Indocyanine Green Fluorescence Angiography Research Articles

Laser speckle flowgraphy has comparable accuracy to indocyanine green fluorescence angiography in assessing bowel blood perfusion.

To investigate the accuracy of laser speckle flowgraphy (LSFG), a noninvasive method for the quantitative evaluation of blood flow using mean blur rate (MBR) as a blood flow parameter in the assessment of bowel blood perfusion compared to indocyanine green fluorescence angiography (ICG-FA). We enrolled 46 patients who underwent left-sided colorectal surgery. LSFG and ICG-FA were applied to assess blood bowel perfusion, with MBR and luminance as parameters, respectively. In both measurement methods, the position where the parameter suddenly decreased was defined as the blood flow boundary line. Subsequently, the blood flow boundaries created after processing the blood vessels flowing into the intestinal tract were determined using LSFG and ICG-FA, and concordance between the two was examined. Blood flow boundaries were visually identified using color tone changes on a color map created based on MBR in LSFG and using differences in luminance in ICG-FA. The distances between the transection line and blood flow boundaries determined using each method were compared. The location of blood flow boundaries matched in 65% (30/46) of cases. Although locations differed in the remaining 35% (16/46), all were located on the anal side near the transection line, and the difference was not clinically significant. The average distances between the transection line and blood flow boundary were 2.76 (SD = 3.25) and 3.71 (SD = 4.26) mm, respectively. There was no statistically significant difference between the two groups (p = 0.38). LSFG was shown to have comparable accuracy to ICG-FA, and may be useful for evaluating bowel perfusion.

Abstract PO4-07-07: The construction and clinical research value of the prediction model of sentinel lymph node metastasis based on indocyanine green fluorescence quantification in breast cancer

Abstract Objective: To establish a prediction model of sentinel lymph node metastasis by quantitative indocyanine green fluorescence analysis in breast cancer. Methods: From May 2023 to June 2023, 20 patients with breast cancer underwent modified radical mastectomy in the General Surgery Department of Jiangsu Provincial People's Hospital were chosen for research and analysis. Sentinel lymph node were taken from all the patients. The sentinel lymph nodes were located by using the double staining method of subcutaneous injection of Methylene blue and intravenous injection of indocyanine green. The postoperative pathology is used as the standard for evaluating the presence or absence of metastatic cancer in lymph nodes. At the same time, the transcutaneous fluorescence of sentinel lymph node was recorded and the peak time of fluorescence intensity curve was plotted. To establish a logistic diagnostic prediction model and fluorescence threshold, the sentinel lymph node was incised during operation and the fluorescence of sentinel lymph node was recorded again. The criteria for ICG positive determination are determined by the Youden index, which was used to judge the lymph nodes above the threshold in the Logistic diagnostic prediction model. Lymph nodes below the threshold determined in the Logistic diagnostic prediction model are the criteria for ICG negative determination. Cases with less than 3 sentinel lymph node were excluded. Results: 19 cases were ultimately selected. Methylene blue staining data was taking as the judgment standard of sentinel lymph node. Fluorescence imaging was 100% in 14 patients, 66.7% (2/3) in 1 patient, and 125%-150% (5/4-6/4) in 4 patients. Fluorescence quantification values below 2.91 are negative lymph nodes, and values above 4.69 are positive lymph nodes. Moreover, caution is required between 2.91 and 4.69. Combining with the fluorescence dynamic attenuation curve, the positive group has a plateau curve, while the negative group mostly has a decline curve. Combining fluorescence quantification with fluorescence dynamic attenuation curve, the diagnostic rate of positive lymph nodes has a lower false negative rate compared to simple fluorescence quantification and fluorescence dynamic attenuation curve. Conclusion: The quantitative difference value of indocyanine green fluorescence angiography can be used to predict the positive metastasis of sentinel lymph node in breast cancer, making it an attempt to exempt sentinel lymph node biopsy. Citation Format: Yang Wu, Wei Zhang, Jinhai Tang. The construction and clinical research value of the prediction model of sentinel lymph node metastasis based on indocyanine green fluorescence quantification in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-07-07.

