Colonoscopy

Colonoscopy is the most consequential procedure in gastroenterology — both as the diagnostic gold standard for lower GI symptoms and as the primary preventive intervention against colorectal cancer. Quality metrics (cecal intubation rate, withdrawal time, adenoma detection rate, bowel-prep adequacy) directly correlate with cancer-prevention efficacy, and modern practice tracks them systematically.

Water-assisted colonoscopy — using either water immersion (water replaces air during insertion) or water exchange (water is suctioned during insertion) — has shown improvements in cecal intubation rate, patient comfort, and adenoma detection compared with conventional air insufflation. Right-colon adenoma detection in particular benefits from the better mucosal exposure water-assisted technique provides.

Terminal ileum intubation is straightforward in most cases when the ileocecal valve is identified and the scope is advanced under direct vision through the lower lip of the valve. It adds important diagnostic yield for suspected Crohn's disease, terminal ileitis, and ileal lymphangiectasia, and demonstrates technical mastery of cecal anatomy.

Withdrawal-phase technique — slow circumferential mucosal inspection, use of a distal cap, position changes for the right colon, and retroflexion in the rectum and right colon — remains the highest-yield phase of the procedure for adenoma detection.