Near Infra-red Imaging with Indocyanine Green for diagnosis and laparoscopic treatment of Endometriosis

Indocyanine green (ICG) is nowadays increasingly used in gynecological surgery, both in oncological and benign fields. It is frequently used in the identification of lymphatic tissue, but if injected intravenously, it binds to plasma proteins and persists in the vascular system, helping in the definition of the vascular network

Given the typical neovascularization of endometriosis, related to chronic inflammation, the visualization of abnormal areas of peritoneal vascularization could be useful to better identify and define the endometriosis lesions in their real extension and to visualize the lesions even when not obvious, as in puckered peritoneal lesions. For all of this, several methods have been proposed to improve the intraoperative treatment of endometriosis through enhancing the human vision power, with encouraging results.

The use of cameras with near-infrared radiation imaging (NIR) after injection of ICG represents one of the most encouraging methods in this experimental scenario, demonstrating a good profile of safety and accuracy as an intraoperative diagnostic method.

The aim of this study is to assess the diagnostic value of NIRICG imaging in the surgical treatment of endometriosis compared with the standard of treatment, that is laparoscopy in white light (WL), and the standard diagnostic method, that is pathologic finding.

A total of 50 women undergoing laparoscopy for suspected endometriosis will be studied over a period of 2 years. It will be a single arm prospective study.

Laparoscopy will be performed using the standard technique of the primary surgeon. During surgery, the abdomen and pelvis will be visually inspected using direct laparoscope visualization under WL conditions. All suspected areas will be classified as either peritoneal superficial endometriosis (PE) or deep infiltrating endometriosis (DIE). All suspected PE will be classified as white, black, and red lesions and documented with their anatomic location in the surgical record under WL condition. Similarly, all suspected DIE lesions will be also recorded with their anatomic location in the surgical record (retrocervical, vaginal, rectosigmoid, bladder lesions, etc.) under WL condition.The patient will then be administered 0.25 mg/kg of ICG intravenously. After an interval time of a minimum of 5 min, NIR-ICG imaging will be activated and the whole surgical field will be inspected with this filter. Doses will be repeated maximum thrice during surgery.

Every specimen resected during surgery will be considered as “suspect lesion” for endometriosis when visualized with WL and/or with NIR-ICG until pathological confirmation is obtained. If a suspect lesion is visualized with NIR-ICG and not in WL or, conversely, only with WL, it will be named “suspect occult lesion” (s-OcL), and only after conformation by pathology, it will be considered “confirmed occult lesion” (c-OcL). In addition, a random control biopsy from an apparent negative peritoneum visualized in WL and NIR-ICG imaging will be taken for all patients (control cases).A surgical specimen will be considered as “pathologic” when containing endometriosis foci (stroma and/or gland and/or hemosiderin) and/or acute or chronic sclerosing inflammatory infiltrate.Perioperative surgical complications will be documented. Statistical calculations will be performed using the Statistical Package for Social Sciences.