Randomized clinical study on diagnostic accuracy of magnified endoscopic examination with narrow band imaging (NBI) for small depressive lesion in the stomach

INTERVENTION: Magnified endoscopic examination with NBI system Conventional non‐magnified examination without NBI system CONDITION: Gastric cancer PRIMARY OUTCOME: Diagnostic accuracy SECONDARY OUTCOME: (1)Diagnostic sensitivity; (2)Diagnostic specificity; (3)Time required for confirming the endoscopic diagnosis; (4)Added efficacy of magnified examination with NBI on conventional non‐magnified examination without NBI; (5)Frequency of endoscopically inconclusive lesions INCLUSION CRITERIA: (a)Depressive undiagnosed lesion within 10mm in length without ulceration or erosion in the stomach (b)Written informed consent (3)20<=age