EFFECT OF BOLUS SIZE ON DEGLUTITION AND ESOPHAGEAL TRANSIT IN HEALTHY DOGS

Contrast videofluoroscopy is the gold standard procedure for evaluating dysphagia in humans, but quantitative measures vary depending on bolus size and consistency. We hypothesized that quantitative measures made during videofluoroscopy of swallowing in dogs would differ between bolus sizes and consistencies. Ten healthy adult dogs were enrolled a prospective, crossover experimental study and underwent contrast videofluoroscopy while swallowing liquid (5, 10, and 15 ml) and canned food (3, 8, and 12 g) boluses. Maximum pharyngeal contraction occurred significantly later with medium solid boluses than with medium liquid boluses, with a mean difference of 0.021 s (adjusted P = 0.042). Upper esophageal sphincter opening occurred significantly earlier with large solid boluses than with medium solid boluses, with a mean difference of 0.018 s (adjusted P = 0.025). Thoracic esophageal transit time was significantly longer with small solid boluses than with small liquid boluses, with a mean difference of 0.68 s (adjusted P = 0.004). Odds of primary esophageal peristalsis occurring were significantly (18.5 times) higher with large solid vs. large liquid boluses (adjusted P = 0.031). No other statistical comparisons reached significance. Based on these results, we recommend a standardized approach to videofluoscopy in dogs with determination of quantitative measures using medium liquid and soft food boluses to minimize effects of size. Furthermore, we conclude that measurements made on liquid swallows should not be directly compared to measurements made on soft food boluses.     

RADIOGRAPHIC ASPECTS OF GASTRIC ULCERS IN DOGS

This paper is a retrospective analysis of the radiographic appearance of one benign and four malignant gastric ulcers in dogs. The benign gastric was diagnosed radiographically following gastric surgery and was healed at necropsy 28 months after diagnosis. Malignant gastric ulcers were confirmed at surgery and/or necropsy. None of the five ulcers penetrated the normally expected gastric contour. Mucosal fold pattern was either partially or completely effaced with all five ulcers. Undermining appeared to be present asymmetrically in the benign and one malignant ulcer, and symmetrically in one malignant ulcer. Tissue surrounding the ulcers joined the normal gastric wall very abruptly in three malignant ulcers. This transition was more gradual in the benign ulcer and was not identified in one malignant ulcer. None of these ulcers completely fit the criteria used in people to diagnose benign gastric ulcer. Prospective evaluation of more cases with a more thorough radiographic technique is needed     

THE EFFECT OF OBLIQUITY ON THE RADIOGRAPHIC APPEARANCE OF THE TEMPOROMANDIBULAR JOINT IN DOGS

The temporomandibular joint is formed between the condyloid process of the mandible and the mandibular fossa of the temporal bone. The basic anatomy of this joint was assessed and described in a series of skulls including dolichocephalic, mesaticephalic and brachycephalic breeds. The facial index and rotational angles were measured with the facial index providing a useful method of classifying skull types but the rotational angle being of limited use in assessment of the temporomandibular joint until normal breed values are established. Equipment was designed to allow repeatable positioning of the temporomandibular joint for radiography at a variety of lateral and long axis rotational angles relative to the central x-ray beam. The regions of the joint and anatomic features visualized in each view are demonstrated. 10 degrees rotation was required in either axis to project the joints independently of each other. Lateral rotational angles of 10 to 30 degrees in mesaticephalic and dolichocephalic breeds and 20 to 30 degrees in brachycephalics and long axis rotational views of 10 to 30 degrees depending on the region of interest were considered to be the most useful.     

