DOUBLE CONTRAST GASTROGRAPHY IN THE NORMAL DOG

Double contrast gastrography affords more accurate detection of gastric lesions because it allows direct evaluation of mucosal pattern contours. The technic involves the induction of gastric hypomotility with intravenous glucagon, gastric intubation for the introduction of air and high-density barium directly into the stomach, and positional manipulation for maximal air-barium interface demonstration. Some dogs require sedation. Although fluoroscopic observation is an asset in isolating gastric anatomic abnormalities, this study may be performed using conventional radiographic equipment without fluoroscopic guidance. Double contrast gastrography is used to demonstrate the stomach mucosal surface by coating it with high-density barium and having the mucosa contrast with the air-filled gastric lumen. There are three elements to each double contrast image: the dependent surface, the nondependent surface, and the barium pool. The barium pool is manipulated to coat the mucosal surface and fill depressions of the dependent surface. Protrusions of the dependent surface appear as radiolucencies in the barium pool. Depressions and protrusions of the nondependent surface are outlined by barium. Double contrast gastrography is indicated in dogs where clinical signs suggest anatomic changes in the gastric mucosal surface, e.g., neoplasms, ulcers, or polyps. Concurrent gastrointestinal motility evaluation is precluded by sedation and the glucagon-induced gastric hypomotility.     

Upper gastrointestinal examinations: a radiographic study of clinically normal beagle puppies

A total of 24 upper gastrointestinal examinations were performed on four weanling beagle puppies over six weeks, using liquid barium (10 ml/kg bodyweight of 60 per cent w/v barium sulphate suspension] and barium food (8 g/kg of crushed kibble dog food and 7 ml/kg bodyweight of 60 per cent w/v barium sulphate suspension) as contrast media. The radiographic appearance was similar to that noted in adult dogs except for the consistent location of the pylorus on or near the midline. Duodenal pseudoulcers were seen more often with liquid barium and the caecal shadows were identified more often with the longer examination time with barium food. The stomach of the puppies appeared to have discriminatory emptying function; that is, semi-solid food was emptied from the stomach at a slower rate (210 to 450 minutes) than liquid (60 to 90 minutes). Solid meals emptied faster in puppies than in adult dogs. Dosages of 13 to 15 mg/kg bodyweight for the liquid barium examination and 14 g of ground kibble and 16 ml of barium sulphate suspension per m² of body surface area for the barium food examination are suggested as more appropriate for contrast studies in puppies.     

GASTRIC LYMPHOSARCOMA IN A DOG: A CASE REPORT

A 9-year-old female spayed mixed-breed dog was presented with a ten-week history of vomiting. A survey abdominal radiograph showed a soft tissue mass on the lesser curvature of the stomach and an adjacent thickened greater curvature. A barium contrast study confirmed the presence of this mass. The radiographic diagnosis was gastric tumor. Radiographic signs of gastric neoplasia include soft tissue masses or thickening of the stomach wall, delayed gastric emptying, immobility of portions of the stomach wall, and residual stomach-wall staining by barium. Necropsy revealed a gastric lymphosarcoma that had infiltrated the entire circumference of the pyloric antrum. The most common gastric malignancy in the dog is adenocarcinoma. Gastric lymphosarcoma is considered rare.     

BARIUM SULFATE BRONCHOGRAPHY IN HORSES

Barium sulfate bronchograms were performed on four 454-kg (1000-lb), adult, mixedbreed horses. Approximately 100 ml of 100% w/v premixed barium sulfate suspension was insufflated into a caudodorsal portion of one lung. Excellent bronchograms were obtained through six generations of bronchial divisions. Bronchograms of diagnostic quality were present for at least 30 minutes. Radiographs at 24 hours showed that most of the barium had been removed from the lung. At 48 hours, tiny barium nodules were essentially all that remained. One hundred and thirty milliliters of barium sulfate initially resulted in overfilling of the bronchial tree and prolonged retention of the contrast medium. Six weeks after bronchography, histopathologic examination of the perfused fixed lungs of two horses showed a very mild inflammatory response to the barium. One of the four horses received two barium sulfate bronchograms. This horse was observed and found to be free of any side effects for 15 months after the second bronchogram.     

