ENDOSCOPIC ULTRASONOGRAPHIC FINDINGS OF THE PANCREAS AFTER PANCREATIC DUCT LIGATION IN THE DOG

Endoscopic ultrasonographic evaluation and gray-scale histogram analysis of pancreatic atrophy after pancreatic duct ligation were performed in four normal adult dogs. Using endoscopic ultrasonography, markedly dilated pancreatic ducts were visualized, and the pancreas became gradually atrophied with a hyperechoic parenchyma. In gray-scale histogram analysis of the pancreas, mean brightness increased gradually until 8 weeks, then decreased temporally. Standard deviation of the histogram increased markedly and then fluctuated until the 4th week, after which the mean brightness and standard deviation became stable. At 4 weeks postoperatively, collapse of most pancreatic acinar structures were observed, and each atrophic lobule was associated with a significantly large amount of interstitial fibrous tissue at histopathology. At 12 weeks postoperatively, most exocrine tissue had decreased and was partly replaced by fibrous and fatty tissue. These changes of mean brightness and standard deviation reflected the histologic analysis. These findings indicated that endoscopic ultrasonography is a useful technique to image such atrophic disorders of the pancreas as chronic pancreatitis. Furthermore, gray-scale histogram analysis provides helpful information for ultrasonographic tissue characterization of the pancreas.     

ADRENAL ULTRASONOGRAPHY IN THE DOG

The ultrasonographic appearance of the normal canine adrenal gland has not been described. This is due to the small size and shape of the canine adrenal glands, overlying abdominal viscera, similar acoustic texture to that of the surrounding tissue, frequent abundant perirenal fat, and the lack of patient compliance. Adrenal enlargement in association with hyperadrenocorticism, secondary to hyperplasia or neoplasia, can sometimes be identified by finding a distinct structure cranial and/or medial to the cranial pole of either kidney. Case history reports are used to characterize the appearance of adrenal enlargement from hyperplasia and adrenocortical adenocarcinoma. Additional case history reports are included to illustrate possible interpretation problems. Lack of ultrasonographic visualization of the adrenal gland does not rule out the possibility of enlargement, particularly if the enlargement in mild.     

ENDOSCOPIC ULTRASONOGRAPHY FOR THE DIAGNOSIS OF INTRATHORACIC LESIONS IN TWO DOGS

Endoscopic ultrasound was developed initially in humans to overcome limitations of conventional ultrasound in examining certain internal organs due to intervening bone or air-filled structures. Endoscopic ultrasound has been used most widely in investigation of the gastrointestinal tract in humans, but many intrathoracic applications as well as endoscopic ultrasound-guided techniques have recently been described. Mediastinal and pulmonary structures can be examined with endoscopic ultrasound since a high frequency ultrasound probe can be brought into close contact with the areas of interest via a transesophageal approach. The purpose of this report is to describe the application of endoscopic ultrasound as an aid in the diagnosis of intrathoracic disease in the dog. Two dogs, one with a history of prior esophageal foreign body extraction, the other with apathy, weakness and dyspnea were referred for further investigation. Both dogs had caudal intrathoracic soft tissue opacities diagnosed radiographically, but their origin and nature were difficult to determine. Conventional ultrasound was limiting in both dogs due to their location and superimposition of gas-filled structures. With endosonography lesions were characterized more completely. We have found endoscopic ultrasound to be an elegant diagnostic tool for the investigation of radiographically detected intrathoracic lesions in the dog whose origins are difficult to determine or do not lend themselves to investigation by conventional ultrasound. Endoscopic ultrasound provides valuable diagnostic information complementary to that provided radiographically which aids in therapeutic planning. Endoscopic ultrasound was also more sensitive for detecting mediastinal lymphadenomegaly than radiography in one of the dogs. An additional advantage of endoscopic ultrasound is the fact that US-guided tissue sampling can be performed during the examination.     

RENAL AND HEPATIC ULTRASONOGRAPHY IN THE NEONATAL DOG

The ultrasonographic appearance and size of the liver and kidneys of a litter of five pups was examined from birth until six months of age, and compared with a group of five adults of the same breed. Increased renal cortical echogenicity was evident for the first two weeks of life. Up to 12 weeks of age renal size was relatively large in comparison with body size parameters. After 12 weeks measures of renal size were proportionate with body size and were not significantly different from adult dogs. The neonatal liver had a similar ultrasonographic appearance to the adult, although in the first eight weeks parenchymal echogenic stippling was less coarse and portal veins were less well delineated. Measures of hepatic length were inaccurate during the first four weeks after birth due to changes in body conformation. From eight weeks to six months of age these measures were proportionate with body size, although the ratios differed from adult dogs.     

