Standard versus high definition colonoscopy.

Interventions: 1. Group A: Standard colonoscopes; 2. Group B: HD colonoscopes; 3. Group C: HD colonoscopes and I-scan Surface Enhancement (SE) (level 4); 4. Group D: HD colonoscopes and I-scan Surface Enhancement (SE) (level 4) and I-scan Colon Mode. Primary outcome(s): Adenoma detection rate (ADR): The total number of adenomatous lesions (histological proven) divided by the number of patients per arm in all four groups. Study Design: Randomized controlled trial, Single blinded (masking used), Active, Parallel