Indocyanine Green (ICG) fluorescence imaging is increasingly utilised in endoscopic pituitary surgery to enhance intraoperative visualisation and surgical accuracy. This systematic review evaluates the efficacy and clinical utility of ICG in improving tumour delineation, extent of resection, and anatomical orientation during pituitary surgery.

A systematic PRISMA-guided search of multiple electronic databases was conducted through February 2025. Eligible studies included adult patients undergoing endoscopic pituitary surgery with intraoperative ICG use and reported surgical or diagnostic outcomes. Eleven studies, comprising 150 patients, met the inclusion criteria. Data on patient demographics, tumour characteristics, ICG administration protocols, fluorescence metrics, surgical and endocrine outcomes were extracted and analysed using weighted and proportional methods.

ICG fluorescence visualised targets in 93.6% of cases (n = 87/93, range 75-100%) with onset 20 seconds to 32.5 minutes post-injection. Non-functioning adenomas were most common (55%, n = 68/124), predominantly macroadenomas. ICG improved margin delineation, enabled mapping of the internal carotid artery and cavernous sinus, and aided real-time differentiation of adenoma from normal gland. Where studies reported diagnostic performance, Delayed-Window ICG (DWIG) demonstrated sensitivity 89% and specificity 75%, while Second-Window ICG (SWIG) showed sensitivity 100% with specificity 20-29%. Complications were low; transient diabetes insipidus was most frequent (n = 6). Gross total resection was achieved in most cases (n = 53/65, range 80-87.5%), and no ICG-specific adverse events were reported.

ICG fluorescence appears to be a promising adjunct for endoscopic pituitary surgery, improving intraoperative visualisation and anatomical guidance. Distinct from prior narrative reviews, we present a technique-stratified synthesis (bolus, DWIG, SWIG) that integrates clinical outcomes. Standardised protocols and high-quality prospective studies are needed to validate diagnostic performance and define routine use.