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.     

ULTRASONOGRAPHIC DETERMINATION OF RENAL VOLUME IN THE DOG

Ultrasonographic linear and area measurements were performed on both kidneys of 15 clinically healthy dogs. Renal volumes were calculated from linear and area data applying three prolate ellipsoid models. Ultrasonographic volumes were then compared using linear regression analysis with kidney volumes measured in vitro by water displacement. In vivo ultrasonographic volumes had a statistically significant relationship with the in vitro volume. The highest correlation was provided by the single plane area method. There was also a correlation between body weight and ultrasonographically detected renal volume, suggesting that ultrasound imaging may be a useful method for assessment of renal volume changes in dogs with renal disease.     

SONOGRAPHIC APPEARANCE OF RENAL NEOPLASIA IN THE DOG

Eight dogs with renal neoplasia were radiographically and sonographically examined. An enlarged, nonopacified kidney was seen on the excretory urogram in four dogs, but differentiation between a solid mass or severe hydronephrosis was not possible. The excretory urogram suggested an avascular lesion in one kidney, but differentiation between solid or cystic disease was not possible. Renal neoplasia was diagnosed in two dogs by excretory urography. Radiographic examination suggested splenic neoplasia in one dog. Solid masses were sonographically diagnosed in all dogs. A metastatic lesion was sonographically diagnosed in the opposite kidney of one dog that was missed on the radiographic examination. Ultrasonography com-plemented radiography as a diagnostic modality in eliciting additional information on renal disease. Sonograms did not allow determination of tumor cell type or whether the tumor was benign or malignant.     

ULTRASONOGRAPHIC IMAGING OF THE VAGOSYMPATHETIC TRUNK IN THE DOG

The purpose of this study was to evaluate the applicability of ultrasonographic imaging of the vagosympathetic trunk in the dog. Cervical ultrasound was performed in 30 healthy dogs. In all 30 dogs the vagosympathetic trunk was detected as a hypoechoic structure in the carotid sheath, adhering the dorsomedial surface of the common carotid artery. The echotexture of the nerve was heterogeneous with anechoic areas separated by hypoechoic bands. A scanner equipped with a 5 to 8 MHz linear array probe was used for imaging and measurements. The diameter of the vagosympathetic trunk ranged from 0.59 to 2.48 mm varying in correlation to the body weight. In summary, ultrasonography is a helpful noninvasive method to image and evaluate the cervical vagosympathetic trunk in the dog.     

IMAGING DIAGNOSIS—ULTRASONOGRAPHIC APPEARANCE OF SKELETAL MUSCLE METASTASES IN A DOG WITH HEMANGIOSARCOMA

A 13‐year‐old spayed female German shepherd dog was presented for acute onset of lethargy, anorexia, and disseminated erythematous skin lesions. Thoracic radiographs and abdominal ultrasonographic findings were consistent with metastatic hemangiosarcoma. Multiple, ill‐defined, irregularly shaped hypoechoic nodules were also detected within the thoracic and abdominal wall. Hemangiosarcoma metastases to the skeletal muscle were confirmed based on histopathological examination. Multivisceral involvement was also confirmed by necropsy. Metastatic neoplasia should be considered as a differential diagnosis for dogs with ill‐defined, irregular, hypoechoic, intramuscular nodules.     

