Indocyanine Green Fluorescence Intensity Research Articles

Validation of a semi-quantitative scoring system and workflow for analysis of fluorescence quantification in companion animals

SignificanceMany commercially available near-infrared (NIR) fluorescence imaging systems lack algorithms for real-time quantifiable fluorescence data. Creation of a workflow for clinical assessment and post hoc analysis may provide clinical researchers with a method for intraoperative fluorescence quantification to improve objective outcome measures.AimScoring systems and verified image analysis are employed to determine the amount and intensity of fluorescence within surgical specimens both intra and postoperatively.ApproachLymph nodes from canine cancer patients were obtained during lymph node extirpation following peritumoral injection of indocyanine green (ICG). First, a semi-quantitative assessment of surface fluorescence was evaluated. Images obtained with a NIR exoscope were analysed to determine fluorescence thresholds and measure fluorescence amount and intensity.ResultsPost hoc fluorescence quantification (threshold of Hue = 165–180, Intensity = 30–255) displayed strong agreement with semi-quantitative scoring (k = 0.9734, p < 0.0001). Fluorescence intensity with either threshold of 35–255 or 45–255 were significant predictors of fluorescence and had high sensitivity and specificity (p < 0.05). Fluorescence intensity and quantification had a strong association (p < 0.001).ConclusionThe validation of the semi-quantitative scoring system by image analysis provides a method for objective in situ observation of tissue fluorescence. The utilization of thresholding for ICG fluorescence intensity allows post hoc quantification of fluorescence when not built into the imaging system.

Real-time fluorescence-guided adhesiolysis with indocyanine green in intra-abdominal surgery (with video)

Intra-abdominal adhesions have consistently posed a challenge for surgeons during procedures. This study aims to investigate the feasibility of utilizing indocyanine green (ICG) in conjunction with near-infrared imaging for the detection of intra-abdominal adhesions. In vitro, we analyzed factors affecting ICG fluorescence. We divided SD rats into groups to study ICG excretion in different digestive tract regions. Additionally, we reviewed surgical videos from previous cholecystectomy cases, categorizing them by ICG injection timing and assessing fluorescence imaging in various digestive tract regions. Finally, we preoperatively injected ICG into two cholecystectomized patients with abdominal adhesions, guiding intraoperative adhesiolysis with near-infrared fluorescence imaging. In vitro, we observed a significant influence of protein and ICG concentrations on ICG fluorescence intensity. Our rat experiments unveiled a strong and highly significant correlation (Kendall’s tau-b = 1, P < 0.001) between the timing of ICG injection and the farthest point of intestinal fluorescence. A retrospective case analysis further validated this finding (Kendall’s tau-b = 0.967, P < 0.001). Under the guidance of fluorescence navigation, two cholecystectomized patients with intra-abdominal adhesions successfully underwent adhesiolysis, and no postoperative complications occurred. The intraoperative combination of ICG with near-infrared fluorescence imaging effectively enhances the visibility of the liver, bile ducts, and various segments of the gastrointestinal tract while providing real-time navigation. This real-time fluorescence guidance has the potential to aid surgeons in the dissection of intra-abdominal adhesions.

Changes in choroidal hemodynamics of form-deprivation myopia in Guinea pigs

PurposeWe studied changes in the choroid, particularly variation in blood flow, during the development of myopia. The hemodynamic mechanism in play remains unclear. We evaluated blood flow by quantitating indocyanine green (ICG) fluorescence in a guinea pig model of form-deprivation myopia. MethodsGuinea pigs were divided into form-deprivation myopia (FDM) and normal control (NC) groups. Ocular biometric and choroidal hemodynamics parameters were quantitatively derived via ICG imaging, and included the maximal ICG fluorescence intensity (Imax), rising time (Trising), blood flow index (BFI), and mean transit time (MTT). ResultsForm deprivation was associated with significant interocular differences in terms of both refractive error and axial length. ICG fluorescence hemodynamic maps of fundal blood flow and vasculature density were evident. In deprived eyes, the fluorescence signals exhibited significantly longer Trising and MTT but lower Imax and BFI than fellow eyes and NC group. The interocular differences in terms of the ocular biometric and hemodynamic parameters were significantly correlated. Hemodynamic analysis of choriocapillaris lobules revealed weakened fluorescence intensity and prolonged arrival and filling times in deprived eyes. Form deprivation reduced the number of lobulated choriocapillaris structures. ConclusionForm-deprivation myopia triggered changes in the hemodynamic and vascular network structures of the choroid and choriocapillaris. The ICG fluorescence imaging/analysis method provides a unique tool for further myopia research.

