LUMBO-SACRAL VERTEBRAL SINUS VENOGRAPHY VIA TRANSJUGULAR CATHETERIZATION IN THE DOG

A technic for percutaneous transjugular catheterization of the median sacral vein (MSV) was developed in the dog. This technic provides a means for visualizing the vertebral sinuses in the lumbo-sacral area. Temporary external occlusion of the caudal vena cava coincident with injection of contrast medium was necessary to get consistent, symmetrical filling of the vertebral sinuses. Dissections confirmed variation in location of the MSV and presence of valves at the terminus of this vessel. Angiograms performed using the seventh lumbar intervertebral vein, cranial gluteal vein, and internal iliac vein were less satisfactory due to incomplete filling of the vertebral sinuses.     

DILATED CORONARY SINUS IN A DOG WITH PERSISTENT LEFT CRANIAL VENA CAVA

This paper describes the electrocardiographic, echocardiographic (two-dimensional, M-mode, contrast and Doppler) and non-selective angiocardiographic features in a 3 year old female Beagle with dilated coronary sinus due to persistent left cranial vena cava. Negative P waves in leads III and aVR and a positive P wave in lead aVL were seen. Echocardiographically, a hipoechoic circular structure was seen between the left atrium and the pericardium in the area where the coronary sinus is located. A velocity pattern with two peaks was obtained, one systolic with velocity = 0.44 ± 0.05 m/sec and the other diastolic with velocity = 0.27 ± 0.01 m/sec. By M-mode echocardiography, at level of the aorta and the left atrium, a linear structure was identified between the left atrium and the pericardium; this structure was characterized by phasic movements of the anterior wall during the cardiac cycle. Following a left cephalic vein injection of saline, bubbles were seen within the coronary sinus; when saline was injected into the right cephalic vein, bubbles were also seen within the coronary sinus and right atrium and ventricle. Non-selective angiocardiography confirmed a dilated coronary sinus with persistent left cranial vena cava. The right cranial vena cava was absent. The dog was clinically normal and the unusual vessel was an incidental finding.     

RUPTURE OF THE LEFT AORTIC SINUS INTO THE PULMONARY ARTERY IN A DALMATIAN DOG

An 18-month-old male Dalmatian dog was presented for veterinary evaluation after the pet owner observed a sudden onset of weakness. An acquired continuous cardiac murmur was detected on physical examination. Two-dimensional echocardiographic examination revealed structural abnormalities of the proximal aorta and pulmonic valve. Doppler echocardiographic studies and cardiac catheterization demonstrated the presence of a proximal aorticopulmonary shunt. A diagnosis of left aortic sinus rupture and aorticopulmonary fistula was made. Antemortem diagnosis of aortic sinus rupture in the dog has not, to our knowledge, been reported previously. The anatomical variant of left aortic sinus rupture resulting in the development of a fistula from the aorta to the main pulmonary artery is, apparently, uncommon in all species.     

TRANSOSSEOUS VERTEBRAL VENOGRAPHY: A DIAGNOSTIC AID IN LUMBOSACRAL DISEASE

Transosseous vertebral venography as a technic for investigating disease of the lumbosacral region is described. The technic preferred by the author is an intraosseous injection of contrast medium into the body of L7. Using a caudal needle, 10 ml of contrast medium was injected manually and a radiograph was made as the last milliliter was introduced. Contrast medium filled the lumbar venous sinuses and, by reflux, filled the sacral sinuses caudally to the S2–3 intervertebral foramen. Lumbosacral disease caused an obstruction to contrast medium flow and narrowed or deviated the vertebral venous sinus. Complications of transosseous vertebral venography were extravasation of contrast medium into the epidural space and surrounding soft tissue, and trauma to the sixth lumbar nerve in one dog. The procedure was contraindicated in the presence of local infection and when anesthesia was an undue risk.     

