Objective—To ultrasonographically measure the thickness of the individual wall layers of the duodenum, jejunum, and colon of dogs. Animals—85 dogs with no clinical signs or ultrasonographic evidence of gastrointestinal tract disease. Procedures—Total wall thickness and thickness of the mucosa, submucosa, muscularis, and serosa were measured ultrasonographically in the duodenum, jejunum, and colon of each dog. Results—The mucosal layer was the thickest layer of the duodenum and jejunum. There was a significant difference in thickness of the mucosal layer between small and large dogs. Mean ± SD thickness of the mucosal layer of the duodenum for small, medium, and large dogs was 2.4 ± 0.5 mm, 2.6 ± 0.6 mm, and 2.8 ± 0.5 mm, respectively. Mean ± SD thickness of the mucosal layer of the jejunum for small, medium, and large dogs was 1.8 ± 0.4 mm, 2.0 ± 0.4 mm, and 2.2 ± 0.5 mm, respectively. The remaining wall layers of the duodenum and jejunum were similar in thickness, and there were no significant differences among small, medium, and large dogs. All layers contributed equally to the total colonic wall thickness. Mean ± SD thickness of the colonic wall for small, medium, and large dogs was 1.5 ± 0.3 mm, 1.4 ± 0.5 mm, and 1.6 ± 0.4 mm, respectively. Conclusions and Clinical Relevance—Values for thickness of the wall layers of the duodenum, jejunum, and colon of dogs reported here may be useful for assessing gastrointestinal tract diseases primarily targeting a specific wall layer.

Objective-To determine ultrasonographic features and reference values of the anatomy of the abdomen of common rats (Rattus norvegicus). Animals-20 adult male and 20 adult female rats. Procedures-A complete abdominal ultrasonographic examination was performed with the rats sedated. The cadavers of 4 rats were used for anatomic comparisons. Two cadavers were dissected and 2 cadavers were frozen and then cross-sectioned by use of an electric bandsaw. Slices were cleaned with water and photographed on each side. Correlations between variables were determined. Results-The ultrasonographic anatomy of the abdomen was determined, including measurements of the kidneys and adrenal glands and thickness of the walls of the stomach (saccus caecus, fundus, and pylorus), duodenum, and cecum. A significant positive correlation between kidney size and body weight was detected. The dorsoventral measurements of the left and right adrenal gland were significantly different, regardless of sex. Dorsoventral measurements of the right adrenal gland were significantly different between males and females. Conclusions and Clinical Relevance-The ultrasonographic images and data provided an atlas of the ultrasonographic anatomy of common rats that may be useful to veterinary radiologists, clinicians, and researchers.