Clinical vignette Fortuitous diagnosis of a persitent left cranial vena by color flow Doppler echocardiography in a dog

A persistent left cranial vena cava is described in an asymptomatic three-year-old female Shi Tzu. The purpose of this report is to show the value of color flow Doppler echocardiography in the diagnosis of this uncommon congenital cardiovasular abnormality.     

Transvenous pacemaker placement in a dog with atrioventricular block and persistent left cranial vena cava

The case reported herein describes the placement of a permanent transvenous pacemaker in an older dog with a previously undiagnosed persistent left cranial vena cava (PLCVC) and recent onset symptomatic third-degree atrioventricular (AV) block. On presentation the dog was found to have atrial flutter and third-degree AV block and echocardiography demonstrated evidence of chronic valvular disease and pulmonary arterial hypertension. The persistent left cranial vena cava was discovered via angiography when difficulties were encountered with pacemaker placement. Successful right ventricular pacing necessitated passage of the lead through the coronary sinus. The attendant complications in pacemaker placement in the presence of a PLCVC are well-described in man but, to the authors' knowledge, have not been described in companion animals.     

Multimodality imaging of an azygous continuation of the caudal vena cava in a dog with pulmonary thromboembolic disease

A 5‐year‐old spayed female English Bulldog was evaluated for acute anorexia, lethargy, respiratory distress, and syncope. Contrast‐enhanced computed tomography revealed the vascular malformation of azygous continuation of the caudal vena cava with extensive thrombus formation and pulmonary arterial thromboembolic disease. The patient was hospitalized for supportive treatment and was prescribed long‐term clopidogrel therapy. The patient survived to discharge and at last follow‐up remained clinically stable. While this vascular malformation has been reported in canines, to the authors’ knowledge, this is the first reported case of pulmonary thromboembolic disease in a canine concurrent with this condition.     

Cor triatriatum sinister and persistent left cranial vena cava in a kitten

An approximately 8-week-old, 0.61 kg, male Bengal kitten was evaluated by the referring veterinarian for a 5-day history of sneezing, lethargy, anorexia, coughing, and dyspnea. Thoracic radiographs revealed cardiomegaly with left atrial enlargement, a patchy distribution of pulmonary edema, and loss of abdominal detail.     

Anatomical anomalies and variations of main thoracic vessels in dogs: a computed tomography study

IntroductionThere is scarce information about the prevalence of anomalies and anatomical variations of the main great thoracic vessels in dogs, particularly in dogs without congenital heart disease.AnimalsThe study included 878 privately owned dogs.Material and methodsComputerized tomography (CT) thoracic studies carried out between 2011 and 2014 for a variety of reasons were reviewed. The prevalence of anomalies and anatomical variations of the aorta and vena cava, the arterial branches of the aortic arch and the main branches of the intrathoracic veins in dogs with no evidence of congenital heart disease was evaluated. Poor-quality CTs, CTs with thoracic pathology that impaired visualization or those of young dogs with clinical evidence or suspicion of congenital cardiac disease were excluded.ResultsEight hundred two CT studies were analysed. Eight dogs (1%) showed an anatomic anomaly. The most common anomaly was an aberrant retroesophageal right subclavian artery (n = 7, 0.8%). One dog showed a dilated azygos vein secondary to an interrupted vena cava. Three types of branching of the common carotid arteries were observed: both arteries arising at the same point (type I: n = 506/742; 68.2%), separated (type II: n = 212/742; 28.6%) or from a common trunk (type III: n = 24/742; 3.2%).ConclusionsMajor anatomical variations or anomalies of the main great thoracic vessels in dogs without congenital cardiac disease were rare. An aberrant retroesophageal right subclavian artery was the most common anomaly found. Three slight variations of common carotid artery branching were identified. These findings might be of relevance for surgical or catheterization procedures.     

Diagnostic accuracy of magnetic resonance imaging for meniscal tears in dogs affected with naturally occuring cranial cruciate ligament rupture

A stifle magnetic resonance (MR) imaging protocol was developed based on the appearance of the cruciate ligaments and menisci in normal dogs. Proton density images were subjectively considered to have the highest likelihood of detecting a meniscal lesion. Following this initial evaluation, the accuracy of high-field MR imaging to detect meniscal tears in dogs was evaluated in 11 dogs suffering from naturally occurring cranial cruciate ligament rupture. Dogs underwent MR imaging of the affected stifle before surgery. MR imaging and surgical findings were assessed independently, and then compared. Five tears of the medial meniscus were correctly diagnosed with MR imaging and 19 normal menisci were accurately characterized as such, based on MR images. In one medial meniscus, changes consistent with meniscal degeneration were seen on MR images but this was not seen at surgery. With regard to the lateral meniscus, one false positive diagnosis of a tear was made and this likely represented a normal variation. One other lateral meniscus had changes consistent with meniscal degeneration but, as with the similar lesion seen in the medial meniscus, this was not confirmed surgically. The global sensitivity of MR imaging for the diagnosis of a meniscal tear was 100% and the specificity was 94%. High-field MR imaging is a reliable method to diagnose meniscal tears preoperatively and this may be useful in selecting the surgical approach to clinically abnormal joints and may decrease the need for arthrotomy.     

