Effect of various thoracic radiographic projections on the appearance of selected thoracic viscera

OBJECTIVES: To assess the effect of different radiographic projections on thoracic width, as well as position and visibility of the trachea, principal bronchi, cardiac silhouette, aorta, caudal vena cava (CVC) and oesophagus. METHODS: Right lateral recumbency (RLR), left lateral recumbency (LLR), dorsoventral (DV) and ventrodorsal (VD) thoracic radiographs of 42 dogs were reviewed retrospectively. RESULTS: In 78 per cent of cases the thoracic width was significantly larger on the VD projection than on the DV projection. The angle of divergence formed by the principal bronchi was significantly larger on the VD projection than on the DV projection in 80 per cent of dogs. A cardiac silhouette bulge at 1 to 2 o'clock was apparent on the VD projection in 22 per cent of dogs but was never seen on DV projections. The descending aorta was more visible at the 4 to 5 o'clock cardiac silhouette level on the DV projection and laterally at the T8 level on LLR projections. The CVC was better seen on VD and LLR projections. The oesophagus was visible as a soft tissue opacity in LLR in large dogs with normal thoracic conformation in 35 per cent of cases. CLINICAL SIGNIFICANCE: The DV projection appears to be more reliable for assessing the cardiac silhouette, the descending aorta and the angle of divergence of the principal bronchi. The VD projection should be considered for evaluating the CVC. LLR should be used for assessing the descending aorta and CVC.     

Anatomical variations of the thoracic duct in the dog

Anatomical variations can be frequently found in the lymphatic system, which is also true for the shape and course of the thoracic duct (ductus thoracicus), the biggest lymph vessel in the body. From 2012 to 2019, the thoracic duct was successfully dissected in 43 dog carcasses that were used in the anatomy course at the Faculty of Veterinary Medicine, University of Zagreb. The thoracic duct originated from the cranial border of the cisterna chyli as one lymph vessel in 36 dogs (83.7%), as two vessels in six dogs (14%) and as three vessels in one dog (2.3%). We divided the observed thoracic duct variations into six groups according to their anatomical similarities. Considering the specific embryonic development, we can conclude that all observed variations are the result of minor deviations from the standard ontogenesis. However, the importance of thoracic duct variations is significant in surgical procedures done in the thoracic cavity to prevent or cure the chylothorax. Since this research showed variations in 39 out of 43 dogs (90.7%) throughout the whole course of the thoracic duct, great care must be taken while performing the ligation or embolization of the thoracic duct.     

A stereological analysis on the calculation of the volume values of thoracic segments in ducks

Stereology is a method for examining two-dimensional objects as three-dimensional objects. The aim of this study was to offer volume values for thoracic segments in ducks by means of stereological methods. This study examined the data obtained from stereological analysis of the total volume and grey and white matter volume values of the thoracic segment, a part of the adult duck spinal cord with a weight of 3–4 kg. In the study, study samples consisted of 10 adult ducks (Anas) used without gender discrimination. To perfuse all of the animals, 10% formaldehyde was utilised. The perfused animals were kept in 10% formaldehyde for one week. The spinal cord was uncovered following the removal of arcus vertebrae parts of thoracic vertebrae in the thoracic part of dissected ducks. Tissue samples of thoracic segments were taken; 5-µm-thick cross sections from these tissue samples were taken via microtome. Attention was paid to obtaining samples at the ratio of 1/250 by taking 12 cross sections from each segment. The cross sections were subjected to haematoxylin-eosin staining. Photographs of all cross sections were taken using a microscope. The volume values of all tissue and grey and white matter structures in each thoracic segment of the spinal cord were calculated. The total volume, grey and white matter volume densities in thoracic segments of ducks, as well as the data obtained as a result of proportioning volume values of one another are represented in the conclusion section of this study.     

Cardiac measurements on thoracic radiographs of cats

Measurements of the heart and thorax were made on lateral and ventrodorsal thoracic radiographs of normal cats. The degree of correlation between selected cardiac and thoracic measurements was determined. Absolute measurements and ratios of measurements in normal cats and in cats with certain cardiac diseases were compared and their diagnostic value was evaluated. It was concluded that on the lateral thoracic radiograph the ratio of the cranio-caudal width of the heart to the distance between the cranial border of the fifth rib and the caudal border of the seventh rib was a highly reliable indicator of cardiac enlargement. On the ventro-dorsal radiograph the ratio of the maxium width of heart to the width of the thorax at the same level was the best indicator of increases in cardiac size.     

