COMPUTED TOMOGRAPHY BRONCHIAL LUMEN TO PULMONARY ARTERY DIAMETER RATIO IN DOGS WITHOUT CLINICAL PULMONARY DISEASE

Bronchiectasis is diagnosed in humans using multiple computed tomography (CT) criteria, the most important being dilatation of the bronchi. The most widely used criterion for detection of bronchial dilatation is a bronchial lumen to pulmonary artery diameter (bronchoarterial [BA]) ratio >1.0. No studies have been performed to determine the BA ratio in normal dogs. Thoracic CT images of 24 dogs without clinical pulmonary disease were reviewed. The BA ratio of the lobar bronchi of the left cranial (cranial and caudal parts), right cranial, right middle, left caudal, and right caudal lung lobes was measured. The mean of the mean BA ratio for all dogs was 1.45±0.21 (99% confidence interval [CI]=1.34–1.56). The mean of the mean BA ratio as determined by lung lobe was 1.45±0.04 (99% CI=1.41–1.49). The range of individual BA ratios was 0.8–2.0. There was no significant difference in mean BA ratios as a function of lung lobe ( P =0.60). The BA ratio in these clinically normal dogs was consistent and may be a useful tool in evaluating for bronchiectasis on CT images. BA ratios >2.0 were not identified in this population, suggesting a threshold to differentiate normal from abnormal bronchi.     

Blood Flows in Tributaries of the Portal Vein: Anatomical and Angiographic Studies in Normal Beagle Dogs

Liver anatomy, particularly its vascularization, has been investigated in many studies in dogs. Knowledge of blood flow from the main tributaries of the portal vein (PV) is necessary to explain the preferential sites of secondary lesions within the liver based on the site of the initial malignant lesion. How these flows come together was established in an earlier ex vivo study. Here, we highlight in vivo the blood flows from the main PV tributaries and their distribution in the liver of normal dogs. Portographs of the main PV tributaries were obtained in seven dogs after injection of an angiographic contrast medium. After euthanasia, the livers and their portal vascularization (PV and tributaries) were extracted for a comparative corrosion cast study. Flows were demonstrated in the cranial mesenteric vein, caudal mesenteric vein and splenic vein. However, no proper flow could be distinguished for the gastroduodenal and ileocolic veins. All these tributaries primarily supply the lateral liver lobes (right or left). Most of our observations indicate that the cranial mesenteric, caudal mesenteric and splenic veins primarily supply the right lateral lobe and the caudate process of the caudate lobe and secondarily the left lateral lobe, left medial lobe and the quadrate lobe. The two other tributaries (gastroduodenal and ileocolic veins) primarily supply the right lateral lobe and the caudate process of the caudate lobe.     

家禽肝门静脉系统

以铸型方法观察了家禽肝门静脉的分支。其中，鸡有左、右肝门静脉各１支，左叶有左外叶颅侧支、左外叶尾侧支和左内叶支，右叶有右叶颅侧支及右叶尾侧支；鹅、鸭则有左肝门静脉２支，右肝门静脉１支。左叶有左外叶颅侧支和左外叶尾侧支，右叶有右叶颅侧支和尾侧支。左、右肝门静脉于横部汇集，并向颅侧及尾侧发出许多分支。此外，还强调和讨论了家禽肝门静脉系统在分布上的一些特点     

Symptomatic partial anomalous pulmonary venous connection in a kitten

A 3-month-old intact female American Shorthair cat, with syncope and tachypnea, underwent cardiac examination which identified no heart murmur or gallop. Thoracic radiography disclosed mild generalized enlargement of the cardiac silhouette and a bronchial and interstitial pattern throughout the lungs. Echocardiography identified tubular structures near the left atrium. After agitated saline contrast imaging, persistent left cranial vena cava with unroofed coronary sinus was suspected. Computed tomography angiography showed the right cranial, right caudal and left caudal pulmonary veins draining into the coronary sinus and flowing into the right atrium. The left cranial pulmonary vein drained normally into the left atrium. Partial anomalous pulmonary venous connection (PAPVC) was diagnosed. The kitten was treated with diuretics but died of heart failure 2 months later. Permission for necropsy was not granted. This case represents symptomatic PAPVC in a kitten. Most pulmonary veins were connected abnormally with the coronary sinus. The prognosis was grave because of refractory heart failure.     

