Introduction: Endometriosis is a common health problem, affecting 10% of women of reproductive age. Laparoscopic surgery is proven to relieve pain and to improve fertility in women with endometriosis. However, identifying peritoneal endometriosis lesions may be difficult due to their polymorphic aspects. Endometriosis lesions harbor a high degree of neovascularization. The visualization of tissue perfusion by the additional use of near infrared fluorescence imaging with indocyanine green (ICG) may improve the detection of endometriosis lesions.
Material and methods: In a single-center, prospective, single-arm pilot study, patients undergoing laparoscopic surgery for suspected endometriosis and/or infertility were recruited. All patients first had white light imaging with systematical documentation of all suspicious areas. ICG was then administered intravenously at .3 mg/kg bodyweight and the near infrared imaging was activated and an identical documentation of suspected lesions was performed again. After removal, the specimen were sent to pathology.
Clinical trial registration: clinicaltrials.gov NCT03850158.
Results: In total, 173 suspected lesions were identified and excised, of which 150 had histologically proven endometriosis. Of the total number, 166 suspected lesions were detected using white-light and 32 with ICG. Among the 32 suspected lesions found with ICG, 22 were confirmed to be endometriosis. Seven additional lesions were identified with ICG alone, of which only one was histologically proven endometriosis. Positive predictive values were 89.8%, 68.8% and 86.7% for white-light laparoscopy alone, near-infrared (NIR)-ICG visualization alone, and the combination of white-light and NIR-ICG, respectively. ICG exposure time, previous abdominal surgery and rARSM stage showed a statistically significant impact on the ICG detection rate. In seven patients, ICG was used for the resection of deep infiltrating nodules from the rectum. In these cases, NIR fluorescence imaging with ICG was useful to define the borders between an endometriotic nodule and healthy tissue.
Conclusions: The diagnostic value of NIR-ICG imaging in identifying endometriosis appears to be minimal. ICG exposure time over 20 minutes, no previous abdominal surgery and low rASRM stages have a significant positive effect on the ICG detection rate. NIR fluorescence imaging with ICG was helpful in the resection of deep infiltrating nodules in providing a better visualization of endometriosis.
Keywords: fluorescence imaging; indocyanine green; laparoscopy; near-infrared optics; occult endometriosis.
© 2020 Nordic Federation of Societies of Obstetrics and Gynecology.