ULTRASONOGRAPHIC EXAMINATION OF CERVICAL MASSES IN THE DOG AND CAT

The ultrasonographic appearance of clinically undifferentiated neck masses for which a definitive diagnosis was eventually obtained in nineteen dogs and one cat is presented in this report. Multiple lesions were seen ultrasonographically in 4 dogs and no cervical abnormalities were seen in 2 dogs resulting in 22 lesions in 20 annuals. Of 7 benign lesions, there were 2 patients with reactive lymph nodes from a regional inflammatory process, and 1 patient each with primary pyogranulomatous lymphadenitis, arteriovenous malformation, foreign body granuloma, cellulitis, and hematoma. Of 15 malignant lesions, 7 were thyroid carcinomas, 3 were lymphomas with submandibular and cervical lymph node enlargement, 3 were lymph node enlargements associated with regional metastasis of malignant tumors, one was a leiomyosarcoma and one was a carotid body tumor. One dog with a diffuse soft tissue swelling of the ventral cervical region had only slight asymmetry of the thyroid lobes on ultrasound examination and no abnormalities of the neck at post mortem. A second dog examined with ultrasound 4 months after surgical removal of a carotid body tumor had no evidence of tumor recurrence. Ultrasonographic examination provided information regarding the character of the lesions, the tissue or organ of origin, and invasion into other anatomic structures. Ultrasound examination in conjunction with fine needle or tissue biopsy provided a definitive diagnosis in those animals in which biopsies were performed.     

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.     

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.     

SONOGRAPHIC APPEARANCE OF UREMIC GASTROPATHY IN FOUR DOGS

Gastrointestinal signs are common in dogs with uremia. Structural changes in the stomach associated with uremia in dogs include ulceration, edema, necrosis, gastric wall thickening, submucosal arteriopathy, and mineralization of the gastric mucosa and submucosa. Upon ultrasonographic evaluation of the abdomen in four dogs with severe uremia due to chronic renal disease, a thickened gastric wall, thickened rugal folds, and a hyperechoic line at the mucosal-luminal interface due to mineralization of the gastric mucosa were found. Ultrasonography was more sensitive than survey radiography for the identification of gastric lesions associated with uremia in these dogs.     

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.     

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 INTRAVASCULAR TRANSIT OF AGITATED SALINE IN NORMAL DOGS FOLLOWING ULTRASOUND GUIDED PERCUTANEOUS SPLENIC INJECTION

Portosystemic shunts (PSSs) allow portal blood to bypass the liver and enter the systemic circulation. Definitive diagnosis requires surgical identification, positive contrast portography, ultrasonography, or scintigraphy. This study was designed as a preliminary step to developing an alternative/adjuvant protocol to these imaging modalities. The main goals were to establish a technique for ultrasound‐guided percutaneous trans‐splenic injection of agitated saline, to evaluate the feasibility of performing the test to explore the postsplenic portal vasculature highlighted by the microbubbles, and to ascertain whether agitated saline microbubbles cross the sinusoidal barrier. Agitated saline was injected into the spleen of 20 healthy sedated dogs under sonographic guidance. The transducer was then repositioned to visualize the portal vein, the caudal vena cava, and the right atrium through different acoustic windows. Satisfactory results were achieved in all dogs. The microbubbles were visualized in all dogs as small intense echo signals within the portal vein at the level of the porta hepatis immediately after injection. In 18 out of 20 dogs, the echogenic signal of the microbubbles disappeared immediately once within the hepatic parenchyma, whereas in two dogs, the echoes from the microbubbles lasted for several seconds within the intrahepatic portal vasculature. The absence of microbubbles beyond the sinusoidal barrier in all of the healthy dogs included in this study makes trans‐splenic injection of agitated saline a candidate as an adjuvant technique for the diagnosis of PSS, being easy to perform and repeat, as well as safe and technically feasible.     

ULTRASONOGRAPHIC EXAMINATION OF THE PHARYNX AND LARYNX OF THE NORMAL DOG

Real-time ultrasonographic examination of the canine larynx was performed in 12 normal dogs using a 7.5-mHz mechanical sector scanner combined with a stand-off. A variety of breeds and ages were examined. All examinations were performed in nonsedated, conscious animals. Transverse scans were found to provide the most reliable and interpretable images. Identification of laryngeal structures included the epiglottis, laryngeal and cricoid cartilages, and the vocal cords. In conscious animals, abduction and adduction of the vocal cords associated with respiration could be identified if the animal was made to pant during the examination. Movement of the vocal cords could also be quantified by pulse-wave Doppler recording. In all animals, recordings were made during inspiration only, with muscular vibration at a rate less than 0.1 m/s.     

