title: Endocytoscopy is a promising modality with high diagnostic accuracy for gastric cancer.
abstract: OBJECTIVE
  Endocytoscopy (ECS) enables in vivo microscopic imaging, which allows analysis of mucosal structures at the cellular level; however, limited data are available on the validity of ECS in the stomach. The aim of this study was to evaluate the feasibility of ECS in the diagnosis of early gastric cancer.
  
  
  METHODS
  Gastric lesions that were the targets of histopathological diagnosis by endoscopic submucosal dissection or biopsy specimen were prospectively enrolled and evaluated using a single charge-coupled device-integrated endocytoscope, following double staining with crystal violet and methylene blue. High grade ECS atypia was defined according to specific irregularities in gland structure and cell nuclei. The primary end point was the accuracy of ECS diagnosis for gastric cancer, using histopathological diagnosis as the gold standard.
  
  
  RESULTS
  A total of 82 lesions were investigated, including 23 early gastric cancers, 10 gastric adenomas, and 49 non-neoplastic lesions. Ten lesions could not be clearly observed by ECS because of poor staining due to viscous mucus or plaque; thus, assessability rates with ECS were 88 % in total and 91 % for gastric cancer. High grade ECS atypia was observed in 86 % of assessable gastric cancers, but not in any cases of gastric adenomas or non-neoplastic lesions. The sensitivity, specificity, positive and negative predictive values of high grade ECS atypia as the criterion for the diagnosis of gastric cancer were 86 %, 100 %, 100 %, and 94 %, respectively. No serious complications occurred during or after the examinations.
  
  
  CONCLUSIONS
  ECS is a clinically feasible modality to obtain in vivo histology, with high diagnostic accuracy in gastric cancer.
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kaise
authors.affiliation: Department of Pathology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohkura
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Iizuka
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kimura
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nomura
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kuribayashi
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamada
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamashita
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Furuhata
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kikuchi
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Ogawa
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Matsui
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Mitani
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Tokyo, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Hoteya
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000236:Adenoma / Q000473:pathology*; D004396:Coloring Agents; D005240:Feasibility Studies; D005753:Gastric Mucosa / Q000473:pathology*; D005773:Gastroscopy / Q000379:methods*; D005840:Gentian Violet; D006801:Humans; D008751:Methylene Blue; D010865:Pilot Projects; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000473:pathology*
chemical_list: D004396:Coloring Agents; D005840:Gentian Violet; D008751:Methylene Blue