Abstract
The findings of radial endoscopic ultrasound (EUS) and abdominal ultrasound (AUS) in the descending part of the duodenum in healthy dogs were compared, and the usefulness of radial EUS was assessed. Like AUS, radial EUS could distinguish the layered structure of the duodenum, i.e., the mucosal layer, submucosal layer, mucsularis layer, and serosa layer. Further, EUS was able to distinguish the mucosal surface layer and the mucosal layer in the mucosal layer. The total of mucosal and submucosal layers measured by AUS was 0.4 mm thicker than that measured by radial EUS (p<0.05). There was also a correlation between body weight and the total thickness of the mucosal and submucosal layers (p<0.0001, r=0.67). Therefore, when using radial EUS, it is necessary to consider the difference of thickness, and accordingly a new reference value should be determined on basis of body weight. In the future, specific changes in the mucosal structure of gastrointestinal diseases might be observed more closely by radial EUD.
