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Background and study aims: Endoscopists must maneuver both endoscope and treatment device during procedures, requiring them to release their hand from the scope to manipulate the treatment device. Aiming to improve this situation, we developed a new device called the Thumb Drive. Patients and methods: The Thumb Drive comprises a controller and catheter. After attaching the controller to the endoscope’s grip, the catheter is inserted into the forceps channel. The treatment device is then inserted into the Thumb Drive and fixed with its tip protruding from the endoscope tip. A single endoscopist resected 10 lesions in a porcine stomach by endoscopic submucosal dissection (ESD) using the Thumb Drive. Results: All lesions were resected en bloc using this new device without any perforations. The mean incision, dissection, and operative times were 97.2 ± 48.7 seconds, 121.6 ± 53.6 seconds, and 218.8 ± 67.8 seconds, respectively. Conclusions: The Thumb Drive enables the endoscopist to manipulate the treatment device with the thumb while handling the endoscope with the right hand during ESD. Its utility should be examined in in vivo studies as a next step.

Background and study aim: 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. Patients and 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. Conclusion: ECS is a clinically feasible modality to obtain in vivo histology, with high diagnostic accuracy in gastric cancer.

Background and aim: High-grade atypia demonstrated by endocytoscopy may be a key criterion for the diagnosis of gastric cancer. We therefore sought to verify whether endocytoscopic atypia can provide satisfactory levels of diagnostic accuracy and concordance among trainee and expert endoscopists. Method: A total of 100 lesions evaluated by endocytoscopy and histopathology were enrolled to create an endocytoscopic image catalog (44 early cancers, 10 low-grade adenomas, 46 non-neoplastic lesions). Four endoscopists (two trainees and two experts) independently reviewed the catalog images and evaluated each of them for the presence or absence of endocytoscopic atypia. High-grade endocytoscopic atypia, as a criterion for cancer diagnosis, was defined as the consistent observation of any of the following features: lumen absence, lumen fusion, and irregular nuclei showing the three typical features (heterogeneous shape, swelling, and disarrangement). Results: High-grade endocytoscopic atypia was observed in 78 %, 18 %, and 4 % of cancers, adenomas, and non-neoplastic lesions, respectively. The sensitivity, specificity, accuracy, and positive and negative predictive values for cancer diagnosis by endocytoscopy were 78.4 %, 93.3 %, 87.3 %, 85.4 %, and 87.3 %, respectively. The concordance rate for the results of high-grade endocytoscopic atypia was good among the four endoscopists (κ value 0.682). No significant difference in diagnostic accuracy or concordance was observed between trainee and expert endoscopists. Conclusion: Using the defined high-grade atypia as a diagnostic criterion of cancer, endocytoscopy provided a satisfactory level of accuracy and concordance for the diagnosis of early gastric cancer, regardless of endoscopic expertise.