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 FINDINGS IN CANINE GASTRIC NEOPLASIA IN 13 PATIENTS

The ultrasonographic findings in 13 canine patients with histopathologically proven gastric tumors were reviewed. The echogenicity of gastric wall lesions was variable and independent of the type of tumor. All dogs had an increase in gastric wall thickness and in only one dog was the wall layering intact. Regional lymph node involvement was a common finding, but abnormalities within the liver were seen in only one patient. Gastric neoplasia was observed most commonly in middle-aged and old, medium- to large-sized dogs. Carcinoma was the most common tumor found. In this study, with a limited number of animals and limited tumor types, it appeared that thickening of the gastric wall, accompanied by loss of gastric wall layering and enlargement of regional lymph nodes were ultrasonographic signs likely to be found with gastric neoplasia. In this limited study the histologic type of gastric tumor could not be predicted on the basis of the ultrasound examination.     

HEPATIC ULTRASONOGRAPHIC AND PATHOLOGIC FINDINGS IN DOGS WITH CANINE SURPERFICIAL NECROLYTIC DERMATITIS

A unique, "honeycomb" pattern was found on ultrasonographic evaluation of the liver of 5 dogs with canine superficial necrolytic dermatitis (hepatocutaneous syndrome). This pattern consisted of variably-sized, hypoechoic regions measuring 0.5–1.5 cm in diameter surrounded by highly echogenic borders. Histologically, the hypoechoic regions corresponded to distinct regenerative nodules bounded by severely vacuolated (fat-laden) hepatocytes, numerous bile ductules, and a network of reticulin and fine collagen fibers representing remnants of collapsed hepatic lobules. While certain features of the architectural disruption were characteristic of cirrhosis, the lesion lacked the extensive fibrosis and reduced liver size usually associated with chronic cirrhosis. To our knowledge, this hepatic ultrasonographic pattern has only been seen with canine superficial necrolytic dermatitis. Therefore, it appears to be pathognomonic in a dog with questinable skin lesions. A liver biopsy is required to confirm the unique histopathologic features of the hepatopathy found in this syndrome.     

RADIOTHERAPY OF CANINE NON-TONSILLAR SQUAMOUS CELL CARCINOMA

The records of 14 dogs treated with megavoltage radiation for non-tonsillar oral squamous cell carcinoma were reviewed to determine the efficacy of this treatment modality. Total radiation dose was either 48 or 57 Gray (Gy), while dose per fraction was either 3.0 or 4.0 Gy. Median disease free interval and survival were 365 and 450 days, respectively. Median disease free interval was shorter in dogs older than nine years (210 days) as compared with dogs less than or equal to nine years old (470 days), (p < .005). Median survival was shorter in dogs older than nine years (315 days) as compared with dogs less than or equal to nine years old (1080 days), (p < 0.02). Weight, stage, anatomic subsite, intraoral location, duration of disease, prior surgery, and number of radiation fractions did not appear to influence disease free interval or survival. Data presented herein suggest that survival in dogs with non-tonsillar squamous cell carcinoma receiving megavoltage radiation may be longer than that achieved with orthovoltage radiation or surgery. Megavoltage radiation appears to be an effective treatment for non-tonsillar oral squamous cell carcinoma in dogs. Further study is needed to determine the optimal time-dose sched-ule.     

CANINE ORAL NONTONSILLAR SQUAMOUS CELL CARCINOMA

The records of 33 dogs treated with radiation therapy for nontonsillar oral squamous cell carcinoma (SCC) were reviewed to determine which, if any, prognostic factors affected local tumor recurrence and survival. Information was collected on nine factors: age, sex, anatomic subsite, intraoral location, bone involvement, radiation dose, portal size, and tumor recurrence. Product limit survival estimates indicated than only anatomic subsite was significantly related to disease-free interval. Mean disease-free interval was 12.0, 3.4, and 1.8 months for maxilla, mandible, and soft tissue subsites, respectively. Four factors were significantly associated with survival. The intraoral location (listed in descending survival time: rostral > caudal > rostral and caudal), tumor recurrence (no > yes), relative portal size (less than 100 cm²/m² > greater than or equal to 100 cm²/m²), and age at diagnosis (less than or equal to 6 years > greater than 6 years) were of prognostic importance. Based on these data, a prospective randomized clinical trial for the treatment of nontonsillar oral SCC would be appropriate.     

