Colonic tattooing using fluorescence imaging with light-emitting diode-activated indocyanine green: a feasibility study

Abstract

Purpose: We investigated the feasibility of a fluorescence imaging technique using light-emitting diode (LED)-activated indocyanine green (ICG) fluorescence.

Methods: Indocyanine green injections were given to patients undergoing preoperative colonoscopy for early colon cancer or colon adenoma. During subsequent laparotomy, the colon was first observed with the naked eye, and then using a prototype machine with a charge-coupled device (CCD) video camera equipped with a cutoff filter and a LED at a wavelength of 760 nm as the light source.

Results: LED-induced fluorescence showed tumor localization clearly and accurately in all ten patients (100%) enrolled in this study, whereas it was seen with the naked eye as a green spot in only two patients (20%) (P = 0.0077; Wilcoxon's signed-rank test). There were no complications of LED-induced fluorescence and no inflammatory signs were noted on the hematoxylin-eosin-stained slides for the identified injection sites in the resected specimens.

Conclusions: Colonic tattooing using this fluorescence imaging technique of LED-activated ICG fluorescence is a new concept of colonic marking based on the characteristics that ICG is a near infrared fluorescent dye, and is useful, without any adverse effects, to identify perioperatively the tumor localization.