Barium swallow as an aid to the diagnosis of grass sickness

Twenty-five horses, suspected on clinical grounds of having grass sickness, were given a barium swallow. Using image intensification the passage of the barium bolus was followed radiographically from the pharynx to the stomach. All 18 horses in which grass sickness was later confirmed at post mortem examination showed defective oesophageal motility. Although the specificity of the abnormality could not be proven, the technique offers a valuable aid to the ante mortem diagnosis of grass sickness.     

GASTROINTESTINAL STUDIES IN THE GREEN IGUANA: TECHNIQUE AND REFERENCE VALUES

Five healthy green iguana (Iguana iguana) were used to determine appropriate technique and normal transit times for gastrointestinal contrast studies and to describe normal radiographic anatomy. The animals were maintained at 27-29 degrees C. There was rapid transit through a U shaped stomach, with a median gastric emptying time of 8 h, and median small intestinal transit and small intestine emptying times of 4 h and 16 h respectively. Median large colon transit and emptying times were 15 h and 66 h. Maintaining the iguana at a reduced ambient temperature increased all of these times. The vaso-vagal response or mechanical methods were adequate for restraint. A 25 ml/kg dose of a 25% w/v suspension of barium administered by stomach tube gave the best results. Lateral and ventrodorsal projections of the abdomen should be made immediately following the administration of the barium and at 1-hour intervals for the first 6 h and at 12-hour intervals thereafter until barium can be identified in the distal descending small colon.     

SCINTIGRAPHIC EVALUATION OF SOLID-PHASE GASTRIC EMPTYING IN THE DOG

A technique for scintigraphically quantitating solid-phase gastric emptying in the dog was developed in a Beagle model. The test meal was determined to empty in a linear fashion, indicating a solid-phase label. The evaluation was performed on a group of dogs presented for gastrointestinal signs that were judged to have normal liquid barium sulfate fluoroscopic and radiographic studies. The results of this study indicate that this technique is valuable for identifying those patients with surgically correctable pyloric obstruction that exhibit normal gastric emptying of liquid barium.     

Radiographic and gross anatomy of the nasolacrimal duct of the horse

The anatomy of the nasolacrimal duct of the horse was studied grossly and radiographically, using barium contrast dacryocystorhinography and methyl methacrylate casts. Radiographic contrast studies were performed on 4 specimens and gross dissections were performed on 6 specimens. Dacryocystorhinography accurately delineated the course of the nasolacrimal duct, as was subsequently demonstrated by gross dissection. A 60% barium sulfate suspension produced good radiographic contrast, allowing critical assessment of the anatomic features of the nasolacrimal duct.     

POSITIVE-CONTRAST RHINOGRAPHY

Contrast rhinography is a simple noninvasive procedure that may be a useful diagnostic method for positive-contrast radiographic evaluation of the nasal cavity, nasopharynx, and paranasal sinuses in the dog. A standardized and reliable technique was developed using healthy adult Greyhounds. The radiographic appearance of the regional anatomy after intranasal administration of positive-contrast medium was established. Four contrast media: 60% propyl iodine, 37% organically bound iodine, a 60% barium sulfate suspension, and a 30% barium sulfate suspension were evaluated on the basis of their radiographic contrast and detail, distribution, and degree of evoked tissue reaction as defined by clinical assessment. A 30% barium sulfate suspension was selected using these criteria. Contrast medium enhanced the radiographic appearance of the regional anatomy when compared with noncontrast techniques. A procedure for positive-contrast radiographic evaluation of the nasal cavity, nasopharynx, and paranasal sinuses is described in detail. Recommendations are made regarding methods of contrast medium administration and positioning to ensure uniform distribution within the area of interest.     