COMPARATIVE PERFORMANCE OF RADIOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF MIDDLE EAR DISEASE IN 31 DOGS

The purpose of this study was to compare computed tomography (CT) and radiography for diagnosing the presence and severity of middle ear disease in dogs with a history of chronic otitis externa. Thirty-one dogs undergoing a total ear canal ablation and bulla osteotomy were studied. Three normal dogs served as controls. All dogs were examined using radiography and CT. Three radiologists independently evaluated imaging studies in random order. A visual analog scale method was used for scoring certainty and severity of middle ear disease. Surgical findings were recorded intra-operatively. Bulla lining samples were submitted for histopathologic evaluation and scored by a single pathologist who also used a visual analog scale system. Findings from both imaging modalities agreed more closely with surgical findings than with histopathologic findings. With either surgical or histopathologic findings as the gold standard, CT was more sensitive than and as specific as radiographs for predicting presence and severity of middle ear disease. Observer performance with CT was more consistent than the performance with radiographs in the detection of changes that occur with middle ear disease. Both radiography and CT were more accurate for predicting the severity of the disease than its presence. Findings indicate that CT is more accurate and reliable than radiography in diagnosing middle ear disease for dogs having concurrent otitis externa, but only when severity of disease is moderate or high. With low severity of disease, diagnostic certainty for both modalities becomes more variable.     

CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE PANCREAS IN HEALTHY DOGS AND IN DOGS WITH ACUTE PANCREATITIS

Pancreatitis is the most frequent disease affecting the exocrine pancreas in dogs and reliable diagnostic techniques for predicting fatal complications are lacking. Contrast‐enhanced ultrasound (CEUS) improves detection of tissue perfusion as well as organ lesion vascular pattern. Objectives of this prospective case control study were to compare perfusion characteristics and enhancement patterns of the pancreas in healthy dogs and dogs with pancreatitis using CEUS. Ten healthy dogs and eight dogs with pancreatitis were selected based on physical examination, abdominal ultrasound, and blood analysis findings. A CEUS study of the pancreas was performed for each dog and two observers who were aware of clinical status used advanced ultrasound quantification software to analyze time‐intensity curves. Perfusion patterns were compared between healthy and affected dogs. In dogs with acute pancreatitis, mean pixel and peak intensity of the pancreatic parenchyma was significantly higher than that of normal dogs (P = 0.05) in between 6 and 60 s (P = <0.0001–0.046). This corresponds to a 311% increase in mean pixel intensity in dogs with acute pancreatitis compared to healthy dogs. Wash‐in rates were greater and had a consistently steeper slope to peak in dogs with pancreatitis as opposed to healthy dogs. All dogs with pancreatitis showed a decrease in pixel intensity 10–15 days after the initial examination (P = 0.011) and their times to peak values were prolonged compared to the initial exam. Findings from the current study supported the use of CEUS for diagnosing pancreatitis, pancreatic necrosis, and disease monitoring following therapy in dogs.     

IMAGING ASSESSMENT OF THE MODIFIED DOUBLE CONTRAST BARIUM ENEMA USING CARBOXYMETHYLCELLULOSE ON RADIOGRAPHY AND ULTRASONOGRAPHY IN DOGS

A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.     

COMPARISON OF THE EFFECT OF LAPAROSCOPIC AND CONVENTIONAL PYLORIC SURGERY ON GASTRIC EMPTYING IN DOGS

The effect of a laparoscopic approach and pyloric surgery on canine gastrointestinal activity, particularly gastric emptying time, is not well understood. The purpose of this study was to compare the effect of laparoscopic and conventional pyloric surgery, in Ramstedt pyloromyotomy and Heineke-Mikulicz pyloroplasty, on complete gastric emptying time in 20 clinically normal dogs. Dogs were divided into four groups of five animals: dogs with laparoscopic Ramstedt pyloromyotomy, conventional Ramstedt pyloromyotomy, or laparoscopic Heineke-Mikulicz pyloroplasty, and the conventional Heineke-Mikulicz pyloroplasty group. Gastric emptying time using barium sulfate mixed with dry kibble dog food was measured fluoroscopically before and 1 month after surgery. Gastric emptying of solids was significantly enhanced in the pyloroplasty groups in the postoperative period compared with preoperative emptying. Just as after conventional pyloromyotomy, gastric emptying time after laparoscopic pyloromyotomy was not statistically different as compared with preoperative values. This study indicates that the fluoroscopic test meal is a valuable tool for defining complete gastric emptying time in normal dogs. We conclude that pyloromyotomy was less effective in decreasing complete gastric emptying time than Heineke-Mikulicz pyloroplasty in normal dogs. The possibility of decreasing complete gastric emptying time by laparoscopic surgery suggests a potential clinical application for this technique in small animals.     