Descriptive anatomic study of the great vessels of the heart in the capuchin monkey Cebus apella (Linnaeus, 1758)

The aim of this study was to describe the anatomy of the great vessels of the heart in capuchin monkey (Cebus apella) and to compare with those of other primates, including humans. The hearts were prepared through fixation in 10% formalin and subsequently dissected using standard techniques and instruments. The arterial and venous systems were perfused with colored latex solution via the femoral vessels. An ascending cylindrical branch with relatively great caliber was identified in the aorta artery, in addition to an aortic arch, from which three great arteries were originated, the brachiocephalic trunk, the left common carotid artery and the left subclavian artery. After a course of variable extension, the pulmonary trunk divided into right and left pulmonary arteries. The caudal vena cava was morphologically similar to that of humans, except for its association with the cardiac lobe of the right lung, whereas the cranial vena cava was formed by the two braquiocephalic veins and received the azygos vein close to right atrium. The pulmonary veins, in number of six, ended at the posterior face of the left atrium, differently from both humans and other primates. In conclusion, the morphology of the great vessels of the heart in Cebus apella was similar to that of humans and other primates, although some differences are evidenced with regards to topography and number of anatomic structures, particularly the relationship of the caudal vena cava with the cardiac lobe of the right lung and the presence of six pulmonary veins in Cebus apella.     

Gross Anatomy of the Canine Portal Vein

The gross anatomy of the portal vein of 21 dogs was studied by venous portography, corrosion casting, and gross dissection. The portal vein in all specimens originated by confluence of the cranial and caudal mesenteric veins. Its large tributaries were the splenic and gastroduodenal veins, which entered the portal vein between its origin and the hepatic porta. At the hepatic porta, the portal vein divided into a short right branch and a larger left branch. The right branch ramified in the caudate process of the caudate lobe and in the right lateral lobe of the liver. The left branch was essentially the continuation of the portal vein from which successive branches passed to each of the remaining lobes of the liver and the papillary process of the caudate lobe.     

RADIOGRAPHIC CHARACTERIZATION OF PRIMARY LUNG TUMORS IN 74 DOGS

Primary pulmonary neoplasia is well recognized in dogs and prognosis depends upon the tumor type. The purpose of this retrospective study was to characterize the radiographic appearance of different primary lung tumors with the goal of establishing imaging criteria to separate the different types. Three‐view thoracic radiographs of 74 dogs with histologically confirmed pulmonary anaplastic carcinoma (n = 2), adenocarcinoma (n = 31), bronchioalveolar carcinoma (n = 19), histiocytic sarcoma (n = 21), and squamous cell carcinoma (n = 1) were evaluated. Radiographs were assessed for tumor volume, affected lobe, location within lobe, overall pulmonary pattern, presence of cavitation, mineralization, air bronchograms, lymphadenomegaly, and pleural fluid. Histiocytic sarcomas were significantly larger than other tumor types (271 cm³; P = 0.009) and most likely to be found in the left cranial (38%; 8/21) and right middle (43%; 9/21) lung lobes, whereas adenocarcinomas were most likely to be found in the left caudal (29%; 9/31) lung lobe. Fifty‐seven percent (12/21) of histiocytic sarcomas had an internal air bronchogram. Findings indicate that a large mass in the periphery or affecting the whole lobe of the right middle or left cranial lung lobe with an internal air bronchogram is likely to be an histiocytic sarcoma.     

THE CANINE LATERAL THORACIC RADIOGRAPH

Selected structures seen on right and left lateral thoracic radiographs of 12 dogs were evaluated for differences in position, size, and shape. The size and position of the cardiac silhouette were different when thoracic radiographs made in left and right lateral recumbency were compared. These changes were, however, considered insignificant. The position of the right cranial lobe bronchus relative to the left varied in right lateral recumbency and left lateral recumbency. The right cranial lung lobe was better aerated when dogs were positioned in left lateral recumbency.
Lesions seen in the caudal portion of the left cranial lung lobe or the right middle lobe were masked when the affected lobe was dependent, and enhanced when the affected lung lobe was non-dependent. It is believed that this difference occurred due to compression of the dependent lung with greater aeration of the non-dependent lung.     

