Assessment of duodenal villous morphology in canine IBD using magnification endoscopy with water immersion technique (WIT) and image skeletonization

Abstract Inflammatory Bowel Disease (IBD) is an idiopathic disorder characterized by chronic, nonspecific gastrointestinal signs. Gastrointestinal endoscopy with histopathology is the gold standard for confirming inflammation and assessing severity. Although endoscopic criteria for IBD in dogs exist, detailed evaluation of duodenal villi morphology remains limited. In human medicine, magnification endoscopy with water immersion technique (WIT) and image skeletonization have proven useful for assessing villous atrophy in celiac disease. Only one veterinary study has applied these methods. This study aimed to assess the feasibility of WIT combined with skeletonized image analysis for evaluating duodenal villi in dogs with IBD. Thirty-three dogs undergoing endoscopy for suspected IBD were included. For each dog, five sub-images (7.5 × 7.5 mm²) were selected and skeletonized. The number of branches (B) and junctions (J) were quantified and cor- related with histopathological inflammation grades. Skeletonized images before (nW) and after (W) WIT were compared based on average (AV) and maximum (Max) branch lengths. AV and Max branch lengths were significantly higher post- WIT. B and J values decreased with increasing severity of IBD. This study demonstrates that WIT and quantitative image analysis are simple, safe, and feasible for evaluating duodenal villous morphology in dogs with IBD. WIT could be routinely integrated into standard endoscopic procedures, offering immediate, standardized staging of IBD and enhancing diagnostic information.