The aim of the study is to establish a new and more accurate method to visualize the peritoneal changes caused by endometriosis using Indocyanine Green mediated fluorescence imaging. The hypothesis is that Indocyanine Green, a fluorescent dye that has wide applications throughout medicine in identifying vascularity of tissues and neo-vascularization, could facilitate the localization and excision of endometriotic lesions exploiting the hypervascularization due to the chronic inflammation. The already published Pilot Study GRE-ENDO (Cosentino F, Near-Infrared Imaging with Indocyanine Green for Detection of Endometriosis Lesions (Gre-Endo Trial): A Pilot Study.), encouraged the effort of a larger prospective trial. Based on the mini-max two-stage design by Simon [Simon R. Optimal two stage design for phase II clinical trials], the investigators tested the null hypothesis that the true rate of pathologically assessed endometriosis would improve from 87% to the clinically relevant alternative of 100.0%, as assessed by NIR-ICG laparoscopy.

Patients were recruited within the clinical routine after indication for laparoscopy under consideration of the inclusion and exclusion criteria.

The sample size was calculated according to the study design by Simon (Simon R. Optimal two stage design for phase II clinical trials), using an α-error of 0.01 (two-sided) and a β-error of 0.90. Considering a patient dropout of approximately 10%, the study was planned to enrol at least 47 women.

The first abdominal and pelvi's inspection was made using direct laparoscope visualization under white light conditions. All areas suspected of peritoneal endometriosis was classified as white, black and red lesions and recorded together with their anatomic location in the surgical record for the purposes of subsequent extirpation. After the first visual inspection the patient was administered with 0.05 - 0.25 mg /(kg BW) Indocyanine Green intravenously. The Indocyanine Green imaging mode of the Olympus Indocyanine Green Imaging System was activated and suspected areas in Indocyanine Green imaging mode were recorded with them corresponding appearance in white light mode. If suspected areas were visible either in white light or Indocyanine Green imaging mode, specific sample has been taken from these areas. In addition, control biopsy specimens from inconspicuous peritoneum has been taken.

Inclusion Criteria:

• Suspected endometriosis with necessity for laparoscopic confirmation and resection
• Regular menstrual cycles

Exclusion Criteria:

• Patients younger than 18 years and older than 50 years at time of operation
• Subject with previous history of adverse reaction or allergy to Indocyanine Green, iodine, shellfish or iodine dyes
• Documented allergy to sulfur containing compounds
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to Indocyanine Green
• Subject has significant liver disease, cirrhosis or liver insufficiency with abnormal liver function tests (Total bilirubin increased by factor 1.5 than normal and/or serum glutamic oxaloacetic transaminase increased by factor 2 than normal)
• Subject has uremia, serum creatinine (> 2.0 mg/dl)
• Subject has severe coronary heart disease (instable angina pectoris)
• Pregnant or breast-feeding women
• Subject actively participating in another drug, biologic and/or device protocol
• The presence of medical conditions contraindicating general anesthesia or standard surgical approaches
• Subject has any medical condition, which in the judgment of the Investigator and/or designee makes the subject a poor candidate for the investigational procedure