1887

The stomach

image of The stomach
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Abstract

The stomach is a hollow organ with a musculoglandular wall. It is located in the cranial part of the abdominal cavity, caudal to the liver. It is divided into several regions left to right: the gastric fundus; the body; the pyloric antrum; and the pyloric canal. The fundus forms a pouch arising from the left dorsal part of the stomach. The stomach communicates with the oesophagus through the cardia and with the duodenum through the pylorus. The gastric curvatures are described. The greater curvature is convex and forms the caudoventral border of the stomach, extending from the left side of the cardia to the pylorus. The lesser curvature is concave, and extends from the right side of the cardia to the pylorus. The deep part of the greater inserts on to the greater curvature, and the left lobe of the pancreas is located in this region of insertion. The angular incisure is the point of maximal angulation on the lesser curvature. This chapter discusses Normal radiographic anatomy; Contrast radiography; Ultrasonography; and Gastric diseases.

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Figures

Image of 9.1
9.1 VD radiograph of the cranial abdomen in a dog. The gastric lumen is clearly visible owing to the presence of air within it. The gastric folds are particularly easily identified in this case, and are oriented parallel to the greater curvature of the stomach. The different compartments of the stomach are visible.
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9.2 Lateral view of the abdomen in a cat. The stomach does not contain air and therefore silhouettes with the liver shadow in the cranial abdomen.
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9.3 Left lateral view of the abdomen in a normal dog. Food is present in the fundus of the stomach giving a heterogenous pattern and opacity. Gas is present in the pyloric antrum, which is the non-dependent portion of the stomach on this view. A small amount of gas is also seen in the proximal portion of the descending duodenum. Note the distended caudal oesophagus.
Image of 9.4
9.4 VD views of the abdomen in a cat. The stomach is J-shaped and clearly identified here because it contains gas. Its great axis is parallel to the spine. View following administration of barium sulphate. Note the J shape of the stomach filled with barium. In cats the stomach is almost entirely on the left side, with only the pylorus being superimposed on the spine (or slightly to the right if the stomach is distended).
Image of 9.5
9.5 Variation in aspect of the stomach on the lateral view as a result of thoracic conformation. The axis of the 10th pair of ribs is represented as a grey line. Wide, short thorax. Intermediate thorax. Narrow, long thorax. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and are printed with her permission.
Image of 9.6
9.6 Variation in aspect of the gastric gas bubble in the dog, depending on the radiographic view. DV view. VD view. Left lateral view. Right lateral view. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and are printed with her permission.
Image of 9.7
9.7 Right lateral view of the abdomen in a dog. Note the rounded soft tissue opacity caudal to the hepatic shadow in the cranioventral abdomen. This corresponds to the gastric antrum, which in right lateral recumbency is in the dependent portion of the stomach and therefore is filled with fluid.
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9.8 Left lateral view of the abdomen of the same dog as in Figure 9.7 . The gastric antrum is filled with air and forms a rounded image of gas lucency in the cranioventral part of the abdomen.
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9.9 Pneumogastrography in a dog presented for chronic vomiting. An oblong mass of soft tissue (arrowed) is seen in the cranioventral region of the stomach, outlined by the injected air. An adenocarcinoma was diagnosed.
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9.10 Short axis and long axis views of the gastric fundus of a clinically and ultrasonographically normal dog. The stomach is nearly empty and contains only a small amount of gas in some portions. The rugal folds give the stomach wall a striated appearance.
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9.11 Normal pylorus. Long axis view of the pyloric antrum (a) on the right, the pyloric canal (p) and the duodenum (d) on the left. The wall of the pyloric canal sometimes has a hyperechoic appearance.
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9.12 Normal stomach. Long axis view of the gastric fundus of a clinically and ultrasonographically normal dog. The stomach is moderately distended with hypoechoic fluid containing multiple gas bubbles, seen as hyperechoic specks throughout the gastric contents. The rugal folds are barely visible; note the clear distinction of the wall layers.
