EFFECTS OF FASTING AND INTRALUMINAL CONTRAST ENHANCEMENT ON ULTRASONOGRAPHIC APPEARANCE OF THE EQUINE SMALL INTESTINE

The equine small intestine is challenging to evaluate ultrasonographically. In humans, hydrosonography has been used to improve ultrasonographic images of the small intestine. We hypothesized that fasting horses for 24 h would enhance the ability to image the small intestine transabdominally by separating intestinal loops and reducing intraluminal gas, and that the administration of intragastric contrast agent would further improve that ability. Ten healthy horses were examined ultrasonographically under three treatment conditions: (a) regular diet, (b) after a 24‐h fast, and (c) fasted plus intragastric administration of water and mineral oil. During each phase of the study, 30‐s video clips were obtained from four predetermined abdominal windows, and were examined to determine diagnostic quality. Fasting improved the ability to obtain high‐quality images of the small intestine significantly. The addition of contrast agent resulted in qualitative improvement in image quality, but differences did not result in statistically significant improvement.     

ULTRASONOGRAPHIC APPEARANCE OF CANINE PARVOVIRAL ENTERITIS IN PUPPIES

The ultrasonographic appearance of the gastrointestinal tract of puppies suffering from parvoviral enteritis was characterized. Forty puppies between 6 and 24 weeks of age with confirmed canine parvoviral enteritis were examined ultrasonographically within 24 h of admission. Sonographic findings included fluid‐filled small intestines in 92.5% of subjects, and stomach and colon in 80% and 62.5% of subjects, respectively. Generalized atony was present in 30 subjects and weak peristaltic contractions indicative of functional ileus observed in the remaining 10 subjects. The duodenal and jejunal mucosal layer thicknesses were significantly reduced when compared with normal puppies with mean duodenal mucosal layer measuring 1.7 mm and jejunal mucosal layer 1.0 mm. Additionally, a mucosal layer with diffuse hyperechoic speckles was seen in the duodenum (15% of subjects) and the jejunum (50% of subjects). The luminal surface of the duodenal mucosa was irregular in 22.5% of subjects and the jejunal mucosa in 42.5% of subjects. In all of these subjects, changes were accompanied by generalized indistinct wall layering. Small intestinal corrugations were seen within the duodenum in 35% of subjects and within the jejunum in 7.5%. A mild amount of anechoic free peritoneal fluid was observed in 26 subjects and was considered within normal limits and a moderate amount of anechoic free peritoneal fluid was observed in six subjects. The jejunal lymph node size was within normal limits. None of the above changes are pathognomonic for canine parvoviral enteritis but finding them in combination is highly suggestive.     

ULTRASONOGRAPHIC APPEARANCE OF FELINE ALIMENTARY LYMPHOMA

Abdominal ultrasonography was performed in seven cats with intestinal lymphoma and four cats with gastric lymphoma. Ultrasonographic abnormalities included the presence of a hypoechoic mass associated with the gastrointestinal tract, focal or diffuse thickening of the gastric wall, symmetric thickening of the bowel wall, loss of the normal layered appearance of the gastrointestinal wall, and abdominal lymphadenopathy. The thickness of the stomach wall ranged from 8 to 22 mm in cats with gastric lymphoma, and the thickness of the bowel wall ranged from 5 to 20 mm in cats with intestinal lymphoma. Fine needle aspiration of a gastrointestinal lesion was performed without complication in six cats, and was diagnostic for lymphoma in five out of six. Results of this study indicate that ultrasonography is an effective noninvasive means of identifying lesions consistent with alimentary lymphoma in cats.     

ULTRASONOGRAPHIC APPEARANCE OF CANINE GASTRIC POLYPS

Benign gastric polyps are uncommon in dogs and most are discovered incidentally. Polyps protruding into the pyloric antrum can cause gastric outflow obstruction. Clinical and ultrasonographic findings in seven dogs with histologically confirmed benign mucosal gastric polyps were reviewed. Sonographic findings such as shape, size, echogenicity, location, evidence of gastric wall thickening, wall layering, and size of regional lymph nodes were recorded. Five sessile and two pedunculated masses of different sizes (range 7–60 mm) and echogenicities were found. They primarily arose from the mucosal layer and protruded into the gastric lumen. Only one dog had a large inhomogeneous mass with a poorly visualized gastric wall layering. The polyps were all single, and were located in the pyloric antrum in six out of seven dogs. Although the ultrasonographic appearance allowed a presumptive diagnosis of mucosal gastric polyp, the final diagnosis was determined from histopathologic examination.     