SONOGRAPHIC INVESTIGATION OF TRANSITIONAL CELL CARCINOMA OF THE URINARY BLADDER IN SMALL ANIMALS

This report compares results from imaging of transitional cell carcinoma of the urinary bladder in 15 dogs using intravenous urography, double-contrast cystography, and ultrasonography. Intravenous urography demonstrated filling defects in the urinary bladder in 3 of the 5 cases examined with this modality. Double-contrast cystography identified bladder masses in 8 of 10 animals. Ultrasonography was the only imaging modality which detected bladder masses in all patients.     

NEEDLE-TRACT IMPLANTATION FOLLOWING US-GUIDED FINE-NEEDLE ASPIRATION BIOPSY OF TRANSITIONAL CELL CARCINOMA OF THE BLADDER, URETHRA, AND PROSTATE

Localized tumor implantation of the ventral abdominal wall was found at 2, 5, and 8 months following percutaneous ultrasound-guided fine-needle aspiration biopsy (FNAB) of transitional carcinoma of the bladder, urethra, or prostate in 3 dogs. To our knowledge this complication has not been reported in dogs following FNAB. Despite the rarity of needle-tract implantation, the potential for this complication with transitional cell carcinomas is apparently not negligible and warrants consideration. We recommend traumatic urethral catheterization to obtain a cytologic diagnosis of potential transitional cell carcinomas of the lower urinary tract or prostate whenever possible until more information becomes available. However, needle-track implantation is so rare that it should not influence the decision to perform a percutaneous FNAB if the urethra cannot be catheterized.     

TRANSITIONAL CELL CARCINOMA OF THE URETHRA IN FOUR FEMALE DOGS: ITS URETHROGRAPHIC APPEARANCE

ansitional cell urethral carcinoma in four female dogs is reported. Lesion distribution in the proximal two thirds of the urethra and the radiographic appearance with retrograde positive contrast urethrography were similar in each dog. The normally smooth longitudinal urethral striations were replaced by multiple small, poorly marginated intraluminal masses that resulted in a generalized moth-eaten appearance. Extension of contrast medium into the periurethral tissues also occurred. Retrograde urethrography, a simple diagnostic technic, aided in establishing a differential diagnosis in dogs that had urine retention and stranguria.     

ULTRASONOGRAPHIC PARAMETERS OF NORMAL CANINE ADRENAL GLANDS: COMPARISON TO NECROPSY FINDINGS

Ultrasonographic evaluation of the adrenal glands was performed in 14 fasted healthy adult dogs. Frequency of visualization was 100% for both the left and right adrenal glands. Moderate correlation was present between Ultrasonographic and gross measurements of thickness for both left (r_s= 0.727; p < .005) and right (r_s= 0.537; p < .05) adrenal glands. However, no correlation was found between Ultrasonographic and gross measurements for length or width of either adrenal gland. Differentiation of adrenal cortex and medulla was possible in 79% of left adrenal glands and 64% of right adrenal glands. The echogenicity of the adrenal glands was less than that of the renal cortex in all dogs. Factors which made evaluation of the adrenal glands more difficult included pyloric gas, intestinal gas, and deep-chested body conformation.     

ULTRASONOGRAPHIC DESCRIPTION OF CANINE MASTITIS

Ultrasonographic images were acquired of the mammary glands of 40 bitches with physiologically lactating (n = 20) or inflamed glands (n = 20). Echogenicity, structure, homogeneity, thickness, and distinguishability of each tissue layer were assessed. Additionally, overall echogenicity was noted. In the normal lactating gland, different tissues could be differentiated easily. The parenchyma was, without exception, separated from adjacent tissues and was visible as medium echogenic tissue with a coarse-grained structure. The tissue always had some echogenic lines and anechoic areas and was slightly heterogeneous. The loss of distinct layering of the tissue was characteristic of an inflamed mammary gland and inflamed regions had reduced echogenicity. Additionally in five bitches with mastitis, the ultrasound examination was repeated five times for documentation of the progress of the illness and associated changes, supplemented with a color Doppler sonogram to assess changes in blood vessel density. Information from the examinations carried out via B-mode did not allow treatment success to be predicted. Two bitches with reduced blood vessel density centrally had a poor outcome whereas three bitches with increased blood vessel density had a good outcome. Thus, Doppler sonography might be a useful tool to obtain information of the prognosis in acute canine mastitis.     

