Clinical Efficacy of Endocytoscopy for Gastrointestinal Endoscopy

Abstract

Endocytoscopy (EC) is a contact-type optical endoscope that allows in vivo cellular observation during gastrointestinal endoscopy and is now commercially available not only in Japan but also in Asian, European Union, and Middle Eastern countries. EC helps conduct a highly accurate pathological prediction without biopsy. Initially, EC was reported to be effective for esophageal diseases. Subsequently, its efficacy for stomach and colorectal diseases has been reported. In this narrative review, we searched for clinical studies that investigated the efficacy of EC. EC seems to accurately diagnose gastrointestinal diseases without biopsy. Most of the studies aimed to clarify the relationship between endocytoscopic findings of gastrointestinal neoplasia and pathological diagnosis. Some studies have investigated non-epithelial lesions or diseases, such as inflammatory bowel disease or infectious diseases. However, there are few high-level pieces of evidence, such as randomized trials; thus, further studies are needed.

Keywords: Endocytoscopy; Lower gastrointestinal endoscopy; Magnifying endoscopy; Upper gastrointestinal endoscopy.

Fig. 1.

Endocytoscopic classification for esophageal squamous cell carcinoma, proposed by Shimamura et al. [11]. Their classification has three categories. The upper row shows typical endocytoscopic images and the lower row shows corresponding hematoxylin and eosin staining. (A, D) reveals cytoplasm-rich cells with large rhomboid-shaped cells and a uniform pattern of small and round nuclei. (B, E) shows slightly higher cellular density compared with A, D and the nuclei appear small or mildly enlarged. (C, F) shows a significant increase in the cellular density with loss of cellular structure along with a demarcation line, and the nuclei are enlarged with heterogeneity in size and shape. EC, endocytoscopy.

Fig. 2.

Endocytoscopic classification for colorectal lesions, proposed by Kudo et al. [5]. Their classification is based on the structure of the crypts and the shape of the nuclei. EC, endocytoscopy.

Fig. 3.

Endocytoscopic classification based on narrow-band imaging, proposed by Kudo et al. [34]. This classification is based on the shape and arrangement of the surface microvessels. EC, endocytoscopy.

Fig. 4.

The endocytoscopic scoring system for ulcerative colitis, proposed by Maeda et al. [42]. The intramucosal capillary/crypt (ICC) index comprises a capillary index and a crypt index. We defined the capillary index as follows: 0, normal or unrecognizable; 1, deformed or dilated; 2, dense; 3, deformed and dilated and the crypt index as follows: 0, normal or unclear; 1, linear; 2, twisted. EC, endocytoscopy; ICC, intramucosal capillary/crypt.