Tissue perfusion in DIEP flaps using Indocyanine Green Fluorescence Angiography, Hyperspectral imaging, and Thermal imaging

Flap necrosis continues to occur in skin free flap autologous breast reconstruction. Therefore, we investigated the benefits of indocyanine green angiography (ICGA) using quantitative parameters for the objective, perioperative evaluation of flap perfusion. In addition, we investigated the feasibility of hyperspectral (HSI) and thermal imaging (TI) for postoperative flap monitoring. A single-center, prospective observational study was performed on 15 patients who underwent deep inferior epigastric perforator (DIEP) flap breast reconstruction (n=21). DIEP-flap perfusion was evaluated using ICGA, HSI, and TI using a standardized imaging protocol. The ICGA perfusion curves and derived parameters, HSI extracted oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) values, and flap temperatures from TI were analyzed and correlated to the clinical outcomes. Post-hoc quantitative analysis of intraoperatively collected data of ICGA application accurately distinguished between adequately and insufficiently perfused DIEP flaps. ICG perfusion curves identified the lack of arterial inflow (n=2) and occlusion of the venous outflow (n=1). In addition, a postoperatively detected partial flap epidermolysis could have been predicted based on intraoperative quantitative ICGA data. During postoperative monitoring, HSI was used to identify impaired perfusion areas within the DIEP flap based on deoxyHb levels. The results of this study showed a limited added value of TI. Quantitative, post-hoc analysis of ICGA data produced objective and reproducible parameters that enabled the intraoperative detection of arterial and venous congested DIEP flaps. HSI appeared to be a promising technique for postoperative flap perfusion assessment. A diagnostic accuracy study is needed to investigate ICGA and HSI parameters in real-time and demonstrate their clinical benefit.

Outcomes of nonrejection in weakly fluorescent intestine detected by indocyanine green fluorescence angiography: a case series of infants

BackgroundIndocyanine green fluorescence angiography, a validated noninvasive imaging technique, is used to assess tissue vascularization. Here, we report three infant patients who underwent intraoperative indocyanine green fluorescence angiography and suffered from postoperative complications caused by the lack of weak fluorescent intestinal resection and assessed residual intestinal perfusion.Case presentationWe observed the clinical characteristics and operative findings of patients treated from January 2022 to December 2022. Indocyanine green (0.5 mg/kg) was intravenously injected. The first patient was a 29-day-old girl with surgical necrotizing enterocolitis who underwent intraoperative indocyanine green fluorescence angiography at the first- and second-look operations. The proximal jejunum was difficult to diagnose to detect blood flow during the second-look operation. The second patient was a 32-day-old boy with surgical necrotizing enterocolitis. A part of the antimesenteric mucosa of the patient that exhibited weak fluorescence was preserved; however, it formed postoperative hematomas. The third patient was a 30-day-old boy with midgut volvulus. Weak fluorescence in the intestinal wall was observed 5 cm of the small intestine from the ileocecal valve was preserved, but it formed a stricture, and the patient underwent ileocecal resection after 30 days.ConclusionsWeak fluorescence in the intestine in infants by performing indocyanine green fluorescence angiography is associated with a high risk of non-recovering ischemic lesions and postoperative complications.

