Page 80 - Fluorescence-guided cancer surgery

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Chapter 5
The total individual dose of ICG varied, depending on the ease of surgical resection of the adenoma. The initial ICG gift was prior to tumor removal, the second gift at the end of the procedure, to control for completeness of resection. Most patients thus received a total dose of 10 mg ICG. In one patient, NIR uorescence imaging showed tumor remnants, which were subsequently removed. A third ICG dose was administered to again check for remnants. The longest time-interval between ICG administration and obtaining images in uorescence mode was 62 minutes (#12). At this point, weak uorescence signal was still present, but did not show any contrast ratio. According to study protocol, this led to additional administration of ICG.
Tumor resection was typically done with conventional white light. In two patients (#1 and #3) we performed the tumor resection using predominantly the blue light of NIR uorescence imaging (up to 9:15 minutes after ICG administration). Although visibility under these lighting conditions is clearly much poorer than with conventional white light, tumor resection seemed facilitated. It was possible to remove the pituitary adenoma in a standard way with curretes and suction. Tumor resection was deemed complete when the gland showed an even bright enhancement under NIR uorescence imaging. In one of these two patients, a Cerebro Spinal Fluid (CSF) leakage occurred at the opening of the dura and was not related to the resection of the tumour under NIR uorescence imaging.
In this limited number of patients, we did not nd a relation between tumour type and ICG signal. No adverse reactions associated with the use of ICG or the NIR uorescence imaging system, were observed. Complications associated with the surgical procedure included: 1) leakage of intraoperative CSF in one case (#3); and 2) intraoperative venous bleeding in another case (#9).
DISCUSSION
In this study, successful identi cation of the normal pituitary gland and pituitary adenomas was possible using endoscopic NIR uorescence imaging using low dose ICG. In all assessable patients with a histologically proven adenoma, a contrast ratio between adenoma and normal gland was observed. In the only one study on NIR uorescence imaging in pituitary surgery of Litvack et al.14 the administered dose of ICG (up to 75 mg) was relative high for NIR uorescence