Comparing laser speckle contrast imaging and indocyanine green angiography for assessment of parathyroid perfusion

Accurate intraoperative assessment of parathyroid blood flow is crucial to preserve function postoperatively. Indocyanine green (ICG) angiography has been successfully employed, however its conventional application has limitations. A label-free method overcomes these limitations, and laser speckle contrast imaging (LSCI) is one such method that can accurately detect and quantify differences in parathyroid perfusion. In this study, twenty-one patients undergoing thyroidectomy or parathyroidectomy were recruited to compare LSCI and ICG fluorescence intraoperatively. An experimental imaging device was used to image a total of 37 parathyroid glands. Scores of 0, 1 or 2 were assigned for ICG fluorescence by three observers based on perceived intensity: 0 for little to no fluorescence, 1 for moderate or patchy fluorescence, and 2 for strong fluorescence. Speckle contrast values were grouped according to these scores. Analyses of variance were performed to detect significant differences between groups. Lastly, ICG fluorescence intensity was calculated for each parathyroid gland and compared with speckle contrast in a linear regression. Results showed significant differences in speckle contrast between groups such that parathyroids with ICG score 0 had higher speckle contrast than those assigned ICG score 1, which in turn had higher speckle contrast than those assigned ICG score 2. This was further supported by a correlation coefficient of -0.81 between mean-normalized ICG fluorescence intensity and speckle contrast. This suggests that ICG angiography and LSCI detect similar differences in blood flow to parathyroid glands. Laser speckle contrast imaging shows promise as a label-free alternative that overcomes current limitations of ICG angiography for parathyroid assessment.

Investigation of optimizing indocyanine green solution for in vivo lymphatic research using near-infrared fluorescence indocyanine green lymphangiography

Despite the tireless efforts of many researchers in lymphatic research, indocyanine green (ICG) solution conditions suitable for lymphatic circulation tests have not been perfectly established yet. We aimed to investigate the optimal in vivo conditions of ICG solution to avoid photobleaching and quenching effects, which may affect the accuracy of lymphatic circulation evaluation. After ICG fluorescence intensity (or ICG intensity) was assessed under different in vitro conditions, the image quality of brachial lymph nodes (LNs) and collecting lymphatic vessels (LVs) in eight rats was investigated. The in vitro results showed that ICG intensity depends on concentration and time in various solvents; however, the brightest intensity was observed at a concentration of 8–30 μg/mL in all solvents. ICG concentration in the albumin (bovine serum albumin; BSA) solution and rat’s plasma showed more than two times higher fluorescence intensity than in distilled water (DW) in the same range. However, saline reduced the intensity by almost half compared to DW. In the in vivo experiment, we obtained relatively high-quality images of the LNs and LVs using ICG in the BSA solution. Even at low concentrations, the result in the BSA solution was comparable to those obtained from high-concentration solutions commonly used in conventional circulation tests. This study provides valuable information about the conditions for optimal ICG intensity in near infrared fluorescence indocyanine green (NIRF-ICG) lymphangiography, which may be useful not only for the diagnosis of lymphatic circulation diseases such as lymphedema but also for preclinical research for the lymphatic system.