Clinical and computational development of a patient-calibrated ICGFA bowel transection recommender

IntroductionIntraoperative indocyanine green fluorescence angiography (ICGFA) aims to reduce colorectal anastomotic complications. However, signal interpretation is inconsistent and confounded by patient physiology and system behaviours. Here, we demonstrate a proof of concept of a novel clinical and computational method for patient calibrated quantitative ICGFA (QICGFA) bowel transection recommendation.MethodsPatients undergoing elective colorectal resection had colonic ICGFA both immediately after operative commencement prior to any dissection and again, as usual, just before anastomotic construction. Video recordings of both ICGFA acquisitions were blindly quantified post hoc across selected colonic regions of interest (ROIs) using tracking-quantification software and computationally compared with satisfactory perfusion assumed in second time-point ROIs, demonstrating 85% agreement with baseline ICGFA. ROI quantification outputs detailing projected perfusion sufficiency-insufficiency zones were compared to the actual surgeon-selected transection/anastomotic construction site for left/right-sided resections, respectively. Anastomotic outcomes were recorded, and tissue lactate was also measured in the devascularised colonic segment in a subgroup of patients. The novel perfusion zone projections were developed as full-screen recommendations via overlay heatmaps.ResultsNo patient suffered intra- or early postoperative anastomotic complications. Following computational development (n = 14) the software recommended zone (ROI) contained the expert surgical site of transection in almost all cases (Jaccard similarity index 0.91) of the nine patient validation series. Previously published ICGFA time-series milestone descriptors correlated moderately well, but lactate measurements did not. High resolution augmented reality heatmaps presenting recommendations from all pixels of the bowel ICGFA were generated for all cases.ConclusionsBy benchmarking to the patient’s own baseline perfusion, this novel QICGFA method could allow the deployment of algorithmic personalised NIR bowel transection point recommendation in a way fitting existing clinical workflow.

Cuboid Bone for Distal Radius Reconstruction: An Anatomical Cadaver Study

Abstract Background The cuboid bone (CB) of the foot has been suggested as a potential source of autologous reconstruction of the distal radius (DR). This study sought to examine the feasibility of harvesting the CB as a vascularized bone transfer for DR reconstruction. Purposes We evaluated the feasibility of a vascularized bone transfer of the CB by performing the flap dissection, analyzing its pedicle and demonstrating its perfusion using indocyanine green (ICG) fluorescence angiography. Methods Ten feet from five fresh-frozen cadaver specimens were dissected. The lateral tarsal artery (LTA) mean diameter, length, and emerging point were described. The CB mean length and the mean length of the bone segment harvested were reported. ICG injection was used to demonstrate its blood supply. Results The average length of the pedicle was 68.26 ± 3.12 mm. The mean diameter was 1.43 ± 0.15 mm. The CB had a mean anterior–posterior length of 40.81 ± 5.05 mm. The harvested bone had a mean length of 15.05 ± 2.03 mm. All CBs showed enhancement after ICG injection. Conclusion The CB presented reasonable anatomical similarities with the DR and a long and consistent pedicle with an adequate blood supply observed during ICG injection. Clinical Relevance This study supports the possibility of using the CB as a vascularized bone transfer for autologous reconstruction of the articular surface of the DR. Further study is warranted.

Evaluation of Neuroma Perfusion with Indocyanine Green Fluorescence Angiography

Evaluation of Neuroma Perfusion with Indocyanine Green Fluorescence Angiography

A Challenging Case of Thumb Replantation Aided by Intraoperative Indocyanine Green Fluorescence Angiography.

This study presents a case of thumb replantation performed despite several risk factors: age, comorbidities, and trauma mechanism are major adverse prognostic factors directly impacting thumb replantation. Most of the literature backs up this claim that a thumb that works, even partially, is a better outcome for the patient than amputation. We performed thumb replantation on a 94-year-old patient with type 2 diabetes mellitus who arrived at the emergency department with a thumb avulsion due to a dog bite. The intraoperative indocyanine green fluorescence angiography method aided us in carrying out the operation. We successfully used indocyanine green angiography intraoperatively to guide surgical debridement and evaluate the efficacy of anastomosis and reperfusion of the replanted segment during surgery. Two months after the operation, the patient had regained satisfactory hand function. Although indocyanine green angiography is not a technology created for revascularization procedures, it is instrumental in assessing vascular function and predicting a successful outcome. Given its undeniable potential, more research is needed on the possibility of widespread use in hand surgery and its indications.

