Application of Diagnostic Imaging in Exotic Animal Gastroenterology

Imaging of an exotic animal with gastroenteric disease is often essential to make a diagnosis. The selection of a modality and its effective use needs careful consideration in each case. Obtaining a high-quality image and its interpretation are an acquired skill. This article describes how to obtain a high-quality image, and then presents guidelines for its interpretation.

Radiation Dose Reduction in Different Digital Radiography Systems: Impact on Assessment of Defined Bony Structures in Bearded Dragons (Pogona vitticeps)

Three different digital detector systems were used to study the effect of a defined radiation dose reduction on the image quality of digital radiographs in bearded dragons (Pogona vitticeps). A series of radiographs of seven bearded-dragon cadavers with a body mass ranging from 132 g to 499 g were taken in dorsoventral projection. The digital systems employed included two computed radiography systems (CR) (one system with a needle-based and one with a powdered-based scintillator) and one direct radiography system (DR). Three levels of the detector dose were selected: A standard dose (defined based on the recommended exposure value of the CR_P, D/100%), a half dose (D/50%), and a quarter dose (D/25%). Four image criteria and one overall assessment were defined for each of four anatomic skeletal regions (femur, rib, vertebra, and phalanx) and evaluated blinded by four veterinarians using a predefined scoring system. The results were assessed for differences between reviewers (interobserver variability), radiography systems, and dosage settings (intersystem variability). The comparison of the ratings was based on visual grading characteristic (VGC) analysis. Dose reduction led to significantly lower scores in all criteria by every reviewer, indicating a linear impairment of image quality in different skeletal structures in bearded dragons. Scores did not differ significantly between the different systems used, indicating no advantage in using a computed or direct radiography system to evaluate skeletal structures in bearded dragons. The correlation was significant (p ≤ 0.05) for interobserver variability in 100% of the cases, with correlation coefficients between 0.50 and 0.59. While demonstrating the efficacy of the use of digital radiography in bearded dragons and the similar quality in using different computed or direct radiography systems, this study also highlights the importance of the appropriate level of detector dose and demonstrates the limits of post-processing algorithm to compensate for insufficient radiation doses in bearded dragons.

Anatomic-radiographic aspects and gastrointestinal transit time in boa constrictor amarali stull, 1932 (Squamata, Boidae)

ABSTRACT The goal of this study was to describe the gastrointestinal transit technique in the Boa constrictor amarali. For that purpose, we obtained simple radiographic images of seven serpents, subsequently administering a 25mL/kg dose of barium sulfate and establishing a radiographic sequence at the following times: 5 minutes; 1, 2, 3, 6, 9, 24, 48, 72 and 96 hours, extending to 120 and 126 hours for one animal. The mean esophageal transit was 26.71±19.48 hours; the mean gastric filling time was 28.57±27.22 minutes and the emptying time was 60±12 hours; the mean filling time of the contrast medium in the small intestine was 3±2.16 hours and the emptying time was 97±15.65 hours. We also obtained the mean filling time of the large intestine, which was 40±11.31 hours. We found that the mean passage time of the contrast medium through the cranial gastrointestinal tract - until the complete elimination of barium sulfate from the small intestine -was 97±15.65 hours. In addition to determining the gastrointestinal transit time, the technique used allowed for the morphological identification of the alimentary canal.

Blind Trading: A Literature Review of Research Addressing the Welfare of Ball Pythons in the Exotic Pet Trade

Simple Summary

The Ball python is a small species that is commonly kept as an exotic pet across the world. Despite huge numbers of these snakes being kept and traded in the pet industry, there is very little information available about how catching, breeding, transporting and housing them in captivity could impact their welfare. Our study reviewed the published literature for this species and found 88 relevant peer-reviewed scientific papers. Physical health was the predominant focus of research, with numerous studies reporting on disease, injury or clinical treatments. Far fewer papers focused on other aspects of Ball python wellbeing, including behaviour, nutrition, environment or mental condition. We also found that very few studies focused on wellbeing prior to pet ownership, i.e., during the early stages of the trade chain when they are caught from the wild, transported, or bred in captivity. We recommend that more research is needed to assess the impact of the exotic pet trade on this species’ welfare. In particular, research on welfare conditions during capture and transportation of wild Ball pythons, and the potential effects of captive breeding, could help reduce suffering throughout the trade.

