BACKGROUND AND AIMS Endocytoscopy, a next-generation endoscopic system, facilitates observation at a maximum magnification of ×520. To our knowledge, no study has reported high-precision diagnosis of colorectal low-grade adenoma, endoscopically. We aimed to reveal which endocytoscopic findings may be used as indicators of low-grade adenoma and to assess whether a "resect and discard" strategy using endocytoscopy is feasible. METHODS Lesions diagnosable with endocytoscopy were examined retrospectively between May 2005 and July 2017. A normal pit-like structure in endocytoscopic images was considered a normal pit (NP) sign and used as an indicator of low-grade adenoma. The primary outcome was the diagnostic accuracy of the NP sign for low-grade adenoma. We evaluated agreement rates between endocytoscopic and pathologic diagnosis for surveillance colonoscopy interval recommendation (SCIR) and performed a validation study to verify the agreement rates. RESULTS For 748 lesions in 573 cases diagnosed as colorectal adenoma using endocytoscopy, the results were as follows: sensitivity of the NP sign for low-grade adenoma, 85.0%; specificity, 90.7%; positive predictive value, 96.6%; negative predictive value, 66.1%; accuracy, 86.4%; and positive likelihood ratio, 9.2 (P < .001). The agreement rate between endocytoscopic and pathologic diagnosis for SCIR was 94.4% (95% confidence interval [CI], 92.2%-96.1%; P < .001) under United States guidelines and 96.3% (95% CI, 94.5%-97.7%; P < .001) under European Union guidelines. All inter- and intraobserver agreement rates for expert and nonexpert endoscopists had κ values ≥0.8 except one nonexpert pair. CONCLUSIONS Endocytoscopy is an effective modality in determining the differential diagnosis of colorectal low-grade adenoma. (University Hospital Medical Information Network Clinical Trials database registration number: UMIN000018623.).

中文翻译：

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内窥镜检查用于大肠低度腺瘤的鉴别诊断：“切除并丢弃”策略的新可能性。

背景与目的内窥镜检查是下一代内窥镜检查系统，可最大放大520倍进行观察。据我们所知，尚无研究在内镜下对大肠低度腺瘤进行高精度诊断的报道。我们旨在揭示哪些内窥镜检查结果可用作低度腺瘤的指标，并评估使用内窥镜检查“切除并丢弃”策略是否可行。方法回顾性分析2005年5月至2017年7月可通过内窥镜检查诊断的病变。内窥镜检查图像中的正常凹坑状结构被视为正常凹坑（NP）征象，并被用作低度腺瘤的指标。主要结果是NP征对低度腺瘤的诊断准确性。我们评估了内镜和病理学诊断之间的一致性率，以监测结肠镜检查间隔建议（SCIR），并进行了一项验证性研究以验证一致性率。结果经内镜检查诊断为573例结直肠腺瘤的748例病变，结果如下：NP征对于低度腺瘤的敏感性为85.0％。特异性为90.7％；阳性预测值为96.6％；阴性预测值，占66.1％；准确度86.4％; 正似然比为9.2（P <.001）。根据美国指南，SCIR的内镜检查与病理学诊断的符合率为94.4％（95％置信区间[CI]，92.2％-96.1％； P <.001）和96.3％（95％CI，94.5％-97.7％） ； P <.001）。除一对非专家外，所有专家和非专家内镜医师的观察者间和观察者内同意率均为κ值≥0.8。结论内镜检查是确定大肠低度腺瘤鉴别诊断的有效方法。（大学医院医学信息网络临床试验数据库注册号：UMIN000018623。）。