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 atime-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 asufficient 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 aplanned 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 apreternatural anus and an anastomosis are highlighted.

Indocyanine green fluorescence angiography could reduce the risk of anastomotic leakage in rectal cancer surgery: a systematic review and meta-analysis of randomized controlled trials.

Several papers have shown that use of indocyanine green (ICG) decreases incidence of anastomotic leakage (AL) during colonic surgery, but no clear evidence has been found for rectal cancer surgery. Therefore, with this systematic review and meta-analysis of randomized controlled trials (RCTs) we aimed to assess if ICG could also reduce risk of AL in rectal cancer surgery. PubMed, Scopus, CINAHL and Cochrane databases were searched for RCTs assessing the effect of intraoperative ICG on the incidence of AL of the colorectal anastomosis. Pooled relative risk (RR) and pooled risk difference (RD) were obtained using models with random effects. Risk of bias was evaluated with the Rob2 tool and the quality of evidence was assessed using the GRADE Pro tool. Four RCTs were included for analysis, with a total of 1510 patients (743 controls and 767 ICG patients). The rate of AL was 9% in the ICG group (69/767) and 13.9% (103/743) in the control group (p = 0.003, RR -0.5, 95% CI -0.827 to -0.172, heterogeneity test 0%, p = 0.460). The RD in terms of incidence of AL was significantly decreased by 4.51% (p = 0.031, 95% CI -0.086 to -0.004, heterogeneity test 28%, p = 0.182) when using ICG. Our meta-analysis suggested that use of ICG during rectal cancer surgery could reduce the rate of AL.

Impact of standardising indocyanine green fluorescence angiography technique for visual and quantitative interpretation on interuser variability in colorectal surgery.

Intra-operative colonic perfusion assessment via indocyanine green fluorescence angiography (ICGFA) aims to address malperfusion-related anastomotic complications; however, its interpretation suffers interuser variability (IUV), especially early in ICGFA experience. This work assesses the impact of a protocol developed for both operator-based judgement and computational development on interpretation consistency, focusing on senior surgeons yet to start using ICGFA. Experienced and junior gastrointestinal surgeons were invited to complete an ICGFA-experience questionnaire. They subsequently interpreted nine operative ICGFA videos regarding perfusion sufficiency of a surgically prepared distal colon during laparoscopic anterior resection by indicating their preferred site of proximal transection using an online annotation platform (mindstamp.com). Six ICGFA videos had been prepared with a clinical standardisation protocol controlling camera and patient positioning of which three each had monochrome near infrared (NIR) and overlay display. Three others were non-standardised controls with synchronous NIR and overlay picture-in-picture display. Differences in transection level between different cohorts were assessed for intraclass correlation coefficient (ICC) via ImageJ and IBM SPSS. 58 clinicians (12 ICGFA experts, 46 ICGFA inexperienced of whom 23 were either finished or within one year of finishing training and 23 were junior trainees) participated as per power calculations. 63% felt that ICGFA should be routinely deployed with 57% believing interpretative competence requires 11-50 cases. Transection level concordance was generally good (ICC = 0.869) across all videos and levels of expertise (0.833-0.915). However, poor agreement was evident with the standardised protocol videos for overlay presentation (0.208-0.345). Similarly, poor agreement was seen for the monochrome display (0.392-0.517), except for those who were trained but ICG inexperienced (0.877) although even here agreement was less than with unstandardised videos (0.943). Colorectal ICGFA acquisition and display standardisation impacts IUV with this specific protocol tending to diminish surgeon interpretation consistency. ICGFA video recording for computational development may require dedicated protocols.

Perfusion Dynamics during Secondary Flap Debulking with Liposuction.

