Indocyanine Green Patterns Research Articles

Correlation Between Indocyanine Green Fluorescence Patterns and Grade of Differentiation of Hepatocellular Carcinoma: A Western Prospective Cohort Study.

Background. Most of the available evidence on the use of indocyanine green (ICG) fluorescence in clinical practice consists of articles published by surgeons of the Asian-Pacific area. We performed a prospective cohort study to assess the patterns of ICG fluorescence in Western hepatocellular carcinoma (HCC) counterparts.Methods. From April 2019 to January 2022, a total of 31 consecutive patients who underwent laparoscopic liver resection (LLR) for superficial HCC were enrolled in this prospective study. All patients underwent laparoscopic staging with both laparoscopic ultrasound (LUS) and ICG fluorescence imaging.Results. A total of 38 hepatocellular carcinomas (HCCs) were enrolled: 23 superficial (surfacing at the liver's Glissonian capsule), 5 exophytic, 5 shallow (<8mm from the hepatic surface) and 5 deep (>10mm from the hepatic surface). The detection rate with preoperative imaging (abdominal CT/MRI), LUS, ICG fluorescence and combined modalities (ICG and LUS) was 97.4%, 94.9%, 89.7% and 100%, respectively. The five deep seated lesions underwent ultrasound-guided laparoscopic thermal ablation. The other 33 HCCs were treated with minimally invasive liver resection. Intraoperative ultrasound patterns were registered for each single nodule resected. The ICG fluorescence pattern was classified in two types: total fluorescence (all the tumoral tissue showed strong and homogeneous fluorescence), n = 9/33 (27.3%), and non-total fluorescence (partial and rim fluorescence), n = 24/33 (72.7%). There was a statistical correlation between ICG patterns and grade of differentiation. Almost all lesions with uniform fluorescence pattern were well-differentiated HCCs (G1-G2), while partial and rim-type fluorescence pattern were more common among moderately and poorly differentiated HCCs (G3-G4) (88.9% vs 11.1%, 37.5% vs 62.5%, P = .025, respectively).Conclusions. ICG fluorescence imaging could be used to identify early the grade of HCC, ie intraoperatively, thus influencing the intraoperative treatment.

Relationship between perimetric increase and fluoroscopic pattern type in secondary upper limb lymphedema observed by Indocyanine green lymphography.

To ascertain the relationship between the perimetric differences obtained between the limbs and the type of fluoroscopic pattern observed by Indocyanine green (ICG) lymphography in patients with upper limb lymphedema.A correlational descriptive study was carried out in 19 patients with upper limb lymphedema secondary to breast cancer. The perimetric increase was recorded in 11 anatomical regions after ICG injection, fluoroscopic patterns were identified using an infrared camera. The ICG patterns were categorized into worse (stardust, diffuse) or better (linear, splash) patterns.The pattern coincidence between the anterior and posterior regions of the edematous extremities was 45%. At the wrist level, a difference of 2 cm was associated with the presence of a worse fluoroscopic pattern, whereas perimeter differences of 4.25 cm in the elbow and 2.25 cm in the arm (12 cm from the epicondyle) were associated with the presence of a better fluoroscopic pattern.The perimetric differences observed between the healthy and affected upper limbs in 4 specific anatomical areas allowed us to predict the type of fluoroscopic pattern. ICG lymphography has facilitated the study of the posterior regions of edema, which are difficult to visualize using other imaging techniques.

Changes in Indocyanine Green Lymphography Patterns after Physical Treatment in Secondary Upper Limb Lymphedema.

Indocyanine green (ICG) lymphography is used to evaluate the lymphatic function before and after pneumatic compression or post-manual lymphatic drainage. The aim of this study was to ascertain the changes in the fluoroscopic pattern produced by the provision of complex physical therapy. This prospective analytic (pretest-posttest) study was conducted in 19 patients with upper lymphedema secondary to breast cancer. Nine patients were excluded due to ICG found after 3 weeks. The ICG patterns were analyzed under basal conditions and after three weeks of treatment. After the treatment, 45% of the patients presented tracer remains in the affected limb, and this finding was significantly related to time of the lymphedema development. In one subject, the patterns remain unchanged or cannot be defined. Three of the ten patients observed present the worsening of at least 1 of the patterns and in the rest of the subjects, six cases, the improvement of the patterns is observed. In 60% of the cases, the most severe pattern reversed towards slight (splash) cases, and moderate cases reversed towards a slight case in 70% of cases. Therefore, after treatment with complex physical therapy, the pathological patterns observed in the pretest, which evolved positively, reverted their severity toward milder disease patterns or towards normality.

Efficacy of indocyanine green fluorescence in predicting parathyroid vascularization during thyroid surgery.

