| Background and aims Endoscopic diagnosis of sessile serrated adenoma/polyp (SSA/P) is challenging because of their subtle appearance. Narrow-band imaging (NBI) is useful for diagnosis, but its utility with concurrent chromoendoscopy (CE), especially to detect small SSA/P, is unproven. Patients and methods This prospective study enrolled 367 consecutive patients who underwent screening colonoscopy with the finding of serrated polyps. Patients were divided into derivation and validation cohorts: Diagnostic criteria using different endoscopic modalities were generated by regression analysis in the derivation cohort and were validated in the validation cohort for sensitivity, specificity, and accuracy.Results There were 180 patients with 119 SSA/P and 147 hyperplastic polyps (HP) in the derivation cohort and 187 patients with 177 SSA/P and 125 HP in the validation cohort. With white-light endoscopy (WLE) plus NBI, mucus cap, surface grooves, and expanded crypt were most associated with SSA/P. With WLE plus CE, II-O pit pattern, mucus cap, and superficial telangiectasia were most associated with SSA/P. With combined use of these three modalities, II-O pit pattern, mucus cap, and surface grooves were most associated with SSA/P. For large serrated polyp, NBI in combination with CE had a better accuracy than NBI alone (91% vs. 86%, p = 0.025) to distinguish SSA/P from HP. CE alone had a better accuracy than NBI alone for distinguishing small SSA/P from small HP (85% vs. 72%, p < 0.0001).Conclusion Compared with NBI alone, adjunctive use of CE can improve the diagnostic accuracy for distinguishing SSA/P from HP, especially for small SSA/P. Moreover, combination use of mucus cap, surface grooves and II-O pit pattern provided a best diagnostic yield for small SSA/P. Key words: Sessile serrated adenoma/polyp; image-enhanced endoscopy |