Cystic cholangioma in the thoracic cavity of a rat

A female congenic rat produced by repeated backcrossing of Nihon rats, a model for hereditary renal cell carcinoma, to Brown Norway rats was necropsied at 24 months of age. At necropsy, a white mass about 1 centimeter in size was observed in the thoracic cavity, and the mass partly adhered to the esophagus and the diaphragm. Histologically, the mass was clearly circumscribed by connective tissue, and consisted of neoplastic cuboidal epithelial cells that showed cystic tubular proliferation. Some islands of well-differentiated hepatocytes and some vessels were observed in the mass. Immunohistochemically, the tumor cells were strongly positive for cytokeratin and partly positive for vimentin but were negative for mesothelin and Von Willebrand Factor. The positive rate for Ki-67 was 2.4%. Based on these histological and immunohistochemical evidences, we diagnosed this tumor as a cystic cholangioma that might have arisen from the ectopic hepatic tissue in the thoracic cavity.     

Abdominal and thoracic radiography in the neonate.

Plain and contrast radiographic techniques are used infrequently in the diagnostic evaluation of abdominal or thoracic disease in the adult horse because of the animal's large body size and the limited availability and expense of suitable equipment. The importance of radiography as a critical tool has also been lessened through the accessibility of ultrasound, although this technique is limited by depth and offers only a superficial window. Traditional radiographic techniques can be readily used in young foals because of their small body size, and radiography frequently provides critical information that aids in decision making. The ability to physically restrain a foal allows not only standing lateral images, but laterally recumbent and ventrodorsal views without the necessity for general anesthesia.     

Effect of an isoxsuprine-resin preparation on blood flow in the equine thoracic limb.

The effects of an oral isoxsuprine-resin preparation on the blood flow in the thoracic limb of seven horses was determined by thermography. Treatment with the oral resin preparation resulted in increased skin temperatures compared with the non-medicated controls. The maximal temperature differences, 2.2 degrees C for the horses treated with 0.9 mg/kg and 1.8 degrees C for the horses treated with 1.2 mg/kg, occurred four hours after dosing. Plasma total isoxsuprine, determined in three horses, was detectable two hours after oral dosing and maximal eight hours after dosing, but free isoxsuprine could not be detected. Receptor binding studies demonstrated strong alpha-receptor binding, and this binding was so strong that even at isoxsuprine concentrations below the detection level receptors could have been stimulated.     

Clinicopathological features of lymphosarcoma involving the thoracic cavity in the horse

The clinical and post mortem features of 11 cases of lymphosarcoma involving the thoracic cavity are reviewed. The clinical findings included inappetence, weight loss, pectoral oedema, dyspnoea, pleural effusion and distension of the jugular veins. Dysphagia was present in three cases. At post mortem examination lesions were found in the abdomen as well as the chest in eight cases; clinical signs of abdominal disease were present in two cases. The features of nine other similar cases recorded in the literature are reviewed.     

Clinical considerations of the thoracic limb.

The avian skeleton is significantly different from the mammalian skeleton, and these differences are important when providing fracture repair and postoperative care for the avian patient. Successful repair depends on an understanding of fracture management and healing and of the anatomical, physiologic, and behavioral concerns of avian patients. Having knowledge of fracture repair without an understanding of the unique needs of avian patients' results in a disappointing treatment response.     

Comparison of examination of thoracic radiographs and thoracic computed tomography in dogs with appendicular osteosarcoma

Appendicular osteosarcoma (OSA) is a highly metastatic tumour in dogs. The aim of the study was to compare thoracic radiographs with thoracic computed tomography (CT) in the staging of canine appendicular OSA. In all, 39 canine patients histologically diagnosed with OSA were reviewed in the retrospective study. All dogs underwent radiographic examination as well as CT examination of the thoracic cavity. Pulmonary nodules were detected radiographically in two cases (5%), whereas the CT imaging showed that pulmonary nodules were evident in 11 cases (28%, P = 0.024). There was an improved detection of small pulmonary nodules in the lung parenchyma with CT (P = 0.021). The number of nodules in CT examination had a significant negative influence on survival time (P = 0.005). However, whether nodules were present in CT or not did not influence overall survival (P = 0.368). CT examination was superior to thoracic radiography in the screening and detection of pulmonary nodules in dogs with OSA.     

