Page 75 - Fluorescence-guided cancer surgery

the resection of the adenoma was performed making alternating use of visual and uorescence guidance. Additional boluses of 5 mg ICG were administered after partial resection of the adenoma, in order to obtain new NIR uorescence images. At the surgeons’judgment of complete resection, new NIR uorescence imaging was performed to ensure identi cation of any residual adenomatous tissue. For analysis of uorescence signal, images were obtained 45 seconds after ICG administration.
Intraoperative endoscopic near-infrared uorescence imaging system
Intraoperative NIR uorescence imaging of the pituitary gland was performed using a newly developed endoscopic high de nition (HD) uorescence imaging system by Karl Storz GmbH & Co. KG Germany, the Image Hub I. This system consists of a plasma light guide and a 0-degree angle 5.4-mm endoscope, applicable for white light (WL), auto uorescence and ICG-imaging. The system was used for intraoperative conventional imaging (WL mode) and real-time uorescence imaging (760-nm light, ICG mode). It allows for easy switching between WL mode and ICG mode using a foot pedal. The overlay of conventional and uorescent images is not yet possible but anatomical orientation could be maintained due to the easy switching between light modes. Images were recorded using a charge-coupled device camera.
Statistical and image analysis
SPSS statistical software package (Version 20.0, Chicago, IL) was used for statistical analysis. Fluorescent signal of pituitary adenoma and normal gland were reported both qualitatively and quantitatively. Snapshots were taken from the recorded operating videos, for further analysis. For qualitative analysis, uorescent signal was classi ed as ++, +, +/- and -. Two observers – M.V. (one of the operating neurosurgeons) and Q.T. – scored the uorescent signal independently. Where scoring discrepancies occurred, agreement was reached by reassessing the images. Quantitative uorescent signal was measured using ImageJ version 1.49b (a public domain Java-based image processing program developed at the National Institute of Health). With ImageJ, regions of interest (RoI) were drawn circumventing the uorescent signal of the adenoma and normal pituitary tissue. Fluorescence Contrast Ratios (FCRs) were calculated by dividing the uorescent signal of both RoIs. FCRs were reported as mean. Patient age was reported as median and range.
Imaging in pituitary surgery 73