusion of blood vessels, poorly described as a complication of acute pancreatitis.

METHODS

We retrospectively reviewed a prospectively maintained registry of all pancreatic diseases referred to our center from 2013 to 2018, in order to determine the causes of early death. We identified three patients who died within 48 h after hospital admission from severe acute pancreatitis complicated by irreversible non-occlusive mesenteric ischemia. Their clinical presentation, management, and outcomes were herein reported.

RESULTS

Three consecutive patients with severe acute pancreatitis developed non-occlusive mesenteric ischemia within the first 5 days after onset of symptoms and died 48 h after non-occlusive mesenteric ischemia diagnosis despite optimal intensive care management and surgery, giving a prevalence of 3/609 (0.5%). Symptoms were unspecific with consequently potential delayed diagnosis and management. High doses of norepinephrine required for hemodynamic support (n = 3) potentially leading to splanchnic vessels vasoconstriction, transient hypotension (n = 3), and previous severe ischemic cardiomyopathy (n = 1) could be involved as precipitating factors of non-occlusive mesenteric ischemia.

CONCLUSION

Non-occlusive mesenteric ischemia can be a fatal complication of acute pancreatitis but is also challenging to diagnose. Priority is to reestablish a splanchno-mesenteric perfusion flow. Surgery should be offered in case of treatment failure or deterioration but is still under debate in early stage, to interrupt the vicious circle of intestinal hypoperfusion and ischemia.

Application of Fluorescent Dyes in Visceral Surgery: State of the Art and Future Perspectives

Background

Through the improvement and implementation of advanced intraoperative imaging, the indications for intraoperative fluorescence have spread to various fields of visceral surgery. Indocyanine green (ICG)-based fluorescence angiography and the imaging systems using this certain dye are currently the cornerstone of intraoperative, fluorescence-based medical imaging.

Summary

The article focuses on principles and approaches of intraoperative fluorescence in general surgery. The current clinical practice of intraoperative fluorescence and its evidence are described. Emerging new fields of application are put in a perspective. Furthermore, the technique and possible pit-falls in the performance of intraoperative ICG fluorescence angiography are described in this review article.

Key Messages

Overall growing evidence suggests that intraoperative fluorescence imaging delivers valuable additional information to the surgeon, which might help to perform surgery more exactly and reduce perioperative complications. Perfusion assessment can be a helpful tool when performing critical anastomoses. There is evidence from prospective and randomized trials for the benefit of intraoperative ICG fluorescence angiography during esophageal reconstruction, colorectal surgery, and surgery for mesenteric ischemia. Most studies suggest the administration of 2.5-10 mg of ICG. Standardized settings and documentation are essential. The benefit of ICG fluorescence imaging for gastrointestinal sentinel node detection and detection of liver tumors and colorectal metastases of the liver cannot clearly be estimated duo to the small number of prospective studies. Critical points in the use of intraoperative fluorescence imaging remain the low standardization and reproducibility of the results and the associated difficulty in comparing the results of the existing trials. Furthermore, little is known about the influence of hemodynamic parameters on the quantitative assessment of ICG fluorescence during surgery.

Techniques for intraoperative evaluation of bowel viability in mesenteric ischemia: A review

Acute mesenteric ischemia (AMI) is a deadly and common surgical emergency. While several imaging modalities aid in the diagnosis of AMI preoperatively, there are limited intraoperative tools for surgeon decision making regarding bowel viability. Here we offer a review of the utility and limitations of the many extensively studied techniques. We classify each of these modalities into three hallmarks of healthy bowel: oxygenation, myoelectric activity and perfusion. Finally, we offer a brief discussion of emerging and promising techniques to assist surgeons in intraoperative decision making for patients with mesenteric ischemia.

Evaluation of Parathyroid Glands with Indocyanine Green Fluorescence Angiography After Thyroidectomy

BACKGROUND

Indocyanine green fluorescence angiography (ICGA) is a new adjunct that has been used in surgical procedures to assess blood flow. This study evaluated the utility of ICGA compared to visual inspection to predict parathyroid function, guide autotransplantation and potentially decrease permanent hypoparathyroidism.

METHODS

This was a retrospective study of patients who underwent total or near-total thyroidectomy (T-NT) between January 2015 and March 2018. Patients with preoperative hyperparathyroidism and those undergoing reoperation were excluded. Patients who had ICGA were compared to T-NT patients without ICGA. Data were analyzed to assess the frequency of autotransplantation and incidence of hypoparathyroidism between groups.