Lower extremity trauma often necessitates reconstruction with flap transfer. One of the reconstructive goals is a thin soft tissue coverage with appropriate contour. Therefore, a secondary debulking of the flap is usually performed. Debulking through conventional lipectomy is compared with liposuction followed by excision of the defatted flap excess. Demographic data, surgical details, and postoperative outcomes are compared and analyzed. The perfusion dynamics of the flaps undergoing liposuction debulking are studied by means of perioperative indocyanine green fluorescence angiography, as well as postoperative laser Doppler imaging. Patients undergoing lipectomy (n = 69; 57.5%) or liposuction (n = 51; 42.5%) debulking had a similar rate of postoperative complications. Partial necrosis was observed in 7.2% (lipectomy) versus 7.8% (liposuction) of flaps. Fluorescence angiography showed a substantial decrease in flap perfusion following the infiltration with an epinephrine-containing tumescent solution (74.3% ± 8.2% prior to infiltration versus 16.8% ± 7.1% after infiltration; p < 0.001), resulting in a dark flap appearance. Laser Doppler imaging confirmed the hypoperfusion on postoperative day 1. Secondary debulking of a lower extremity flap can be safely and efficiently performed through liposuction combined with peripheral excision of the defatted flap in a single stage. Perfusion studies may show a misleading hypoperfusion of the defatted flap, which does not accurately predict subsequent necrosis or complications.

Dynamic Mixed-Reality Patient-Specific Aneurysm Clipping Simulation for Two Cases-A Feasibility Study.

Intracranial aneurysm (IA) clipping is a complex neurosurgical procedure which demands advanced technology to minimize risks and maximize patient outcomes. This study aims to evaluate the feasibility of training patient-specific microsurgical clipping procedures using a mixed-reality physical neurosurgical simulator for unruptured IA. Two board-certified neurosurgeons were asked to simulate surgery in 2 patient-specific left-side unruptured middle cerebral artery-bifurcation IA models. The study was conducted in the operation theater under realistic conditions using a mixed-reality physical neurosurgical simulator. Time, procedural, and outcome-related information was collected. The participating neurosurgeons were encouraged to attempt all possible clipping strategies, even those deemed suboptimal, reporting the outcome of each strategy. Finally, to evaluate the feasibility and added value of integrating indocyanine green fluorescence angiography (ICG-FA) with the simulator, the ICG-FA videos for each clipping strategy were analyzed and compared with the reported clipping outcomes. Between 4 and 8, different clipping strategies were applied per aneurysm model; the number of strategies was higher in Patient Model 1 (6.5 ± 1.5) (more complex aneurysm) than in Patient Model 2 (5.0 ± 1.0). The clipping strategies differed between surgeons. At most, 53.5 minutes were necessary to complete each training session, but more than double the time was spent on the more complex aneurysm. Up to 53.8% (Patient Model 1) and 50% (Patient Model 2) of the attempted strategies were discarded by the neurosurgeons during the simulation. Evaluation of aneurysm occlusion through ICG-FA was specific, although sensitivity was poor. The present mixed-reality patient-specific simulator allows testing, anticipating, and discarding different aneurysm microsurgical clipping strategies regardless of the pathology complexity. Specific limitations should be considered regarding ICG-FA aneurysm inspection after clipping.

IBC-Oxford University2023_BJSOral_20Video Presentation: Fundectomy and Indocyanine green fluorescence angiography in revisional laparoscopic Roux-en-Y gastric bypass