RADIOGRAPHIC FINDINGS IN THE THORAX OF DOGS WITH LEPTOSPIRAL INFECTION

Thoracic radiographs of 4 dogs with confirmed and 1 dog with suspected leptospirosis were reviewed. In all dogs a reticulonodular pulmonary opacity was noted, affecting the entire lung in 3 and predominantly the caudodorsal lung field in 2 dogs. The radiographic lung pattern described is associated with pulmonary hemorrhage probably due to endothelial damage and vasculitis. Pulmonary manifestations in dogs with leptospirosis may be misinterpreted and attributed to neoplasia, pneumonia, edema, hemorrhage due to disseminated intravascular coagulopathy, adult respiratory distress syndrome and pulmonary thromboembolism.     

ULTRASONOGRAPHY OF GASTRIC ULCERATION IN THE DOG

The clinical, ultrasonographic and, when available, histopathologic findings of gastric ulceration in 7 dogs were reviewed. The most common clinical signs were vomiting, hematemesis, melena, weight loss and anemia. Ultrasonographic features of gastric ulcer included local thickening of the gastric wall, possible loss of the 5-layer structure, the presence of a wall defect or "crater", fluid accumulation in the stomach and diminished gastric motility.The localized gastric thickening varied from 9 to 16 mm. The ulcer crater was often located in the center of the thickened site and appeared as a mucosal defect associated with persistent accumulation of small echoes, most likely representing microbubbles. In this preliminary study, there was no definitive ultrasonographic distinction between benign and malignant ulcers.     

THE EFFECT OF DORSAL VERSUS VENTRAL RECUMBENCY ON THE RADIOGRAPHIC APPEARANCE OF THE CANINE THORAX

The thorax of nine dogs was radiographed with a vertical beam in both dorsal (VD) and ventral (DV) recumbency. The radiographs were evaluated subjectively and objectively for differences in appearance. To help explain appearance differences, lateral thoracic radiographs were made with the dogs in dorsal and ventral recumbency using a horizontally (laterally) directed x-ray beam. The appearance of thoracic viscera in VD and DV vertical beam radiographs differed. In VD vertical beam radiographs the craniocaudal axis of the heart appeared longer, the heart had a more consistent positional relationship to the thoracic spine, a larger area of the accessory lung lobe was visible, and a greater length of the caudal vena cava was visible. In DV radiographs the caudal lobar pulmonary arteries were more easily identified. The selection of dorsal versus ventral recumbency for thoracic radiography should be based on the clinical status of the patient and the reason(s) for which the radiograph is being made.     

THE USE OF A BARIUM MEAL TO EVALUATE TOTAL GASTRIC EMPTYING TIME IN THE DOG

Total gastric emptying time was determined in nine mongrel dogs using a barium meal contrast procedure. Within the group, total gastric emptying time ranged from 7.0–15.0 hours. Comparison of the population mean showed a statistical difference (p − 0.01) from previously published values. Individual dogs showed consistent total gastric emptying time over three trials. The technique can be used to test the effect of a procedure on total gastric emptying time when a normal value has been established for the dog. Due to the wide range of normal values observed, evaluation of clinical patients could be difficult unless there is a gross abnormality in function.     

VACUUM PHENOMENON IN TWELVE DOGS

The clinical and imaging features of twelve dogs with vacuum phenomena are reviewed. Gas accumulations were identified as radiolucent areas within the intervertebral discs of the cervical, thoracic, and lumber spine, the joint spaces in the sternum, and the shoulder joint. The intervertebral and sternal gas accumulations were associated with other radiographic features of degeneration such as endplate sclerosis and spondylosis. Gas attributable to vacuum phenomenon has not been previously described in the sternum of animals. Abnormal radiographic positioning stresses or instability were through to be responsible for the focal gas accumulations.     

