Feline vaccine-associated sarcomas

Feline vaccine-associated sarcomas have presented many challenges. Initially, the etiopathogenesis and biological behavior of these tumors had to be characterized, and strategies implemented to move tumors away from problematic sites. Next, diagnostic and treatment recommendations evolved as the biologic behavior of vaccine-associated sarcomas forced early and aggressive intervention. Current therapeutic strategies are expensive, at times debilitating, and frequently fail to effect tumor control. This review summarizes the known history, epidemiology, etiology, and clinical management of vaccine-associated sarcomas after a decade of work. The next challenges must be to find more practical and effective solutions, and to eliminate the cause of vaccine-associated sarcomas.     

Computed tomography features of bronchial and non-bronchial collateral arterial circulation development in a dog diagnosed with multiple chronic pulmonary thrombi

A 5 year-old female Lhasa Apso was diagnosed with a large right pulmonary artery thrombus, multiple smaller pulmonary thrombi, and pulmonary hypertension. In addition, thoracic computed tomography angiography revealed numerous periesophageal arterial vessels, tortuous and dilated bronchial arteries, and an enlarged tortuous left phrenic artery, consistent with systemic bronchial and non-bronchial collateral arterial circulation development. These features of chronic pulmonary arterial thrombi have not been described in dogs but are recognized in people. One year after the diagnosis, the dog was still alive and there were no clinical signs reported.     

COMPUTED TOMOGRAPHIC ARTHROGRAPHY OF THE NORMAL CANINE STIFLE

Computed tomographic (CT) imaging of eight normal cadaveric canine stifles was performed before and after intra-articular administration of iodinated contrast medium. Transverse CT images were reconstructed in dorsal, parasagittal, and oblique planes. The following ligamentous structures were identified on transverse CT images in all stifles: cranial cruciate ligament, caudal cruciate ligament, medial meniscus, lateral meniscus, and the medial and lateral collateral ligaments. The following ligamentous structures were identified on transverse computed tomographic arthrography (CTA) images in all stifles: cranial cruciate ligament, caudal cruciate ligament, medial meniscus, lateral meniscus, meniscofemoral ligament, cranial meniscotibial ligaments, caudal meniscotibial ligaments, intermeniscal (transverse) ligament, and the medial and lateral collateral ligaments. The patellar tendon was identified on transverse and reconstructed dorsal and sagittal CT and CTA images in all stifles. Multiplanar reconstructions enabled further evaluation of the continuity of the cranial and caudal cruciate ligaments and menisci. The medial and lateral collateral ligaments were not clearly identified on CT or CTA multiplanar reconstructed images.     

Morphological and Imaging Evaluation of the Metacarpophalangeal and Metatarsophalangeal Joints in Healthy and Lame Donkeys

The donkey is of socio-economic value yet imaging techniques in both healthy and abnormal limbs are a limiting factor in research and medicine. The objective was to determine anatomical features of both healthy and clinically abnormal donkey metacarpophalangeal and metatarsophalangeal joints (n = 13) using anatomical dissection, casting, X-ray and computed tomography. The joint capsule contained two palmar/plantar and two dorsal recesses. The proximal–palmar or plantar recess was larger than the distodorsal recess and potential sites of approaches to the recesses were determined. Soft tissue structures were distinguished using computed tomography at 300 mA, which was superior to 120 mA. This methodology gave better assessments of the synovial tendon sheath, joint recesses, and cruciate, collateral, and short sesamoidean ligaments. Computed tomography provided outstanding discrimination between the cortex and medulla of the third metacarpal, the proximal sesamoid bones, the proximal phalanx, and excellent details of the osseous structures. Although the joints appeared free from exostosis using X-ray; the position and extension of exostosis in pathologically affected donkeys (a novel finding) were revealed using computed tomography with 300 mA in comparison to 120 mA. The study also provided an anatomical record of the metacarpophalangeal and metatarsophalangeal joints using the latest technology, which could impact on clinical situations including anesthesia injection sites.     