Experimental study of the quantification of indocyanine green fluorescence in ischemic and non-ischemic anastomoses, using the SERGREEN software program

Tissue ischemia is a key risk factor in anastomotic leak (AL). Indocyanine green (ICG) is widely used in colorectal surgery to define the segments with the best vascularization. In an experimental model, we present a new system for quantifying ICG fluorescence intensity, the SERGREEN software. Controlled experimental study with eight pigs. In the initial control stage, ICG fluorescence intensity was analyzed at the level of two anastomoses, in the right and in the left colon. Control images of the two segments were taken after ICG administration. The images were processed with the SERGREEN program. Then, in the experimental ischemia stage, the inferior mesenteric artery was sectioned at the level of the anastomosis of the left colon. Fifteen minutes after the section, sequential images of the two anastomoses were taken every 30 min for the following 2 h. At the control stage, the mean scores were 134.2 (95% CI 116.3–152.2) for the right colon and 147 (95% CI 134.7–159.3) for the left colon (p = 0.174) (Scale RGB—Red, Green, Blue). The right colon remained stable throughout the experiment. In the left colon, intensity fell by 47.9 points with respect to the pre-ischemia value (p < 0.01). After the first post-ischemia determination, the values of the ischemic left colon remained stable throughout the experiment. The relative decrease in ICG fluorescence intensity of the ischemic left colon was 32.6%. The SERGREEN program quantifies ICG fluorescence intensity in normal and ischemic situations and detects differences between them. A reduction in ICG fluorescence intensity of 32.6% or more was correlated with complete tissue ischemia.

Electromagnetic Tracking and Optical Molecular Imaging Guidance for Liver Biopsy and Point-of-Care Tissue Assessment in Phantom and Woodchuck Hepatocellular Carcinoma.

To evaluate an integrated liver biopsy platform that combined CT image fusion, electromagnetic (EM) tracking, and optical molecular imaging (OMI) of indocyanine green (ICG) to target hepatocellular carcinoma (HCC) lesions and a point-of-care (POC) OMIto assessbiopsy cores, allbased on tumor retention of ICGcompared to normal liver, in phantom and animal model. A custom CT image fusion and EM-tracked guidance platform was modified to integrate the measurement of ICG fluorescence intensity signals in targeted liver tissue with an OMI stylet or a POC OMI system. Accuracy was evaluated in phantom and a woodchuck with HCC, 1day after administration of ICG. Fresh biopsy cores and paraffin-embedded formalin-fixed liver tissue blocks were evaluated with the OMI stylet or POC system to identify ICG fluorescence signal and ICG peak intensity. The mean distance between the initial guided needle delivery location and the peak ICG signal was 5.0 ± 4.7mm in the phantom. There was complete agreement between the reviewers of the POC-acquired ICG images, cytology, and histopathology in differentiating HCC-positive from HCC-negative biopsy cores. The peak ICG fluorescence intensity signal in the ex vivo liver blocks was 39 ± 12 and 281 ± 150 for HCC negative and HCC positive, respectively. Biopsy guidance with fused CT imaging, EM tracking, and ICG tracking with an OMI stylet to detect HCC is feasible. Immediate assessment of ICG uptake in biopsy cores with the POC OMI system is feasible and correlates with the presence of HCC in the tissue.

Drug penetration enhancement techniques in ablative fractional laser assisted cutaneous delivery of indocyanine green.

