Background This study aimed to evaluate a new computational histology prediction system based on colorectal polyp textural surface patterns using high definition white light images. Methods Textural elements (textons) were characterized according to their contrast with respect to the surface, shape, and number of bifurcations, assuming that dysplastic polyps are associated with highly contrasted, large tubular patterns with some degree of bifurcation. Computer-aided diagnosis (CAD) was compared with pathological diagnosis and the diagnosis made by endoscopists using Kudo and Narrow-Band Imaging International Colorectal Endoscopic classifications. Results Images of 225 polyps were evaluated (142 dysplastic and 83 nondysplastic). The CAD system correctly classified 205 polyps (91.1 %): 131/142 dysplastic (92.3 %) and 74/83 (89.2 %) nondysplastic. For the subgroup of 100 diminutive polyps (≤ 5 mm), CAD correctly classified 87 polyps (87.0 %): 43/50 (86.0 %) dysplastic and 44/50 (88.0 %) nondysplastic. There were no statistically significant differences in polyp histology prediction between the CAD system and endoscopist assessment. Conclusion A computer vision system based on the characterization of the polyp surface in white light accurately predicted colorectal polyp histology.

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Background and study aims: To assess experimentally endoscopic submucosal tunnel dissection (ESTD) as an alternative technique of endoscopic submucosal resection. Patients and methods: This was a prospective, randomized, comparative experimental animal study carried out over a period of 9 months at the surgical research and teaching center of Aix-Marseille University, France. Virtual esophageal and gastric lesions measuring 3 cm in diameter were resected in pigs weighing 25 to 30 kg. The primary aim was to evaluate ESTD’s efficacy compared with endoscopic submucosal dissection (ESD). The secondary aims were to determine complication rates as well as to assess procedure time and procedure speed, histologic quality of the resected specimen, and procedure cost. Results: Eighteen procedures (9 ESD and 9 ESTD) were performed in nine pigs. The technical success rate was 88.9 % for both techniques, with one single failure in each. The en bloc resection rate was 100 % for ESTD and 88.9 % for ESD (one failure). The complication rate (22 %) and median procedure time were similar but dissection speed was quicker with ESTD in the esophagus (P = 0.03). Median procedure cost (728 Euros for ESD and ESTD) did not differ. On histologic examination, the lateral margins were healthy in 100 % of ESTD and in 88.9 % of ESD (P = 0.49). Deep resection margins were of better quality in ESTD (median submucosal thickness: 1307.1 µm vs. 884.7 µm; P = 0.039). Conclusions: ESTD is feasible and safe but not superior in the treatment of superficial esophageal/gastric lesions in porcine models compared with ESD. Nevertheless it provides a better quality histologic specimen.

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BACKGROUND AND AIMS : Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is an emerging and minimally invasive technique, which seems promising for the treatment of focal pancreatic and peripancreatic lesions. Our aim was to prospectively evaluate the feasibility, safety, technical and clinical success of pancreatic and extra-pancreatic EUS-RFA. METHODS : We prospectively collected clinical and technical data regarding all patients submitted to EUS-RFA in two Belgian academic centers, from June/2018 to February/2022. Feasibility, adverse events and follow-up were also assessed. RESULTS : Twenty-nine patients were included, accounting for thirty-five lesions : 10 non-functioning neuroendocrine tumors (29%), 13 pancreatic insulinoma (37%), 1 adenocarcinoma lesion (3%) and, finally, 11 intra and extra-pancreatic metastatic lesions (31%). Technical success was achieved in 100%, with a median of 3 power applications per lesion (IQR 2). The majority of patients (59%) presented no collateral effects, three (10.3%) developed non-severe acute pancreatitis and four (14%) mild abdominal pain. At 6 months follow-up (n=25), 36% of patients showed radiological complete response, 16% presented a significant partial response and 48% showed <50% decrease in diameter. At 12 months (n=20), 30% showed complete necrosis and 15% > 50% decrease in diameter. Hypoglycemia related to insulinoma was immediately corrected in all 13 cases, with no recurrence during follow-up. CONCLUSIONS : EUS-RFA is feasible, safe and effective for the treatment of pancreatic and peripancreatic tumors. Larger and longer multicentric prospective studies are warranted to establish its role in the management of focal pancreatic lesions and oligo-metastatic disease. Symptomatic insulinoma currently represent the best indication.