Case-Control Comparison of Cervical Spine Radiographs From Horses With a Clinical Diagnosis of Cervical Facet Disease With Normal Horses

The accuracy of using radiographs to diagnose cervical facet osteoarthritis (CFA) in horses is undetermined. Further investigation is required to determine the clinical significance of radiographic evidence of CFA, the prevalence of radiographic changes in horses without clinical signs, and the long-term efficacy of intra-articular CFA treatment. The objectives of this study is to compare degenerative changes of the cervical facet joints of the cervical vertebrae on radiographs of horses with clinical signs of CFA with healthy cohort-matched horses, to compare clinical findings between groups, and to obtain follow-up information on the long-term outcome in treated horses. This is a retrospective case-control cohort-matched comparison study of horses treated for cervical facet disease versus horses with no clinical signs of cervical facet disease. Horses diagnosed with CFA and treated with intra-articular injection of corticosteroids were included. Follow-up information on recovery from treatment was obtained via telephone survey of owners/trainers. Healthy horses with no clinical signs of CFA were matched to treated horses by breed, sex, age, and sport as the control group. Two blinded radiologists reviewed cervical spine radiographs for each horse and recorded CFA score and intravertebral/intervertebral measurements. Clinical and radiographic parameters were compared between treatment and control groups. There was a significant difference in CFA grades for C5-6 and C6-7 between horses with presence of clinical signs and healthy horses. However, interobserver agreement between radiologists for grading CFA was moderate and only 56% of values were identical for both observers. Atrophy of the neck was present on clinical examination in most cases in the treatment group. Dressage horses were overrepresented. Overall, 64% of horses returned to their previous level of performance after treatment. Clinical examination data collected for the treatment group were retrospective and were obtained by different clinicians. Eight owners/trainers were not able to be reached for the survey. There was a significant difference in CFA grades for C5-6 and C6-7 between horses with presence of clinical signs and healthy horses. Despite these statistical differences, the clinical diagnosis of CFA based on radiographic grading alone is questionable because of the lack of agreement between the radiologists. To strengthen the diagnosis, clinical signs of facet disease, in particular atrophy of the neck muscles, need to be present to make this diagnosis. Intra-articular corticosteroid injection was effective at allowing most treated horses to return to athletic use..     

Effects of detomidine on equine oesophageal function as studied by contrast radiography

The effects of sedation with detomidine on oesophageal function were assessed by contrast radiography in 10 healthy adult thoroughbred horses. Barium swallows were monitored by means of image intensification, first without sedation and then after the intravenous administration of detomidine at doses of 10 and 20 micrograms/kg bodyweight. The transit time of contrast agent to the oesophageal hiatus was recorded and each swallow was scored for markers of oesophageal dysfunction. Analysis of the data indicated that there were highly significant dose dependent increases in the transit time, the retention of barium within the longitudinal mucosal folds, and retrograde peristalsis and pooling of contrast agent within the oesophagus at both the thoracic inlet and caudal to the base of the heart. The degree of gastrooesophageal reflux was not affected at either dosage. These changes in oesophageal function were similar to those recorded from cases of grass sickness and indicate that care should be taken in the interpretation of studies of swallowing in animals that have been given detomidine before a radiographic examination.     

Radiation exposure to personnel during examination of limbs of horses with a portable hand-held fluoroscopic unit.

OBJECTIVES: To determine radiation exposure to personnel during fluoroscopic imaging of limbs of horses with a portable unit and to determine distance from the c-arm at which radioprotective clothing is not required. DESIGN: Repeated-measures cohort study. SAMPLE POPULATION: Part 1, 1 forelimb and 1 hind limb from each of 5 equine cadavers; parts 2 and 3, personnel involved during imaging of limbs of 5 and 9 horses, respectively. PROCEDURE: Radiation exposure rates were mapped around the suspended c-arm of a portable fluoroscopy unit during imaging of various joints of equine cadaver limbs. During similar examinations in live horses, exposure rates to the fluoroscopist and assistant were measured. Mean duration for fluoroscopy of various joints was determined by observing an experienced fluoroscopist. Exposure to fluoroscopists and assistants per examination and per annum was estimated. RESULTS: Radiation exposure rates were dependent on distance and direction relative to the c-arm and consistently highest on the tube side of the unit. Exposure was significantly greater than background amounts until approximately 4.7 m from the c-arm. During examination of live horses, exposure was highest to the fluoroscopist's hand nearest the tube. Typically, exposure to the fluoroscopist and assistant during carpal examination was 25 to 40 times greater than that for comparable radiographic examination. Annual exposure for fluoroscopists was more than twice the recommended maximum permissible dose. CONCLUSIONS AND CLINICAL RELEVANCE: Fluoroscopic imaging of limbs of horses represents a major source of radiation exposure. Annual maximum permissible doses of radiation will be rapidly exceeded if required radioprotective clothing is not worn.     