Image of 9.13
9.13 Lateral radiographic view of the abdomen in a dog presented with a history of acute abdominal distension, tympany and vomiting. A major gaseous distension of the stomach and abnormal positioning of the gastric compartments are visible. The fundus is displaced caudoventrally and the pyloric region is displaced craniodorsally. A line of soft tissue opacity is seen between the compartments (arrowed), and this compartmentalization is an important feature that allows the diagnosis of gastric volvulus to be established.
Image of 9.14
9.14 Lateral radiographic view of the abdomen in a dog presented with abdominal distension, tympany and vomiting of several days duration. A major gastric dilatation is evident in the cranial abdomen and the stomach demonstrates mixed soft tissue and gas opacity. Because of the fluid and gas content, an impression of thickening of the ventral wall of the stomach is present on this radiographic image. This is a false impression and is due to the geometrical arrangement of gas on the one hand and fluid silhouetting with the gastric wall on the other hand. The pyloric region is displaced craniodorsally and the fundus is displaced caudoventrally. In this case a diagnosis of chronic GDV can be established.
Image of 9.15
9.15 Dog presented with acute vomiting. Right lateral view of the abdomen. There is marked gaseous distension of the stomach. Gas is mostly present in the fundic region in this case, which is expected on the right lateral view if this compartment is in the normal position. Left lateral view of the abdomen. There is gaseous dilatation of the pyloric antrum and descending duodenum, whilst the fundic region is dilated by fluid. The pyloric antrum is easily recognized as a triangular lucency and is located in the normal position in the cranioventral abdomen. The fact that it is gas-filled on this view also suggests that it is probably on the right side of the abdomen. The diagnosis was severe gastric dilatation, without volvulus.
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9.16 VD radiograph of the abdomen in a cat with feline dysautonomia. Note the severe gaseous distension of the stomach. The caudal oesophagus is also dilated and its wall is visible in the caudal thoracic region, forming two lines of soft tissue opacity joining at the oesophageal hiatus. Intestinal paralytic ileus is also visible in the rest of the abdominal cavity.
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9.17 Marked aerophagia causing gaseous distension of the stomach in a dog.
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9.18 Lateral radiographic view of the abdomen in a dog presented with a history of chronic vomiting. Gaseous distension of the stomach is evident, and opaque granular material has accumulated in the region of the gastric body and pyloric antrum. These are signs of a chronic gastric obstruction, which in this case was due to a pyloric tumour.
Image of 9.19
9.19 Lateral view of the abdomen in a dog presented for vomiting. Granular opacities are present in the ventral portion of the stomach, which is distended with a fluid opacity. Its caudal margin is seen at the level of L2–L3. The tubular granular opacity seen in the ventral portion is in the area of the pyloric antrum. It corresponds to the accumulation of indigestible particles cranial to a sub-obstruction of the gastric outflow (‘gravel sign’). In this case polypoid gastritis was the cause of the pyloric outflow obstruction.
Image of 9.20
9.20 Positive-contrast gastrography in a dog that presented with a history of chronic vomiting. VD view obtained 30 minutes after the administration of barium sulphate suspension. No contrast medium is visible in the duodenum and the mucosal contour in the pyloric region appears to be irregular, with a characteristic ‘apple core’ aspect. The most distal part of the contrast medium column at the pylorus is teat-shaped on this image. VD view obtained 2.5 hours after the administration of barium sulphate suspension. No sign of gastric emptying is visible and the aspect of the contrast medium column in the pyloric region remains the same (‘apple core’ appearance). The diagnosis was one of markedly delayed gastric emptying and the abnormal aspect of the contrast medium column in the pyloric region was compatible with chronic pyloric stenosis. Infiltrative disease was suspected. In this case pyloric adenocarcinoma was confirmed at surgery.