IMAGING DIAGNOSIS—ULTRASONOGRAPHIC APPEARANCE OF SMALL BOWEL METASTASIS FROM CANINE MAMMARY CARCINOMA

A 10‐year‐old entire female Beagle dog was evaluated for an acute history of lethargy, anorexia, and diarrhea. Mammary tumors were detected during physical examination. Ultrasonographic scanning revealed the presence of a unique pattern of multiple, well‐defined and well‐marginated hypoechoic nodules in the muscularis layer of the jejunum. These nodules were not associated with changes in the rest of the normal intestinal layering and were not causing signs of intestinal obstruction. Mammary carcinoma metastases to the intestinal muscularis layer were diagnosed based on histopathological examination.     

ULTRASONOGRAPHIC APPEARANCE OF OVARIAN TUMORS IN 10 DOGS

Signalment, clinical history, physical examination, clinicopathologic, readiographic and ultrasonographic findings of 10 female dogs with histologically confirmed ovarian neoplasms were reviewed. Ultrasonographic images and reports were reviewed for (1) location, size, outer margins, and echogenicity of the mass(es), (2) presence of free abdominal fluid, (3) evidence of uterine abnormalities, and (4) signs of metastatic disease. The masses were classified according to their ultrasonographic pattern in solid, solid with cystic component, and cystic. The masses were ultrasonographically reported as being of ovarian origin in eight dogs, and this origin was included in the list of differentials in the remaining two dogs. When present, abdominal effusions and uterine abnormalities were diagnosed by means of ultrasound.     

VARIABILITY IN THE ULTRASONOGRAPHIC APPEARANCE OF THE PANCREAS IN HEALTHY DOGS COMPARED TO DOGS WITH HYPERADRENOCORTICISM

Anecdotally, an unusually hyperechoic pancreas can be found in seemingly healthy dogs on ultrasound examination and the prevalence and clinical significance of this finding is unknown. The objective of this study was to describe the prevalence of a hyperechoic and/or heterogenous pancreas in healthy dogs and correlate these findings to weight, age, and body condition score (BCS). An additional objective was to describe the prevalence of a hyperechoic and/or heterogenous pancreas in dogs with hyperadrenocorticism and compare this to the healthy dogs. Pancreata of 74 healthy dogs were evaluated prospectively and pancreatic echogenicity and echotexture were graded. Each dog's age, BCS, and weight were recorded. Dogs were screened for health by physical examination, serum chemistry panel, urine specific gravity, and a canine pancreatic lipase immunoreactivity assay. Pancreatic images for 92 dogs having hyperadrenocorticism were also reviewed and pancreatic echogenicity and echotexture were recorded. The prevalence of pancreatic hyperechogenicity in normal dogs was 7% (5 of 74) and heterogeneity was 40% (30 of 74). No correlation existed between pancreatic echogenicity and weight, age, or BCS (P > 0.1 for all sets). A statistically significant increase in the proportion of dogs having a hyperechoic pancreas was found in the hyperadrenocorticism sample of dogs (40%, 37 of 92, P < 0.0001). The underlying cause of pancreatic variability in the few healthy dogs and in dogs with hyperadrenocorticism is unknown and the varying appearance of the pancreas in these samples confounds interpretation of diseases such as chronic pancreatitis.     

ULTRASONOGRAPHIC APPEARANCE OF SPLENIC DISEASE IN 101 CATS

The sonographic findings in 101 cats with splenic abnormalities are presented. Diagnosis was made by ultrasound-guided fine needle aspirate or fine-needle biopsy (n = 91), ultrasound-guided core biopsy (n = 1), surgical core biopsy (n = 1), or necropsy (n = 10). Two cats had more than one diagnostic procedure (fine needle aspirate and necropsy or core biopsy and necropsy). The splenic abnormalities included lymphosarcoma (n = 30), mast cell tumor (n = 27), extramedullary hematopoiesis and/or lymphoid hyperplasia (n = 27), epithelial tumors (n = 6), mesenchymal tumors (n = 4), malignant histiocytosis (n = 2), myeloproliferative disease (n = 2), pyogranulomatous inflammation (n = 2), erythroleukemia (n = 1), eosinophilic syndrome (n = 1), hematoma (n = 1), and granulomatous splenitis (n = 1). Three cats had more than one splenic abnormality (mast cell tumor and metastatic carcinoma, pyogranulomatous inflammation and lymphoid hyperplasia, histiocytic lymphosarcoma, and lymphoid hyperplasia). Pathognomonic changes were not seen for any of the diseases.     

ULTRASONOGRAPHIC APPEARANCE OF ORTHOTOPIC URETEROCELE IN A DOG

A three-year-old, intact male, Siberian husky was evaluated for a two day history of dysuria. Sonographically there was an anechoic cyst-like structure in the urinary bladder. The abnormality appeared to be a'cyst within a cyst', which is a characteristic ultrasonographic feature of ureterocele in humans. Ultrasonography may be a useful means of establishing a diagnosis of ureterocele in dogs.     