Clinical application of multidetector computed tomography and magnetic resonance imaging for evaluation of cranial nerves in horses in comparison with high resolution imaging standards

Although horses are affected by cranial nerve disease, our understanding of these structures' imaging anatomy is limited, and the optimal modality for imaging of each of these nerves is unclear. The aim of this study was to describe the imaging appearance of the equine cranial nerves on high‐resolution 1.5T magnetic resonance imaging (MRI) and computed tomography (CT) scans of a cadaver head, and with these as standards, examine the utility of MRI and CT performed in clinical cases. High‐resolution MRI and CT images were prospectively acquired of the head of a normal Thoroughbred gelding following euthanasia. Ten clinical cases undergoing high‐field MRI under general anaesthesia and 10 clinical cases undergoing CT in the standing horse under sedation were retrospectively evaluated by three reviewers to assess cranial nerve visibility. On high‐resolution, thin‐slice, MRI scans of the normal cadaver head, each of the 12 cranial nerves and their topographic location could be appreciated. On high‐resolution cadaver CT, cranial nerves II, V and VII were clearly visible, but others were less easily identified; osseous structures were clearly visualised. Clinical MRI and CT allowed for variable visualisation of the cranial nerves, dependent on the sequence and the orientation of scan planes. High‐field MRI allowed excellent visualisation of equine cranial nerves, whereas CT allowed for more detailed visualisation of the osseous canals and foramina. In live horses, the ability to identify all 12 nerves is challenging with either MRI or CT; however, high‐field MRI enables better visualisation of the nerve bundles than CT.     

Persistent left cranial vena cava draining into the left atrium associated with pulmonary stenosis in a French bulldog

A 5-month-old female French bulldog was evaluated for the presence of a heart murmur. Through clinical and echocardiographic evaluations, a severe Type A pulmonary stenosis was diagnosed. Angiography during right ventricular catheterization for valvuloplasty revealed drainage from a persistent left cranial vena cava (PLCVC) into the left atrium; this was confirmed later by contrast echocardiography. This report is the first to describe this anatomical variant of a PLCVC in a dog.     

Evaluation of left ventricular function with cardiac magnetic resonance imaging and echocardiography after administration of dobutamine and esmolol in healthy beagle dogs

Unlike echocardiography, cardiac magnetic resonance imaging (cardiac MRI) results in a near-exact assessment of cardiac structures and function. However, most veterinary studies have focused on dogs with normal cardiac function. We hypothesized that there would be significant differences in cardiac measurements between cardiac MRI and echocardiography when left ventricular (LV) function was abnormal. This study was undertaken to compare measurements of LV function produced by cardiac MRI and echocardiography in dogs whose LV function was altered by pharmacological agents. This study was conducted with six healthy beagle dogs. We increased left ventricular contractility by administration of dobutamine; we decreased cardiac contractility with esmolol. Stroke volume measurements were made by using both cardiac MRI and echocardiography under seven different conditions with general anesthesia: control, three doses of esmolol (100, 200, and 500 µg/kg/min), and three doses of dobutamine (10, 20, and 50 µg/kg/min). Experiments involving each condition were conducted at least 1 week apart. When LV contractility was normal, ejection fraction (EF) and stroke volume (SV), as measured by echocardiography and cardiac MRI, were not significantly different. However, when contractility was changed by pharmacological agents, EF and SV were overestimated by echocardiography, compared to MRI. Evaluation of cardiac function in patients treated with pharmacological agents should be conducted carefully because EF and SV measured by echocardiography can be overestimated, compared with EF and SV obtained by cardiac MRI.     