Abstract

Extensive numbers of Ball pythons are caught, bred, traded and subsequently kept in captivity across the world as part of the exotic pet industry. Despite their widespread availability as pets, relatively little is known about the potential welfare challenges affecting them. We reviewed the literature for research focused on the health and welfare of Ball pythons in the international pet trade. From a total of 88 articles returned from the search criteria, our analysis showed that very few actually focused on trade (10%) or animal welfare (17%). Instead, the majority (64%) of articles focused on veterinary science. There was a considerable bias towards physical health, with most studies neglecting the four other domains of animal welfare (behaviour, nutrition, environment and mental health). Furthermore, very few studies considered Ball pythons prior to resulting pet ownership, during wild capture and transportation or captive breeding operations. Our review demonstrates that our current understanding of welfare for Ball pythons traded as exotic pets is limited. We recommend that future research should focus on aspects of the industry that are currently overlooked, including the potential consequences of genetic selection during captive-breeding and the conditions provided for snakes prior to and during international transportation.

Specific anatomy and radiographic illustration of the digestive tract and transit time of two orally administered contrast media in Inland bearded dragons (Pogona vitticeps)

The aim of this study was to describe the specific gross and radiographic anatomy of the digestive tract of inland bearded dragons (Pogona vitticeps). Eleven bearded dragon cadavers of both sexes (6 females, 5 males) were dissected to examine, measure, and document the specific gross anatomy of the alimentary canal. Measurements collected from the cadavers included snout-vent length, total length of the alimentary canal, and the lengths of the individual sections of the gastrointestinal tract, including the esophagus, stomach, small intestine, ampulla coli, isthmus coli, rectum, and the distance from the coprodeum to the vent opening. Twenty-two healthy adult bearded dragons (13 females, 9 males) maintained under standardized husbandry conditions underwent a physical examination, blood collection, and whole-body dorsoventral and lateral survey radiographs; these animals were used to provide the radiographic images of the complete digestive tract. For the subsequent contrast passage studies, two different contrast media, barium sulfate (BaSO₄, Barilux suspension) and an iodinated ionic radiocontrast agent (Sodium meglumine amidotrizoate [SMAT], Gastrografin), were used. Water-diluted Barilux suspension (dose 9 ml/kg) was administered orally to 5 bearded dragons, while Gastrografin (dose 5ml/kg) was administered orally to 21 bearded dragons. Four animals were used for both contrast media studies, but received a break of four weeks in between. Dorsoventral and laterolateral radiographs were collected at 0 (baseline), 15, 30, and 45 minutes and 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 30, and 36 hours after each contrast medium was administered. Both contrast media were found to illustrate the alimentary tracts in the adult bearded dragons. Transit time was substantially faster with SMAT, and SMAT illustrated the entire gastrointestinal tract within 36 hours; BaSO₄ did not fully illustrate the gastrointestinal tract in 36 hours. These results might serve as a guideline for the interpretation of subsequent contrast studies in this lizard species.

Normal computed tomographic features and reference values for the coelomic cavity in pet parrots

Background

The increasing popularity gained by pet birds over recent decades has highlighted the role of avian medicine and surgery in the global veterinary scenario; such a need for speciality avian medical practice reflects the rising expectation for high-standard diagnostic imaging procedures. The aim of this study is to provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species.

Results

Contrast-enhanced computed tomographic studies of the coelomic cavity were performed in 5 blue-and-gold macaws, 4 African grey parrots and 6 monk parakeets by means of a 4-multidetector-row CT scanner. Both pre- and post-contrast scans were acquired. Anatomical reference cross-sections were obtained from 5 blue-and-gold macaw, 7 African grey parrot, and 9 monk parakeet cadavers. The specimens were stored in a −20 °C freezer until completely frozen and then sliced at 5-mm intervals by means of a band saw. All the slices were photographed on both sides. Individual anatomical structures were identified by means of the available literature. Pre- and post-contrast attenuation reference values for the main coelomic organs are reported in Hounsfield units (HU).