Study of lobation and vascularization of the lungs of wild boar (Sus scrofa)

The purpose of this study was to describe the anatomy of the lungs of wild boars for comparison with those of domestic swine. It was found that the right lung of the wild boar is divided into four lobes: cranial, median, caudal and accessory, whereas the left lung is divided into two lobes: cranial and caudal. In 93.4% of the cases, right pulmonary artery separates into the ascendant, descendant, median, accessory and caudal branches. In 73.3% of the cases, left pulmonary artery separates most frequently to form three branches to the cranial lobe, whereas the median lobe is generally supplied by only one arterial branch. There is a single pattern of bronchial distribution: in the right lung a tracheal bronchus leads to the cranial lobe, where it separates into the cranial and caudal bronchi and there are also bronchi to the median, caudal and accessory lobes. In the left lung, the large bronchus separates to form two branches, one of which further separates to form two branches to the cranial lobe whereas the other forms a single branch to the caudal lobe.     

Caudal pulmonary artery to vein ratio on radiography can predict pulmonary hypertension in dogs with mitral regurgitation

Pulmonary hypertension (PH) is an important predictor of poor outcomes in dogs with mitral regurgitation (MR). The feasibility of radiography to predict PH in dogs with MR is unknown. This retrospective, observational, and analytic study aimed to identify a radiographic parameter to predict PH in dogs with MR. A total of 302 dogs diagnosed with MR on echocardiography were enrolled. Medical record and radiographic findings such as the size of the main pulmonary artery, left atrium, left ventricle, and right chamber, and cranial and caudal pulmonary arteries and veins were evaluated according to the presence of PH. The diameters of the cranial and caudal pulmonary vessels were compared to the fourth rib and the ninth rib, respectively, and the ratio of the pulmonary artery to the corresponding vein (CdPA/CdPV) was calculated. Pulmonary hypertension was diagnosed in 77 dogs (25.5%) and the prevalence of PH increased with MR grade. The CdPA/CdPV was significantly higher (P < 0.001) in the presence of PH. Multivariate analysis showed that the CdPA/CdPV was the only independent radiographic parameter that had a significant association with PH in dogs with MR (P = 0.028). The cut-off value of the CdPA/CdPV = 1.10 showed 90.6% specificity and 31.1% sensitivity for detecting PH in dogs with MR. In dogs with MR, PH can be predicted with high specificity when the caudal pulmonary artery is 1.1 times larger than the corresponding vein on radiographs.     

A clinical study on velocity patterns of pulmonary venous flow in canine heartworm disease

In this study, we evaluated methods of determining the velocity patterns of pulmonary venous flow (PVF) in dogs and then investigated the relationship of the patterns to cardiac functions in heartworm disease (HD) by transthoracic echocardiography (TTE). The results revealed that there was a good correlation between PVF patterns determined by transesophageal echocardiography (TEE) and TTE in animals lying on their left sides. The measurement of S and D wave velocities (PVS and PVD) by TTE was shown to allow clinical determination of the velocity patterns of PVF in dogs. The HD groups showed significant increases in PVS and PVD, and S and D wave time-velocity integrals (S-TVI and D-TVI) of the right cranial lobe PVF, when compared with the normal group, as determined by TTE (P<0.05). In contrast, the HD groups produced significant decreases in PVD and D-TVI of the right caudal lobe PVF compared with the normal group (P<0.05), and a significant increase in the ratio of S-TVI to (S-TVI + D-TVI) (P<0.05). It is, therefore, suggested that measurement of the velocity patterns of the right cranial and caudal lobe PVF could be one method of assessing the stages of obstructive lesions in the pulmonary artery.     

