Supplementary Material for: Usefulness and Educational Benefit of a Virtual Scale Endoscope in Measuring Colorectal Polyp Size

Introduction: The virtual scale endoscope (VSE) is a newly introduced endoscope that helps endoscopists in measuring colorectal polyp size (CPS) during colonoscopy by displaying a virtual scale. This study aimed to determine the usefulness of the VSE for CPS measurement and the educational benefit of using VSE images to improve CPS estimation accuracy. Methods: This study included 42 colorectal polyps in 26 patients treated at Hiroshima University Hospital. In Study 1, CPS measured using a VSE before endoscopic mucosal resection was compared with CPS measured on resected specimens, and the agreement between the two measurement methods was evaluated via Bland–Altman analysis. In Study 2, 14 endoscopists (5 beginners, 5 intermediates, and 4 experts) took a pre-test to determine the size of 42 polyps. After the pre-test, a lecture on CPS measurement using VSE images was given. One month later, the endoscopists took a post-test to compare CPS accuracy before and after the lecture. Results: In Study 1, Bland–Altman analysis revealed no fixed or proportional errors. The mean bias ± 95% limits of agreement (±1.96 standard deviations) of the measurement error was -0.05 ± 0.21 mm, indicating that the agreement between two measurement methods was sufficient. In Study 2, the accuracy of CPS measurement was significantly higher among beginners (59.5% vs. 26.7%, p < 0.01) and intermediates (65.2% vs. 44.3%, p < 0.05) in the post-test than in the pre-test. Conclusion: The VSE accurately measures CPS before resection, and its images are useful teaching tools for beginner and intermediate endoscopists.

引言：虚拟标尺内镜（virtual scale endoscope, VSE）是一款新型内镜，可在结肠镜检查过程中通过显示虚拟标尺，帮助内镜医师测量结直肠息肉尺寸（colorectal polyp size, CPS）。本研究旨在评估VSE用于结直肠息肉尺寸测量的应用价值，以及使用VSE图像提升结直肠息肉尺寸估算准确性的教学效益。方法：本研究纳入广岛大学医院收治的26例患者共42枚结直肠息肉。研究1中，将内镜黏膜切除术（endoscopic mucosal resection）前使用VSE测得的结直肠息肉尺寸与切除标本的测量结果进行对比，并通过布兰德-奥特曼（Bland–Altman）分析法评估两种测量方法的一致性。研究2中，招募14名内镜医师（其中新手5名、中级医师5名、专家4名）完成预测试，对42枚息肉的尺寸进行估算。预测试结束后，开展针对VSE图像结直肠息肉尺寸测量方法的专题授课。1个月后，内镜医师完成复测，对比授课前后结直肠息肉尺寸估算的准确性。结果：研究1的布兰德-奥特曼分析结果显示，不存在系统误差或比例误差。测量误差的平均偏差±95%一致性界限（±1.96倍标准差）为-0.05±0.21 mm，表明两种测量方法的一致性良好。研究2中，新手组（59.5% vs. 26.7%，p<0.01）与中班组（65.2% vs. 44.3%，p<0.05）在复测中的结直肠息肉尺寸测量准确性均显著高于预测试。结论：VSE可在息肉切除前精准测量结直肠息肉尺寸，其相关图像可作为面向内镜新手与中级医师的有效教学工具。