Abstract Introduction Revisional bariatric procedures are increasingly prevalent. These procedures are more complex with higher risk of complications as compared to primary procedures. The potential indications for revisional laparoscopic gastric bypass (R-LRYGB) may include weight regain and gastroesophageal reflux disease (GORD). This video abstract presents role of fundectomy and Indocyanine green fluorescence angiography (ICG-FA) for perfusion assessment of gastric pouch in R-LRYGB. Methods and Operative technique A 40-year-old female with previous laparoscopic adjustable gastric band (LAGB) surgery underwent R-LRYGB procedure following approval at bariatric multidisciplinary team meeting. LAGB was removed due to band slippage and chronic pouch dilatation, 2 years prior to the revisional procedure. Preoperative BMI was 53 kg/m2. Pre-operative upper gastrointestinal endoscopy was normal. The operative technique included dissection of angle of His, access into lesser sac along lesser curve below 2nd vessel off left gastric artery (LGA) and division of short gastric vessels to gain access to leaser sac from lateral aspect. The stomach was divided horizontally with linear stapler (EndoGIA 60 Gold cartridge), level with second vessel off LGA followed by creation of vertical gastric pouch over a size 34 Oro-gastric tube, that included excision of gastric fundus. ICG was administered intravenously according to an agreed protocol for the study. Karl Storz Image1 STM Rubina system with overlay and monochromatic modes was used for perfusion assessment. ICG-FA was utilised for qualitative assessment of gastric pouch perfusion before and after linear stapled gastro-jejunal anastomosis. Results Operative time was 240 minutes. Adhesions were encountered in the lesser sac at the site of previous LAGB. Fundectomy allowed better visualisation of lesser sac, adhesiolysis and facilitated creation of gastric pouch. ICG perfusion of gastric pouch was satisfactory. The postoperative length of stay was 2 days. There were nopostoperative complications at 6 months follow-up. The patient achieved 42% excess weight loss (BMI 43) over 6 months period. Conclusions Fundectomy is a safe and feasible operative step in R-LRYGB in patients with previous primary LAGB. ICG-FA is a promising qualitative assessment tool in revisional bariatric procedures.

OGC O08 Quantification of fluorescence angiography for visceral perfusion assessment in gastric conduit reconstruction: measuring agreement between two software algorithms

Abstract Background Building evidence suggests that fluorescence angiography is capable of reducing anastomotic leakage rates. Many software-based quantification algorithms have been developed aiming to obtain an objective measure for intraoperative visceral perfusion at the anastomotic site. Validation and comparison of these models in the current literature is scarce. The aim of this study was to measure agreement between two independently developed software algorithms for the quantitative assessment of visceral perfusion using indocyanine green fluorescence angiography. Methods 81 video recordings from patients who underwent fluorescence angiography-guided Ivor Lewis esophagectomy with gastric conduit reconstruction between August 2020 and February 2022 were available for analysis. In this dataset, we standardized patient, theatre, camera and imaging display variables. Recordings were analyzed retrospectively based on intraoperatively selected regions of interest using two software based-quantification algorithms (AMS and CPH). Quantitative parameters derived from the fluorescence time curve (FTC) were recorded. The comparison focused on the predefined primary outcome variable for quantitative perfusion assessment "normalized maximum slope". Agreement between the two software algorithms was evaluated in a Bland-Altman analysis. Quantitative parameters in patients with anastomotic leakage were compared to those without. Results Out of 81 video recordings, 70 could be processed using both algorithms. The output values for the normalized maximum slope from the AMS and the CPH software held a moderate-to-strong correlation in a linear regression model (R-squared: 0.544, p&amp;lt;0.001). The Bland-Altman plot indicated a mean±SD difference of 0.037±0.018 arbitrary units for the normalized maximum slope, with significant differences between the two software measurements (p&amp;lt;0.001). Proportional bias was observed using linear regression in the Bland-Altman plot (R-squared=0.715, p&amp;lt;0.001). Disparities between the two measurement methods became proportionally larger among higher mean values. Neither of the two software methods showed a significant difference in perfusion measurement between the anastomotic leakage and no leakage groups (p=0.32 and p=0.51). Differences in signal processing, such as smoothing techniques and window selection, were identified as potential factors contributing to the disparity in outcomes. Conclusions The two software-based quantification methods for visceral perfusion demonstrated significant differences. Varying agreement among quantification methods should be considered while interpreting studies that report quantitative parameters and derived thresholds for clinical endpoints, as there may be a limited external validity.