Partial anomalous pulmonary venous connection in a dog

A 2-year-old male intact Belgian Malinois was presented for exercise intolerance. A grade III/VI left basilar systolic murmur was detected. Echocardiography revealed moderate right atrial and ventricular dilation and increased pulmonic outflow velocity. Thoracic radiographs showed right heart enlargement and a dilated caudal vena cava. In addition, on the left lateral projection, an enlarged aberrant right cranial pulmonary lobar vein was suspected to be diverging ventrally from the course of the right cranial lobar bronchus and inserting more ventrally than normal in the region of the right atrium. A left-to-right pulmonary vascular shunt was suspected, and the patient underwent further diagnostics under general anesthesia. An agitated saline study was positive, suggestive of a concurrent right to left shunt. A right heart catheterization was performed. Angiography was inconclusive. Oximetry testing revealed an increase in oxygen saturation within the right atrium at the level of the caudal cava supportive of a left-to-right shunt in this region. Computed tomography angiography revealed a large single pulmonary vein that anomalously entered into the caudolateral aspect of the right atrium (left-to-right shunt) and was suspicious for a small arteriovenous malformation between the right caudal pulmonary artery and the right pulmonary vein returning to the left atrium (right to left shunt). The patient was diagnosed with a partial anomalous pulmonary venous connection and a possible arteriovenous malformation.     

Computed tomographic morphology and clinical features of extrahepatic portosystemic shunts in 172 dogs in Japan

Canine extrahepatic congenital portosystemic shunts (EH-cPSS) are classified into several anatomical types, depending on the origin and termination of the shunt vessel. The aim of this retrospective study was to determine the proportion and clinical features of each anatomical shunt type in a population of dogs presented to a veterinary teaching hospital in Japan. Dogs diagnosed with EH-cPSS using computed tomographic (CT) portography were included (n = 172) and shunts were classified based on previous reports. Clinical data were collected from case records and analysed statistically. The most common anatomical type was the spleno-phrenic shunt (n = 64), followed by the spleno-azygos (n = 38), right gastric-caval (n = 29), spleno-caval (n = 21), right gastric-caval with caudal loop (n = 9), right gastric-phrenic (n = 6), colono-caval (n = 3), spleno-phrenic and azygos (n = 1), and porto-caval (n = 1) shunts. Spleno-phrenic and spleno-azygos shunts were diagnosed more frequently in older dogs than right gastric-caval and spleno-caval shunts (P < 0.05). The portal vein/aortic (PV/Ao) ratio was significantly larger in dogs with spleno-phrenic shunts than in dogs with spleno-azygos, right gastric-caval or spleno-caval shunts (P < 0.05). The PV/Ao ratio was significantly larger in dogs with spleno-azygos shunts than in dogs with right gastric-caval shunts. Dogs with spleno-phrenic shunts had significantly lower serum alkaline phosphatase activities than those with right gastric-caval or spleno-caval shunts. Dogs with spleno-phrenic shunts had significantly lower fasting ammonia concentrations than those with spleno-caval shunts.     

Non-selective computed tomography angiography of a vascular ring anomaly in a dog

Non-selective computed tomography angiography (CTA) is an emerging imaging technique that will have continued application in veterinary medicine because of its short scan time, use of a single, peripheral venous injection and availability of more detailed anatomic information—including 3-dimensional reconstructions. The improved anatomic detail may facilitate veterinary students' learning of complex aortic arch malformations and details relative to the surgical approach. Herein we describe application of its use in a dog with a vascular ring anomaly due to a persistent right fourth aortic arch and left ligamentum arteriosum. Additionally, we compare images with a normal dog.     