RADIOGRAPHIC, ULTRASONOGRAPHIC, AND COMPUTED TOMOGRAPHIC APPEARANCE OF ALVEOLAR ECHINOCOCCOSIS IN DOGS

Alveolar echinococcosis is a rare metacestodal infection of humans and domestic animals with Echinococcus multilocularis and predominantly affects the liver. In humans, diagnosis is based on serology, ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI), techniques that have not yet been validated for the diagnosis of alveolar echinococcosis in dogs. Therefore, the purpose of this retrospective study was to describe the radiographic, ultrasonographic, and CT appearance of canine alveolar echinococcosis. Eleven dogs with confirmed alveolar echinococcosis (PCR or histology from biopsy material of metacestode tissue) diagnosed between 1995 and 2003 were included in the study. The age of the dogs at initial presentation ranged from 7 months to 10.5 years. Abdominal radiographs were made in nine animals, abdominal ultrasonography was performed in 10 dogs, and two CT studies in one dog, respectively. The history, clinical presentation, and laboratory findings for the 11 dogs were unspecific, the most frequent clinical finding being nonpainful progressive abdominal distention. All radiographed dogs had large liver masses; they contained small mineralizations in five. The most frequent ultrasonographic finding was multiple large cavitary masses with or without wall mineralizations. Seven animals received surgical and subsequent medical therapy with albendazole (10mg/kg) and all went into clinical remission. This study reviewed for the first time imaging findings associated with alveolar echinococcosis. The disease has to be included in the list of differential diagnoses in dogs with large, cavitary liver masses, particularly when mineralization is noted.     

ULTRASONOGRAPHIC APPEARANCE OF INTRA-ABDOMINAL GRANULOMA SECONDARY TO RETAINED SURGICAL SPONGE

This report describes two animals (one dog and one cat) with a retained surgical sponge. Both had nonspecific clinical signs. Clinical examination, ultrasonography and cytologic examination were used to identify an abdominal mass compatible with a granuloma. The lesions were surgically removed and confirmed histologically as granulomas secondary to a retained sponge. The ultrasonographic appearance was very similar in both animals.     

ULTRASONOGRAPHIC APPEARANCE OF URETHRAL TRANSITIONAL CELL CARCINOMA IN TEN DOGS

The mucosal margin of the urethra is best assessed by positive contrast urethrography, but ultrasonography offers complementary information such as urethral wall thickness and size of medial iliac lymph nodes. Ultrasonography of the urethra is quick, noninvasive and does not require sedation or general anesthesia. In patients with complete urethral obstruction, ultrasonography may be the only way to image the urethra. Twelve dogs which were presented to Tufts University School of Veterinary Medicine with clinical signs referable to the urinary bladder, urethra or vagina were examined ultrasonographically. Seven were neutered females and five were neutered males. Each dog had a hyperechoic, nonshadowing line at the epithelial surface of the proximal urethra. In the seven female patients and one of the males, the urethral wall was also thick and hypoechoic to surrounding tissue. In the other males, the urethral epithelial changes were at the level of the prostate, and the limits of the urethra were not visible. In six dogs, the urethral change was the only abnormality seen, while in six, bladder wall, bladder luminal and/or prostatic parenchymal changes were also detected. Three patients had hydronephrosis, and one had enlarged medial iliac lyumph nodes. Biopsies were obtained via suction with urinary catheterization (n = 6), exploratory celiotomy (n = 3), urethroscopy (n = 2), or at post-mortem (n = 1). A histopathologic diagnosis of urethral transitional cell carcinoma was obtained in ten dogs. The ultrasonographic appearance was not pathognomonic for transitional cell carcinoma, as one dog with transitional cell dysplasia and one dog with severe ulcerative and necrosupperative cystitis and urethral stricture had similar findings.     

ULTRASONOGRAPHIC APPEARANCE OF CHRONIC HYPERTROPHIC PYLORIC GASTROPATHY IN THE DOG

Chronic hypertrophic pyloric gastropathy was diagnosed using ultrasound in six dogs that were presented for chronic vomiting. An evenly thick hypoechoic layer surrounding the pyloric lumen was visualized ultrasonographically in dogs with grades 1 or 2 chronic hypertrophic pyloric gastropathy. This was histologically found to correspond with a thickened muscular layer. Gastric wall thickness was greater than or equal to 9 mm in all six dogs. In dogs with grade 1 or 2 chronic hypertrophic pyloric gastropathy, the hypoechoic muscular layer was greater than or equal to 4 mm.     

