Knowing the position of the endoscope within the abdomen is important for performing a high-quality, painless colonoscopy. The recently introduced magnetic endoscopic imaging (MEI) system provides a continuous, real-time image of the endoscope during the entire procedure.

To compare MEI versus standard colonoscopy with on-demand fluoroscopy on unsedated patients, as performed by experienced and inexperienced endoscopists.

Randomized, controlled trial.

Endoscopy outpatient clinic.

This study involved 810 consecutive patients (391 randomized to standard group; 419 randomized to MEI) referred for colonoscopy.

MEI or standard approach (involving on-demand fluoroscopy) during colonoscopy.

Perceived patient pain and cecal intubation rate and time to cecum.

For inexperienced endoscopists, the cecal intubation rate was significantly higher in the MEI group (77.8%) compared with the standard group (56.0%), P = .02 but not for experienced endoscopists (94.0% for MEI and 96.0% for standard group, P = .87). Inexperienced endoscopists had less need for assistance from a senior colleague when they used MEI (18.5%) compared with the standard technique (40.0%), P = .02. Mean (± standard deviation) time to reach the cecum was 14.0 ± 12.2 minutes in the MEI group and 15.3 ± 14.2 minutes in the standard group, P = .67.

Single center, unblinded study.

Inexperienced endoscopists improved their colonoscopy performance when they used MEI, compared with the standard technique, but experienced endoscopists did not. The MEI may be advantageous to use for colonoscopy centers educating endoscopists. (Clinical trial registration number: NCT00519129.)