ULTRASONIC EXAMINATION OF THE PANCREAS IN HEALTHY COWS

The purpose of this study was to describe the ultrasonographic appearance of the normal bovine pancreas and to establish reference values for healthy cattle. Ultrasonographic examinations were performed on the right side of 20 healthy cows. Ultrasonographically the body and right limb of pancreas appeared as a triangle-shaped structure associated with the liver, portal vein, right kidney, and duodenum. In comparison to normal liver, the pancreas appeared isoechoic or slightly more echogenic. The right lobe of the pancreas was evaluated from the right flank to the eleventh intercostal space, and the body of the pancreas was visualized from the twelfth to the tenth intercostal space. The left lobe of the pancreas could not be seen because of its dorsomedial location. In 9 cows, the accessory pancreatic duct was located near the right lobe of the pancreas and appeared as two parallel echogenic lines with a hypoechogenic area between them. The diameter of the accessory pancreatic duct varied from 6 to 8 mm. The pancreaticoduodenal vein was seen in 5 cows. The diameter of the pancreaticoduodenal vein varied from 3 to 4 mm. The ultrasonographic characteristics determined in this study may serve as a reference in the evaluation of cows with suspected pancreatic disease.     

ULTRASONOGRAPHY OF GASTRIC ULCERATION IN THE DOG

The clinical, ultrasonographic and, when available, histopathologic findings of gastric ulceration in 7 dogs were reviewed. The most common clinical signs were vomiting, hematemesis, melena, weight loss and anemia. Ultrasonographic features of gastric ulcer included local thickening of the gastric wall, possible loss of the 5-layer structure, the presence of a wall defect or "crater", fluid accumulation in the stomach and diminished gastric motility.The localized gastric thickening varied from 9 to 16 mm. The ulcer crater was often located in the center of the thickened site and appeared as a mucosal defect associated with persistent accumulation of small echoes, most likely representing microbubbles. In this preliminary study, there was no definitive ultrasonographic distinction between benign and malignant ulcers.     

ULTRASONOGRAPHY OF THE NORMAL FELINE PANCREAS AND ASSOCIATED ANATOMIC LANDMARKS: A PROSPECTIVE STUDY OF 20 CATS

The sonographic appearance of the feline pancreas and associated anatomic landmarks including the pancreatic duct, duodenum, duodenal papilla, portal vein, and gastric lymph node were evaluated in 20 healthy, awake cats. The pancreas appeared nearly isoechoic to surrounding mesenteric tissues, isoechoic to slightly hyperechoic to adjacent liver lobes, and hypoechoic to the spleen. The mean thickness measurements for the right pancreatic lobe, body, and left pancreatic lobe were 4.5 mm (range 2.8-5.9), 6.6 mm (range 4.7-9.5), and 5.4 mm (range 3.4-9.0), respectively. The pancreatic duct was consistently visualized in the left pancreatic lobe and had a mean thickness of 0.8 mm (range 0.5-1.3). It could be differentiated from the pancreatic vessel, by its central location, and the duct's lack of Doppler flow signal. The duodenum was used as a landmark to identify the right lobe of the pancreas. The mean duodenal wall thickness measurement was 2.8 mm (range 2.1-3.8) in sagittal section, and 3.0 mm (range 2.2-4.4) in transverse section. The duodenal papilla was identified in 4 of 20 cats. It ranged in size from 2.9 to 5.5 mm in width, and had a maximum height of 4.0 mm in transverse section. The portal vein was used as a consistent anatomic landmark for identification of the left lobe and body of the pancreas. The mean diameter of the portal vein at the level where the pancreatic body joins the left pancreatic lobe was 4.3 mm (range 2.7-5.9) when viewed in sagittal section, and 4.5 mm (range 3.6-6.1) in transverse section. The gastric lymph node was identified cranial and ventromedial to the pyloroduodenal angle in 6 of 20 cats. It had an asymmetrical shape with a larger caudal pole in five of the six cats. The largest dimensions of the gastric lymph node were 10 mm in length, and 6 mm in width for the larger caudal pole, and 5.1 mm in width for the smaller cranial pole.     