ULTRASONOGRAPHIC APPEARANCE AND CLINICAL FINDINGS IN 14 DOGS WITH GALLBLADDER MUCOCELE

Fourteen dogs with enlarged gallbladders and immobile stellate or finely striated bile patterns on ultrasound are described. Smaller breeds and older dogs were overrepresented, with 4/14 Cocker Spaniels. Most dogs presented for nonspecific clinical signs such as vomiting, anorexia and lethargy. Abdominal pain, icterus and hyperthermia were the most common findings on physical examination. All dogs except one had serum elevation of total bilirubin and/or alkaline phosphatase, alanine aminotransferase and gamma glutamyl transferase. All dogs were diagnosed with a gallbladder mucocele upon histologic and/or macroscopic evaluation. Ultrasonographically, mucoceles are characterized by the appearance of the stellate or finely striated bile patterns and differ from biliary sludge by the absence of gravity dependent bile movement. On ultrasound, gallbladder wall thickness and wall appearance were variable and nonspecific. The cystic or common bile duct were normal sized in 5 dogs although all 5 had evidence of biliary obstruction at surgery or necropsy. Loss of gallbladder wall integrity and/or gallbladder rupture were present in 50% of the dogs, all located in the fundus. Gallbladder wall discontinuity on ultrasound indicated rupture whereas neither bile patterns predicted the likelihood of gallbladder rupture. Pericholecystic hyperechoic fat or fluid were suggestive of but not diagnostic for a gallbladder rupture. Cholecystectomy appears to be an appropriate treatment for mucoceles, if not to treat a gallbladder rupture, at least in most dogs to prevent it since gallbladder wall necrosis was identified by histology in 9 of 10 dogs. Mucosal hyperplasia was present in all gallbladders examined histologically. Positive aerobic bacterial culture was obtained from bile in 6 of 9 dogs. Cholecystitis was diagnosed histologically in 5 dogs and 4 dogs had signs of gallbladder infection solely upon bacterial bile culture. Gallbladder infection was not present with all the mucoceles suggesting that biliary stasis and mucosal hyperplasia may be the primary factors involved in mucocele formation. Based on the results of our study, we suggest two alternate courses of action in the presence of a distended gallbladder with an immobile ultrasonographic stellate or finely striated bile pattern: a cholecystectomy when clinical or biochemical signs of hepatobiliary disease are present or a medical treatment (antibiotics and choleretics) and patient monitoring by follow-up ultrasound examinations when the patient does not have clinical or biochemical abnormalities. An aerobic bile culture should be obtained in all patients, by ultrasound-guided fine needle aspirate or at surgery.     

ULTRASONOGRAPHIC EVALUATION OF GASTROINTESTINAL DISEASES IN SMALL ANIMALS

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.     

ULTRASONOGRAPHIC APPEARANCE OF HISTOPLASMOSIS IDENTIFIED IN THE SPLEEN IN 15 CATS

Histoplasmosis is the second most common fungal infection reported in the cat. The disseminated form involving lung, liver, lymph nodes, spleen, and bone marrow is a frequent manifestation of the disease. Limited information is available in the literature regarding the ultrasonographic appearance of the spleen in cats with disseminated or splenic histoplasmosis. A retrospective review of splenic ultrasound images from 15 cats confirmed to have histoplasmosis by splenic aspirates was performed. Size, echotexture, echogenicity, margin appearance, presence of nodules, and the overall shape of the spleen were reported in each case. Splenomegaly was documented in all cases (15/15) and a hypoechoic appearance of the spleen was documented in 14/15 of cases. The spleen was diffusely and uniformly affected in 14/15 (six homogenous and eight with a subtle mottled appearance) and had discrete nodules in 1/15 cats. Histoplasmosis should be included in the differential list for an enlarged and hypoechoic spleen in cats with consistent clinical findings. Additionally, ultrasound guided splenic aspirate may be a useful method to obtain a cytology sample for diagnosis.     

ULTRASONOGRAPHIC APPEARANCE OF THE LOWER URINARY TRACT IN FIFTEEN NORMAL HORSES

The purpose of this study was to describe the normal ultrasonographic appearance of the caudal portion of the equine ureters, pelvic urethra, and urinary bladder and to assess ureteral contractility. Fifteen horses with no evidence of urinary tract disease (five females, five intact males and five geldings) were studied. The lower urinary tract was evaluated ultrasonographically using a transrectal approach. The normal ultrasonographic appearance and anatomic location of structures of the lower urinary tract were evaluated and anatomic relationships described. Both ureters were identified dorsal to the bladder and at their openings into the bladder. Their relationship and different appearance from the male deferent ducts/ampullae and vesicular glands was noted. Ultrasonographic measurements of the diameter of the ureters and urethra were obtained and the ureteral, urethral, and urinary bladder wall thickness recorded. The normal parameters established in this study will be useful during sonographic examination of horses with suspected urinary tract disease. Transrectal ultrasonographic examination is valuable in assessing the presence and frequency of ureteral contractions as well as in detecting structural abnormalities of the lower urinary tract. The use of high-frequency transrectal ultrasound transducers allows for excellent visualization of the structures of the equine lower urinary tract.