摘要AIM:To compare high resolution colonoscopy (Olympus Lucera) with a megapixel high resolution system (Pentax HiLine) as an in-service evaluation.METHODS:Polyp detection rates and measures of performance were collected for 269 colonoscopy procedures.Five colonoscopists conducted the study over a three month period,as part of the United Kingdom bowel cancer screening program.ration (X2 P = 0.98),caecal intubation rates (X2 P = 0.67),or depth of sedation (X2 P = 0.64).Mild discomfort was more common in the Pentax group (X2 P = 0.036).Adenoma detection rate was significantly higher in the Pentax group (X2 test for trend P = 0.01).Most of the extra polyps detected were flat or sessile adenomas.CONCLUSION:Megapixel definition colonoscopes improve adenoma detection without compromising other measures of endoscope performance.Increased polyp detection rates may improve future outcomes in bowel cancer screening programs.