Magnified endoscopy with narrow-band imaging for the differential diagnosis of superficial non-ampullary duodenal epithelial tumors

Differentiation of low-grade adenoma (Vienna category 3, C3) and high-grade adenoma/carcinoma (C4/5) among superficial non-ampullary duodenal epithelial tumors (SNADETs) using magnified endoscopy with narrow-band imaging (MNBI) is not established. The aim of this study is to clarify the diagnostic ability of MNBI to differentiate between C3 and C4/5 among SNADETs.A total of 585 MNBI images taken from 156 SNADETs were evaluated in a test and validation phase. In the test phase, MNBI patterns were extracted based on the combination of surface structure and vasculature. Comparison between MNBI patterns and histology was performed to establish diagnostic criteria to differentiate between C3 and C4/5. In the validation phase, the accuracy and interobserver agreement of the diagnostic criteria were assessed.Four MNBI patterns (network, disappeared, white opaque substance and intrastructural vessels) with distinctive histological features were selected. The median number of MNBI patterns observed among C3 and C4/5 differed with significance (1 vs 2, p < .01). The pattern of disappeared was suggestive of C4/5. Diagnosis of C4/5 by using the criteria of 2 or more MNBI patterns or presence of disappeared pattern revealed a sensitivity of 76%, specificity of 63% and accuracy of 72%. Interobserver agreement of recognizing MNBI patterns was moderate (kappa 0.59).Diagnosis based on MNBI patterns is useful to differentiate between C3 and C4/5 lesions among SNADETs.