Background and ObjectivesTopical drug delivery can be increased by pretreatment of the skin with ablative fractional laser (AFXL). Several physical penetration enhancement techniques have been investigated to further improve AFXL‐assisted drug delivery. This study investigated the influence of three of these techniques, namely massage, acoustic pressure wave treatment, and pressure vacuum alterations (PVP) on the distribution of the fluorescent drug indocyanine green (ICG) at different depths in the skin after topical application on AFXL pretreated skin.Materials and MethodsIn ex vivo human skin, test regions were pretreated with AFXL (10,600 nm, channel depth 300 μm, channel width 120 μm, density 15%). Subsequently, ICG was applied, followed by massage, acoustic pressure wave treatment or PVP. ICG fluorescence intensity (FI) was assessed after 1, 3, and 24 hours at several depths using fluorescence photography.ResultsFI was higher when using enhancement techniques compared to control (AFXL‐only) up to 3 hours application time (P < 0.05). After 3 hours, mean surface FI was highest after acoustic pressure wave treatment (61.5 arbitrary units; AU), followed by massage (57.5AU) and PVP (46.9AU), respectively (for comparison: AFXL‐only 31.6AU, no pretreatment 14.9AU). Comparable or higher FI was achieved already after 1 hour with enhancement techniques compared to 3–24 hours application time without. After 24 hours, no significant differences between enhancement techniques and AFXL‐only were observed (P = 0.31).ConclusionPenetration enhancement techniques, especially acoustic pressure wave treatment and massage, result in improved drug accumulation in AFXL‐pretreated skin and reduce the application time needed. Lasers Surg. Med. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Core-Satellite Nanomedicines for in Vivo Real-Time Monitoring of Enzyme-Activatable Drug Release by Fluorescence and Photoacoustic Dual-Modal Imaging.

It remains an unresolved challenge to achieve spatial and temporal monitoring of drug release from nanomedicines (NMs) in vivo, which is of crucial importance in disease treatment. To tackle this issue, we constructed core-satellite ICG/DOX@Gel-CuS NMs, which consist of gelatin (Gel) nanoparticles (NPs) with payloads of near-infrared fluorochrome indocyanine green (ICG) and chemo-drug doxorubicin (DOX) and surrounding CuS NPs. The fluorescence of ICG was initially shielded by satellite CuS NPs within the intact ICG/DOX@Gel-CuS NMs and increased in proportion to the amount of DOX released from NMs in response to enzyme-activated NMs degradation. For more comprehensive understanding of the drug-release profile, a theoretical model derived from computer simulation was employed to reconstruct the enzyme-activatable drug release of the ICG/DOX@Gel-CuS NMs, which demonstrated the underlying kinetics functional relationship between the released DOX amount and recovered ICG fluorescence intensity. The kinetics of drug release in vivo was assessed by administrating ICG/DOX@Gel-CuS NMs both locally and systemically into MDA-MB-231 tumor-bearing mice. Upon accumulation of ICG/DOX@Gel-CuS NMs in the tumor, overexpressed enzymes triggered the degradation of the gelatin scaffold as well as the release of DOX and ICG, which can be visually depicted with the ICG fluorescence signal increasing only in the tumor area by fluorescence imaging. Additionally, the photoacoustic signal from CuS NPs was independent from the physical status of ICG/DOX@Gel-CuS NMs and hence was utilized for real-time NMs tracking. Thus, by taking advantage of the core-satellite architecture and NMs degradability in tumor site, the DOX release profile of ICG/DOX@Gel-CuS NMs was monitored by fluorescence and photoacoustic dual-modal imaging in a real-time noninvasive manner.

Quantitative assessment of fluorescence intensity of ICG in sentinel nodes in early gastric cancer.

The sentinel node (SN) detection by dual tracer method using indocyanine green (ICG) and a radioisotope (RI) has been recommended for early gastric cancer. However, institutions are limited due to radioactivity in the RI method. The greatest advantage of the RI method is that it objectively assesses RI uptake as a numerical value. The aim of the present study was to verify the usefulness of ICG fluorescence intensity in SN. Seventeen patients with early gastric cancer were enrolled in this study. RI uptake by each lymph node was measured using Navigator GPS and fluorescence nodes were identified using the hyper eye medical system (HEMS). Fluorescence intensity in fluorescence nodes was evaluated using ICG intensity imaging software (Mizuho, Japan) of the HEMS. The total number of dissected lymph nodes was 227, with an average of 13.3 per patient. The numbers of HN, FN-S, and FN-B were 64, 77, and 34. RI uptake was significantly greater by FN-S than by non-FN-S (P = 0.0016). The median fluorescence intensity value was higher in HN than in non-HN (P < 0.001). A correlation was observed between RI uptake and fluorescence intensity. Dissecting FNs with fluorescence intensity levels of 1-6 resulted in 92.1% dissection of HNs. It is possible that the evaluation of fluorescence intensity is useful for selected SNs instead of RI tracer. If fluorescence intensity is measurable in surgery, an infrared fluorescence method using ICG may be useful and safe for the detection of SN in early gastric cancer.

