LARYNGEAL ADENOCARCINOMA IN A DOG

Laryngeal adenocarcinoma was diagnosed in a 5-year-old golden retriever dog with no history of respiratory or pharyngeal difficulties. Radiographically the basihyoid bone was destroyed by the neoplasm, and extensive soft tissue mineralization ventral to the larynx was also present. Complete surgical resection was not possible due to diffuse involvement of the tongue and larynx. Cobalt-60 teletherapy was used for treatment of the tumor. There was no clinical evidence of tumor regrowth at approximately 12 months post treatment. This is an unusual example of primary laryngeal neoplasia due to the absence of clinical respiratory abnormalities and the aggressive destruction of the basihyoid bone.     

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.     

MAGNETIC RESONANCE IMAGING OF THE INTRATEMPORAL FACIAL NERVE IN IDIOPATHIC FACIAL PARALYSIS IN THE DOG

The most common cause of peripheral facial nerve paralysis in dogs, in the absence of otitis media, is thought to be idiopathic. Gadolinium-enhanced (Gd) magnetic resonance (MR) imaging has been used to study peripheral facial weakness in humans with a wide variety of disorders, including Bell's palsy, the clinical equivalent of idiopathic facial nerve paralysis in dogs. Gd-MR imaging may be useful to demonstrate abnormal enhancement of the intratemporal facial nerve. The aim of this study was to define the role of the Gd-MR imaging in dogs with idiopathic facial nerve paralysis, with regard to pattern of enhancement, and to search for prognostic information. Six dogs with peripheral facial nerve paralysis, followed between 2003 and 2005, were studied. Physical and neurologic examinations, as well as clinical tests, were performed, including routine hematology, serum biochemistry, thyroid screening, cerebrospinal fluid analysis, and MR imaging. The time interval between the onset of the clinical signs, the progress of the disease, and the final recovery was noted in each dog. The following four intratemporal segments of the facial nerve were analyzed: internal acoustic meatus, labyrinthine segment/geniculate ganglion, tympanic segment, and mastoid segment. Along its length, contrast enhancement was found in four dogs. In this group, contrast enhancement of the facial nerve was found in all segments of two dogs, in three segments of one dog, and in one segment of the other dog. In the four dogs with enhancement, one recovered completely in 8 weeks and three have not recovered completely. The two dogs without evidence of enhancement recovered completely in an average time of 4 weeks.     

ULTRASONOGRAPHY OF LARYNGEAL MASSES IN SIX CATS AND ONE DOG

Ultrasonography of laryngeal abnormalities in small animals allows the identification of laryngeal masses because of the resulting distortion of normal structural/anatomical relationships. It also allows fine-needle aspirates to be taken with minimal risk of causing hemorrhage or edema affecting the already narrowed laryngeal lumen. Findings in six cats and one dog with laryngeal abnormalities are described.     

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.     

TESTICULAR ULTRASOUND IN THE NORMAL DOG

The testicles of ten dogs presented for routine castration were imaged with real time ultrasound. A scanning technique using multiple imaging planes (sagittal, transverse, and dorsal planes) was developed to image the testicles and epididymi. The testes were characterized by a coarse medium echo pattern. The mediastinum testis was consistently seen as a 0.2 cm wide linear hyperechoic structure in the central long axis of the testis. The ability to identify and the appearance of the epididymis was variable. The tail was consistently seen as an anechoic to hypoechoic structure. Ultrasound images were compared for anatomical structure with frozen gross sections. Ultrasonic and gross measurements were made and analyzed. Individual gross and ultrasonic measurements compared favorably. Linear regression coefficients between body surface area versus testicular length and diameter were 0.73 and 0.58 respectively. A Wilcoxin signed rank test for similarity p = 0.33 value was found when comparing the right to the left testicle.     

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 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.     

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.     

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.     

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.     

DOPPLER ULTRASOUND OF THE PROSTATE IN NORMAL DOGS AND IN DOGS WITH CHRONIC LYMPHOCYTIC-LYMPHOPLASMOCYTIC PROSTATITIS

The prostate gland of 11 normal dogs and five dogs with histological confirmed chronic lymphocytic or lymphoplasmocytic prostatitis were imaged with grey-scale and Doppler ultrasound. Three vessel types (prostatic artery, capsular artery and parenchymal artery) were identified with color Doppler and the resistive index and maximum and minimum velocities were measured with pulsed wave Doppler. No differences between normal dogs and dogs with prostatitis was identified in either grey-scale ultrasound or in any Doppler parameters measured. Regardless of histologic diagnosis, acepromazine (0.05 mg/kg IV) caused a significant decrease in capsular artery maximum and minimum velocities and prostatic artery resistive index. This study establishes normal Doppler ultrasound parameters for the intact male canine prostate gland. Additional studies are necessary to further evaluate the clinical utility of Doppler ultrasound in canine prostatic diseases.     

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.     

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.     

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.     

DIAGNOSTIC SENSITIVITY OF SUBJECTIVE AND QUANTITATIVE LARYNGEAL ULTRASONOGRAPHY FOR RECURRENT LARYNGEAL NEUROPATHY IN HORSES

Recurrent laryngeal neuropathy (RLN) is the most common cause of laryngeal hemiplegia in horses and causes neurogenic atrophy of the intrinsic laryngeal muscles, including the cricoarytenoideus lateralis muscle. Recurrent laryngeal neuropathy results in paresis to paralysis of the vocal fold and arytenoid cartilage, which limits performance through respiratory compromise. Ultrasound has previously been reported to be a useful diagnostic technique in horses with RLN. In this report, the diagnostic sensitivity of subjective and quantitative laryngeal ultrasonography was evaluated in 154 horses presented for poor performance due to suspected upper airway disease. Ultrasonographic parameters recorded were: cricoarytenoideus lateralis echogenicity (subjective and quantitative), cricoarytenoideus lateralis thickness, vocal fold movement, and arytenoid cartilage movement. Ultrasonographic parameters were then compared with laryngeal grades based on resting and exercising upper airway endoscopy. Subjectively increased left cricoarytenoideus lateralis echogenicity yielded a sensitivity of 94.59% and specificity of 94.54% for detecting RLN, based on the reference standard of exercising laryngeal endoscopy. Quantitative left cricoarytenoideus lateralis echogenicity values differed among resting laryngeal grades I–IV. Findings from this study support previously published findings and the utility of subjective and quantitative laryngeal ultrasound as diagnostic tools for horses with poor performance.     

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.     

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.     

ULTRASOUND EVALUATION OF THE COXOFEMORAL JOINTS OF THE CANINE NEONATE

The effectiveness of ultrasound in depicting the normal anatomy of the coxofemoral joint in puppies was evaluated. Ultrasound images were obtained from twenty Springer Spaniel puppies ranging from one day to twelve weeks of age. The anatomy of the hip joint could be identified up to eight weeks of age. By twelve weeks of age the degree of ossification prevented complete hip joint evaluation. Three different views were utilized. The longitudinal and dorsolateral views were the most useful. Motion of the femoral head within the acetabulum could be observed. Measurements of the acetabulum, femoral head and joint space could be obtained however these measurements were inconsistent. The technique appears to be useful for depicting the anatomy of the neonatal coxofemoral joint however, additional studies utilizing both normal and dysplastic puppies are recommended to determine if this examination will be useful in discriminating between normal and dysplastic puppies.