Intraoperative pulmonary neoplasm identification using near-infrared fluorescence imaging

OBJECTIVES: Near-infrared (NIR) fluorescence imaging provides surgeons with real-time visual information during surgery. The purpose of this pilot trial was to evaluate the safety and feasibility of the intraoperative detection of pulmonary neoplasms with NIR fluorescence imaging after low-dose indocyanine green (ICG) injection. METHODS: Eleven consecutive patients who were scheduled to undergo resection of pulmonary neoplasms were enrolled in this study. ICG (1 mg/kg) was administered intravenously 1 day before surgery, and the retrieved surgical specimens were examined for fluorescence signalling by using NIR fluorescence imaging system on a back table in the operating room. We analysed the fluorescence intensity, pathology, size, depth from the pleural surface and metabolic activity of the pulmonary neoplasms. RESULTS: Fluorescence signalling was detected in all specimens except in one from a patient with primary lung cancer. Two false-positive cases that presented no residual tumour with obstructive pneumonitis, after concurrent chemoradiation therapy for primary lung cancer before the operation, were identified, and their fluorescence intensity was 8.6 ± 0.4. The mean fluorescence intensity of the eight pulmonary tumours was 3.4 ± 1.9, and these tumours did not differ in pathology, size, depth from the pleural surface or metabolic activity. CONCLUSIONS: NIR fluorescence imaging could safely identify pulmonary neoplasms after the systemic injection of ICG. In addition, lowdose ICG is sufficient for NIR fluorescence imaging of pulmonary neoplasms. However, because the passive accumulation of ICG could not be used to discriminate tumours with inflammation, tumour-targeted fluorescence should be developed to solve this problem in the future.