MEASUREMENTS OF THE PULMONARY VASCULATURE ON THORACIC RADIOGRAPHS IN HEALTHY DOGS COMPARED TO DOGS WITH MITRAL REGURGITATION

This study reassessed the previously reported radiographic method of comparing pulmonary vessels versus rib diameter for differentiating healthy dogs and dogs with mitral regurgitation. The width of the right cranial pulmonary artery and vein at the fourth rib level, right caudal pulmonary artery and vein at the ninth rib level, and the diameters of the fourth rib and ninth rib were measured in prospectively recruited healthy dogs (n = 40) and retrospectively recruited dogs with mitral regurgitation (n = 58). In healthy dogs, the pulmonary arteries and accompanying veins were similar in size. The cranial lobar vessels were smaller than the fourth rib. However, 67.5% of right caudal pulmonary artery diameters and 65% of vein diameters were larger than the ninth rib in healthy dogs. The right caudal pulmonary vein diameter in dogs with mitral regurgitation, particularly those within moderate and severe grades, was significantly larger than that in healthy dogs (P < 0.001). The comparative method used to detect enlargement of the right caudal pulmonary vein relative to the accompanying pulmonary artery had the highest sensitivity (80.2%) and specificity (82.5%) for predicting mitral regurgitation. A cut‐off of 1.22 when applying the ninth rib criterion had better specificity (73%) than the most used value ≤ 1 (89.7% sensitivity and 63.8% specificity), although it has less sensitivity (73%). We recommend using the accompanying pulmonary artery and 1.22 × the diameter of the ninth rib as a radiographic criterion for assessing the size of the right caudal pulmonary vein and differentiating healthy dogs from those with mitral regurgitation.     

Biometrical Studies on the Cornea in Some Domestic Animals

The ringed seal ( Phoca hispida ), as well as other seals, exhibit some unique anatomical properties when compared to their terrestrial counterparts. In the ringed seal, the most conspicuous adaptation is the aortic bulb, a large dilatation of the ascending aorta, which is comparable to that found in other seal species and marine mammals. Coronary arteries are similar to those of terrestrial mammals. The branches of the ascending aorta (brachiocephalic trunk, left common carotid artery and left subclavian artery) are similar to those of higher primates and man. The pulmonary trunk originates from the right ventricle near the ventral midline of the thorax. The peculiarities of the venous system are three pulmonary veins, a pericardial venous plexus, a caval sphincter, a hepatic sinus with paired caudal vena cavae and a large extradural venous system. Generally, three pulmonary veins (right, left, middle) empty into the left atrium. The right and left pulmonary veins drain the cranial and middle lung lobes of their respective lung, while the middle pulmonary vein drains both caudal lung lobes and the accessory lobe. The pericardial venous plexus lies on the pericardial pleura on the auricular (ventral) surface the heart. The azygous vein is formed from the union of right and left azygous veins near the 5th thoracic vertebra. The caval sphincter surrounds the caudal vena cava as it passes through the diaphragm. Caudal to the diaphragm, the vena cava is dilated excessively (the hepatic sinus) and near the kidneys it is biphid. Cardiovascular physiological studies have shown some of these anatomical variations, especially of the venous system and the ascending aorta, to be modifications for diving.     

The Great Vessels and Tributaries of the Heart of the Ringed Seal (Phoca hispida)

The ringed seal (Phoca hispida), as well as other seals, exhibit some unique anatomical properties when compared to their terrestrial counterparts. In the ringed seal, the most conspicuous adaptation is the aortic bulb, a large dilatation of the ascending aorta, which is comparable to that found in other seal species and marine mammals. Coronary arteries are similar to those of terrestrial mammals. The branches of the ascending aorta (brachiocephalic trunk, left common carotid artery and left subclavian artery) are similar to those of higher primates and man. The pulmonary trunk originates from the right ventricle near the ventral midline of the thorax. The peculiarities of the venous system are three pulmonary veins, a pericardial venous plexus, a caval sphincter, a hepatic sinus with paired caudal vena cavae and a large extradural venous system. Generally, three pulmonary veins (right, left, middle) empty into the left atrium. The right and left pulmonary veins drain the cranial and middle lung lobes of their respective lung, while the middle pulmonary vein drains both caudal lung lobes and the accessory lobe. The pericardial venous plexus lies on the pericardial pleura on the auricular (ventral) surface the heart. The azygous vein is formed from the union of right and left azygous veins near the 5th thoracic vertebra. The caval sphincter surrounds the caudal vena cava as it passes through the diaphragm. Caudal to the diaphragm, the vena cava is dilated excessively (the hepatic sinus) and near the kidneys it is biphid. Cardiovascular physiological studies have shown some of these anatomical variations, especially of the venous system and the ascending aorta, to be modifications for diving.     