Magnetic resonance imaging findings and clinical associations in 52 dogs with suspected ischemic myelopathy

BACKGROUND: The magnetic resonance imaging (MRI) features of ischemic myelopathy have been described in the human literature and in a small number of cases in the veterinary literature. HYPOTHESIS: The aims of this study were to identify associations among MRI findings, timing of imaging, and presenting neurologic deficits in a large series of dogs with a presumptive diagnosis of ischemic myelopathy. ANIMALS AND METHODS: The medical records and MR images of dogs with a presumptive diagnosis of ischemic myelopathy (2000-2006) were reviewed retrospectively. Inclusion criteria were acute onset of nonprogressive and nonpainful myelopathy, 1.5-tesla MRI of the spine performed within 7 days of onset, and complete medical records and follow-up information. Presumptive diagnosis was based on history, as well as clinical, MRI, and cerebrospinal fluid (CSF) findings. The extent of the lesion on MRI was assessed as the following: (1) the ratio between the length of the hyperintense area on sagittal T2-weighted images and the length of C6 or L2 vertebral body, and (2) the maximal cross-sectional area of the hyperintense area on transverse T2-weighted images as a percentage of cross-sectional area of the spinal cord. RESULTS: Fifty-two dogs met the inclusion criteria. MRI findings were abnormal in 41 dogs and normal in 11 dogs. The presence of MRI abnormalities was not significantly associated with the timing of imaging (P = .3) but was associated with ambulatory status on presentation (P = .04). Severity of signs on presentation was associated with extent of the lesion on MRI (P = .02). CONCLUSION AND CLINICAL IMPORTANCE: The severity of signs on presentation is associated with the presence and the extent of the lesion on MRI.     

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.     

High-resolution fluorodeoxyglucose positron emission tomography and magnetic resonance imaging findings of a pituitary microtumor in a dog

A 16-year-old, castrated, male English cocker spaniel dog was presented due to generalized alopecia. Routine clinical pathology, endocrine and abdominal ultrasonography results were consistent with a diagnosis of pituitary-dependent hyperadrenocorticism. The adenohypophyseal lesion was clearly visualized on both 3 T and 7 T magnetic resonance imaging (MRI) of the pituitary gland. Although biochemical and MRI findings were consistent with a functional pituitary microtumor, a pituitary lesion was not detected using ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET). This report firstly describes the application of high-resolution FDG-PET to a spontaneous pituitary microtumor in a dog.     

Unusual vascular ring anomaly associated with a persistent right aortic arch and an aberrant left subclavian artery in German pinschers

The objective of this study was to describe a specific form of persistent right aortic arch (PRAA) in three German pinscher dogs and to analyse the mode of inheritance in the breed. This type of PRAA is characterised by a left retro-oesophageal subclavian artery in combination with a ligamentum arteriosum originating at the aberrant left subclavian artery (PRAA-SA-LA). This rare combination of anomalies has only been reported in two isolated cases in other dog breeds and the occurrence of any form of PRAA was not previously known to occur in the German pinscher. In the present study, 18 cases of this congenital anomaly were ascertained and their high degree of relatedness and inbreeding could be shown through pedigree analysis. Three of the affected dogs underwent further clinical investigations, and post-mortem examination (two cases) and findings at surgery (one case) verified the diagnosis of PRAA-SA-LA. A monogenic autosomal recessive mode of inheritance was not likely.     

Clinical signs, imaging features, neuropathology, and outcome in cats and dogs with central nervous system cryptococcosis from California

Background: Cryptococcus spp. is a fungal pathogen with a predilection for the central nervous system (CNS). Objectives: To compare the clinical, advanced imaging, and neuropathologic findings in dogs and cats with CNS cryptococcosis, and to evaluate outcome of treatment in these animals. Animals: Twenty‐six cats and 21 dogs with CNS cryptococcosis. Methods: Medical records were reviewed for clinical findings and results of CNS imaging. Archived cerebrospinal fluid and CNS tissue specimens were reviewed for pathology. Findings in cats were compared with those in dogs and the effects of variables on survival were determined by survival curve analysis. Results: When present, pain was localized to the cervical region in dogs and was generalized or localized to the thoracolumbar spine or pelvic limbs in cats. Magnetic resonance imaging (MRI) findings were variable but correlated with CNS histopathological findings of meningitis, meningitis with gelatinous pseudocyst formation, and granulomatous mass lesions. Peripherally enhancing brain lesions were seen only in cats. Histopathologically, the inflammatory response was milder in cats compared with dogs. Remissions of ≥1 year occurred in 32% of treated animals. Altered mentation was associated with negative outcome. Glucocorticoid use after diagnosis was associated with improved survival in the first 10 days. Conclusions and Clinical Importance: Lesions seen on MRI reflected neuropathological findings and were similar to those reported in human patients. The immune response to infection may differ between cats and dogs, or relate to the infecting cryptococcal species. Long‐term (>6 month median survival time) survival may be possible in animals surviving ≥4 days after diagnosis.