Today's Veterinary Practice

JAN-FEB 2018

Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.

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PEER REVIEWED 88 IMAGING ESSENTIALS STOMACH ABNORMALITIES Dilation If the stomach becomes progressively distended or dilated, the stomach wall will become thinner, the wall layering will be difficult to distinguish, and the rugal folds will be less distinct. Depending upon its composition, gastric content may be hypoechoic to hyperechoic. A gas dilated stomach may contain reverberation artifact within the far field of the image, resulting in the inability to visualize abnormalities of the dorsal aspect of the gastric wall or lumen. Pyloric Outflow Obstruction Causes of pyloric outflow obstruction include pyloric stenosis, foreign bodies, inflammatory disease, and neoplasia. Congenital hypertrophic pyloric stenosis causes circumferential thickening of the pylorus and is more common in dogs than cats. Ultrasonographically, gastric wall thickness > 6 to 7 mm and muscular layer thickness > 4 mm is considered pathologic ( FIGURE 9 ). 2 Foreign bodies lodged in the pyloric region typically have an irregular or geometric shape and strong acoustic shadowing. Chronic hypertrophic pyloric gastropathy also causes muscular or mucosal hypertrophy; pyloric wall thicknesses for affected dogs ranges from 9 to 15.3 mm, and the thickness of the muscular layer ranges from 3 to 5.4 mm. 9 Gastric Foreign Bodies Gastric foreign bodies are often diagnosed on survey radiographs and can sometimes be diagnosed using ultrasound, depending on the contents in the gastric lumen. Often, foreign material has a hyperechoic interface with intense distal acoustic shadowing. If the foreign body is surrounded by fluid, it can be readily seen ( FIGURE 10 ). The shape and size of the foreign material varies. Gastric Wall Thickening Non-neoplastic lesions, such as gastritis, can produce a diffuse, mild to moderate thickening with preservation of the wall layering ( FIGURE 10 ). Neoplastic lesions usually cause focal loss of wall layering along with varying degrees of wall thickening ( FIGURE 11 ). 8,14,15 Malignant Gastric Neoplasms Adenocarcinoma is the most common gastric neoplasm in the dog. This neoplasm is extremely rare in the cat. Most carcinomas are located in the lesser curvature and pylorus in the dog. Features of gastric adenocarcinoma include a pseudo- layered pattern, asymmetrical transmural thickening, and altered wall layering with a poorly echogenic lining to the mucosal and/or serosal wall layers. 16-18 FIGURE 9. Longitudinal axis view of the stomach of a dog diagnosed with gastric outflow obstruction. Note the abnormally thickened, hyperechoic muscularis layer of the stomach, measuring up to 1 cm in thickness ( calipers ). FIGURE 10. Transverse axis view of the stomach of a dog with a gastric linear foreign body. Note the hyperechoic foreign material ( black arrowhead ) with distal acoustic shadowing ( ) and gastric wall thickening ( calipers measuring 9 mm thick ), presumptively secondary to gastritis.

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