VENOGRAPHY OF THE ORBITAL VENOUS SYSTEM AND CAVERNOUS SINUSES IN THE GOAT

The technique of venography is described for visualizing the orbital veins and the cavernous sinuses following cannulation of the angularis oculi vein and the subsequent injection of 10 ml sodium iothalamate. The venograms clearly demonstrated the veins of the orbit and cavernous sinuses in most of the animals. Two intercavernous sinuses, rostral and caudal, were visualized. In a few goats, transverse and dorsal longitudinal sinuses of the dorsal system of the dural sinuses were also visualized.     

DENTAL RADIOGRAPHY IN THE DOG WITH A CONVENTIONAL X-RAY DEVICE

This study describes a method of using a conventional x-ray device and film-positioning system for dental radiography in dogs. This system is economical, safe and results in high quality dental radiographs.     

IN VIVO STUDY OF CEREBRAL WHITE MATTER IN THE DOG USING DIFFUSION TENSOR TRACTOGRAPHY

Conventional magnetic resonance imaging (MRI) allows investigators and clinicians to observe the anatomy and injuries of the cerebral white matter (CWM) in dogs. However, dynamic images based on the diffusion tensor (DT) technique are required to assess fiber tract integrity of the CWM. Diffusion tensor tractography (DTT) produces a three‐dimensional representation in which data are displayed on a colored map obtained from the anisotropy of water molecules in the CWM tracts. Fractional anisotropy (FA) is a value that measures changes in water diffusion, which can occur if the CWM tracts are displaced, disrupted, or infiltrated. The goal of this study was to determine the feasibility of DTT for in vivo examination of the normal appearance of CWM in dogs through visual and quantitative analysis of the most representative CWM tracts. Nine tractographies were performed on healthy dogs using a 3T MRI scanner. T1‐ and T2‐weighted images and DTI were acquired at different planes. Using DTT, three‐dimensional reconstructions were obtained. Fractional ansisotropy and apparent diffusion coefficient (ADC) values of the right and left corticospinal tracts, corpus callosum, cingulum, and right and left fronto‐occipital fasciculus were determined. Tract reconstructions were similar in 8/9 healthy dogs. Values for FA and ADC were similar in all the dogs. In one dog, tract reconstructions were inhomogeneous; these were displaced because it had larger lateral ventricles. Findings indicated that DTT is a feasible technique for in vivo study of CWM in dogs and that it complements information from conventional MRI.     

CORCTATION OF THE AORTA IN A DOG

This paper describes coarctation of the aorta with a large fusiform post-stenotic aneurysm in a 6 year old Great Dane. No clinical signs were attributable to the lesion, which was an incidental finding. The radiological and pathological features of aortic coarctation are described.     

COMPUTED TOMOGRAPHY OF AN ACUTE HEMORRHAGIC CEREBRAL INFARCT IN A DOG

Computed tomography (CT) was performed on an eleven-year-old dog four days after an acute onset of seizures and neurologic deficits. A ring-enhancing, intra-axial lesion associated with edema, falcial deviation and non-uniform ventricular compression was identified in the left frontal lobe. An area of ill-defined hyperdensity, compatible with hemorrhage, was noted on corresponding CT images prior to contrast enhancement. At post-mortem examination, a focal, hemorrhagic infarct, characterized by liquif ication necrosis, marked gliosis and neovascularization, was found. The etiology of the infarction could not be identified. The CT findings, however, were similar to those seen in humans with cerebral infarction due to embolic occlusion and subsequent hemorrhage. These findings and the pathophysi-ologic mechanisms behind them are discussed.     

GASTRIC LYMPHOSARCOMA IN A DOG: A CASE REPORT

A 9-year-old female spayed mixed-breed dog was presented with a ten-week history of vomiting. A survey abdominal radiograph showed a soft tissue mass on the lesser curvature of the stomach and an adjacent thickened greater curvature. A barium contrast study confirmed the presence of this mass. The radiographic diagnosis was gastric tumor. Radiographic signs of gastric neoplasia include soft tissue masses or thickening of the stomach wall, delayed gastric emptying, immobility of portions of the stomach wall, and residual stomach-wall staining by barium. Necropsy revealed a gastric lymphosarcoma that had infiltrated the entire circumference of the pyloric antrum. The most common gastric malignancy in the dog is adenocarcinoma. Gastric lymphosarcoma is considered rare.     

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.     