We examined the value of indocyanine green (ICG) fluorescence angiography in predicting parathyroid vascularization following thyroid and central compartment surgeries. Data were prospectively collected on adult patients undergoing thyroid and/or central compartment surgeries. Outcomes were compared in surgeries performed with and without ICG use. ICG scoring was used to quantify the vascularity of parathyroid glands. One hundred eleven patients were included; 43 (38.7%) patients underwent ICG injections. There was no significant difference in mean parathyroid hormone (PTH) changes at the end of surgery (29.24 vs 23.48 pg/mL, P = .38), symptomatic hypocalcemia (7.9% vs 3.9%, P = .37), or length of stay (1.095 ± 0.22 vs 0.912 ± 0.07 days, P = .51) between surgeries performed with and without ICG. The average vascularization score among individuals undergoing ICG angiography was 2.89 out of a maximum of 8 points. Low-flow ICG patterns are not associated with postoperative PTH changes or transient hypocalcemia and may lead to unnecessary parathyroid autotransplantation.

Correlation between indocyanine green (ICG) patterns and real-time elastography images in lower extremity lymphedema patients

Indocyanine green (ICG) lymphography is becoming a popular modality, but unfortunately it is not available in all institutions. Elastography is a relatively new ultrasonographic technique to evaluate tissue elasticity, which visualizes fluid retention as a red region in lymphedema patients. The aim of this study was to evaluate the correlation between elastography and ICG lymphology. Thirty-six legs in 18 patients with secondary lower extremity lymphedema (LEL) and 20 legs in 10 healthy volunteers were examined using elastography. Thirty-six legs in 18 secondary LEL patients were examined using ICG lymphography. Elastography was performed on both legs at the following three sites: medial thigh (MT), medial leg (ML), and anterior ankle (AA). The area of the red region in the subcutaneous tissue demonstrated by elastography was calculated using Image software. ICG lymphography findings were classified into the following four patterns: linear (ICG1), splash (ICG2), stardust (ICG3), and diffuse (ICG4) patterns. As ICG pattern progressed, the red region area was likely to increase. There was a correlation between ICG patterns and red region area according to the severity at bilateral MT (rs = 0.665), ML (rs = 0.623), and AA (rs = 0.668). Significant difference was demonstrated among group means of the red region area by analysis of variance (healthy vs. ICG1 vs. ICG2 vs. ICG3 vs. ICG 4: 14.4 ± 5.7 vs. 15.1 ± 10.3 vs. 25.2 ± 6.2 vs. 30.8 ± 9.4 vs. 35.0 ± 2.8; P < 0.001). The area of the red region in the subcutaneous tissue shown using elastography, which represents fluid, increases with the aggravation of lymphedema demonstrated by ICG patterns. As elastography is performed by ultrasonography, which is available in most institutions, elastography could be a useful alternative evaluation for lymphedema severity when ICG lymphography is not available.

Indocyanine Green Dye Excretion in Bile Reflects Graft Function After Living Donor Liver Transplantation