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9.21 Pylorospasm in a Dobermann presented for vomiting. On this lateral view taken after barium administration, and on subsequent radiographs, there was a circumferential narrowing of the pyloric canal with a teat-shaped pattern. In this case a spasm associated with severe gastritis was the cause but annular neoplastic infiltrates should also be considered.
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9.22 VD view of the abdomen 60 minutes after barium sulphate administration in a 22-year-old Miniature Poodle presented for chronic vomiting. The mucosal surface of the pyloric antrum is irregular (‘apple core’ appearance of the contrast medium column) and there is a round filling defect in the most distal portion of the pyloric canal, which is obliterating the lumen and is continuous with the cranial gastric wall. Chronic hypertrophic pyloric gastropathy or a neoplastic disease was suspected. Endoscopy revealed severe lesions of polypoid gastritis and the round filling defect represented a large polyp.
Image of 9.23
9.23 Pyloric outflow obstruction. Ultrasonogram of an 8-year-old Pug diagnosed with a history of weight loss and vomiting. The stomach is severely distended and contains a large amount of fluid and particulate material, which has a layered distribution: the hyperechoic mineralized particles creating acoustic shadowing in the most dependent portion of the stomach are followed by particulate material without shadowing and then a layer of hypoechoic fluid. This is indicative of a pyloric outflow obstruction; the accumulation of mineralized particles leads to a ‘gravel sign’ on radiographs. Long axis image of the pylorus and proximal duodenum. The hyperechoic lumen of the pyloric canal and proximal duodenum is narrowed and distorted, compressed by a mass in the proximal duodenum (arrowed) causing an outflow obstruction. The mass was surgically removed and a leiomyosarcoma was diagnosed histopathologically.
Image of 9.24
9.24 Hypertrophic pyloric gastropathy. Long axis image of the gastric antrum and pylorus of a 3-year-old neutered Pug bitch, presented with a 2-day history of acute vomiting and abdominal pain. The antrum is distended and filled with fluid and ingesta. The stomach is contracting forcefully; however, the pyloric canal is very narrow and the wall of the pylorus is thickened (arrowed). Short axis image showing the mild thickening of the muscular layer (arrowed).
Image of 9.25
9.25 Dog with a history of acute vomiting. Lateral radiographic view of the abdomen. A radiopaque foreign body is visible in the region of the gastric body. VD view of the abdomen. The radiopaque foreign body is again clearly visible in the region of the gastric body.
Image of 9.26
9.26 Dog presented with a history of acute vomiting. Lateral radiographic view of the abdomen. Linear opacities are visible in the region of the gastric body. VD view of the abdomen. The linear opacities are again identified in the region of the gastric fundus and body. They corresponded to gastric foreign bodies.
Image of 9.27
9.27 Positive-contrast gastrography in a dog presented with a history of acute vomiting. Lateral view of the abdomen. A filling defect is visible in the region of the gastric body. This filling defect is ovalshaped and seems to be intraluminal in origin because it is surrounded by the contrast medium. VD view of the abdomen. The intraluminal filling defect is visible in the pyloric antrum region and is semi-circular in shape. The foreign body was confirmed as a piece of plastic ball.
Image of 9.28
9.28 Left lateral radiographic view of the abdomen of the same dog as in Figure 9.27 , after the barium sulphate has partially left the stomach. On this view, the pyloric portion of the stomach does not contain contrast medium but is filled with gas. The new contrast provided by the air allows the barium-coated foreign body to be clearly identified as a crescent-shaped image.
Image of 9.29
9.29 Lateral view of the abdomen of a 9-year-old Domestic Shorthaired cat presented for vomiting. An upper gastrointestinal barium series had been obtained 12 hours before and there is persistent barium in the pyloric antrum with an irregular pattern, suggestive of barium retained within a gastric foreign body. In this case it was a large hair-ball.
Image of 9.30
9.30 Lateral view of the abdomen of a 3-year-old Labrador Retriever presented for vomiting, obtained 12 hours after the administration of barium sulphate. There is barium retained in the pyloric antrum, which has an irregular shape and opacity. It was confirmed as a piece of fabric soaked with barium.
