Evaluation of Microcirculation in Colon Wall and Bowel Anastomosis by Laser Induced Fluorescence Video Angiography of Indocyanine Green

In our study the investigators prospectively include patients with colon cancer requiring elective surgical operation. All types of colon resection were carried out according to standard procedures. Guidelines for preoperative examination according to NGICG (Norwegian Gastro-Intestinal Cancer Group) to grade the disease, select the most suitable patients and plan further treatment.

Microcirculation of colon wall was assessed by dynamic laser-induced-fluorescence-videoangiography (IC-VIEW, PULSION Medical Systems AG, Munich, Germany) of indocyanine green (ICG). ICG is a water-soluble tricarbocyanine dye that binds strongly to plasma proteins after intravenous injection and is exclusively distributed in intravascular space. Additionally this system houses a laser (energy Pi = 0.16 W, wavelength = 780 nm) that causes excitation/illumination of the fluorescence light from intravascular plasma bound ICG. This light has a spectral range near-infrared energy (NIR) with a maximum at 805 nm and emits fluorescence at 835 nm. It passes through infrared filter on a digital video camera and results in recording of real time fluorescent image from perfusion of plasma bound ICG within small plexus of blood vessels in the bowel wall. Besides that it also demonstrates perfusion from surrounding structures such as appendix epiploic and pericolic fat. The maximum penetration of the laser into tissue is 3-5 mm and general normal thickness of colon wall is 3-5 mm. This method makes it a presentable tracer for tissue perfusion of anterior bowel wall.