Feasibility of parathyroid gland autofluorescence imaging after indocyanine green fluorescence angiography.

In thyroid surgery, autofluorescence allows the parathyroid glands (PTGs) to be located very early to protect them. Moreover, indocyanine green (ICG) fluorescence angiography (ICG-FA) allows for assessing the viability of the PTGs and identifying blood vessels to preserve them. The main limitation of using ICG-FA is that once ICG has been injected, it is no longer possible to observe PTG autofluorescence using existing devices. This study aimed to describe an approach that allows for visualization of the PTGs by autofluorescence, even after ICG injection. We redesigned the FLUOBEAM® LX system to excite fluorescence at 685 nm and detect fluorescence between 700 and 900 nm. This device had short-pass filters at 775 nm that helped to split the contributions of the PTG autofluorescence and ICG fluorescence. Tests were performed on extemporaneous PTG preparations placed next to ICG droplets to assess for rejection of the ICG signal. A low-pass filter at 775 nm detected 60% of the autofluorescence signals and 10% of the ICG signals. These findings support the possibility of visualizing PTG autofluorescence despite multiple ICG injections and measuring the balance between ICG and autofluorescence signals.

Correlation between Indocyanine Green Fluorescence Angiography and Laser Speckle Contrast Imaging in a Flap Model.

Indocyanine green fluorescence angiography (ICG-FA) is used to assess tissue intraoperatively in reconstructive surgery. This requires an intra-venous dye injection for each assessment. This is not necessary in laser speckle contrast imaging (LSCI); therefore, this method may be better suited for tissue evaluation. To determine this, we compared the two methods in a porcine flap model. One random and one pedicled flap were raised on each buttock of six animals. They were assessed with LSCI at baseline, when raised (T0), at 30 minutes (T30) and with ICG-FA at T0 and T30. Regions of interest (ROI) were chosen along the flap axis. Perfusion, measured as perfusion units (PU) in the LSCI assessment and pixel-intensity for the ICG-FA video uptake, was calculated in the ROI. Correlation was calculated between PU and pixel-intensity measured as time to peak (TTP) and area under curve for 60 seconds (AUC60). Correlation between LSCI and AUC60 for the ICG-FA in corresponding ROI could be seen in all flaps at all time points. The correlation was higher for T0 (r=0.7 for random flap and r=0.6 for pedicled flap) than for T30 (r=0.57 for random flap and r=0.59 for pedicled flap). Even higher correlation could be seen PU and TTP (T0: random flap r=-0.8 and pedicled flap r=0.76. T30: random flap r=-0.8 and pedicled flap r=0.71). There is a correlation between PU from LSCI and TTP and AUC60 for ICG-FA, indicating that LSCI could be considered for intraoperative tissue assessment.

Reduction of Uncertainty in Bolus Transit Time Measurement in Quantitative Fluorescence Angiography

Abstract During cerebral revascularization surgeries, blood flow values help surgeons to monitor the quality of the procedure, e.g., to avoid cerebral hyperperfusion syndrome due to excessively enhanced perfusion. The state-of-the-art technique is the ultrasonic flow probe that has to be placed around the blood vessel. This causes contact between probe and vessel, which, in the worst case, leads to rupture. The recently developed intraoperative indocyanine green (ICG) Quantitative Fluorescence Angiography (QFA) is an alternative technique that overcomes this risk. However, it has been shown by the developer that the calculated flow has deviations. After determining the bolus transit time as the most sensitive parameter in flow calculation, we propose a new two-step uncertainty reduction method for flow calculation. The first step is to generate more data in each measurement that results in functions of the parameters. Noise can then be reduced in a second step. Two methods for this step are compared. The first method fits the model for each parameter function separately and calculates flow from models, while the second one fits multiple parameter functions together. The latter method is proven to perform best by in silico tests. Besides, this method reduces the deviation of flow comparing to original QFA as expected. Our approach can be generally used in all QFA applications using two-point theory. Further development is possible if number of dimensions of the achieved parameter data are broadened that results in even more data for processing in the second step.