Image of 9.31
9.31 Gastric foreign body. Long axis view of the stomach of a 4-year-old neutered female Siamese cat with a 1-week history of intermittent vomiting. The stomach contains some fluid and gas. In the gastric fundus there is a round structure with a hyperechoic surface and a strong distal acoustic shadow consistent with a gastric foreign body. A trichobezoar was removed using endoscopic forceps.
Image of 9.32
9.32 VD radiographic view of the abdomen of a cat presented with a history of chronic vomiting. The stomach is filled with air, which provides a good natural contrast and allows the identification of a parietal mass arising from the greater curvature of the stomach, protruding into the gastric lumen. This mass is of soft tissue opacity and has a smooth contour. It was confirmed as a gastric lymphoma.
Image of 9.33
9.33 Lateral radiographic view of the abdomen in a dog presented with a history of chronic vomiting. The stomach is moderately distended by gas, which provides a natural good contrast. Gastric wall thickening is seen in the cranioventral region associated with an irregular, scalloped mucosal contour. This sign is compatible with a parietal infiltration but it may also represent blood clots or mucosal debris adhering to the mucosal surface. Either an endoscopic examination or a contrast study is necessary to confirm the hypothesis of gastric wall infiltration. In this case, it was a localized infiltrative lesion caused by a gastric adenocarcinoma.
Image of 9.34
9.34 Positive-contrast gastrography in a dog presented with a history of chronic vomiting. Left lateral view of the abdomen. Barium sulphate fills the region of the gastric fundus. Two filling defects are identified in the ventral region of the stomach, which are continuous with the gastric wall and protrude towards the gastric lumen. Right lateral view of the abdomen. On this view there is better filling of the pyloric region by the barium. A filling defect originating from the cranial gastric wall is seen, as well as two other digit-shaped filling defects in the pyloric canal. These multiple filling defects were attributable to multiple masses associated with a gastric adenocarcinoma.
Image of 9.35
9.35 Double-contrast gastrography in a dog presented with a history of chronic vomiting. DV view. VD view. Right lateral view. Left lateral view. The distribution of the contrast medium varies depending on the radiographic view and this allows different parts of the stomach to be evaluated on each image. (a) A narrowing of the gastric lumen can be seen in the pyloric region on the DV view. (b,c) The mucosal contour in this region appears to be irregular on the VD view as well as on the right lateral view. These abnormal images were caused by a pyloric adenocarcinoma. Note in (a) the small out-pouching of contrast medium along the lesser curvature, protruding towards the exterior of the stomach; this corresponds to gastric ulceration associated with chronic gastric disease.
Image of 9.36
9.36 Double-contrast gastrography in a dog presented with a history of chronic vomiting. VD radiograph of the abdomen shows that, although the stomach is well distended by air, the mucosal folds are abnormally prominent, thick and tortuous. A small rectangular out-pouching of contrast medium is also identified along the greater curvature, just to the left of the lumbar spine, corresponding to a gastric ulceration (arrowed). Lateral view of the abdomen. The mucosal folds appear to be abnormally thick and tortuous (arrowed). This dog had a diffuse form of gastric lymphosarcoma.
Image of 9.37
9.37 Typical ultrasonographic characteristics based on tumour type. Leiomyoma in a 14-year-old neutered male Shih Tzu with a history of diabetes mellitus. Abdominal ultrasonography was performed to recheck a splenic nodule seen several months previously. In the gastric fundus, there is a well defined hypoechoic mass protruding into the lumen of the stomach. The wall layering is not visible in the area of the mass, which seems to be continuous with the muscular layer of the stomach wall. A biopsy was performed and a leiomyoma was diagnosed. Gastric carcinoma. Long axis ultrasonogram of the stomach of an 11-year-old neutered Brittany Spaniel bitch with a 1-week history of vomiting. The stomach wall is severely thickened (18 mm) and has lost the normal layering. A hyperechoic layer of tissue (arrowed) is present in the centre of the otherwise very hypoechoic wall, consistent with ‘pseudolayering’. Gastric lymphosarcoma. A 7-year-old neutered female Domestic Shorthaired cat was presented for vomiting blood and anorexia. A cranial abdominal mass was palpated. On the axial ultrasonogram of the stomach at the level of the fundus, there is severe almost circumferential thickening of the stomach wall with complete loss of wall layering. The stomach wall is uniformly hypoechoic. Gastric and mesenteric lymph nodes were moderately enlarged. Lymphosarcoma was diagnosed on fine-needle aspiration of the stomach wall.
