Shandro Benjamin M, Emrith Khemraj, Slabaugh Gregory, Poullis Andrew, Smith Melvyn L
Department of Gastroenterology, St George's University Hospitals NHS Foundation Trust, London SW17 0QT, United Kingdom.
Centre for Machine Vision, University of the West of England, Bristol BS16 1QY, United Kingdom.
World J Gastrointest Endosc. 2020 May 16;12(5):138-148. doi: 10.4253/wjge.v12.i5.138.
Colonoscopy screening for the detection and removal of colonic adenomas is central to efforts to reduce the morbidity and mortality of colorectal cancer. However, up to a third of adenomas may be missed at colonoscopy, and the majority of post-colonoscopy colorectal cancers are thought to arise from these. Adenomas have three-dimensional surface topographic features that differentiate them from adjacent normal mucosa. However, these topographic features are not enhanced by white light colonoscopy, and the endoscopist must infer these from two-dimensional cues. This may contribute to the number of missed lesions. A variety of optical imaging technologies have been developed commercially to enhance surface topography. However, existing techniques enhance surface topography indirectly, and in two dimensions, and the evidence does not wholly support their use in routine clinical practice. In this narrative review, co-authored by gastroenterologists and engineers, we summarise the evidence for the impact of established optical imaging technologies on adenoma detection rate, and review the development of photometric stereo (PS) for colonoscopy. PS is a machine vision technique able to capture a dense array of surface normals to render three-dimensional reconstructions of surface topography. This imaging technique has several potential clinical applications in colonoscopy, including adenoma detection, polyp classification, and facilitating polypectomy, an inherently three-dimensional task. However, the development of PS for colonoscopy is at an early stage. We consider the progress that has been made with PS to date and identify the obstacles that need to be overcome prior to clinical application.
结肠镜检查用于检测和切除结肠腺瘤是降低结直肠癌发病率和死亡率的关键措施。然而，结肠镜检查时高达三分之一的腺瘤可能会被漏诊，并且大多数结肠镜检查后的结直肠癌被认为是由这些漏诊的腺瘤发展而来。腺瘤具有三维表面地形特征，使其与相邻的正常黏膜区分开来。然而，白光结肠镜检查无法增强这些地形特征，内镜医师必须从二维线索中推断它们。这可能导致漏诊病变的数量增加。多种光学成像技术已在商业上开发出来以增强表面地形。然而，现有技术间接增强表面地形，且是在二维层面，并且证据并不完全支持它们在常规临床实践中的使用。在这篇由胃肠病学家和工程师共同撰写的叙述性综述中，我们总结了现有光学成像技术对腺瘤检出率影响的证据，并回顾了用于结肠镜检查的光度立体成像（PS）技术的发展。PS是一种机器视觉技术，能够捕捉密集的表面法线阵列以呈现表面地形的三维重建。这种成像技术在结肠镜检查中有几个潜在的临床应用，包括腺瘤检测、息肉分类以及辅助息肉切除术（这是一项本质上的三维任务）。然而，用于结肠镜检查的PS技术尚处于早期发展阶段。我们考虑了迄今为止PS技术所取得的进展，并确定了在临床应用之前需要克服的障碍。