RADIOGRAPHIC STUDIES OF GASTRIC EMPTYING IN SUCKLING CAMELS

A suspension of barium sulfate in camel milk was used as a contrast medium to assess gastric anatomy and emptying in camels. Two doses were evaluated: 10 ml/Kg and 20 ml/Kg. The lower dose was found to be inadequate for stomach opacification. The higher dose results in sufficient distention and opacification. Contrast medium was administered by placing the solution into the mouth of the camel. The reticular groove reflex was not observed. Water sacs were filled immediately after barium administration and interval emptying and filling of these sacs occurred until the initiation of abomasal emptying. The abomasum did not begin to empty until approximately 5 hours after administration of the contrast medium; abomasal emptying was not complete until approximately 24 hours after contrast medium administration.     

Comparison of endoscopic,necropsy and histology scoring of equine gastric ulcers

Equine gastric ulcer syndrome (EGUS) represents a major health problem in performance horses. Much debate exists regarding endoscopic gastric ulcer scoring systems and their ability accurately to predict severity or depth of gastric ulcers. The purpose of this study was to evaluate the ability of an endoscopist to count gastric ulcers and predict gastric ulcer severity or depth using 2 endoscopic scoring systems and compare them to the same gastric ulcers see on necropsy and histopathology. Endoscopic examination of the stomach was performed under general anaesthesia on 23 mixed breed yearling horses, after feed was withheld for 24 h. Gastric ulcers were scored using 2 systems, number/severity-scoring (N/S) and practitioner simplified (PS) systems. After endoscopy, the horses were subjected to euthanasia and the stomach mucosa examined blindly and scored again at necropsy using above scoring systems. Representative gastric ulcers were then placed in 10% formalin and processed routinely for histopathology. The gastric ulcers were scored using a histopathology system (HSS) based on ulcer depth. Number scores in the N/S scoring system and PS on endoscopic and necropsy examinations were compared using Friedman 2 way analysis of variance. Where significant differences between variables were found a post hoc analysis was conducted using a Tukey's Studentised range (HSD) test. Severity scores using the N/S (ENGS) and PS scores recorded for the stomach via endoscopy and scores from HSS were evaluated for significant association using a Mantel-Haenszel Chi-square and Pearson moment correlation coefficient analysis. Significance was P < 0.05. All horses had gastric ulcers in the nonglandular mucosa via endoscopic examination and at necropsy examination. Mean nonglandular ulcer number (ENGN) score was significantly (P = 0.0024) lower on endoscopic examination compared to the score at necropsy (NNGN); whereas PS scores were not significantly different on endoscopy when compared to necropsy examination. A significant but weak association was found between ENGS and HSS (3.89, P = 0.048; r = 0.453, P = 0.045) and no correlation was found between PS and HSS (1.2, P = 0.272; r = 0.117; P = 0.622). Only 1/23 horses had glandular ulcers observed via endoscopic examination whereas, 6/23 horses had glandular ulcers at necropsy and on histopathology. The prevalence of EGUS is high in stalled yearling horses. The endoscopist may underestimate the number of gastric ulcers and may not be able accurately to predict the severity or depth of those ulcers present in the nonglandular equine stomach. Furthermore, the endoscopist may miss glandular gastric ulcers.     

EFFECT OF METHYLCELLULOSE ON UPPER GASTROINTESTINAL QUALITY IN DOGS

This study was performed to evaluate and optimize a small bowel contrast technique using barium and methylcellulose in dogs. Ten healthy dogs underwent both a conventional upper gastrointestinal study that used only barium and a modified study that used barium and methylcellulose. The control group received 10 mL/kg of 40% barium suspension. Experimental groups were divided into three subgroups given 15 mL/kg of different viscosities (low, moderate, and high viscosity) of 0.5% methylcellulose after 4 mL/kg of 40% barium suspension. Compared with the control group, dogs receiving methylcellulose had higher-quality upper gastrointestinal studies. Moderate viscosity of methylcellulose was superior to the other methylcellulose groups. In conclusion, the use of methylcellulose is a simple and effective method for improving the image quality in an upper GI examination.     

