Effect of magnetic endoscope imaging on colonoscopy performance: a randomised controlled trial

Background Colonoscopy can be technically challenging because of unpredicta ble colonoscope looping. Without imaging, straightening the colonoscope is sometimes difficult since the endoscopist has to guess where the tip is. Ma gnetic endoscope imaging (MEI), a new non-radiographical technique for pict uring the colonoscope shaft in real time, could facilitate loop straighteni ng and thus improve performance. Methods We assessed trainees and endoscopists with much experience of routi ne outpatient colonoscopy. In group 1, trainees examined 113 consecutive pa tients. MEI views were recorded in all examinations, but procedures were ra ndomised to be done by two trainees, either with the endoscopist and endosc opy assistants viewing the imager display (n=58), or without the imager vie w (n=55). In group 2, two skilled endoscopists were randomised las with gro up 1) to undertake consecutive examinations (n=183) either with (n=92) or w ithout (n=91) the MEI view. MEI views of ail procedures were analysed retro spectively. Findings in both groups, intubation times were shorter (median 11.8 min [4. 3-31.5] vs 15.3 min [4-67] [group 1]; 8.0 min [2.6-40.8] vs 9.3 min [2.5-52 .6] [group 2]) and number of attempts at straightening the colonoscope fewe r (median 5 [0-20] vs 12 [0-57] [group 1]; 7 [0-55] vs 10 [0-80] [group 2]) , when the endoscopist was able to see the imager view. In group 1, colonos copy completion rates were also higher (100% [58] vs 89% [49]) and duration of looping was reduced (median 3 min [0-18.8] vs 5.4 min [0-44.5]) when th e imager could be seen. Abdominal hand pressure was more effective when the endoscopist and endoscopy assistant could see the imager view. Interpretation MEI significantly improves performance of colonoscopy, parti cularly when used by trainees, or by experts in technically difficult cases ; loops were straightened or controlled effectively, resulting in quick int ubation times and high completion rates.