Diagnostic Performance of Magnifying Endoscopy With Crystal Violet Staining for Superficial Non-ampullary Duodenal Epithelial Tumors: A Single-center Prospective Study.

Objectives: We previously reported a potential diagnostic algorithm for superficial non-ampullary duodenal epithelial tumors (SNADETs) using white-light magnifying endoscopy with crystal violet staining (ME-CV). This study aimed to determine the diagnostic performance of the scheme and compare it with the conventional white-light endoscopy (WLE) scoring system in a prospectively accumulated cohort. Methods: This was a single-center prospective cohort study conducted over a 3-year period. The primary endpoint was the diagnostic performance of ME-CV in distinguishing Vienna classification (VCL) category 4/5 (C4/5) from category 3 (C3) SNADETs, including the positive predictive value (PPV) and negative predictive value (NPV), as evaluated by two expert endoscopists. We compared the diagnostic performance of the WLE and ME-CV algorithms. Results: Fifty patients with SNADETs were enrolled. The inter-observer agreement for the WLE scoring system and the ME-CV algorithm was good (kappa 0.66 and 0.63). The PPV and NPV of the ME-CV algorithm, when applied by expert endoscopists, were 25.6% and 90.2%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of the WLE scoring system were 43.8%, 73.8%, 24.1%, 87.3%, and 69.0%, respectively. The sensitivity, specificity, and accuracy of the ME-CV algorithm were 62.5%, 65.5%, and 65.0%, respectively. Comparison of the diagnostic performance between the two systems demonstrated the significantly higher sensitivity of the ME-CV algorithm (WLE, 43.8%; ME-CV, 62.5%; p = 0.029). Conclusions: The ME-CV algorithm had higher sensitivity than the WLE scoring system for distinguishing VCL C4/5 from VCL C3 in SNADETs, suggesting its potential to improve diagnosis and for selecting appropriate endoscopic resection.