The accuracy of real-time histology prediction (hyperplastic vs. adenomas) of colonic polyps using white light high-definition endoscopes is suboptimal. Blue laser imaging (BLI) is a new system for image-enhanced endoscopy using laser light, that is incorporated in the last generation Fuji high- definition videocolonscopes ELUXEO. Blue laser imaging (BLI) utilizes two monochromatic lasers instead of xenon light: a 410 nm laser visualizes vascular microarchitecture, similar to narrow band imaging, and a 450 nm laser provides white light by excitation.This system should enhance the microvascular pattern of superficial lesions, making the histological prediction easier.

Aim of the study is to compare the accuracy of white light and BLI systems in real-time histology prediction of colonic polyps.

For this purpose all colonscopies will be performed in a standard fashion using white light. When a polyps <10mm in size will be identified, patients will be randomized in two groups. In the Group 1 (White Light Grroup), all polyps <10mm will be evaluated with white light and prediction of histology (hyperplastic versus adenomatous) will be made by means of white light. In the Group 2 (BLI Group) , all polyps <10mm in size will be evaluated with BLI and scored as hyperplastic (type 1) or adenomatous (type 2) by applying the NICE (Narrow-band Imaging International Colorectal Endoscopic) classification, indicating color/vessel/surface pattern. The level of endoscopist's confidence in predicting histology (high or low confidence) for any polyp will be also recorded.

Diagnostic performances of the endoscopists (sensitivity, specificity, positive and negative predictive values) will be calculated comparing endoscopist's prediction and pathology report, considered as reference standard in both study groups in order to evaluate the accuracy of real-time histology prediction by using BLI or white light.

Inclusion Criteria:

• All outpatients referred for colonoscopy

Exclusion Criteria:

• inadequatete bowel preparation (Boston Bowel Preparation Scale (BBPS) < 2 in one colonic segment)
• previous colonic resection
• inflammatory bowel disease
• ereditary polyposic syndromes
• patients on antithrombotics precluding polyp resection
• absence of informed consent
• inpatients or patients undergoing urgent colonscopy