Intraoperative Real-time Near-infrared Image-guided Endoscopic Endonasal Surgery for Pituitary Tumors

Abstract

Abstract Background: In endoscopic endonasal surgery of pituitary tumors, the intraoperative judgment and tissue identification depend largely on surgeons’ surgical experience. Objective: To assess whether the delayed-window indocyanine green (ICG) (DWIG) technique can visualize and distinguish the normal pituitary gland and tumor under the endoscope in real-time during surgery. Methods: Eight patients with pituitary adenoma who received 12.5 mg ICG were observed by near-infrared (NIR) fluorescence during the surgery to identify the pituitary gland and tumors. Results: The normal pituitary gland and pituitary adenoma were visualized by NIR fluorescence in all 8 patients. The relative ratio of the fluorescence emission of the normal gland to that of the tumor (signal-to-background ratio [SBR] normal gland/tumor) increased after 15 min, peaking at 5.8±4.9 at 90 min. It suggested that pituitary gland was more clearly visualized during that period. The tumor/blood (SBR tumor) and normal gland/ blood (SBR gland) NIR fluorescence was significantly positively correlated with each Ktrans on dynamic contrast-enhanced MRI, indicating blood–brain barrier (BBB) permeability. Conclusions: This study showed the utility of the DWIG technique for identifying a normal pituitary gland from a tumor in endoscopic endonasal surgery from 15 to 90 min following ICG administration, “negative tumor staining”. Permeability can contribute to gadolinium enhancement on MRI and to ICG retention and NIR fluorescence in a normal pituitary gland and tumor.