ULTRASONIC DETERMINATION OF KIDNEY VOLUME IN THE DOG

Canine kidney measurements were obtained in vivo using ultrasound before and after anesthesia and were compared with direct caliper measurements at laparotomy. Following excision, the kidney dimensions were also measured ultrasonically in a water bath and the results were used to calculate kidney -volume by a modified parallel planimetric method and three variations of a prolate ellipsoid method. The calculated volume was compared with actual kidney volume determined by volume displacement. All methods were found to underestimate actual volume so that a linear correction of ultrasonically calculated volume was required to predict actual volume. The modified parallel planimetric method and a prolate ellipsoid method using height and width determinations cranial and caudal to the renal pelvis were the best models. The prolate ellipsoid model was chosen for subsequent kidney volume calculations because of its simplicity. The noninvasive calculation of kidney volume using ultrasound was sufficiently accurate to be clinically useful, particularly when serially evaluating kidney size changes in the same dog.     

ULTRASONOGRAPHIC FEATURES OF GRASS AWN MIGRATION IN THE DOG

The aim of this study was to describe the ultrasonographic features of grass awns in soft tissue. A 10 MHz linear transducer was used. Ultrasound images from 25 dogs (27 awns) were collected and compared with the results from water bath studies using wild oat seeds (Avena spp.) collected in the field. Wild oat seeds were the most common grass awn found in soft tissue of dogs. Ultrasonographically grass awns appeared as a double/triple spindle-shaped echogenic interface within soft tissue. The same appearance was observed in water bath studies. In four dogs, the grass awn was removed surgically with a clamp introduced into a fistulous tract, using sonographic guidance. The grass awn was not found surgically in only three dogs, suggesting more attention during surgery. Ultrasonography is a useful diagnostic imaging technique to identify grass awns within soft tissue.     

ULTRASONIC FEATURES OF EXPERIMENTALLY INDUCED, ACUTE PANCREATITIS IN THE DOG

Acute, necrotizing pancreatitis was experimentally produced in three dogs by injection of oleic acid into the accessory pancreatic duct. The ultrasonic features of acute pancreatitis were compared with the radiographic and gross pathologic findings. It was concluded that ultrasonography was very useful for the detection and characterization of experimental pancreatitis. The results must be carefully compared with the ultrasonic abnormalities found in naturally occurring, acute canine pancreatitis before the usefulness of pancreatic sonography can be determined for this disease in the dog     

APPROACHES FOR ULTRASONOGRAPHIC EVALUATION OF LONG BONES IN THE DOG

The objective of this study was to identify access portals for ultrasonographic evaluation of canine long bones (humerus, radius, ulna, femur, and tibia). A 7.5 MHz linear transducer was used in five medium-sized dogs (range of 25-35 kg body weight). Good approaches could be identified for all long bones. For the proximal humerus, a cranial portal, and the distal humerus, a lateral portal is suggested. For the radius and ulna, a craniolateral approach seemed to be the best. In the hindlimb, a medial approach for the femur and a craniolateral approach for the tibia were the most effective approaches.     

ULTRASONIC DETECTION OF SPLENIC NECROSIS IN THE DOG

Ultrasonographic findings of splenic infarction and necrosis in three dogs are presented. Two previously unreported ultrasonographic patterns are identified: (1) Focal, hypoechoic or isoechoic, circular, wellmarginated nodular masses with peripheral lesions causing deformation of the splenic margin. (2) Diffuse hypoechoic or heteroechoic coarse/"lacy" parenchymal pattern with no deformation of margin. The presence of gas within the splenic parenchyma of one dog was detected by both radiography and ultrasonography. Ultrasonographic patterns of splenic infarction in both man and the dog are discussed     