Evaluation of liposomal behavior in the gastrointestinal tract after oral administration using real-time in vivo imaging

Liposomes are regarded as promising drug carriers for enhancing the pharmacological effects of poorly absorbed drugs, such as peptides, following oral administration. Liposomal surface modifications by mucoadhesive polymers could improve drug absorption through interactions with the mucus layer. The main purpose of this study was to establish a method of monitoring the behavior of liposomes within the body after oral administration, particularly in the gastrointestinal (GI) tract, using a real-time in vivo imaging system (IVIS) to elucidate the behavior of surface-modified liposomes. Indocyanine green (ICG) was used as a near-infrared dye to label chitosan (CS) or glycol CS (GCS)-modified liposomes, and to observe the dynamic behavior of the liposomes in rats by noninvasive IVIS after oral administration. First, we validated IVIS results of the rat abdomens by comparing them to quantitative measurements of ICG fluorescence intensity in tissue homogenates. Nano-sized small unilamellar vesicles were retained longer than micro-sized multilamellar vesicles in the GI tract. Furthermore, surface-modified liposomes showed longer-term retention in the GI tract than unmodified liposomes in fasted rats. Moreover, surface modification by CS or GCS effectively prevented the excretion of liposomes from the GI tract and prolonged retention in fed rats.

Influence of vessel stenosis on indocyanine green fluorescence intensity assessed by near-infrared fluorescence angiography.

Although useful for visualizing blood flow during revascularization surgery, the permeability of near-infrared fluorescence (NIR) angiography using indocyanine green (ICG) does not allow for vessel stenosis visualization. We hypothesized that changes in ICG fluorescence intensity reflect vessel stenosis, and evaluated the influence of stenosis on blood flow by ex vivo experimentation. The vessel stenosis model comprised a silicon tube, a graft occluder, and artificial blood. During near-infrared angiography, the fluorescense intensity was calculated during pre- and post-stenosis of an artificial circuit, using a NIR angiography. We measured the maximum fluorescence intensity and the time to maximum fluorescence intensity. Severe stenosis (≥75%) attenuated the increase in ICG fluorescence intensity in the tube significantly, pre- and post-stenosis. The time to maximum fluorescence intensity did not differ between sites pre- and post-stenosis, irrespective of stenosis severity. Stenosis affected the ICG fluorescence intensity through the vessel. Thus, quantitative analysis using NIR angiography may detect severe vessel stenosis (≥75%), and the extinction curve of indocyanine fluorescence intensity may support the evaluation of blood flow. The absence of differences in the time to maximum fluorescence intensity for degrees of stenosis might suggest a limitation of previous conventional qualitative assessments.

Development of ultrasound-assisted fluorescence imaging of indocyanine green.

Indocyanine green (ICG) accumulation in hepatocellular carcinoma means tumors can be located by fluorescence. However, because of light scattering, it is difficult to detect ICG fluorescence from outside the body. We propose a new fluorescence imaging method that detects changes in the intensity of ICG fluorescence by ultrasound-induced temperature changes. ICG fluorescence intensity decreases as the temperature rises. Therefore, it should theoretically be possible to detect tissue distribution of ICG using ultrasound to heat tissue, moving the point of ultrasound transmission, and monitoring changes in fluorescence intensity. A new probe was adapted for clinical application. It consisted of excitation light from a laser, fluorescence sensing through a light pipe, and heating by ultrasound. We applied the probe to bovine liver to image the accumulation of ICG. ICG emits fluorescence (820nm) upon light irradiation (783nm). With a rise in temperature, the fluorescence intensity of ICG decreased by 0.85%/°C. The distribution of fluorescent ICG was detected using an ultrasonic warming method in a new integrated probe. Modulating fluorescence by changing the temperature using ultrasound can determine where ICG accumulates at a depth, highlighting its potential as a means to locate hepatocellular carcinoma.