EFFECT OF SEDATION ON CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE SPLEEN IN HEALTHY DOGS

Contrast‐enhanced ultrasound of the spleen enables the dynamic assessment of the perfusion of this organ, however, both subjective and quantitative evaluation can be strongly influenced by sedative agent administration. The purpose of this prospective, experimental study was to test effects of two sedative agents on splenic perfusion during contrast‐enhanced ultrasound of the spleen in a sample of healthy dogs. Contrast‐enhanced ultrasound of the spleen was repeated in six healthy Beagles following a cross‐over study design comparing three protocols: awake, butorphanol 0.2 mg/Kg intramuscular (IM), and dexmedetomidine 500 μg/m² IM. After intravenous injection of a phospholipid stabilized sulfur hexafluoride microbubble solution (SonoVue®, Bracco Imaging, Milano, Italy), the enhancement intensity and perfusion pattern of the splenic parenchyma were assessed and perfusion parameters were calculated. Normal spleen was slightly heterogeneous in the early phase, but the parenchyma was homogeneous at a later phase. Sedation with butorphanol did not modify perfusion of the spleen. Dexmedetomidine significantly reduced splenic enhancement, providing diffuse parenchymal hypoechogenicity during the entire examination. Measured parameters were significantly modified, with increased arrival time (AT; (< 0.0001) and time to peak (TTP; P < 0.0001), and decreased peak intensity (PI; P = 0.0108), wash‐in (P = 0.0014), and area under the curve (AUC; P = 0.0421). Findings supported the use of butorphanol and contraindicated the use of dexmedetomidine as sedatives for splenic contrast ultrasound procedures in dogs. Short‐term and diffuse heterogeneity of the spleen in the early venous phase was determined to be a normal finding.     

GASTRIC EMPTYING OF SOLID RADIOPAQUE MARKERS IN HEALTHY DOGS

The gastric emptying of 1.5 mm diameter (small) and 5.0 mm diameter (large) radiopaque markers (BIPS) was assessed in 20 dogs. The markers were fed to the dogs in a test meal and abdominal radiographs were made hourly thereafter. Studies were repeated three times in each dog. The variation between two veterinarians interpreting the radiographs was low. The sex, age and day of the study did not have a significant effect on the lag phase or the time taken to empty 25%, 50% and 75% of the markers (T₂₅, T₅₀ and T₇₅ respectively). There was a weak but significant positive correlation between the body weight and T₅₀. There was no significant difference in gastric emptying parameters between the large and small markers.
The mean gastric emptying versus time curve of the small markers on day one was chosen to represent the reference curve for healthy dogs. The lag phase of the small markers on day one was 2.45 ± 2.04 hours, the T₂₅ was 4.85 ± 2.15 hours, the T₅₀ was 6.05 ± 2.99 hours and the T₇₅ was 8.32 ± 2.72 hours (mean ± SD).     

CONTRAST RHINOGRAPHY IN THE RADIOGRAPHIC EVALUATION OF DISEASES AFFECTING THE NASAL CAVITY, NASOPHARYNX, AND PARANASAL SINUSES IN THE DOG

Positive-contrast rhinography is a simple noninvasive procedure that can be used for radiographic evaluation of the nasal cavity, nasopharynx, and paranasal sinuses in the dog. After assuring the safety of the procedure, it was employed for evaluation of six dogs with nasal and paranasal disease. Contrast rhinography contributed to the identification and assessment of the disease and aided in the diagnosis in dogs where survey radiography was not helpful. This paper proposes the use of positive-contrast rhinography for radiographic evaluation of diseases affecting the nasal cavity, nasopharynx, and paranasal sinuses in the dog.     