Brain Abscess in a 4-Month-Old Filly: A Case Report

Although recognized as a possible complication to sepsis, there are few published reports on brain abscesses in foals. This case report describes a 4-month-old Icelandic filly that, as a neonate, had a history of pyrexia and lameness, which resolved with antibiotic treatment. Approximately 3 months later, the foal developed neurological signs which were initially attributed to trauma; she was referred for further investigation. The clinical signs were consistent with a lesion of the right forebrain. Computed tomography examination revealed a mass, approximately 6 cm in diameter, located in the right cerebral hemisphere craniolateral to the right lateral ventricle. Because of the poor prognosis, the foal was killed, and a postmortem was performed. The findings confirmed the presence of an abscess of the right cerebral hemisphere, leading to severe atrophy of the cortex and dilation of both lateral ventricles. The left hemisphere was moderate-to-severe atrophic and had displaced to the left. Streptococcus equi subspecies zooepidemicus was isolated in pure culture from the abscess. The clinical features of the foal were compared with the pathological findings.     

Computed tomography imaging of a leopard tortoise (Geochelone pardalis pardalis) with confirmed pulmonary fibrosis: a case report

An approximately 20-year-old, female Leopard tortoise (Geochelone pardalis pardalis) was presented with dypsnea, wheezing, anorexia and depression. Whole body radiographs revealed generalized diffuse unstructured ‘interstitial lung pattern’ with thickened pulmonary septae while computed tomography (CT) showed emphysematous lung parenchyma and thickened pulmonary septae bordered by irregular ground-glass opacity with smaller areas of ‘honeycombing’. These imaging findings together with histopathologic findings were compatible with chronic, extensive ‘interstitial’ pulmonary fibrosis.     

Diagnosis of congenital aneurysmal giant right auricle in a dog

A five-year-old intact male Golden Retriever was sent to our center for a second cardiac evaluation after the diagnosis of right atrial dilatation. Transthoracic and transesophageal echocardiographic evaluation and echo-contrast study were performed. A diagnosis of aneurysmal right auricle was issued without any sign of other cardiac pathologies. The tomographic evaluation was necessary to estimate the dimension of the aneurysmal area and exclude pericardial defects that may justify this anomaly. This report describes a rare case of aneurysmal giant right auricle in dogs. The diagnosis is accurate with the association of echocardiography and computed tomography.     

Computed tomographic anatomy of the head of the loggerhead sea turtle (Caretta caretta)

The heads of three loggerhead sea turtles were disarticulated and imaged immediately to minimize postmortem changes and then frozen and sectioned. For computed tomography (CT) imaging, the heads were positioned in ventral recumbency. Transverse CT images with soft-tissue window were obtained from the olfactory sac region to the temporomandibular joint region. After CT imaging, the heads were sectioned and the gross sections were compared to CT images, to assist in the accurate identification of the anatomic structures. Different clinically relevant anatomic structures were identified and labelled in two series of photographs (CT images and anatomic cross-sections). CT images provided good differentiation between the bones and the soft tissues of the head. The information presented in this paper should serve as an initial reference to evaluate CT images of the head of the loggerhead sea turtle and to assist in the interpretation of lesions of this region.     

Unilateral external jugular vein aneurysm in a dog

An 11-month-old Staffordshire Bull Terrier was referred with a two-month history of fluctuating unilateral jugular groove swelling, which appeared to enlarge after exercise. There was no history of trauma. Multimodal imaging findings (using transdermal and transesophageal ultrasound and dual phase computed tomography angiography) were consistent with large, saccular, left jugular vein aneurysm, running parallel to the left carotid artery. There did not appear to be any arteriovenous communication present. There were no cardiac abnormalities found on echocardiography. Following surgical excision, histopathological analysis supported the clinical suspicion of a congenital external jugular venous aneurysm.     

Equine Mandibular Fibrosarcoma in Two Horses: Clinical,Diagnostic, and Therapeutic Considerations

A 25 year old Arabian gelding (case 1) presented for a large mandibular swelling involving the caudal aspect of the left horizontal mandible and a 14 year old Quarter Horse gelding (case 2) presented for a soft tissue swelling on the labial mucosa adjacent to 304. Both horses were bright and alert on presentation. Computed tomography allowed for further characterization regarding the extent of bone penetration within the lesions. This facilitated surgical planning and resection in Case 2. Histopathology of both masses diagnosed fibrosarcomas. Case 1 was humanely euthanized due to the severity of bone involvement and the grave prognosis. Case 2 underwent a left subtotal rostral hemimandibulectomy that proved to be successful in complete resection of the fibrosarcoma with a comfortable and cosmetic post-operative outcome. Surgeries that were once deemed radical should be considered for the treatment of neoplastic masses involving the soft tissues and bony structures of the oral cavity. With the aid of computed tomography, assessment of tumor penetration into deeper tissues can be achieved, thus facilitating complete surgical excision.     

