Pathological diagnosis were used as gold standard. Chi-square test or Fisher test were used to calculate the accuracy, sensitivity and specificity of the character evaluation of the lesions. 以病理诊断为金标准,应用卡方检验或Fisher检验计算内镜医师分别对白光内镜图片和i-Scan图片评价的病变性质的准确度、敏感度和特异度,两组间参数比较采用卡方检验。