RADIOGRAPHIC FEATURES OF AORTIC BULB/VALVE MINERALIZATION IN 20 DOGS

The radiographic features of aortic bulb/valve mineralization in 20 dogs were reviewed. Extent, shape, number, and location of mineralization were recorded. Five of the dogs had additional alternate imaging examinations, including bone scintigraphy, echocardiography, and thoracic computed tomography. A necropsy was done on one dog, and the area of mineralization was evaluated using routine histology. The median age was 10 (mean 9.7; SD +/- 2.7) years. There were five males, seven neutered males, one female, and seven neutered females. The breeds were: Irish setter (6); rottweiler (7); chow-chow (1); miniature dachshund (1); borzoi (1); English setter (1); English springer spaniel (1); great Dane (1); and greyhound (1). Dogs with both right and left lateral radiographs (n = 17) had mineralization visible on both views, more conspicuously on the right lateral radiograph (n = 12). Aortic bulb mineralization was identified on the ventrodorsal radiograph of only one dog. On lateral radiographs, the aortic bulb mineralization was localized within the 4th intercostal space and in the craniodorsal quadrant of the cardiac silhouette. In nine of the dogs, there were complex or multiple mineralizations and in 11 dogs, there was a single curvilinear mineral opacity oriented in a caudoventral to craniodorsal direction. In all radiographs, the mineralization was in the expected position of the aortic bulb, and echocardiography (n = 4), spiral computed tomography (n = 2), and necropsy (n = 1) confirmed that the mineralization was within the aortic bulb. Clinical pathologic data of the dogs suggested no reason for metastatic mineralization. Exact etiopathogenesis of the lesions were not determined in this study. Based on the histologic findings in one dog, the mineralization seen in the aortic root is similar to a form of dystrophic mineralization called Monckeberg's calcific arteriosclerosis in humans. No clinical signs attributable to the mineralization were observed.     

ULTRASONOGRAPHIC CHARACTERISTICS OF THE ABDOMINAL ESOPHAGUS AND CARDIA IN DOGS

Differential diagnoses for regurgitation and vomiting in dogs include diseases of the gastroesophageal junction. The purpose of this cross‐sectional study was to describe ultrasonographic characteristics of the abdominal esophagus and gastric cardia in normal dogs and dogs with clinical disease involving this region. A total of 126 dogs with no clinical signs of gastrointestinal disease and six dogs with clinical diseases involving the gastroesophageal junction were included. For seven euthanized dogs, ultrasonographic features were also compared with gross pathology and histopathology. Cardial and abdominal esophageal wall thicknesses were measured ultrasonographically for all normal dogs and effects of weight, sex, age, and stomach filling were tested. Five layers could be identified in normal esophageal and cardial walls. The inner esophageal layer was echogenic, corresponding to the cornified mucosa and glandular portion of the submucosa. The cardia was characterized by a thick muscularis, and a transitional zone between echogenic esophageal and hypoechoic gastric mucosal layers. Mean (±SD) cardial wall thicknesses for normal dogs were 7.6 mm (±1.6), 9.7 mm (±1.8), 10.8 mm (±1.6), 13.3 mm (±2.5) for dogs in the <10 kg, 10–19.9 kg, 20–29.9 kg and ≥30 kg weight groups, respectively. Mean (±SD) esophageal wall thicknesses were: 4.1 mm (±0.6), 5.1 mm (±1.3), 5.6 mm (±1), and 6.4 mm (±1.1) for the same weight groups, respectively. Measurements of wall thickness were significantly correlated with dog weight group. Ultrasonography assisted diagnosis in all six clinically affected dogs. Findings supported the use of transabdominal ultrasonography as a diagnostic test for dogs with suspected gastroesophageal disease.     