Image of 9.38
9.38 Lateral view of the abdomen in a dog presented with a history of chronic vomiting. On this survey radiograph, the gastric lumen can be identified by its air content. There is an impression of gastric wall thickening, especially in the caudal aspect, but this sign must be interpreted with caution because of the lack of gastric distension, and also because this image may have been created by mucus adhering to the mucosa and silhouetting with the gastric wall. In this case, the gastric wall was thickened and the dog had severe lesions of chronic gastritis.
Image of 9.39
9.39 4-month-old Rottweiler presented with a history of acute vomiting. VD radiograph of the abdomen obtained 15 minutes after the ingestion of barium sulphate. Gastric emptying has begun and the mucosal rugal folds appear to be markedly thickened in the region of the gastric fundus. Lateral radiographic view of the abdomen. Abnormally numerous and thickened rugal folds are identified. Endoscopic examination of the stomach revealed severe lesions of acute gastritis in this dog.
Image of 9.40
9.40 VD view of the abdomen in a dog with severe chronic renal failure. Fine linear opacities are seen following the mucosal surface of the fundic region of the stomach, consistent with mucosal mineralization seen with uraemic gastritis.
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9.41 Gastritis in a 16-year-old neutered Dalmatian bitch with a 1-month history of inappetence, weight loss and chronic intermittent vomiting. The stomach wall is irregularly thickened. In some areas the wall thickening is severe, measuring up to 14 mm. There is almost complete loss of layering. A neoplastic infiltrate was suspected and a biopsy of the stomach wall was performed. Severe lymphoplasmacytic and eosinophilic gastritis was diagnosed.
Image of 9.42
9.42 Uraemic gastropathy in a 16-year-old neutered mixed breed bitch presented for evaluation of recently diagnosed renal disease. Short axis ultrasonogram of the gastric fundus showing the hyperechoic mineralization of the mucosa. Note that an acoustic shadow is cast where the rugal folds are the thickest.
Image of 9.43
9.43 Rodenticide toxicity in a 1-year-old male Yorkshire Terrier. A short axis view of the stomach showing severe wall thickening. The wall layers are indistinct and the main pathology is affecting the submucosal layer. Haemorrhage due to the rodenticide toxicity was suspected. Repeat ultrasonogram 1 week after beginning treatment, showing that the stomach wall has normalized.
Image of 9.44
9.44 Lateral radiographic view of the abdomen in a cat presented with a history of chronic vomiting and abdominal tympany associated with acute abdominal syndrome. The overall opacity of the abdominal cavity is markedly decreased owing to the accumulation of free gas. The contrast provided by the free gas is responsible for the abnormally good visualization of the kidneys and margins of the liver, as well as the caudal part of the diaphragm. The diagnosis was pneumoperitoneum caused by perforation of a gastric tumour.
Image of 9.45
9.45 Gastric ulceration in a 9-year-old neutered male Jack Russell Terrier presented for vomiting and a painful cranial abdomen. Short axis image of the stomach showing that the stomach wall is thickened and that there is decreased definition of the wall layers. The mucosa is interrupted focally (arrowed) and hyperechoic material dissects a short distance into the stomach wall, representing either a gas accumulation or a blood clot. This structure did not move during the examination and the patient exhibited pain on light pressure of the transducer in this area. The findings are consistent with a gastric ulcer.

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