Thoracoscopic visualization and ligation of the thoracic duct in dogs

OBJECTIVE: To develop a technique for thoracoscopic visualization and ligation of the thoracic duct in dogs. STUDY DESIGN: In vivo experimental study. ANIMALS: Five mature, healthy dogs. METHODS: Dogs were normal based on physical examination, negative occult heartworm test, normal complete blood count and biochemical profile, and normal thoracic radiographs. The dogs were anesthetized, and a ventral midline laparotomy was performed for catheterization of a mesenteric lymphatic. Lymphangiography was performed to determine thoracic duct anatomy. Thoracoscopy was performed in the caudal, right hemithorax after single lung intubation or bronchial blockade. At least two 10-mm clips were placed across the thoracic duct in each dog. Lymphangiography was repeated to assess duct ligation. If complete duct occlusion was not achieved, thoracoscopy was repeated for additional clip placement. After surgery the dogs were euthanatized, and necropsies were performed. RESULTS: Lymphangiography showed that multiple branches of the thoracic duct were present in every dog; bilateral thoracic duct branches were most common. Thoracoscopic identification and ligation of the thoracic duct was successful in all five dogs. Two dogs required a second thoracoscopic procedure to completely occlude flow of contrast through the thoracic duct. Surgery time for thoracoscopy averaged 59 plus minus 9.6 minutes. Retroperitoneal contrast accumulation after thoracic duct ligation occurred in two dogs. One dog required bilateral pulmonary ventilation. CONCLUSION: Thoracoscopy can be used to visualize the thoracic duct for ligation in normal dogs. CLINICAL RELEVANCE: Thoracoscopic ligation of the thoracic duct may be a therapeutic option for management of chylothorax in dogs.     

Intramedullary epidermoid cyst in the thoracic spine of a dog

A 5 yr old female spayed mastiff was evaluated for a 3-4 mo history of paraparesis and 3 days of acutely worse paraparesis and incontinence. On magnetic resonance imaging, a spinal cord lesion was present at the ninth thoracic vertebra. The lesion was hyperintense on T2-weighted images (T2-W), and a hyperintense rim was present on T1-weighted postcontrast images. Histologic examination showed a cystic mass lined by squamous epithelial cells. Histopathologic diagnosis was an intramedullary epidermoid spinal cyst. Epidermoid cyst should be a differential diagnosis in young dogs with a myelopathy and an intramedullary spinal cord lesion on magnetic resonance imaging examination.     

Postprandial arterial vasodilation in the equine distal thoracic limb

The effects of feeding on blood flow to the equine foot are poorly understood. In a temperature-controlled room, duplex Doppler ultrasonographic observations were made pre- and postprandially of the lateral proper palmar digital artery of 5 horses, randomly assigned to twice and 4 times daily feeding in an unbalanced 2 period crossover design. Arterial diameter and blood velocity were measured over 4 h and additional observations made of heart rate, blood pressure, total plasma protein, packed cell volume, plasma glucose and insulin. There was no effect of the feeding regimen on any variable. Postprandially, there were significant increases in arterial diameter, blood velocity, total plasma protein, plasma glucose and insulin; the other variables were unchanged. It appeared that the normal postprandial response was an increase in blood flow to the foot. The value of ultrasonography for noninvasive investigation of the peripheral vasculature of the conscious horse was established; and in the future it may have a role in the diagnosis of vascular diseases of the foot.     

Veins of the thoracic limb of the Van cat

The drainage of the thoracic limb of the Van cat was performed by the superficial and deep vein systems. The superficial system was constituted by the cephalic vein and its branches. The deep vein system was constituted by the axillary vein and its branches. The two vein systems anastomosed with each other at various points along their courses. The cephalic vein emerged from the external jugular vein together with the superficial cervical vein. The axillary vein continued the subclavian vein. It ran caudoventrally and gave off the subscapular vein, at the level of the shoulder joint, then gave off two independent branches, which were the external thoracic veins. Then the rest of the vessel continued as the brachial vein. The thoracodorsal vein was formed by the communicate ramus vein which arose between the subscapular vein and the brachial vein. The cranial circumflex humeral vein arose double from the subscapular vein. One of them anastomosed with the deep brachial vein and the other one drained the biceps and the deep pectoral muscles. The cranial interosseous vein from the caudal aspects of the brachial vein and passed the interosseous space of the antebrachium then ran to the lateral aspect of the forearm. The caudal interosseous vein arose from the ulnar vein (in two specimens) and the median vein together with the ulnar vein (in two specimens) or independently from the median vein (in one specimen). Although many similarities were found in the veins of the thoracic limb of the Van cat as compared with the domestic cat, some significant differences were noted in the origin, course, anastomosing and ramification of veins of the thoracic limb.