ENDOSCOPIC ULTRASOUND OF THE CANINE ABDOMEN

The aim of this study was to develop a standardized procedure for examination of the canine abdomen using endoscopic ultrasound and to describe the organs and structures that could be identified transgastrically. The abdomen of four healthy dogs and two cadavers were examined with endoscopic ultrasound. Five anatomic landmarks were used for standardized imaging of the cranial abdomen. These were the portal vein, splenic head and body, duodenum, left kidney, and aorta. High-resolution images of the following organs and structures could be made: distal esophagus, gastric wall from the cardia to the pylorus, liver, caudal vena cava, hepatic lymph nodes, liver hilus, and associated vessels, trifurcation of the celiac artery as well as the path of its branches and the left pancreatic limb and body. Structures that were more difficult to image were the distal duodenum and right pancreatic limb, the entire jejunum, ileum, and cecum as well as the tail of the spleen. Endoscopic ultrasound allowed excellent visualization of the gastric wall and regional structures without interference with gas artefacts. Centrally located organs such as the pancreas could be well examined transgastrically with endoscopic ultrasound without interference by overlying intestinal segments as is common with transabdominal ultrasound.     

COMPUTED TOMOGRAPHIC ANATOMY OF THE CANINE PANCREAS

Barium sulfate was administered into the coeliac artery of 5 canine cadavers to allow for contrast computed tomography of the pancreas. Contiguous, 2-mm-thick slices were acquired. Multiplanar and three-dimensional reformatting were performed to clarify the anatomic relationship. After imaging, the cadavers were frozen, cross sections obtained, and plastinated. These were compared to the computed tomography images. Five plain and contrast enhanced computed tomographic series of normal live controls were acquired and evaluated retrospectively. In the study of the canine cadavers the pancreas became opacified and appeared homogenous with irregular contour. In normal live controls, acquiring an image at the end of expiration allowed a detailed view of the pancreatic parenchyma in the non-alterated pancreas, but pancreatic and bile ducts could not be seen. Adjacent to the hepatic hilus the pancreatic body appeared as a dorsoventrally flattened structure bordering on the ventral surface of the portal vein, both in cadavers and normal live controls. The right lobe extended caudodorsally to the right abdominal wall and aligned with the cranial part of the duodenum. The left lobe was adjacent to the gastric body in all dogs although it was separated from the gastric fundus by the dorsal extremity of the spleen in normal live controls. Neither kidney was suitable as an anatomic marker for localization of the pancreas, unlike traditional references in textbooks. We recommended using the portal vein to localize the pancreatic body, the descending duodenum for the right lobe, and the dorsal extremity of the spleen as well as the gastric fundus for the left lobe.     

COLOR DOPPLER ULTRASONOGRAPHY IN PREDICTION OF THE REDUCIBILITY OF INTUSSUSCEPTED BOWEL IN 15 YOUNG DOGS

Color Doppler ultrasonography was performed in 15 young dogs with intestinal intussusception to test the hypothesis that color Doppler findings can be used as a predictor of the manual reducibility of the intussusception at celiotomy. Color flow Doppler ultrasonography indicated blood flow within mesentery of the intussuscepted bowel in 12 of 15 dogs and reduction was achieved in nine of these 12 dogs (75%). In the remaining three dogs and in three dogs where no color Doppler signal were observed, an irreducible intussusception was confirmed at celiotomy. Color Doppler ultrasonography is a useful method for predicting the reducibility of intussusception in dogs.     

CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE PANCREAS IN HEALTHY DOGS AND IN DOGS WITH ACUTE PANCREATITIS

Pancreatitis is the most frequent disease affecting the exocrine pancreas in dogs and reliable diagnostic techniques for predicting fatal complications are lacking. Contrast‐enhanced ultrasound (CEUS) improves detection of tissue perfusion as well as organ lesion vascular pattern. Objectives of this prospective case control study were to compare perfusion characteristics and enhancement patterns of the pancreas in healthy dogs and dogs with pancreatitis using CEUS. Ten healthy dogs and eight dogs with pancreatitis were selected based on physical examination, abdominal ultrasound, and blood analysis findings. A CEUS study of the pancreas was performed for each dog and two observers who were aware of clinical status used advanced ultrasound quantification software to analyze time‐intensity curves. Perfusion patterns were compared between healthy and affected dogs. In dogs with acute pancreatitis, mean pixel and peak intensity of the pancreatic parenchyma was significantly higher than that of normal dogs (P = 0.05) in between 6 and 60 s (P = <0.0001–0.046). This corresponds to a 311% increase in mean pixel intensity in dogs with acute pancreatitis compared to healthy dogs. Wash‐in rates were greater and had a consistently steeper slope to peak in dogs with pancreatitis as opposed to healthy dogs. All dogs with pancreatitis showed a decrease in pixel intensity 10–15 days after the initial examination (P = 0.011) and their times to peak values were prolonged compared to the initial exam. Findings from the current study supported the use of CEUS for diagnosing pancreatitis, pancreatic necrosis, and disease monitoring following therapy in dogs.     

