SONOGRAPHIC CHARACTERISTICS OF INTRAABDOMINAL ABSCESSATION AND LYMPHADENOPATHY ATTRIBUTABLE TO RHODOCOCCUS EQUI INFECTIONS IN FOALS

The sonographic characteristics of intraabdominal abscesses in 11 foals and intraabdominal lymphadenitis in five foals with Rhodococcus equi infections are presented. Intraabdominal abscesses were usually present in the ventral abdomen adjacent to the ventral body wall, well‐marginated, and contained a mixed or complex echo pattern. Lymphadenitis appeared as singular or multiple clusters of lymph nodes of mixed echogenicity adjacent to any portion of the gastrointestinal tract or body wall. Sonographic findings were supported by necropsy examinations, but sonographic measurements consistently underestimated the size of abscess.     

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.     

SONOGRAPHIC EVALUATION OF EXPERIMENTAL BILE DUCT LIGATION IN THE DOG

The common bile duct was surgically ligated in five normal adult dogs. Ultrasonographic examinations of the gallbladder and biliary system were performed after duct ligation at intervals of 24 hours. The sequence of biliary system dilation was from the common duct to the peripheral intrahepatic ducts. Common duct enlargement was evident in 24–48 hours, while peripheral biliary duct dilation was recognized by five to seven days after obstruction. When compared with hepatic and portal veins, dilated biliary ducts were more tortuous and had irregular branching patterns. Gross pathologic changes were correlated with ultrasonographic findings at seven, 14, 15, 18 and 21 days after obstruction.     

SONOGRAPHIC AND RADIOGRAPHIC CHANGES ASSOCIATED WITH SPLENIC TORSION IN THE DOG

The clinical, radiographic, and sonographic signs in three dogs with splenic torsion are presented. AH dogs exhibited weight loss, anorexia, and lethargy. Splenomegaly was consistent radiographic finding in two dogs and large ill-defined midabdominal mass was seen in one dog. The spleen was easily imaged sonographically in all dogs. Splenic sonography in two dogs showed diffuse, hypoechoic pattern consistent with splenic congestion. Hilar splenic vessels were enlarged on the sonograms of two dogs.     

SONOGRAPHIC APPLICATION IN THE DIAGNOSIS OF PYELONEPHRITIS IN CATTLE

Nineteen cattle with pyelonephritis were examined sonographically. A 3.5- and 5.0-MHz convex transducer was used for percutaneous and a 5.5-MHz linear scanner for transrectal examination. Ultrasonographic changes included enlarged kidneys, echogenic material, and flocculent fluid within a dilated and deformed renal sinus and a poor cortical medullary differentiation. Azotemia was detected in 10 and hematuria and proteinuria in all animals. Microbial culture revealed Corynebacterium renale in eight and Escherichia coli in five cattle. Sonography supplemented the clinical examination and clinicopathological analysis by providing additional information on renal disease in these patients.     

IMAGING DIAGNOSIS — RADIOGRAPHY,ULTRASONOGRAPHY, AND COMPUTED TOMOGRAPHY OF A GIANT FECALOMA CAUSING STERCORAL PERFORATION OF THE COLON IN A DOG WITH A PROSTATIC ABSCESS

A mixed‐breed dog presented with tenesmus, hematochezia, and abdominal distension of 2 weeks duration. Radiography showed a large round mass with a “soap‐bubble” appearance and shell‐like mineralization in the caudal abdomen. Computed tomography revealed a lamellate mineralized mass 8 cm in diameter and containing air in the descending colon and prostatic abscess. Heterogeneously contrast‐enhanced, irregularly thickened colonic wall with intramural and peritoneal free gas indicated stercoral colonic perforation. Surgical intervention revealed a tumor‐like giant fecaloma in the descending colon adjoining the prostate with extensive wall rupture and fecal peritonitis. Hypothetically, prostatic inflammation may affect colonic motility with resultant fecaloma formation.     

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 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.     

B‐MODE AND CONTRAST‐ENHANCED SONOGRAPHIC ASSESSMENT OF ACCESSORY SPLEEN IN THE DOG

Four dogs with an accessory spleen are described. The accessory spleens appeared as a round‐to‐triangular structure located in the perisplenic area. They were homogeneous and isoechoic with the adjacent spleen. Contrast‐enhanced ultrasound was performed using a second generation microbubble contrast medium (sulfur hexafluoride). The type and timing of enhancement of the accessory spleen was similar to that of the parent spleen. Contrast‐enhanced ultrasound is a noninvasive modality useful in distinguishing an accessory spleen from a mass of another origin.     

USE OF COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF A CEREBRAL ABSCESS IN A GOAT

A 7-month-old La Mancha doe was presented with a right head tilt and ventral strabismus while circling to the left. History and physical examination led to a tentative diagnosis of a cerebral abscess. Computed tomography revealed a large, complex mass with ring enhancement in the left cerebral hemisphere, supporting the diagnosis. Postmortem examination confirmed the cerebral abscess. Bacterial cultures yielded heavy growth of Actinomyces pyogenes.     