ULTRASONOGRAPHIC IMAGING OF THE LATERAL CEREBRAL VENTRICLES IN THE DOG

Ultrasonography was effectively used to evaluate lateral cerebral ventricles in 28 dogs with persistent fontanelles. There was a significant incidence of ventriculomegaly in miniature and brachycephalic breeds. No relationship was found between the size and the fontanelle and the presence or size of ventriculomegaly. A significant relationship was found between the presence of a fontanelle and the presence of ventriculomegaly. There was no statistically significant relationship found between the presence of clinical signs and ventricular size.     

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.     

ULTRASONOGRAPHIC EXAMINATION OF ABDOMINAL LYMPH NODES IN THE DOG

Ultrasonography is a valuable diagnostic tool for examination of the abdomen. Normal lymph nodes are often indistinct during routine abdominal ultrasonographic examination. Lymph nodes altered by infiltrative or inflammatory processes may become sonographically visible due to enlargement and/or altered echogeńicity. A working knowledge of the anatomic distribution of lymph nodes and the scheme of lymphatic drainage is important for increasing the sensitivity and specificity of abdominal lymph node assessment during ultrasonographic examination.     

THE ROLE OF ULTRASOUND IN THE ASSESSMENT OF LARYNGEAL PARALYSIS IN THE DOG

Forty dogs with clinical signs suggestive of upper respiratory tract disease underwent echolaryngography and laryngoscopy. Laryngoscopy was used as the definitive technique to diagnose laryngeal paralysis. The ultrasound investigation accurately indicated the presence of the paralysis and confirmed the uni- or bilateral nature of the disorder. Findings indicative of laryngeal paralysis included asymmetry or absence of motion of the cuneiform processes (30/30), abnormal arytenoid movement (16/30), paradoxical movement (9/30), caudal displacement of the larynx (2/30) and laryngeal collapse (1/30). Thirty dogs were found to be afflicted with laryngeal paralysis and ten had normal laryngeal motility.     

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.     

SONOGRAPHIC APPLICATION IN THE DIAGNOSIS OF INTRAABDOMINAL ABSCESS IN THE DOG

The sonographic appearance of intraabdominal abscess, excluding prostatic abscess, is presented. The most common sonographic pattern identified for intraabdominal abscess is an irregularly defined, hypoechoic mass with minimal to no through transmission. Definitive diagnosis of intraabdominal abscess using only sonography is not possible, as variations of this common sonographic pattern are imaged. Sonography is best utilized to scan an animal when there is a high suspicion of intraabdominal abscess with no overt physical or radiographic evidence, and to better characterize intraabdominal masses. Sonography can be used to assist in percutaneous aspiration, catheterization, and intraoperative localization of abscessation.     

ULTRASONOGRAPHIC PERCUTANEOUS ANATOMY OF THE CAUDAL LUMBAR REGION AND ULTRASOUND‐GUIDED LUMBAR PUNCTURE IN THE DOG

Subarachnoid lumbar puncture is used commonly in the dog for cerebrospinal fluid collection and/or myelography. Here in we describe the percutaneous ultrasound anatomy of the lumbar region in the dog and a technique for ultrasound‐guided lumbar puncture. Ultrasound images obtained ex vivo and in vivo were compared with anatomic sections and used to identify the landmarks for ultrasound‐guided lumbar puncture. The ultrasound‐guided procedure was established in cadavers and then applied in vivo in eight dogs. The anatomic landmarks for the ultrasound‐guided puncture, which should be identified on the parasagittal oblique ultrasound image are the articular processes of the fifth and sixth lumbar vertebrae and the interarcuate space. The spinal needle is directed under ultrasound‐guidance toward the triangular space located between the contiguous articular processes of the fifth and sixth lumbar vertebrae and then advanced to enter the vertebral canal. Using these precise ultrasound anatomic landmarks, an ultrasound‐guided technique for lumbar puncture is applicable in the dog.