TOLERABILITY AND TUMOR RESPONSE OF A NOVEL LOW‐DOSE PALLIATIVE RADIATION THERAPY PROTOCOL IN DOGS WITH TRANSITIONAL CELL CARCINOMA OF THE BLADDER AND URETHRA

Previously reported radiation protocols for transitional cell carcinoma of the canine lower urinary tract have been ineffective or associated with increased side effects. Objectives of this retrospective, cross‐sectional study were to describe safety of and tumor responses for a novel palliative radiation protocol for transitional cell carcinoma in dogs. Included dogs had cytologically or histologically confirmed transitional cell carcinoma of the bladder or urethra, and were treated with 10 once‐daily fractions (Monday–Friday) of 2.7 Gy. Thirteen dogs were sampled, with six treated using radiation as first‐line (induction) therapy and seven treated using radiation as rescue therapy after failing previous chemotherapy. Within 6 weeks of radiation, 7.6% (1/13) dogs had a complete response, 53.8% (7/13) partial response, 38.5% (5/13) stable disease, and none had progressive disease. Three patients presenting with urethral obstruction had spontaneous micturition restored during the treatment protocol. A single patient with unilateral ureteral obstruction was patent at recheck examination. Median survival time from time of initial diagnosis was 179 days. Median survival time from start of radiation was 150 days. Acute radiation side effects occurred in 31% (4/13) patients and were classified as grade 1 or 2. No significant late side radiation side effects were reported. No variables examined were identified as prognostic factors. Findings indicated that the reported radiation protocol was safe in this sample of dogs with bladder and urethral transitional cell carcinoma. Future prospective studies are needed to determine utility of this treatment as a rescue therapy in patients with complete urinary tract obstruction.     

ULTRASONOGRAPHIC FEATURES OF CANINE GASTROINTESTINAL STROMAL TUMORS COMPARED TO OTHER GASTROINTESTINAL SPINDLE CELL TUMORS

Canine gastrointestinal stromal tumors (GISTs) are a recent subtype of gastrointestinal spindle cell tumor recognized with the increasing use of immunohistochemistry. To our knowledge, no imaging features have been described in immunistochemically confirmed canine GISTs. The objective of this retrospective, cross‐sectional study was to describe ultrasonographic features of canine GISTs compared with other spindle cell tumors. Thirty‐seven dogs with an ultrasonographically visible gastrointestinal mass and a histopathologic diagnosis of spindle cell neoplasia were examined. Immunohistochemistry staining was performed for retrieved tissue samples to further differentiate the tumor type and each sample was interpreted by a single veterinary pathologist. Ultrasonographic features recorded examined included mass echogenicity, homogeneity, presence of cavitation, layer of origin, bowel wall symmetry, and loss of wall layering, location, size, vascularity, and evidence of perforation or ulceration. Tumor types included 19 GISTs, eight leiomyosarcomas, six leiomyomas, and four nonspecified sarcomas. Gastrointestinal stromal tumors were significantly more likely to be associated (P < 0.03) with abdominal effusion than other tumor types. There was overlap between the anatomical locations of all tumors types with the exception of the cecum where all eight tumors identified were GISTs. Besides location, there were no unique ultrasound features of GISTs that would allow distinction from other gastrointestinal spindle cell tumors. Similar to previous studies, GISTs appeared to be the most common spindle cell tumor associated with the cecum in our sample of dogs. The high frequency of abdominal effusion with GIST's was of unknown etiology could possibly have been due to septic peritonitis.     

