Vascular Border Zone Definition Using Intraoperative Hyperspectral Imaging for Resections and Reconstructions in Diseases of the Esophagus, Stomach, Pancreas, Small Intestine, Large Intestine and Rectum to Optimize Anastomotic Healing

The anastomoses were examined under standardized conditions directly after creation. The measurements were performed like described before, using the TIVITA Tissue system (Diaspective Vision GmbH, Am Salzhaff, Germany). This HSI-camera provides hyperspectral images with a high spectral resolution (5 nm) in the visible and near infrared range (500-1000 nm). The distance between camera and object was 30 cm for all measurements. The Number of Effective Pixels at this distance is 640 × 480 (x-, y-axis. The resulting field of view (FOV) has the dimensions 6.4 × 4.8 cm2 and a spatial resolution of 0.1 mm/pixel. The FOV is illuminated by 8 halogen spots (20 W each). The ceiling lights and other light sources were switched off, to avoid artifacts during the measurement (approximately 10 seconds). A RGB image and 4 false color images that represent physiologic parameters are intraoperatively provided by an analysis software. This work is focused on tissue oxygenation (StO2), which represents the relative blood oxygenation in the microcirculation of superficial tissue layers (approximately 1 mm) and the near-infrared (NIR) Perfusion Index, representing tissue layers in 4-6 mm penetration depth.