COMPUTED TOMOGRAPHIC FEATURES OF LUNG LOBE TORSION

The imaging features of lung lobe torsion in 10 dogs (nine complete, one partial torsion) acquired with a helical single‐slice computed tomography (CT) unit are described. Attenuation values of normal, rotated, and adjacent collapsed lung lobes before and after intravenous contrast medium administration were compared. Affected lung lobes were: left cranial (5), right middle (3), right cranial (1), and left caudal (1). CT findings in nine dogs with complete lung lobe torsion included pleural effusion and an abruptly ending bronchus. In eight of these dogs, enlargement, consolidation, emphysema of the affected lung lobe, and mediastinal shift to the contralateral side were present. Rotated lung lobes did not enhance, whereas adjacent collapsed and aerated lung lobes did (P<0.05). Apnea induced with hyperventilation or breath‐hold is essential to reduce motion artefacts and obtain a diagnostic study.     

Congenital cardiac disease in dogs

Thoracic conformation, age, amount of body fat, and stage of respiration and cardiac contraction affect the cardiac silhouette. Deep-chested dogs have an upright, narrow cardiac silhouette about 2 1/2 intercostal spaces wide, while barrel-chested dogs have a round, wide silhouette about 3 1/2 intercostal spaces wide. On LAT films the vessels to a lung lobe should be of equal size and 0.25-1.2 times the diameter of the upper third of the 4th rib at the 4th intercostal space. On DV projections, vessels to the caudal lung lobe should be no larger than the diameter of the 9th rib. Signs of right ventricular enlargement include loss of the cranial waist, increased width of the cardiac silhouette, increased sternal contact of the heart, and an elevated cardiac apex. Signs of left ventricular enlargement include an elevated carina, loss of the caudal waist, and a more perpendicular caudal cardiac border. Signs of left atrial enlargement include separation of mainstem bronchi, compression of the bronchus to the left caudal lung lobe, and an increased distance from the carina to the dorsal border of the caudal vena cava. Enlargement of the aorta and main pulmonary artery segment on a LAT view appears as a soft tissue density obscuring the cranial waist. Pulmonary vascular fields are usually hypervascular in patent ductus arteriosus and interventricular septal defects, normal in uncomplicated aortic or pulmonic stenosis, and hypovascular in tetralogy of Fallot.     

RADIOGRAPHIC EVALUATION OF CANINE HEARTWORM DISEASE COEXISTING WITH RIGHT HEART FAILURE

Thoracic radiographs of 28 dogs with heartworm disease and right heart failure were evaluated subjectively and objectively. Radiographs of all dogs were abnormal. Abnormalities were consistent with those previously reported for heartworm disease but were more severe than those identified in another group of heartworm dogs that did not have right heart failure. The right ventricle and right caudal labor pulmonary artery were enlarged in every dog. The main pulmonary artery, right cranial lobar pulmonary artery, and caudal vena cava were enlarged in 24, 25, and 17 dogs, respectively. Radiographically apparent pathologic pulmonary conditions were present in 25 dogs. Pleural effusion was not identified.     

Macroscopic Anatomy of the Ringed Seal [Pusa (Phoca) hispida] Lower Respiratory System

This investigation serves to document the normal anatomical features of the lower respiratory tract of the ringed seal [Pusa (phoca) hispida]. Evaluation of embalmed specimens and tracheobronchial casts showed that the right lung of this seal consists of four lobes while the left has only three lobes. The ventral margins of the lungs do not reach the sternum causing them to form the boundary of the broad recessus costomediastinalis. Lung lobation corresponds with bronchial tree division. Pulmonary venous drainage includes right and left common veins draining ipsilateral cranial and middle lung lobes, and one common caudal vein draining both caudal lobes and the accessory lobe. The right and left pulmonary arteries divide into cranial and caudal branches at the level of the principal bronchus. The ringed seal has three tracheobronchial lymph nodes. The trachea has an average of 87 cartilages that exhibit a pattern of random anastomoses between adjacent rings. The trachea exhibits to a small degree the dorsoventrally flattened pattern that is described in other pinnipeds. The tracheal diameter is smaller than that of the canine.