QUANTITATIVE ULTRASONIC ASSESSMENT OF LIVER SIZE IN THE DOG

Static and real-time B-mode hepatic ultrasound imaging was performed on 16 anesthetized dogs (7.7–29 kg). Sagittal static B-mode scans were acquired at 1–cm intervals, and transverse scans were made with both static and real-time units. Measurements were made from the surface of the liver to the diaphragm and were tested individually and when added or multiplied together for significant correlation with liver and body weight. Only one of the static B-mode measurements had a significant correlation ( p >0.05), and none of the real-time measurements was dependent on liver weight. Ultrasonographic assessment of canine liver size using these methods was of little value in predicting actual liver weight.     

RENAL SONOGRAPHIC MEASUREMENTS IN THE DOG PRECEDING AND FOLLOWING UNILATERAL NEPHRECTOMY

The purpose of this study was to establish sonographic baseline values for normal kidneys initu and to document sonographic changes following unilateral nephrectomy. Normal canine renal measurements were determined sonographically prior to and following unilateral nephrectomy. These included: cortical thickness (cranial, caudal, dorsal, ventral, lateral and medial), medullary measurements (cranial and caudal) and measurements of the renal silhouette (length, height and width). The latter group of measurements was obtained to determine renal volume. Normal parameters were obtained from sixteen healthy dogs prior to nephrectomy; the unilateral nephrectomy group was comprised of eight of these animals, the remaining eight dogs were part of an allo-transplant study.¹ The mean sonographic value for the length of the kidney was 60.3 mm ± 6.4 (n = 26) while the widths and heights were 34.7 ± 3.8 (n = 27) and 27.8 mm ± 3.3 (n = 26) respectively. Renal cortical measurements were found to be smallest dorsally and ventrally on sagittal and transverse sonograms. The largest volumes were the cranial pole on sagittal scans and the lateral pole on the transverse scans. Pearson correlation coefficient for volume resulted in r values of 0.88, 0.78 and 0.72 for length, height and width (n = 25, dif = 24) respectively.     

SONOGRAPHIC ESTIMATION OF PLEURAL FLUID VOLUME IN DOGS

The aim of this study was to find an ultrasonographic method to estimate pleural fluid volume in dogs. Nine canine cadavers of mixed breed were studied. Using a transsternal view, linear measurements from the pleural surface of the midline of the sternebra at the center of the heart to the furthest ventrolateral point of both right and left lung edges were recorded. Isotonic saline was injected using ultrasound guidance into both right and left pleural spaces and the measurements were repeated using standard increments until 1000 ml total volume was reached. No relationship was identified between mean distance and injected volume up to 100 ml. Thereafter, the mean distance increased in an approximately linear relationship with the cube root of fluid volume. There was a high correlation ( r ≥0.899) between the ultrasonographic measurement and fluid volume within individual dogs, but it was not possible to produce a useful equation to calculate absolute pleural fluid volume for new subjects. Nevertheless, ultrasonography may be used to semiquantitatively monitor pleural fluid volume, so that a decrease in the mean linear measurement obtained reflects a decrease in the total fluid volume.     

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.     

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.     

SCINTIGRAPHIC DIAGNOSIS OF INSULINOMA IN A DOG

Diagnosis of insulin-secreting tumors of the pancreas can usually be made on the basis of endocrine testing and exclusion of other causes of hyperinsulinism. In dogs, these tumors have a poor long-term prognosis due to a high rate of metastases and recurrence; staging (and therefore prognosticating) is difficult and usually done at the time of surgery. The purpose of this article is to describe a canine patient with an insulinoma, discuss the diagnostic imaging options for tumor evaluation and mention future directions for therapy. Insulinoma was suspected in an 8-year-old intact male Irish Setter. Somatostatin receptor scintigraphy using indium In-111 pentetreotide was performed and an area of increased radiopharmaceutical accumulation was found craniomedial to the right kidney. At surgery a small mass lesion in the pancreas and a larger, closely associated mass involving a mesenteric lymph node were removed. Histopathology confirmed the diagnosis of insulinoma with regional lymph node metastasis. The dog recovered from surgery and remained normal fourteen months later.     

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.     

ULTRASONOGRAPHIC DIAGNOSIS OF A DEEP MUSCLE ABSCESS IN A HORSE

A deep muscle abscess was diagnosed in a horse with a clinical history of a painful swelling in the left gluteal region. The thick walled hypoechoic structure seen on presentation and the multiloculated hyperechoic mass seen on reevaluation are common Ultrasonographic appearances of abscesses. Ultrasonographic evaluation allowed characterization of a chronic mass with subsequent successful surgery and treatment.     

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.     

THE SONOGRAPHIC DIAGNOSIS OF CHRONIC PROLIFERATIVE SYNOVITIS IN THE METACARPOPHALANGEAL JOINTS OF A HORSE

Chronic proliferative synovitis is an insidious condition affecting the metacarpophalangeal joints of horses. It results in proliferation of the synovium in the dorsal pouch of the joint in question. Treatment involves surgical excision, thus confirmation of the lesion is important. Classically this has been achieved by means of positive-contrast arthrography, but this article addresses the attributes of ultrasonography, a less invasive imaging technique.