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Background: Capsule endoscopy that could actively move and approach a specific site might be more valuable for the diagnosis or treatment of GI diseases. Objective: We tested the performance of active locomotion of a novel wired capsule endoscope with a paddling-based locomotion mechanism, using 3 models: a silicone tube, an extracted porcine colon, and a living pig. Design: In vitro, ex vivo, and in vivo experiments in a pig model. Setting: Study in an animal laboratory. Interventions: For the in vitro test, the locomotive capsule was controlled to actively move from one side of a silicone tube to the other by a controller-operated automatic traveling program. The velocity was calculated by following a video recording. We performed ex vivo tests by using an extracted porcine colon in the same manner we performed the in vitro test. In in vivo experiments, the capsule was inserted into the rectum of a living pig under anesthesia, and was controlled to move automatically forward. After 8 consecutive trials, the velocity was calculated. Main Outcome Measurements: Elapsed time, velocity, and mucosal damage. Results: The locomotive capsule showed stable and active movement inside the lumen both in vitro and ex vivo. The velocity was 60 cm/min in the silicone tube, and 36.8 and 37.5 cm/min in the extracted porcine colon. In the in vivo experiments, the capsule stably moved forward inside the colon of a living pig without any serious complications. The mean velocity was 17 cm/min over 40 cm length. We noted pinpoint erythematous mucosal injuries in the colon. Limitation: Porcine model experiments, wired capsule endoscope. Conclusions: The novel paddling-based locomotive capsule endoscope performed fast and stable movement in a living pig colon with consistent velocity. Further investigation is necessary for practical use in humans. [ABSTRACT FROM AUTHOR]

BACKGROUND: We developed a capsule endoscope (CE), 'MiRo,' with the novel transmission technology of electric-field propagation. The technology uses the human body as a conductive medium for data transmission. Specifications of the prototype include the ability to receive real-time images; size, 10.8 x 24 mm; weight, 3.3 g; field of view, 150 degrees; resolution of power, 320 x 320 pixels; and transmittal speed, 2 frames per second. OBJECTIVE: To evaluate the clinical safety and diagnostic feasibility of the prototype MiRo, we conducted a multicenter clinical trial. DESIGN AND PATIENTS: All volunteers underwent baseline examinations, including EGD and electrocardiography for the screening of GI obstructive and cardiovascular diseases, before the trial. In the first 10 cases, 24-hour Holter monitoring was also performed. To evaluate the diagnostic feasibility, transmission rate of the captured images, inspection rate of the entire small bowel, and quality of transmitted images (graded as outstanding, excellent, good/average, below average, and poor) were analyzed. RESULTS: Of the 49 healthy volunteers, 45 were included in the trial, and 4 were excluded because of baseline abnormalities. No adverse effects were noted. All CEs were expelled within 2 days, and the entire small bowel could be explored in all cases. The transmission rates of the captured image in the stomach, small bowel, and colon were 99.5%, 99.6%, and 97.2%, respectively. The mean total duration of image transmission was 9 hours, 51 minutes, and the mean transit time of the entire small bowel was 4 hours, 33 minutes. Image quality was graded as good or better in 41 cases (91.1%). Details of the villi and vascular structures of the entire small bowel were clearly visualized in 31 cases (68.9%). CONCLUSIONS: MiRo is safe and effective for exploring the entire small bowel, with good image quality and real-time feasibility. This novel transmission technology may have applications beyond the field of capsule endoscopy. [ABSTRACT FROM AUTHOR]

Background and Aims: In a recent randomized controlled trial, a double bare metal stent (DBS) showed better stent patency than single-layer metal stents. However, clear evidence comparing the efficacy of uncovered (UCDBS) and partially covered (PCDBS) DBSs for distal malignant biliary obstruction (MBO) is lacking. Therefore, we compared the clinical outcomes including stent patency of UCDBSs versus PCDBSs., Methods: A multicenter, randomized study was performed in patients with distal MBO. The primary endpoint was stent patency. Secondary endpoints were the proportion of patients with patent stents at 6 months, risk factors for stent dysfunction, overall survival, technical and clinical success rates of stent placement, and other adverse events (AEs)., Results: Among 258 included patients, 130 were randomly assigned to the PCDBS group and 128 to the UCDBS group. The mean duration of stent patency of the PCDBS (421.2 days; 95% confidence interval [CI], 346.7-495.7) was longer than that of the UCDBS (377.4 days; 95% CI, 299.7-455.0), although total stent dysfunction and stent dysfunction within 6 months were not different between groups. Multivariate analysis indicated that chemotherapy after stent placement was a significant factor for overall survival (hazard ratio, .570; 95% CI, .408-.796) and had a marginal impact on stent patency (hazard ratio, 1.569; 95% CI, .923-2.667). There were no remarkable differences in AEs, including pancreatitis, cholecystitis, and stent migration, between the 2 groups., Conclusions: The use of PCDBSs compared with UCDBSs in patients with distal MBO has unclear benefits regarding stent patency and overall survival, although PCDBSs have a lower rate of tumor ingrowth. (Clinical trial registration number: NCT02937246.)., (Copyright © 2023 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: EUS is an accurate imaging modality for delineating gallbladder (GB) structures; however, its clinical use in differentiating neoplastic GB polyps from nonneoplastic polyps is limited. Thus, we sought to characterize neoplastic GB polyps by analyzing unique EUS features. Our analysis revealed variably shaped, relatively hypoechoic portions in the core of polyps compared with general background echogenicity., Objective: Our purpose was to make a differential diagnosis between neoplastic and nonneoplastic GB polyps of less than 20 mm by use of EUS variables, including hypoechoic foci., Design: Retrospective single-center study., Setting: University teaching hospital., Patients: Patients (n = 88) underwent preoperative EUS and cholecystectomy for GB polyps smaller than 20 mm., Results: Hypoechoic foci were found in 30 of 33 patients (91%) with neoplastic polyps and 6 of 55 (11%) with nonneoplastic polyps. In a multivariate analysis, hypoechoic foci were the only significant predictive factor for neoplastic polyps (odds ratio [OR] 55.4, 95% CI, 8.26-371, P < .001); the sensitivity and specificity were 90% and 89%, respectively. In addition, polyps >15 mm had an increased risk of malignancy (OR 21.7, 95% CI, 2.35-201, P = .007), as did those with hypoechoic foci (OR 10.9; 95% CI, 1.01-117, P = .049)., Limitations: Retrospective review of selected patients from a tertiary medical center., Conclusions: The presence of hypoechoic foci on EUS is a strong predictive factor for neoplastic polyps. EUS may be useful in developing a treatment strategy for GB polyps.

