Transgastric in vivo histology in the peritoneal cavity using miniprobe-based confocal fluorescence microscopy in an acute porcine model

Abstract

Natural orifice transluminal endoscopic surgery (NOTES) is an emerging technology. Apart from its therapeutic implications, this type of access to the peritoneal cavity might also be useful for targeted in vivo histological investigation by means of confocal fluorescence microscopy. In this study we therefore aimed to assess the feasibility of miniprobe-based confocal fluorescence microscopy during transgastric endoscopy in an acute porcine model. Transgastric in vivo histology was performed in five pigs, under general anesthesia. After incision of the anterior gastric wall, a double-channel video gastroscope was advanced into the peritoneal cavity. A flexible confocal miniprobe was introduced through the instrument channel of the endoscope after intravenous injection of 10 mL of fluorescein 1% in four of the pigs and of 50 mL of fluorescein isothiocyanate-dextran 150 000 4% in the fifth pig. The tip of the miniprobe was then placed on the peritoneal layer, the liver, and the spleen for confocal laser microscopy. Probes were easily attached to the peritoneal layer, the liver, and the spleen under direct visualization with the endoscope. Dynamic microscopic images of these organs were obtained with a frame rate of 12 frames per second. The flow of erythrocytes through blood vessels could be seen. The microstructural components of organs, such as lobules of the liver, were also easily identified. In vivo histology in the peritoneal cavity is feasible during NOTES and this technique combines the minimally invasive approach to the intraperitoneal organs afforded by NOTES and real-time, in vivo acquisition of dynamic histological images.