Applications of Near-Infrared Fluorescence Imaging and Angiography of Inferior Vesical Artery in Laparoscopic Lateral Lymph Node Dissection: A Prospective Nonrandomized Controlled Study

BACKGROUND: Near-infrared imaging with indocyanine green has been used to guide lateral lymph node dissection, yet its efficacy and benefits need further investigation. OBJECTIVE: To investigate the efficacy and feasibility of near-infrared fluorescence imaging and angiography of the inferior vesical artery in laparoscopic lateral lymph node dissection. DESIGN: A prospective nonrandomized controlled study. SETTINGS: Single-center study. PATIENTS: Patients with lower rectal cancer who underwent total mesorectal excision plus lateral lymph node dissection. MAIN OUTCOME MEASURES: A cohort of 108 patients was enrolled. After propensity score matching, 29 patients in the near-infrared group and 50 patients in the non–near-infrared group were matched. The total number of harvested lateral lymph nodes, positive lateral lymph nodes, inferior vesical artery preservation, and postoperative urinary function were compared. RESULTS: After propensity score matching, both groups had similar baseline characteristics. The total number of harvested lateral lymph nodes in the near-infrared group was significantly higher (12 vs 9, p = 0.013), but positive lateral lymph nodes were similar between the 2 groups (1 vs 1, p = 0.439). The inferior vesical artery preservation ratio was significantly increased with the aid of indocyanine green angiography (93.1% vs 56.0%, p &lt; 0.001). The non–near-infrared group required more days for urinary catheter removal than the near-infrared group (5 vs 4, p = 0.046). Urinary recatheterization tended to occur more frequently in the non–near-infrared group, with a marginally significant trend (16% vs 0%, p = 0.059). The non–near-infrared group tended to have more cases with residual urine volume ≥50 mL than the near-infrared group (20.0% vs 3.4%, p = 0.087), especially in the bilateral dissection subgroup (41.2% vs 0%, p = 0.041). LIMITATIONS: Small sample size. CONCLUSIONS: Near-infrared imaging increased the number of harvested lateral lymph nodes, whereas real-time indocyanine green fluorescence angiography ensured the preservation of the inferior vesical artery and tended to improve postoperative urinary function.

Intraoperative pancreas stump perfusion assessment during pancreaticoduodenectomy: A systematic scoping review.

Post-operative pancreatic fistula (POPF) is the primary cause of morbidity following pancreaticoduodenectomy. Rates of POPF have remained high despite well known risk factors. The theory that hypoperfusion of the pancreatic stump leads to anastomotic failure has recently gained interest. To define the published literature with regards to intraoperative pancreas perfusion assessment and its correlation with POPF. A systematic search of available literature was performed in November 2022. Data extracted included study characteristics, method of assessment of pancreas stump perfusion, POPF and other post-pancreatic surgery specific complications. Five eligible studies comprised two prospective non-randomised studies and three case reports, total 156 patients. Four studies used indocyanine green fluorescence angiography to assess the pancreatic stump, with the remaining study assessing pancreas perfusion by visual inspection of arterial bleeding of the pancreatic stump. There was significant heterogeneity in the definition of POPF. Studies had a combined POPF rate of 12%; intraoperative perfusion assessment revealed hypoperfusion was present in 39% of patients who developed POPF. The rate of POPF was 11% in patients with no evidence of hypoperfusion and 13% in those with evidence of hypoperfusion, suggesting that not all hypoperfusion gives rise to POPF and further analysis is required to analyse if there is a clinically relevant cut off. Significant variance in practice was seen in the pancreatic stump management once hypoperfusion was identified. The current published evidence around pancreas perfusion during pancreaticoduodenectomy is of poor quality. It does not support a causative link between hypoperfusion and POPF. Further well-designed prospective studies are required to investigate this.