ULTRASONOGRAPHIC FEATURES OF CANINE HEPATIC NODULAR HYPERPLASIA

Hepatic nodular hyperplasia is a benign, usually clinically inapparent, proliferative lesion commonly found at necropsy in older dogs. Three examples of hepatic nodular hyperplasia are described in dogs with clinical signs compatible with hepatic disease in which ultrasonography revealed a variety of echotextural changes in the liver similar to those reported in primary or secondary hepatic neoplasia. In subsequent in vitro ultrasonographic studies of hepatic nodular hyperplasia lesions detected at necropsy in dogs without clinical signs of hepatic disease, only subtle echotextural changes were seen. Hence, hepatic nodular hyperplasia may be inapparent in vivo in many dogs. Hepatic nodular hyperplasia is a potentially confusing sporadic finding which must be considered by ultrasonographers examining dogs with clinical signs of hepatic disease. The diagnosis of hepatic neoplasia should not be made on the basis of ultrasonographic findings alone.     

ULTRASONOGRAPHIC ANATOMY OF THE NORMAL CANINE STIFLE

Ultrasonographic examination of the normal canine stifle joint was performed to characterize its normal anatomy. Stifles of four normal adult dogs were imaged in sagittal and transverse planes and each anatomic structure visualized was recorded. Normal anatomic structures consistently seen included the patellar tendon, medial and lateral menisci, the cranial cruciate ligament and femoral condyle cartilage. The caudal cruciate ligament was visualized in two dogs. Collateral ligaments and meniscal ligaments were not visualized. The dogs were then euthanized and each stifle was isolated. Following removal of superficial muscles and skin, each stifle was imaged in a water bath to definitively identify the structures that had previously been visualized on the live dogs. The ultrasonographic appearance of the isolated stifle specimens was similar to that found in live dogs. The results of this study indicate that ultrasound can be used to image the normal anatomy of the canine stifle. The echogenicity of the patellar ligament, cruciate ligaments, menisci and articular cartilage was similar to that previously reported in equine stifles and human knees.     

ULTRASONOGRAPHIC FINDINGS IN CHOLECYSTOKININ-INDUCED PANCREATITIS IN DOGS

Pancreatitis can be induced in dogs by intravenous infusion of supraphysiologic doses of synthetic cholecystokinin octapeptide (CCK-8). Eight anesthetized female beagles were given either CCK-8 or saline in a randomized, blinded fashion and had abdominal ultrasonography to study the development of pancreatic lesions. Pancreatic lesions were apparent 2 hours after the start of CCK-8 infusion and included swelling, interlobular and subcapsular fluid accumulation and patchy hypoechogenicity of the gland parenchyma. CCK-8 had a variable effect on gallbladder emptying. No signs of biliary obstruction or duodenal lesions were identified. Dogs given CCK-8 had severe edematous pancreatitis at necropsy six hours after the start of the infusion. Compared to the oleic acid model of pancreatitis, CCK-8 infusion induces a rapid onset of pancreatitis and an ultrasonographic appearance that reflects diffuse edema of the gland. The short time-scale of the experiment may account for the relative absence of secondary lesions affecting the biliary tract or duodenum compared to the naturally-occurring disease.     

ULTRASONOGRAPHIC FINDINGS IN 13 HORSES WITH LYMPHOMA

Ultrasonography and radiography are commonly used for staging of lymphoma in horses, however there is little published information on imaging characteristics for horses with confirmed disease. The purpose of this retrospective, case series study was to describe ultrasonographic and radiographic findings for a group of horses with a confirmed diagnosis of lymphoma. A total of 13 horses were sampled. Lymphadenopathy (8/13), peritoneal effusion (6/13), splenic (6/13), and hepatic (5/13) lesions were the most frequently identified. The predominant splenic and hepatic ultrasonographic lesions were hypoechoic nodules, organomegaly, and changes in echogenicity. Digestive tract lesions were detected in three horses and these included focal thickening and decreased echogenicity of the small (2/13) and large intestinal (2/13) wall. Thoracic lesions were predominantly pleural effusion (4/13), lymphadenopathy (4/13), and lung parenchymal changes (3/13). Enlarged lymph nodes were detected radiographically (4/13) and/or ultrasonographically (2/13) in the thorax and ultrasonographically in the abdomen (7/13) and in the caudal cervical region (4/13). Findings supported the use of abdominal and thoracic ultrasonography for lymphoma staging in horses. Ultrasound landmarks for localizing cecal and caudal deep cervical lymph nodes were also provided.     