Elevated plasma factor VIII enhances venous thrombus formation in rabbits: Contribution of factor XI, von Willebrand factor and tissue factor

Elevated plasma levels of factor VIII (FVIII) are associated with increased risk of deep venous thrombosis. The aim of this study is to elucidate how elevated FVIII levels affect venous thrombus formation and propagation in vivo. We examined rabbit plasma FVIII activity, plasma thrombin generation, whole blood coagulation, platelet aggregation and venous wall thrombogenicity before and one hour after an intravenous infusion of recombinant human FVIII (rFVIII). Venous thrombus induced by the endothelial denudation of rabbit jugular veins was histologically assessed. Thrombus propagation was evaluated as indocyanine green fluorescence intensity. Argatroban, a thrombin inhibitor, and neutralised antibodies for tissue factor (TF), factor XI (FXI), and von Willebrand factor (VWF) were infused before or after thrombus induction to investigate their effects on venous thrombus formation or propagation. Recombinant FVIII (100 IU/kg) increased rabbit plasma FVIII activity two-fold and significantly enhanced whole blood coagulation and total plasma thrombin generation, but did not affect initial thrombin generation time, platelet aggregation and venous wall thrombogenicity. The rFVIII infusion also increased the size of venous thrombus 1 hour after thrombus induction. Argatroban and the antibodies for TF, FXI or VWF inhibited such enhanced thrombus formation and all except TF suppressed thrombus propagation. In conclusion, elevated plasma FVIII levels enhance venous thrombus formation and propagation. Excess thrombin generation by FXI and VWF-mediated FVIII recruitment appear to contribute to the growth of FVIII-driven venous thrombus.

Near Infrared Confocal Imaging of the Human Liver During Ongoing Mini-Laparoscopy: A Newly Developed Rigid Endomicroscope with Increased Imaging Plane Depth

Introduction: Histopathology is the gold standard in the diagnosis of liver diseases. However, it can be complicated by sampling error and bleeding and does not allow dynamic tissue monitoring. Confocal laser endomicroscopy (CLE) is a novel imaging modality providing in vivo histology at subcellular resolution during ongoing endoscopy. Previous studies using rigid CLE (Optiscan, Australia) for in vivo liver microscopy have suffered from limited imaging depth (<250 μm) using blue laser light and fluorescein as a contrast agent. Aim of the current study was to evaluate in vivo confocal imaging of the human liver by mini-laparoscopy using a newly developed near infrared (NIR) light probe (Optiscan) in conjunction with indocyanine green (ICG) contrast injection. Methods and Patients: The rigid laparoscopy probe (diameter 6.3 mm) used a 780 nm diode laser for fluorophore excitation. Light emission was detected at >795 nm. Subsurface images at different depths with 0.7 μm lateral resolution at 2-3 sites were generated in real time at 1024×512 pixels (approximating a 1000fold magnification) by gently placing the sterile probe onto the human liver. Targeted liver biopsy of one examined area was performed for histopathological correlation. Results: 22 patients were examined under conscious sedation (44.3yrs (26-67), f: m=6: 16; toxic liver damage n=6, viral n=12, suspected steatosis n=4). Maximum imaging depth was over 350 μm. Typical aspects of normal liver architecture and liver diseases, such as nuclei, sinusoids, fibrous tissue, fatty inclusions and bile ducts could be visualized at high resolution in 21/22 pts. The presence of steatosis and fibrosis was predicted correctly in 81% and 90% of patients, resp., and semiquantitative assessment was possible from images generated in vivo. In accordance with the macroscopic liver aspect, confocal microscopy even detected 2 cases of fibrosis that were not seen in histopathology (suspected biopsy sampling error). ICG fluorescence intensity was dependent on liver function, adding functional information to morphology. No liver damage or severe adverse events were noted upon confocal microscopy. Discussion: The newly developed near infrared confocal probe allowed for the first time in vivo imaging of the human liver with deeper imaging plane depths compared to the so far available blue laser systems. Such an increase of imaging depth could potentially also be used for submucosal imaging of the GI tract. ICG augmented confocal imaging of the human liver is a safe method and allowed in vivo imaging with subcellular resolution of typical aspects of human liver diseases during ongoing mini-laparoscopy.