ULTRASONOGRAPHY OF THE NORMAL CANINE GASTROINTESTINAL TRACT

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 stomach 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 findings 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.     

A COMPARISON OF TWO-DIMENSIONAL ULTRASONOGRAPHY AND RADIOGRAPHY FOR THE DETECTION OF SMALL AMOUNTS OF FREE PERITONEAL FLUID IN THE DOG

The detection of small amounts of free peritoneal fluid in the canine patient can be a diagnostic dilemma. Ultrasonography and radiography have been advocated to detect intraabdominal fluid not detectable by physical exam. The purpose of this study was to determine the more sensitive method for detecting small amounts of free peritoneal fluid. Ultrasound examinations and radiographs were performed after increments (1 ml/lb body weight) of fluid were injected intraperitoneally. Ultrasonography detected fluid in one animal at 2 ml/lb. AH other animals had fluid detected at 3 ml/lb. With radiographs fluid could be detected with a high degree of accuracy at 4 ml/lb. The lateral view was more accurate than the ventrodorsal view in detecting fluid. The authors concluded that Ultrasonography is more sensitive than radiography and is the method of choice to detect small amounts of free peritoneal fluid.     

ULTRASONOGRAPHIC DIAGNOSIS OF GASTROINTESTINAL SMOOTH MUSCLE TUMORS IN THE DOG

Historical, physical examination, clinicopathologic, radiographic and ultrasonographic findings of 13 dogs with gastrointestinal (GI) smooth muscle tumors (11 leiomyosarcomas, 2 leiomyomas) were reviewed. History, including signalment and chief complaint, physical examination and bloodwork were neither sensitive nor specific for GI neoplasia. Imaging procedures, radiology and ultrasonography, detected the presence of abdominal masses in 12 patients, including 9 animals lacking a palpable mass on initial examination. Survey radiographs of 10 of the 13 dogs revealed a mass effect in 5/10 dogs, evidence of peritoneal effusion or free abdominal gas in 3/10 dogs, and an obstructive pattern with gas and fluid distension of the intestinal tract in 1/10 dogs. Ultrasonography identified an abdominal mass in 12/13 dogs, and peritoneal effusion in 5 animals. Ultrasonography correctly recognized an association of the mass with bowel segments by the presence of intraluminal gas, within or adjacent to the mass effect, in 10 dogs, and strongly suggested an intestinal origin in one additional animal. GI smooth muscle tumors often appeared as large masses, eccentrically projecting from the bowel wall, frequently containing single or multiple hypo/anechoic regions. Based on this study we conclude that ultrasonography is more sensitive than survey radiography in the detection of GI smooth muscle tumors, and may present specific features to distinguish smooth muscle tumors from other types of GI tumors. Ultrasonography is recommended as a screening procedure for cases where GI neoplasia is suspected.     

THE USE OF INTRAPERITONEAL FLUID AS A SIMPLE TECHNIQUE FOR ENHANCING SONOGRAPHIC VISUALIZATION OF THE CANINE PANCREAS

Sonographic evaluation of the pancreas was performed in ten healthy research dogs following intraperitoneal fluid administration. Physiological saline solution was aseptically introduced into the peritoneal cavity of each dog to create an acoustic window that would facilitate sonographic delineation of normal pancreatic tissues. Abdominal ultrasound examinations were performed in all dogs before and after the production of the diagnostic hydroperitoneum. Sonograms of the pancreas and other abdominal organs were scored on the basis of image clarity by experienced and novice ultrasonographers. Statistical analysis was then used to compare the effectiveness of each preparation method. A significant difference (P < 0.05) was established between the scores from the diagnostic hydroperitoneum sonograms and the baseline scans performed without intraperitoneal fluid placement. Sonographic visualization scores for the pancreas and other abdominal organs were increased following production of the diagnostic hydroperitoneum. These results indicate that the technique of diagnostic hydroperitoneum will significantly improve ultrasonographic visualization of the pancreas, and may prove useful in the diagnosis of canine pancreatic disease.