Colonic Blood Flow Measurement by Laser Doppler

Colonic blood flow was assessed by a Laser Doppler perfusion image system (PeriScan PIM3 System; Perimed, Stockholm, Sweden), as described previously21 (link). Briefly, an incision was made through abdominal wall to expose peritoneal cavity, and a colon segment 6 to 8 cm proximal to anus was exposed. A computer-controlled optical scanner directed a low-powered He-Ne laser beam over the exposed colon, while epicolic tissues were covered with black soft leather. A color-coded image denoting specific relative perfusion level was displayed on a video monitor, and all images were evaluated with the software LDPIwin 3.1 (PeriScan PIM3 System; Perimed). The magnitude of blood flow was represented by different colors, with blue to red denoting low to high. Results were expressed as percentages of the baseline.