Fig. 1 Artificial intelligence-based polyp measurement during a colonoscopy using water jet as reference. Source: Prof. Alexander Hann, 2024, University Hospital Würzburg.

Graphical Abstract

Graphical Abstract

Graphical Abstract

Graphical Abstract

Fig. 1 Example images illustrating best practice techniques (with B3,4 and C3,4, poor practice examples) in endoscopic mucosal resection for: A global competencies; B injection technique; C snare placement technique; D defect assessment technique; showing: A1,2 full appreciation/ demonstration of the extent of the polyp to be resected; A3 best positioning with respect to the polyp (at 6 o’clock, close to the colonoscope); A4 selection of the appropriate technique for the polyp to be resected (e. g. correct decision for en bloc cold snare polypectomy in this example); A5 tip control (controlled stable and purposeful, resulting in uniform application of snare-tip soft coagulation); B1,2 injection performed in the correct plane, facilitating access to the lesion; B3 transmural nondynamic injection (poor practice); B4 nonlifting, with repeated and failed submucosal injection resulting in intramucosal blebs (poor practice); C1 the snare oriented near to 6 o’clock, visualization of the snare V during closure, with the snare near to the colonoscope; C2 use of the transected tissue edge as a guide (within the defect), and visualization of the snare V during closure, with the snare close to the colonoscope; C3 the snare positioned far from the colonoscope, with too much snare extended from the sheath and no margin of normal tissue (poor practice); C4 poor tissue capture and too far from the colonoscope (likely to result in scraping of polyp tissue and incomplete mucosal layer excision; poor practice); D1 complete margin ablation, following systematic application with entire margin ablation achieved; D2,4 incomplete mucosal layer excision with evidence of residual polyp tissue on islands of muscularis mucosae; D3 residual polyp tissue at the resection margin; D5 evidence of deep mural injury (DMI) type I, with residual polyp tissue at the defect edge, and failed submucosal injection resulting in an intramucosal bleb; D6 intraprocedural bleeding; D7 DMI type I; D8 DMI type III associated with an area of fibrosis; D9 DMI type IV; D10 complete closure of a post-endoscopic mucosal resection (EMR) mucosal defect to prevent post-EMR bleeding.