静松灵对犬胃蠕动影响的研究

通过外科手术的方法将Ag-AgCl乏极化电极固定在犬胃的贲门、幽门和胃底的浆膜上，导线从颈部皮下穿出。用生理多导仪记录正常犬胃肌电活动，静脉注射不同剂量静松灵对犬胃肌电波频率和振幅的影响，以及静在0.5mg/kgBW的静松灵、咪唑克生、哌唑嗪时犬胃肌电的变化，得出以下实验结果：⑴静松灵对犬胃蠕动的作用是以α2肾上腺素能受体激动剂作用为主，兼有α1肾上腺素能受体受体的作用；⑵α1肾上腺素受体在犬胃的分布在贲门和幽门（多于胃底）部；⑶静松灵对犬胃肌电频率和振幅的影响有剂量相关性；⑷静脉注射静松灵引起犬胃肌电波频率和振幅变化的最小剂量是0.05mg/kgBW；⑸0.015mg/kgBW，0.25mg/kgBW,0.50mg/kgBW，和1.0mg/kgBW的静松灵均可引起犬出现不同程度的呕吐；当犬苏醒时，犬胃肌电波振幅的恢复比频率的恢复慢；⑹单独静注0.5mg/kgBW的哌唑嗪或0.5mg/kgBW的咪唑克生时，可以改变犬胃肌电波的振幅，但不改变犬胃的肌电波频率或肌电波波型。用离体器官测定仪记录0.25mg(25ml）的静松灵、咪唑克生或哌唑嗪对犬贲门、幽门、胃底肌条收缩的反应，得到以下结果：⑴静松灵抑制犬胃肌条收缩的作用主要是通过胃肌层中α2肾上腺素受体介导的；⑵贲门和幽门括约肌中有一定数量的α1肾上腺素受体存在，胃底肌层中α1肾上腺素受体能受体的分布很少。     

THORACIC RADIOGRAPHIC FEATURES OF ANTICOAGULANT RODENTICIDE TOXICITY IN FOURTEEN DOGS

Thoracic radiographs and clinical records from 14 dogs with confirmed anticoagulant rodenticide toxicity were reviewed. Twelve of the 14 dogs were presented with a chief complaint of respiratory distress, and 12 had elevated prothrombin and activated partial thromboplastin times consistent with a coagulopathy secondary to a clotting factor deficiency. Thoracic radiographs of the 14 dogs were reviewed and abnomalities included increased mediastinal soft tissue opacity with extra and intrathoracic tracheal narrowing (4/14), increased mediastinal soft tissue opacity without tracheal narrowing (8/14), variable degrees of pleural effusion (13/14) and generalized, patchy interstitial/alveolar pulmonary infiltrates (8/14). Radiographic evidence of cardiomegaly and pulmonary artery abnormalities consistent with concurrent heartworm infestation were detected in one dog. In four dogs, dramatic tracheal narrowing was identified on the lateral thoracic radiograph caused by either mediastinal hemorrhage compressing the trachea or submucosal hemorrhage within the tracheal lumen. The trachea was displaced in a ventral direction in two dogs, and extra and intrathoracic luminal diameter narrowing was evident cranially in all four dogs. Two of these four dogs had soft tissue opacity within the dorsal trachea that extended from the larynx to the intrathoracic trachea. Twelve of the 14 dogs survived with standard treatment protocols utilizing injectable and oral vitamin K₁. One dog died from pancreatitis and disseminated intravascular coagulopathy. The other dog died soon after presentation due to severe, disseminated hemorrhage. Follow-up thoracic radiographs were made in four dogs that survived and showed resolution of the mediastinal, pleural and pulmonary changes within one to five days after the initiation of vitamin K₁ therapy.     

THE EFFECT OF XYLAZINE HYDROCHLORIDE ON THE RADIOGRAPHIC APPEARANCE OF THE STOMACH AND INTESTINE IN THE DOG

Twelve dogs of various breeds, age and weight were injected with xylazine hydrochloride by intravenous and intramuscular routes at various doses. Radiographs of the abdomen were made prior to and at 30, 60 and 90 minutes after injection. The drug produced dilatation of the stomach and the intestines. Radiographic changes were consistent with gastric dilatation and paralytic ileus