The normal sonographic appearance of stomach, small bowel, and colon was determined in normal dogs of small, medium, and large breeds. In all dogs studied, the stomach wall ranged from 3 mm to 5 mm in thickness, and the small and large bowel wall ranged from 2 mm to 3 mm in thickness. Peristalsis was routinely observed in the sto-mach and small bowel, but not in the colon. Ultrasonic identification of five gastrointestinal wall layers corresponding to the mucosal surface, mucosa, submucosa, muscularis propria, and subserosa/serosa was possible. Specific segments of the gastrointestinal (GI) tract were isolated and scanned in a water bath. In one dog, ultrasonic and histologic fmdings were compared and confirmed the anatomical identification found with ultrasound. Similarities and differences between the ultrasonic appearance of the GI tract of humans and small animals are discussed.

Esophageal hiatal hernia was diagnosed in 11 young Chinese Shar-Pei dogs between October 1985 and J u l y 1991. The dogs ranged in age from 2 to 11 months and included 3 females and 8 males. The most common clinical signs were regurgitation, vomiting, and hypersalivation. Physical examination was normal in 6 dogs; abnormal physical examination findings in the other 5 dogs included fever, dehydration, hypersalivation, and pulmonary wheezes and crackles. Laboratory evaluation was significant only for neutrophilia in 5 dogs. A diagnosis of hiatal hernia was made on the basis of survey thoracic radiographic and/or barium esophagram findings of displacement of the esophagogastric junction and stomach into the thoracic cavity; the diagnosis was confirmed by surgery in 9 dogs and at necropsy in 2 dogs. Megaesophagus (n = 7), gastroesophageal reflux (n = 4), and esophageal hypomotility (n = 1) were additional findings in some dogs. Aspiration pneumonia was diagnosed in 7 of the dogs. Medical therapies formulated for the therapy of presumed reflux esophagitis generally failed to resolve the clinical signs associated with the hiatal hernia. Hiatal herniae were surgically repaired in 9 of the Shar-Peis by various combinations of diaphragmatic crural apposition, fixation of the esophagus to the diaphragmatic crus (esophagopexy), and left fundic tube gastropexy. Eight of the animals survived surgery, six of which have been asymptomatic since surgery (19 to 36 months). The megaesophagus, esophageal hypomotility, and bronchopneumonia resolved in all of these dogs. AN ESOPHAGEAL hiatal hernia is a protrusion of abdominal contents through the esophageal hiatus of the diaphragm into the thoracic cavity. It is a relatively uncommon condition affecting both dogs and cats. Two types of esophageal hiatal hernia have been recognized in the dog and cat: 1) sliding hiatal hernia, in which the abdominal segment of the esophagus and parts of the stomach are displaced cranially through the esophageal hiatus,'-'* and 2) paraesophageal hiatal hernia, in which the abdominal segment of the esophagus and lower esophageal sphincter remain in a fixed position but a portion of the stomach herniates into the mediastinum alongside the thoracic es~phagus.'~ In dogs and cats, sliding hiatal hernia is the most common form.The clinical signs associated with hiatal hernia are vanable and range in severity from infrequent episodes of mild anorexia, hypersalivation, and regurgitation to vomiting, hematemesis, and dyspnea. '-I2 Cardiac arrest can occur when large hernias interfere with cardiopulmonary function. Medical therapies have traditionally been directed toward treatment of presumed reflux esophagitis but usually fail to resolve the clinical signs. Surgical stabilization of the normal anatomy by reduction in the size of the esophageal hiatus, fixation of the esophagus to the diaphragmatic crus (esophagopexy), and left fundic gastropexy has yielded good to excellent results. I Most sliding esophageal hiatal herniae have been reported in animals less...

Sonographic findings of 18 dogs and four cats with gastrointestinal (GI) diseases were reviewed. Wall thickness, wall layer identification, wall symmetry, extension of the lesion, nature of the GI contents, motility, and regional and/or systemic involvement were recorded for each animal. Ultrasonographic appearance of gastrointestinal neoplasms, gastrointestinal obstruction, ileus, intussusception, inflammatory GI diseases, and congenital disorders are discussed.

A technique for temporary hepatic vascular occlusion during partial hepatectomy for hepatic arteriovenous (AV) fistulas in the dog is presented in seven dogs, and three additional cases of hepatic AV fistulas are reviewed. Hematologic, serum biochemical, radiologic, and nuclear scintigraphic parameters before and after surgery are discussed; abnormalities included anemia, hypoproteinemia, leukocytosis, increased liver function tests, retrograde filling of the portal vein during celiac angiography, and increased arteriovenous ratios during nuclear scintigraphy. Hemodynamic and pathologic findings are presented, and portal hypertension and secondary multiple portosystemic shunts are described. Clinical improvement was observed in four dogs with follow‐up periods ranging from 5 months to 3 years.

Abdominal discomfort in the foal presents a diagnostic challenge, because the small size of the foal precludes rectal palpation. Standing lateral horizontal beam abdominal radiographs using conventional techniques were evaluated as a diagnostic aid to identify the presence and location of gastrointestinal disorders in foals presented with colic. Forty foals were radiographed prior to surgery (20 foals), necropsy (7 foals), or clinical diagnosis (13 foals). Clinical, surgical, or necropsy findings were then correlated to radiographic findings. Gastrointestinal disease was accurately identified on radiographs as the source of colic in 25 of 26 foals that had surgical or postmortem confirmation. The site of disease, whether gastric, small intestinal, large intestinal, or a combination, was accurately determined from radiographs. Standing lateral abdominal radiographs were determined to be a valuable diagnostic aid in the foal presented with colic.