Application of magnifying endoscopy with narrow-band imaging in diagnosing gastric lesions: a prospective study.

BACKGROUND Magnifying endoscopy with narrow-band imaging (ME-NBI) can more clearly assess the surface pattern and microvascular architecture of gastric lesions. OBJECTIVE To evaluate the diagnostic efficacy of ME-NBI in patients with early gastric cancer. DESIGN Prospective study. SETTING Single academic center. PATIENTS This study involved 164 suspected gastric lesions in 146 consecutive patients who underwent ME-NBI for additional differential diagnosis before treatment. INTERVENTION ME-NBI findings were classified into 3 groups based on irregularities, absence of surface pattern, and microvascular architecture. All lesions were treated endoscopically or surgically, and ME-NBI diagnosis was compared with histopathological findings. MAIN OUTCOME MEASUREMENTS Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of real-time ME-NBI diagnosis were determined. RESULTS The sensitivity, specificity, and accuracy of ME-NBI were 97.3%, 84.4%, and 90.2%, respectively, in distinguishing between cancerous and noncancerous lesions and were 92.3%, 89.7%, and 90.4%, respectively, in distinguishing undifferentiated from differentiated adenocarcinoma. ME-NBI accurately predicted depth of invasion in 37 of 39 differentiated adenocarcinomas (95%). LIMITATIONS The sample size was relatively small. CONCLUSIONS ME-NBI can successfully distinguish between cancerous and noncancerous lesions and between undifferentiated and differentiated adenocarcinomas. Of the 3 patterns on ME-NBI, type A is mainly characteristic of noncancerous lesions, type B is a good indicator of differentiated adenocarcinoma and intramucosal/superficially invasive cancers, and type C is indicative of undifferentiated adenocarcinoma or differentiated cancer with deep submucosal invasion.