RESULTS

In total, 210 patients underwent T-NT: 86 with ICGA and 124 without. Autotransplantation was more common in the ICGA group at 36% compared to 12% in the control (p = 0.0001). There was no correlation with at least one normal parathyroid gland on ICGA and postoperative PTH levels (p = 0.75). There was a difference in having normal postoperative PTH when there were at least two normal parathyroid glands (n = 50) compared to patients with less than two normal ICGA glands (n = 36, p = 0.044). Visual assessment and ICGA assessment of vascularity were in agreement, 245/281 (87%). There were 19 glands (6.8%) that would have undergone autotransplant based on visual inspection that had adequate blood supply on ICGA. Transient hypoparathyroidism was present in 45 out of 124 controls (36%) and 32 out of 86 (37%) in the ICG group.

CONCLUSIONS

ICGA is a novel technique that may improve the assessment of parathyroid gland blood supply compared to visual inspection. ICGA can guide more appropriate autotransplantation without compromising postoperative parathyroid function. At least two vascularized glands on ICGA may predict postoperative parathyroid gland function.

HYPerspectral Enhanced Reality (HYPER): a physiology-based surgical guidance tool

BACKGROUND

HSI is an optical technology allowing for a real-time, contrast-free snapshot of physiological tissue properties, including oxygenation. Hyperspectral imaging (HSI) has the potential to quantify the gastrointestinal perfusion intraoperatively. This experimental study evaluates the accuracy of HSI, in order to quantify bowel perfusion, and to obtain a superposition of the hyperspectral information onto real-time images.

METHODS

In 6 pigs, 4 ischemic bowel loops were created (A, B, C, D) and imaged at set time points (from 5 to 360 min). A commercially available HSI system provided pseudo-color maps of the perfusion status (StO2, Near-InfraRed perfusion) and the tissue water index. An ad hoc software was developed to superimpose HSI information onto the live video, creating the HYPerspectral-based Enhanced Reality (HYPER). Seven regions of interest (ROIs) were identified in each bowel loop according to StO2 ranges, i.e., vascular (VASC proximal and distal), marginal vascular (MV proximal and distal), marginal ischemic (MI proximal and distal), and ischemic (ISCH). Local capillary lactates (LCL), reactive oxygen species (ROS), and histopathology were measured at the ROIs. A machine-learning-based prediction algorithm of LCL, based on the HSI-StO2%, was trained in the 6 pigs and tested on 5 additional animals.

RESULTS

HSI parameters (StO2 and NIR) were congruent with LCL levels, ROS production, and histopathology damage scores at the ROIs discriminated by HYPER. The global mean error of LCL prediction was 1.18 ± 1.35 mmol/L. For StO2 values > 30%, the mean error was 0.3 ± 0.33.

CONCLUSIONS

HYPER imaging could precisely quantify the overtime perfusion changes in this bowel ischemia model.

Discrimination between arterial and venous bowel ischemia by computer-assisted analysis of the fluorescent signal

BACKGROUND

Arterial blood supply deficiency and venous congestion both play a role in anastomotic complications. Our aim was to evaluate a software-based analysis of the fluorescence signal to recognize the patterns of bowel ischemia.

METHODS

In 18 pigs, two clips were applied on the inferior mesenteric artery (group A: n = 6) or vein (group V: n = 6) or on both (group A-V: n = 6). Three regions of interest (ROIs) were identified on the sigmoid: P = proximal to the first clip; C = central, between the two clips; and D = distal to the second clip. Indocyanine Green was injected intravenously. The fluorescence signal was captured by means of a near-infrared laparoscope. The time-to-peak (seconds) and the maximum fluorescence intensity were recorded using software. A normalized fluorescence intensity unit (NFIU: 0-to-1) was attributed, using a reference card. The NFIU's over-time variations were computed every 10 min for 50 min. Capillary lactates were measured on the sigmoid at the 3 ROIs. Various machine learning algorithms were applied for ischemia patterns recognition.

RESULTS

The time-to-peak at the ischemic ROI C was significantly longer in group A versus V (20.1 ± 13 vs. 8.43 ± 3.7; p = 0.04) and in group A-V versus V (20.71 ± 11.6 vs. 8.43 ± 3.7; p = 0.03). The maximal NIFU at ROI C, was higher in the V group (1.01 ± 0.21) when compared to A (0.61 ± 0.11; p = 0.002) and A-V (0.41 ± 0.2; p = 0.0005). Capillary lactates at ROI C were lower in V (1.3 ± 0.6) than in A (1.9 ± 0.5; p = 0.0071), and A-V (2.6 ± 1.5; p = 0.034). The K nearest neighbor and the Linear SVM algorithms provided both an accuracy of 75% in discriminating between A versus V and 85% in discriminating A versus A-V. The accuracy dropped to 70% when the ML had to identify the ROI and the type of ischemia simultaneously.

CONCLUSIONS

The computer-assisted dynamic analysis of the fluorescence signal enables the discrimination between different bowel ischemia models.