Laser speckle contrast imaging for intraoperative semi-quantitative assessment of intestinal blood perfusion during colorectal surgery: a clinical pilot study

INTERVENTION: Assessment of bowel blood perfusion with laser speckle contrast imaging before anastomosis during colorectal resection CONDITION: Colorectal tumor PRIMARY OUTCOME: Evaluation of blood perfusion of the anastomotic site SECONDARY OUTCOME: 1) Reliability; 2) Measuring time; 3) Incidence rate of intraoperative and postoperative complication INCLUSION CRITERIA: 1) patients undergoing elective surgery for colorectal tumor 2) patients who understand purpose of study and reveive informed consent 3) patents with 20 years old or older