Multi-Spectral Fluorescence Imaging of Colon Dysplasia In Vivo Using a Multi-Spectral Endoscopy System

BACKGROUND AND STUDY AIM: To develop a molecular imaging endoscopic system that eliminates tissue autofluorescence and distinguishes multiple fluorescent markers specifically on the cancerous lesions. METHODS: Newly developed multi-spectral fluorescence endoscope device has the potential to eliminate signal interference due to autofluorescence and multiplex fluorophores in fluorescent probes. The multiplexing capability of the multi-spectral endoscope device was demonstrated in the phantom studies and multi-spectral imaging with endoscopy and macroscopy was performed to analyze fluorescence signals after administration of fluorescent probe that targets cancer in the colon. Because of the limitations in the clinical application using rigid-type small animal endoscope, we developed a flexible channel insert-type fluorescence endoscope, which was validated on the colonoscopy of dummy and porcine model. RESULTS: We measured multiple fluorescent signals simultaneously, and the fluorescence spectra were unmixed to separate the fluorescent signals of each probe, in which multiple fluorescent probes clearly revealed spectral deconvolution at the specific targeting area in the mouse colon. The positive area of fluorescence signal for each probe over the whole polyp was segmented with analyzing software, and showed distinctive patterns and significantly distinguishable values: 0.46 ± 0.04, 0.39 ± 0.08 and 0.73 ± 0.12 for HMRG, CET-553 and TRA-675 probes, respectively. The spectral unmixing was finally demonstrated in the dummy and porcine model, corroborating the targeted multi-spectral fluorescence imaging of colon dysplasia. CONCLUSION: The multi-spectral endoscopy system may allow endoscopists to clearly identify cancerous lesion that has different patterns of various target expression using multiple fluorescent probes.