A single-center pilot study on the efficacy and safety of acetic acid–enhanced magnifying endoscopy with narrow-band imaging for diagnosis of colorectal epithelial neoplasms

Abstract

Background and aimsWe investigated the ideal acetic acid (AA) concentration for AA-enhanced, narrow-band imaging (NBI) magnifying endoscopy (ANBI-ME) in the diagnosis of superficial colorectal neoplasms and evaluated its clinical efficacy. MethodsDuring the exploratory phase, we investigated four concentrations (1.5%, 2.25%, 3.0%, and 4.5%) in rotation by performing ANBI-ME on 50 superficial colorectal neoplasms at each concentration. A favorable AA concentration was determined by evaluating the diagnostic accuracy, AA whitening duration (AD), peristalsis, and bleeding following endoscopic resection. In the validation phase, we assessed inter-observer agreements for ANBI-ME with the determined AA concentration and inter-methodological agreements between that and subsequently conducted crystal violet-stained magnifying endoscopy (CV-ME) with the exploratory set and 98 additional patients. ResultsThe diagnostic accuracies were 89.3% (42/47) for 1.5% AA, 92.0% (46/50) for 2.25%, 96.8% (61/63) for 3.0%, and 97.8% (46/47) for 4.5% with no significant difference (p = 0.26). A significant positive correlation was observed between the AA concentrations and ADs (p < 0.001). No significant differences in hyperperistalsis or post-resection bleeding were observed. The optimal AA concentration was determined to be 4.5%. In the validation analysis, the accuracy rates were 72.4% (105/145) using AMBI-ME and 68.3% (99/145) using CV-ME (p = 0.43). Strong agreements were noted between two observers (κ, 0.87 for ANBI-ME; 0.83 for CV-ME) and between the methods (κ, 0.87 and 0.81 for each observer). ConclusionFor diagnosing colorectal lesions, an AA concentration of 4.5% in ANBI-ME was safe and effective. Its diagnostic performance was comparable to CV-ME, and future large-sample studies may confirm its potential as a reliable alternative endoscopic diagnostic method.