Effect of Screening Abdominal Ultrasound Examination on the Decision to Pursue Advanced Diagnostic Tests and Treatment in Dogs with Neurologic Disease

Background

Abdominal ultrasound examinations (AUS) are commonly performed before advanced neurodiagnostics to screen for diseases that might affect diagnostic plans and prognosis.

Objectives

Describe the type and frequency of abnormalities found by AUS in dogs presenting with a neurological condition, identify risk factors associated with abnormalities, and evaluate treatment decisions based on findings.

Animals

Seven hundred and fifty‐nine hospitalized dogs.

Methods

Retrospective study. Medical records of dogs presented from 2007 to 2009 for neurologic disease were searched for signalment, neuroanatomic localization, and AUS findings. Whether dogs had advanced neurodiagnostics and treatment was analyzed.

Results

Fifty‐eight percent of dogs had abnormal findings on AUS. Probability of abnormalities increased with age (P < 0.001). Nondachshund breeds had higher probability of abnormal AUS than dachshunds (odds ratio [OR] = 1.87). Eleven percent of dogs did not have advanced neurodiagnostics and in 1.3%, this was because of abnormal AUS. Dogs with ultrasonographic abnormalities were less likely than dogs without to have advanced neurodiagnostics (OR = 0.3 [95% confidence interval [CI]: 0.17, 0.52]), however, the probability of performing advanced diagnostics was high regardless of normal (OR = 0.95 [95% CI: 0.92, 0.97]) or abnormal (OR = 0.85 [95% CI: 0.81, 0.88]) AUS. Treatment was more often pursued in small dogs and less often in dogs with brain disease.

Conclusions and Clinical Importance

Findings from screening AUS had a small negative effect on the likelihood of pursuing advanced neurodiagnostics. Although it should be included in the extracranial diagnostic workup in dogs with significant history or physical examination abnormalities, AUS is considered a low‐yield diagnostic test in young dogs and dachshunds.     

USE OF CONTRAST‐ENHANCED COMPUTED TOMOGRAPHY TO STUDY THE CRANIAL MIGRATION OF A LUMBOSACRAL INJECTATE IN CADAVER DOGS

Volumes used in lumbosacral epidural injections for anesthesia have remained unchanged since the 1960s. The goals of this cross‐sectional observational study were to characterize the three‐dimensional spread of a lumbosacral epidural injection, as well as confirm that the commonly used volume of 0.2 ml/kg injected into the lumbosacral epidural space reaches the thoracolumbar (TL) junction in the majority (≥80%) of dogs. Ten clinically normal, adult, nonpregnant, mixed‐breed dogs were obtained within five minutes of euthanasia and 0.2 ml/kg of radiopaque contrast medium was injected into the lumbosacral epidural space. A computed tomography scan of the TL spine was performed immediately following the injection. Migration of contrast reached the TL junction in 8 of 10 (80%) dogs. Contrast was well visualized in all epidural planes with contrast travelling predominantly in the dorsal epidural space in 7 of 10 (70%) dogs. There was no significant difference in the weight of dogs where the epidural injectate reached the TL junction and those where it did not (P = 0.16), or in the weight of dogs where the cranial‐most point of the contrast column was in the dorsal versus the ventral epidural space (P = 0.32). This preliminary study supports the use of computed tomography to characterize injectate distribution in the canine thoracolumbar epidural space and provides evidence that a 0.2‐ml/kg volume is likely to reache the TL junction in most dogs. Further studies are needed in live dogs to determine if variables affecting human epidural injectate doses have similar effects in the dog.