A NEW AND VERSATILE LARGE ANIMAL DIAGNOSTIC RADIOLOGY UNIT

The plans and technical specifications of a unit specifically designed for large animal radiography are described. The unit has two examination rooms, one for routine radiography in the standing position and the other for special procedures and investigations utilizing a custom-designed table with a carbon fiber top. The table is computer operated and the x-ray tubes above and below it are capable of penetrating the thickest parts of horses as well as performing such procedures as linear tomography, angiography, and magnification radiography. The facility is equipped with an image intensifier, television monitor, 100 mm spot film camera, Potter-Bucky grid, and Puck film changer as well as a number of additional features for coping with anesthetized large animals. The unit has been in operation for three years and has greatly improved the quality of radiographic examinations as well as opening up some important lines of investigative research     

Bone scintigraphy as an aid in the diagnosis of occult distal tarsal bone trauma in three horses

History, physical examination, and bone scintigraphy were used to diagnose central and/or third tarsal bone trauma in 3 acutely lame horses. In all 3 cases, the results of initial radiographic examination were negative. Bone scintigraphy revealed focal, intense radioisotope uptake at the level of the distal tarsal bones in the 3 horses. Radiographs obtained 4 weeks after injury in one horse demonstrated a slab fracture of the central tarsal bone. Conservative management of the tarsal bone disease resulted in acceptable return to function in all 3 horses.     

Endoscopic findings of the gastric antrum and pylorus in horses: 162 cases (1996-2000)

Medical records and endoscopy images were examined for 209 horses that had gastroscopic examinations performed with a 2.5- or 3-m-long endoscope by one of the authors (MJM) during a 4-year period (1996-2000). The antrum and pylorus were viewed in 162 horses, and the duodenum was viewed in 94 horses. Of these 162 horses, the gastric squamous mucosa was seen in 157 horses and 50% or more of the glandular mucosa of the body of the stomach was seen in 156 horses. Erosions or ulcers were seen in the gastric squamous mucosa in 91 (58%) horses. Erosions or ulcers were seen in the glandular mucosa of the body of the stomach in only 8% of the horses. Lesions consisting of erosion or ulceration were seen in the antrum or pylorus in 94 (58%) horses. Lesions consisting of hyperemia and a rough or "bumpy" appearance were seen in the mucosa of the duodenum of 16 horses. An association between the presence of lesions in the squamous mucosa and the presence of lesions in the mucosa of the antrum/pylorus was examined by Fisher's exact test, and the linear association of lesion severity scores between the squamous mucosa and the mucosa of the antrum/pylorus was tested using a Monte Carlo estimate for linear-by-linear association. There was no association (P = .88) between these sites for presence of lesions or lesion severity scores. Similarly, there was no association between scores for the glandular mucosa in the gastric body and those in the antrum/pylorus. Because of the high prevalence of lesions in the antrum and pylorus of the stomachs of adult horses examined in a hospital setting, the entire stomach should be viewed during a gastroscopic examination.     

GASTRIC EMPTYING IN THE NORMAL DOG A Contrast Radiographic Technique

A total of 22 radiographic studies was made to determine comparative gastric emptying times of two different solid test meals (intact kibble food and ground kibble food mixed with barium sulfate suspension) in four mature (15-26 months) normal Beagle dogs under controlled conditions. Complete gastric emptying times of the intact kibble and ground kibble meals of a given dose (8 g/kg of dog food plus 5-7 ml/kg of the contrast agent) ranged from five to ten hours (7.6 ± 1.98 hours with intact kibble meal and 7.0 ± 1.86 hours with ground kibble meal). Feeding a halfdose of ground kibble meal (4 g/kg of dog food plus 3.5 ml/kg of the contrast agent) resulted in complete gastric emptying times of four to six hours (4.7 ± 0.67 hours). Individual dogs had repeatable gastric emptying times although the times varied among different dogs.     

Fiberoptic gastroduodenoscopy in the horse

A method of fiberoptic gastroduodenoscopy and biopsy was developed for use in large horses. A 275 cm X 13.5 mm fiberendoscope was used to examine the stomach and proximal portion of the duodenum. Food was withheld for 24 to 48 hours before examination. In more than 50 horses, gastric and duodenal structures were easily visualized. A variety of lesions was detected, including parasitic lesions, gastric ulcers, gastric neoplasia, and pyloric stenosis. Mucosal biopsy specimens were obtained in selected cases.