Background and Objective: EUS has become a valuable tool for the selection of patients who are suitable for EMR of early gastric cancer (EGC). The aim of this study was to evaluate the various clinicopathologic factors affecting the diagnostic accuracy of EUS in EGC., Design and Setting: A retrospective, single-center study., Patients: A total of 206 patients suspected of EGC endoscopically who underwent EUS examination and curative treatment for EGC at Severance Hospital, Seoul, Korea, from October 2001 to May 2005 were included., Interventions: We reviewed the medical records of 206 patients and compared preoperative EUS staging with final histopathologic staging of the resected specimen according to the clinicopathologic parameters., Main Outcome Measurements and Results: The diagnostic accuracy of EUS for predicting tumor invasion depth was significantly affected by the histopathologic differentiation and the size of tumor. The differentiated cell types were associated with higher diagnostic accuracy in predicting the tumor invasion. Lesions located in the mid one third of the stomach larger than 3 cm had significantly higher probability of overstaging. Poorly differentiated histologic diagnosis had a significantly higher probability of understaging. There was no significant factor associated with the endosonographic prediction of lymph node metastasis., Conclusions: EGC with undifferentiated histopathologic features or large tumor size is more frequently associated with an incorrect diagnosis in tumor invasion depth by EUS. EGC with a size larger than 3 cm and poorly differentiated histologic diagnosis should be cautiously considered in the decision on treatment modality by pretreatment EUS staging.

Background: Submucosal tumors often are found incidentally at upper endoscopy. Although the majority of the ones less than 5 cm in size are benign, periodic monitoring for incremental changes in size, which can be stressful and bothersome to patients, is essential. If relatively easy and safe, an endoscopic method of removal would be optimal treatment. Conventional endoscopic enucleation technically is difficult and often leads to serious complications, such as bleeding and perforation. A novel method for endoscopic enucleation of submucosal tumors with an insulated-tip electrosurgical knife is reported., Methods: En bloc enucleation was attempted by using an insulated-tip electrosurgical knife in 15 patients (10 men, 5 women; median age 48 years) with submucosal tumors of the esophagus (5) or stomach (5 cardia/fundus, 4 body, one antrum). EUS was performed to determine the layer of origin and the exact size of the submucosal tumor., Results: Tumors arose in the muscularis propria in 11 cases, submucosa in two, and muscularis mucosa in one. Enucleation was relatively easy and successful in 14 cases. In one case, however, piecemeal resection was unavoidable because of fibrotic adhesions with the surrounding tissue; this tumor later was confirmed to be a glomus tumor. Median procedure time was 35 minutes (8-180 minutes) and median size of the submucosal tumors was 2x1.7 cm. The largest lesion, located in the esophagus, measured 6x3 cm. Histopathologic diagnoses included leiomyoma (9), GI stromal tumor (4), stromal tumor of unknown malignant potential (1), and glomus tumor (1). A small perforation occurred in one patient with a 2.5-cm tumor in the anterior wall of proximal gastric body but was managed successfully by endoscopic clip application. Follow-up endoscopy at 2 months in this patient revealed no tumor recurrence and complete healing of the treatment-related ulcer., Conclusions: En bloc endoscopic enucleation of submucosal tumors by using an insulated-tip electrosurgical knife appears to be safer, easier, and less time consuming compared with previously described methods. However, further investigation and comparative studies are required to confirm the safety and efficacy of this method.

Background: This study evaluated the normal pancreaticobiliary ducts of Koreans and assessed the frequency and pattern of variations and anomalies of these structures., Methods: A prospective, nationwide multicenter study was performed in which 10 university hospitals in Korea participated from March 1997 to June 1999. A total 10,243 patients undergoing ERCP were enrolled., Results: The mean (SD) maximal and midportion diameters in millimeters of the common hepatic duct were, respectively, 6.1 (1.8) and 5.3 (1.6). The mean maximal and midportion diameters (mm) of the common bile duct were, respectively, 6.4 (1.8) and 5.5 (1.7). The mean maximal and midportion diameters (mm) of the main pancreatic duct in the head, body and tail were, respectively, 3.2 (1.1), 2.7 (1.0), and 2.5 (2.3); and, respectively, 2.2 (0.9), 1.6 (0.7) and 1.4 (0.6). Pancreaticobiliary duct diameters for patients above the age of 40 were greater than those of patients less than 40 years of age (p < 0.05). The frequency of choledochal cyst and anomalous union of the pancreaticobiliary ducts were, respectively, 0.32% and 4.1%. Pancreas divisum and annular pancreas were found, respectively, in 0.49% and 0.05%., Conclusions: A knowledge of normal pancreaticobiliary ductal structures as well as the frequency and pattern of variations including anomalies is essential for the diagnosis and treatment of pancreaticobiliary disorders.