MAGNETIC RESONANCE IMAGING OF CEREBRAL CORTICAL NECROSIS (POLIOENCEPHALOMALACIA) IN A DOG

A 3-year-old neutered female mixed breed dog was examined because of severe, generalized seizure activity, tetraparesis, and encephalopathic signs. Cerebrospinal fluid (CSF) evaluation was unremarkable except for a mild increase in protein. Serum and CSF titers for infectious diseases were negative. Magnetic resonance (MR) imaging examination of the brain was performed and lesions were found within the cerebral gray matter of the temporal and parietal lobes. The lesions had increased signal intensity on T1, T2, and proton density-weighted images. There was mild inhomogeneous enhancement following intravenous contrast medium administration. Neurologic status improved and the seizures were well controlled, but the dog never regained normal mentation and euthanasia was performed 10 weeks after initial evaluation. At necropsy, severe cerebral cortical necrosis was found in the regions corresponding to the lesions seen on MR imaging examination. Large numbers of fat-containing macrophages (gitter cells) were found within these areas, and are thought to be responsible for the characteristic hyperintensity seen on the MR images.     

FATAL MEDIASTINAL HEMORRHAGE IN A DOG

Rapidly fatal mediastinal hemorrhage in a previously healthy dog is described. The lesion was manifest radiographically by widening of the dorsal mediastinum. Although the exact origin of hemorrhage was not identified, it is hypothesized that one or more dorsal intercostal arteries were ruptured when the dog ran to an abrupt stop at the end of a long chain.     

A REVIEW OF PRIMARY LUNG TUMORS IN THE DOG AND CAT

Primary pulmonary carcinomas are being encountered with increasing frequency in older dogs and cats. The most common presenting complaint in the canine is a nonproductive cough of several weeks' duration, but many affected animals have no abnormal clinical signs in the early stages of the disease. A solitary mass that arises from a single focus in the peripheral pulmonary tissue is the most frequently observed radiographic sign of a primary lung tumor. Often a definitive diagnosis can be made only following thoracotomy with removal or biopsy study of the neoplastic tissue. A classification system based on the prevailing histologic pattern may then be used to categorize most primary lung neoplasms as adenocarcinomas, squamous cell carcinomas, anaplastic carcinomas, or bronchioloalveolar carcinomas. Adenocarcinomas are most common in the dog and cat. Only the neoplastic cell type and the presence or absence of metastatic disease have been found to be of value as prognostic indicators. Following wide surgical resection of the pulmonary mass, dogs with pulmonary adenocarcinomas are reported to have a longer mean survival time than animals with other types of primary lung carcinomas.     

BRONCHOCUTANEOUS FISTULA IN A DOG

A dog with a bronchocutaneous fistula is described. Contrast enhanced computed tomography was useful for diagnosis and treatment of the fistula in this dog.     

COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING OF CAVERNOUS SINUS ENLARGEMENT IN A DOG WITH UNILATERAL EXOPHTHALMOS

Computed tomography (CT), magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were performed on a dog with a two year history of unilateral exophthalmos occurring two years following head trauma. On CT images, an expansile enhancing mass was present along the right intracranial cavernous sinus and extended through the orbital fissure into the retrobulbar space. With MRI, the structure appeared as a signal void due to the presence of rapidly flowing blood. Gadolinium enhancement of the adjacent brain was not present. A vascular origin of the lesion was confirmed with MRA. Based on the CT and MRI findings, the enlarged cavernous sinus and associated ophthalmic plexus were believed to represent an arterialized aneurysm, most likely the result of traumatic arteriovenous fistulization. Treatment consisted of surgical enucleation. At the time of this report, 29 mouths later, the dog remains free of clinical signs.     

EMPHYSEMATOUS PYOMETRA IN A DOG

An 8-year-old intact female West Highland White Terrier was examined for anorexia, vomiting, abdominal distension, and mild purulent vulvar discharge. The results of physical examination, laboratory testing, and radiography are presented. Emphysematous pyometra was suspected and confirmed at surgery. Clostridium perfringens was isolated from the uterine lumen. A brief discussion of emphysematous pyometra is presented.