Background and study aims Recent evidence suggests that lugol chromoendoscopy (LCE) and narrow-band imaging (NBI) have comparable sensitivity for detection of superficial esophageal squamous cell carcinoma (SCC). However, LCE is time-consuming and associated with side effects. The aim of this study was to compare the effectiveness of NBI and LCE in defining resection margins of esophageal SCC. Patients and methods This was a retrospective observational cohort study of patients with esophageal SCC and dysplasia who underwent en-bloc resection between 1999 and 2017 at the Cliniques universitaires Saint-Luc, Brussels. Two groups were defined: 1) inspection with NBI only; and 2) inspection with LCE (with or without NBI). The primary endpoint was complete lateral resection rate. Multivariate regression was used to adjust for potential confounders. Results A total of 102 patients with 132 lesions were included. Lesions were inspected with LCE in 52 % (n = 68) and with NBI only in 48 % (n = 64). Lesions 0-IIa were more frequent in the NBI group (37 %) and 0-IIb (60 %) in LCE. Lesion location, size, and histology and resection technique (endoscopic submucosal dissection in 122/132 cases, 92 %) were similar between the groups. The rate of complete lateral resection for invasive carcinoma was 90 % in LCE group and 94 % in NBI group (P = 0.498) and 65 % and 67 % (P = 0.813), respectively, for dysplasia complete lateral resection. These results remained non-significant after adjusting for potential confounders. Conclusions Mucosal inspection and delineation of tumors with lugol chromoendoscopy before endoscopic resection of esophageal squamous cell lesions was not associated with increased complete lateral resection rate when compared to NBI.

Background and study aims Endoscopic resection requires use of submucosal injection. This study was conducted to assess efficacy and impact on early healing of hyaluronic acid combined with chondroitin sulfate and poloxamer 407 (Ziverel) when used as a solution for submucosal injection. Materials and methods Prospective and comparative study of gastric endoscopic mucosal resection (EMR) with three groups of two Yorkshire pigs. Six submucosal cushions were created in each animal by injecting 2 mL of Ziverel (Group 1) or succinylated gelatin (SG) (Group 2), enabling 12 EMR in each group. Submucosal cushions were created with Ziverel in Group 3, without resection. Electrosurgery unit settings were the same in all cases. EMR defects and injection sites were marked with clips. The animals were sacrificed 7 days later. EMR specimen size and duration of procedure were recorded. EMR specimens and EMR scars and injection sites were evaluated by a blinded pathologist. Results We successfully performed 24 EMR (15 en-bloc and 9 piecemeal, without differences between groups 1 and 2). Mean EMR specimen dimensions were significantly larger in Group 1 (median 19 mm, range 6 – 40 vs 16.6 mm, range 5‑25; P = 0.019), without changing the electrocautery unit settings. Blinded histopathologist assessment of EMR specimens showed less fibrosis in the submucosa and a trend to fewer cautery artifacts with Ziverel and did not identify any significant differences in early healing of resection sites. Conclusion The combination of Ziverel enables EMR and does not negatively affect early healing.

<b><i>Background:</i></b> Regular arrangement of collecting venules (RAC) in gastric mucosa accurately identifies patients without <i>Helicobacter pylori</i> (<i>H pylori</i>) infection. The aim of our study was to evaluate the reproducibility of RAC using white light endoscopy without magnification, in a European country, and to assess the impact of proton pump inhibitors (PPIs). <b><i>Methods:</i></b> A multicenter prospective study with image capture of the distal lesser gastric curvature and gastric biopsies was performed. The presence of starfish-like minute points regularly distributed throughout lesser curvature was considered as RAC positive (RAC+). A set of 20 images was used for the training phase and inter and intra-observer agreements were calculated. <b><i>Results:</i></b> 174 patients were included and 85 (48.9%) were taking PPIs. Kappa values for interobserver and intra-observer agreements were substantial (0.786) and excellent (0.906), respectively. <i>H</i>. <i>pylori</i> infection was diagnosed in 29 patients (16.7%): 10/85 with PPIs and 19/89 without PPIs (11.8% vs. 21.3%; <i>p</i> = 0.09). All RAC + patients were free of <i>H</i>. <i>pylori</i> infection, with a sensitivity and negative predictive value of 100%, regardless of PPI intake. <b><i>Conclusion:</i></b> The endoscopic diagnosis of <i>H</i>. <i>pylori</i> by RAC is an easy-to-learn and highly reproducible technique, even with PPI intake. Our results warrant RAC as a real-time diagnostic method for <i>H</i>. <i>pylori</i>-negative infection in Western practice.