P-1-122 - Surgery of the anomalles of the vertebral artery

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis has been used in moyamoya disease (MD) and non-moyamoya ischemic stroke (non-MD). It is important to monitor hemodynamic changes caused by bypass surgery for postoperative management. We evaluated the bypass blood flow during STA-MCA anastomosis by using indocyanine green (ICG) fluorescence angiography.We evaluated the bypass blood flow in 13 MD and 21 non-MD patients during STA-MCA anastomosis by means of ICG angiography with injection of ICG into the anastomosed STA. The ICG perfusion area was calculated when the ICG fluorescence intensity reached maximum. We measured cortical oxygen saturation before anastomosis by means of visual light spectroscopy.ICG angiography demonstrated bypass blood flow from the anastomosed STA to the cortical vessels in all patients. The ICG perfusion area in MD (20.7 ± 6.6 cm2) was significantly larger than that in non-MD (8.4 ± 9.1 cm2, P < 0.05). The cortical oxygen saturation (58.9% ± 8.3%) in MD was significantly lower than that in non-MD (73.4% ± 9.5%, P < 0.05).ICG angiography with injection of ICG into the bypass artery allowed quantitative assessment of bypass blood flow. The bypass supplies blood flow to a greater extent in MD than in non-MD during surgery. This might be caused by a larger pressure gradient between the anastomosed STA and recipient vessels in MD. These observations indicate that MD requires careful control of systemic blood pressure after surgery to avoid cerebral hyperperfusion syndrome. ICG angiography is considered useful for facilitating safe and accurate bypass surgery and providing information for postoperative management.

P-1-123 - Arterial reconstruction for vertebral artery stenosis at the origin

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis has been used in moyamoya disease (MD) and non-moyamoya ischemic stroke (non-MD). It is important to monitor hemodynamic changes caused by bypass surgery for postoperative management. We evaluated the bypass blood flow during STA-MCA anastomosis by using indocyanine green (ICG) fluorescence angiography.We evaluated the bypass blood flow in 13 MD and 21 non-MD patients during STA-MCA anastomosis by means of ICG angiography with injection of ICG into the anastomosed STA. The ICG perfusion area was calculated when the ICG fluorescence intensity reached maximum. We measured cortical oxygen saturation before anastomosis by means of visual light spectroscopy.ICG angiography demonstrated bypass blood flow from the anastomosed STA to the cortical vessels in all patients. The ICG perfusion area in MD (20.7 ± 6.6 cm2) was significantly larger than that in non-MD (8.4 ± 9.1 cm2, P < 0.05). The cortical oxygen saturation (58.9% ± 8.3%) in MD was significantly lower than that in non-MD (73.4% ± 9.5%, P < 0.05).ICG angiography with injection of ICG into the bypass artery allowed quantitative assessment of bypass blood flow. The bypass supplies blood flow to a greater extent in MD than in non-MD during surgery. This might be caused by a larger pressure gradient between the anastomosed STA and recipient vessels in MD. These observations indicate that MD requires careful control of systemic blood pressure after surgery to avoid cerebral hyperperfusion syndrome. ICG angiography is considered useful for facilitating safe and accurate bypass surgery and providing information for postoperative management.