Fig. 2

a RGB image of linear small bowel model experimental setup. The figure shows a randomly selected semi-circular loop of porcine small bowel bissected using stapler at 12′0 clock position (red arrow). This stapled bowel edge (marked 0 cm) was a benchmark to determine the extent of mesenteric devascularization. The bowel was then partially devascularized to approximately 4 cm from stapled bowel edge (solid black line) to create a perfusion gradient. Regions within this gradient were pre-labeled A = ischemic (0–2 from stapled edge), B = watershed (4–6 cm from stapled bowel) and C = perfused (8–10 cm from stapled bowel) based on naked eye estimates of bowel perfusion and the distance from the margin of devascularization. Bowel perfusion was then measured continuously along this gradient, according to radial distances from the stapled bowel edge (marked by yellow lines). b LSCI image of linear small bowel model experimental setup. The figure shows LSCI contrast images of the same semi-circular loop of porcine small bowel model stapled at 12′0 clock position (red arrow) and partially devascularized to approximately 4 cm from stapled bowel edge (solid black line) to create a perfusion gradient. In the color heatmap, warm colors (red, yellow) represent high perfusion while cool colors (blue) represent low perfusion. Regions within this gradient were pre-labeled A = ischemic, B = watershed and C = perfused based on naked eye estimates of bowel perfusion and the distance from the margin of devascularization. The three labelled bowel segments are represented by different colors on this heatmap. The ischemic bowel segment is dark blue, the watershed segment is green while the perfused segment is yellow/red. For quantitative assessment, RPUs are measured radially over the continous bowel gradient along the mesenteric (dotted red line) and antimesenteric (dotted black line) arcs. The dash black line represents the radial distance (5 cm from the stapled edge) from which the perfusion values start to decrease