ULTRASONOGRAPHIC FINDINGS IN 14 DOGS WITH ECTOPIC URETER

To evaluate ultrasonography as an alternative to contrast radiography for diagnosis of ectopic ureter in dogs, ultrasonography of the urinary tract was performed prospectively in a series of urinary incontinent dogs anesthetized for contrast radiography. Fourteen dogs had ectopic ureter based on surgical, necropsy or unequivocal contrast radiographic findings. There were eight females and six males of a variety of breeds; five were Labrador retrievers. Mean (range) age at the time of diagnosis was 1.2 (0.2–4) years for females and 3.5 (0.3–5) for males (p < 0.05). Ectopic ureters were unilateral in five dogs (2 left; 3 right) and bilateral in nine dogs. Both ultrasound images and contrast radiographs were positive for 21 (91%) ectopic ureters; the same two ectopic ureters were not detected using either modality. The termination of each of the five normal ureters was visible on ultrasound images; two (40%) were visible on radiographs. Other ultrasonographic findings included dilatation of the ectopic ureter and/or ipsilateral renal pelvis in ten (43%) instances, evidence of pyelonephritis in two dogs (with enlargement of the contralateral kidney in one dog), and urethral diverticuli in one dog. Ultrasonography is a practical diagnostic test for ectopic ureter in dogs. In this series there was close correlation between the ultrasonographic and contrast radiographic findings for each ectopic ureter, but ultrasonography enabled more accurate determination of normal ureteral anatomy.     

ABDOMINAL ULTRASONOGRAPHIC FINDINGS IN DOGS NATURALLY INFECTED WITH BABESIOSIS

Canine babesiosis is a tick‐borne disease with a worldwide distribution that can involve multiple organs and result in a wide variety of clinical manifestations. Our goal was to describe the sonographic changes occurring in 72 dogs naturally infected with babesiosis. Seven healthy Beagle dogs were used as a control group. The most common finding in all dogs was splenomegaly with a diffuse heterogenic parenchyma and generally reduced echogenicity. Diffuse hypoechoic hepatomegaly and bilaterally increased cortical echogenicity of the renal parenchyma were found more frequently in severe uncomplicated and complicated babesiosis groups. Mean renal resistive index and pulsatility index (PI) values were 0.66/1.35, 0.73/1.91, and 0.71/1.73 for mild uncomplicated, severe uncomplicated, and complicated babesiosis groups, respectively. A markedly increased PI for complicated and severe uncomplicated groups correlated with anemia and severity of renal damage. Ultrasonography can be an adjunct for diagnosis and monitoring canine babesiosis and its systemic complications. The detection of diffuse heterogeneous splenomegaly can support the diagnosis of Babesia infection, because of the high prevalence of this lesion in these patients.     

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.     

RETROSPECTIVE ASSESSMENT OF THORACIC RADIOGRAPHIC FINDINGS IN METASTATIC CANINE HEMANGIOSARCOMA

Twenty-one dogs with histopathologically confirmed hemangiosarcoma were evaluated by thoracic radiography for metastatic disease. All dogs had histopathologic examinations of the lungs within two weeks of thoracic radiography. Fourteen dogs had histopathologic evidence of pulmonary hemangiosarcoma; metastatic disease was detected radiographically in eleven of these dogs. The most common radiographic pattern was that of poorly defined small coalescing nodules (8 dogs); other radiographic patterns included well-circumscribed nodules (3 dogs) and alveolar infiltrates secondary to hemorrhage (2 dogs). Differential diagnoses for diffuse, poorly defined, coalescing pulmonary opacities should include hemangiosarcoma in addition to edema, lymphoma, systemic mycoses, fibrosis, allergy, toxicosis, and carcinomas.