There are many biochemical parameters that can be used to assess the function of partial liver graft; however, a definitive marker remains to be identified. For example, the color of bile has been reported anecdotally to reflect graft function, but its value has not yet been fully evaluated. Recently, indocyanine green (ICG) K value, that is ICG clearance, was found to be valuable in assessing the function of a whole or partial graft after living donor liver transplantation (LDLT) (1). However, the measurement of ICG dye concentrations in serum is not valid in hyperbilirubinemic patients because of interference while using the spectrophotometer (2). We previously reported the value of ICG dye concentration in the bile in an ICG challenge test in patients undergoing liver resection for bile duct cancer, because ICG is a relatively hydrophobic organic anion that has a high hepatic extraction ratio and is excreted extensively and remains unchanged in bile (3). It has also been reported that ICG excretion in bile could be a good parameter for assessing preoperative liver function in biliary drainage patients because it reflects adenosine triphosphate levels in the liver (4, 5). Thus, this study evaluates ICG excretion in bile after LDLT as a potential novel parameter of partial liver graft function. This prospective study was approved by the local institutional review board, and written informed consent was obtained from all patients. Of 37 consecutive patients who underwent liver transplantation between April 2005 and March 2007, 32 patients who received duct-to-duct biliary reconstruction were studied (median age 53 years; right lobe graft:left-sided graft 19:13; and graft volume/standard liver volume median 46%). One week after LDLT, we performed a fasting ICG injection test (0.5 mg/kg; Diagnogreen Inj.; Daiichi Seiyaku, Tokyo, Japan), and bile was collected through biliary external stenting reported earlier (6) while blocking natural light. ICG concentrations in bile at 0, 30, 120, and 360 min after injection were measured by spectrophotometer at a wavelength of 805 nm. Blood samples were also taken before ICG injection and 15 min after injection. All data were expressed as median values with ranges. The pattern of change in ICG excretion after ICG injection showed distinct two patterns. Type I (n=24) showed a steep increase and a peak within 2 hr and returned to baseline within 6 hr, whereas type II (n=8) showed a low peak of less than 1 micromole per liter during the 6-hr observation period. Table 1 shows various detailed parameters of type I and type II patients and their LDLTs. The parameters that correlated with ICG patterns were compared between the two groups, and donor age and graft type were found to have a significant influence on the type of ICG excretion in bile. Also, it shows the relationship between the type of ICG excretion in bile and various graft functions such as jaundice, prothrombin activity, and ICG retention rate at 15 min. In fact, because retention rate of ICG at 15 min after injection was correlated with type of ICG excretion in bile, ICG retention rate at 15 min can substitute the excretion pattern in bile. Several type II patients had prolonged jaundice after LDLT due to outflow block (n=1), acute cellular rejection (n=2), or unknown cause (n=5).TABLE 1: Factors influencing types of ICG excretion in bile and various outcomes after LDLTTo clarify changes in ICG pattern over time, the same challenge test was performed at 3 months after LDLT. Most patients remained or became type I (data not shown). Six of the eight patients who were classified as type II at 1 week after LDLT were classified as type I at 3 months after LDLT. Remaining two patients had prolonged jaundice until approximately 6 months after LDLT and recovered without jaundice. These two patients were complicated with biliary stricture and chronic rejection at 3 months after LDLT. Donor age has been reported to be an important factor of graft quality and liver regeneration (7). In addition, we demonstrate in this study that not only donor age but also graft type affects the bile excretion of the graft liver. Right posterior sector grafts are sometimes problematic because the portal vein is smaller at the second-grade bifurcation, causing relative portal hypertension and biliary stricture (8) Type II pattern at 1 week after LDLT is not a predictor of poor outcome with a partial graft, although prolonged jaundice should be expected. In fact, duration until the disappearance of icterus is of great interest after liver transplantation. This study also demonstrates that ICG excretion in bile is a direct indicator of prolonged severe jaundice. Susumu Eguchi Mitsuhisa Takatsuki Kosho Yamanouchi Masaaki Hidaka Akihiko Soyama Tetsuo Tomonaga Yoshitsugu Tajima Takashi Kanematsu Department of Surgery Nagasaki University Graduate School of Biomedical Sciences Sakamoto, Nagasaki, Japan

Residual Indocyanine Green Fluorescence Pattern after Vitrectomy with Internal Limiting Membrane Peeling in High Myopia

The use of indocyanine green (ICG) during intraoperative internal limiting membrane (ILM) peeling is common for various macular diseases. The authors observed residual ICG after vitrectomy for high myopia-related macular diseases and found a unique pattern specific to its pathologic features. Observational case series. Twelve eyes of 12 patients with high myopia who had undergone vitrectomy with ICG-assisted ILM peeling were included (macular hole [MH], six eyes; MH and retinal detachment, three eyes; and myopic foveoschisis, three eyes). Patterns of residual ICG were observed in the posterior retina using the Heidelberg Retina Angiograph 2 (Heidelberg Engineering, Heidelberg, Germany) after surgery and were compared. The minimum follow-up was six months. Two control eyes of two patients without intravitreal ICG also were included in this study. The residual ICG fluorescence was observed in all eyes except for the control eyes. The pattern of residual ICG fluorescence depended on the degree of myopic chorioretinal atrophy. In eyes with no or minimum chorioretinal atrophy, the pattern was similar to that of an idiopathic MH. The ICG pattern was unique in those with moderate or severe atrophy. A strong ICG signal was observed at the area of diffuse atrophy and at the edge of the patchy atrophy and staphyloma. No ICG fluorescence was observed inside the patchy atrophy. Residual ICG fluorescence was observed in high myopia. ICG accumulation seems to depend on the status of the retinal pigment epithelial (RPE) underlying the posterior retina. RPE cells may play an important role in the kinetics of the residual ICG.

Indocyanine Green Angiographic Findings in Choroidal Hemangiomas: A Study of 75 Cases

Indocyanine green (ICG) angiography is a new diagnostic modality that was suggested, in small series, to provide a typical angiographic pattern in cases of choroidal hemangioma. Our study, through an exceptionally large series of 75 patients, assessed in a prospective way whether a typical ICG pattern of choroidal hemangioma exists and what would be its possible variations. The most constant feature is the sequence of the different ICG angiographic phases. The arterial phase demonstrates the filling of intratumoral vessels on a hypofluorescent tumoral background. During the venous phase, the hemangioma reaches a stage of maximal ICG-A fluorescence, with superimposed hyper- and hypofluorescent spots. Sturge-Weber cases have also extratumoral hyperfluorescent spots. The late phase shows a hypofluorescent lesion with residual hyperfluorescent caverns and a well-delineated, but complex border structure.