Conclusions

The results provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species.

Radiographic anatomy and barium sulfate contrast transit time of the gastrointestinal tract of bearded dragons (Pogona vitticeps)

The positive contrast gastrointestinal study is a common non-invasive diagnostic technique that does not require anesthesia and enables good visualization of the digestive tract. Radiographic anatomy and reference intervals for gastrointestinal contrast transit time in inland bearded dragons (Pogona vitticeps) were established using seven animals administered 15 ml/kg of a 35% w/v suspension of barium by esophageal gavage. Dorso-ventral and lateral radiographic views were performed at 0, 15, 30 min, 1, 2, 4, 6, 8, 12 h, and then every 12 h up to 96 h after barium administration. Gastric emptying was complete at a median time of 10 h (range 4-24 h). Median jejunum and small intestinal emptying times were 1 h (range 30 min-2 h) and 29 h (range 24-48 h), respectively. Median transit time for cecum was 10 h (range 8-12 h). Median time for contrast to reach the colon was 31 h (range 12-72 h) after administration. Results were compared to those obtained in other reptilian species. This technique appeared safe in fasted bearded dragons and would be clinically applicable in other lizard species.

Nutritional support of reptile patients

Providing nutritional support to reptile patients is a challenging and often misunderstood task. Ill reptiles are frequently anorexic and can benefit greatly from appropriate nutrition delivered via a variety of assist-feeding techniques. Neonatal reptiles can also be very challenging patients because many fail to thrive without significant efforts to establish normal feeding behaviors. This article presents ideas supporting the benefit of timely nutritional support as well as specific recommendations for implementation of assist feeding. Also discussed are a few nutritional issues that affect captive reptile species.

Continuous imaging of esophagogastric junction in patients with reflux esophagitis using 320-row area detector CT: a feasibility study

BACKGROUND AND AIM

The function of the lower esophageal sphincter (LES) is evaluated using an esophageal manometric study. However, information regarding the surrounding organs is difficult to obtain with use of a sensor catheter. We investigated the utility of 320-row area detector computed tomography (CT) to evaluate morphological changes of the esophagogastric junction and surrounding organs.

METHODS

The study subjects were 18 healthy volunteers and 29 patients with reflux esophagitis (RE). Immediately after swallowing a diluted contrast agent, continuous imaging of the esophagogastric junctional area was performed for 15 s. Using CT images, the presence or absence of esophageal hiatal hernia, His angle before and after swallowing, size of the diaphragmatic hiatus, morphologically identified-LES (MI-LES) length, intraluminal horizontal area of MI-LES during relaxation phase, MI-LES thickness, abdominal esophagus length, subcutaneous fat area, visceral fat area, and esophagogastric junction fat area were evaluated.

RESULTS

Analysis of CT images showed more frequent occurrence of hiatal hernia, greater His angle, and a larger diaphragmatic hiatus in patients with severe RE, while the lengths of MI-LES and abdominal esophagus were shorter in those patients. Visceral and esophagogastric junction fat areas tended to be greater in patients with RE. In all subjects, the posterior wall of the MI-LES was thicker than the anterior wall.

CONCLUSION

Continuous imaging with 320-row area detector CT is useful to evaluate morphological changes in the esophagogastric junction area in both normal individuals and patients with reflux esophagitis.

Imaging diagnosis-pulmonary-tracheobronchial prolapse in a new Caledonian giant gecko (Rhacodactylus leachianus)

A 3-year-old male New Caledonian giant gecko, or Leach's gecko (Rhacodactylus leachianus) presented with acute lethargy and coelomic distention. Findings from survey radiographs and an upper gastrointestinal tract contrast study were consistent with severe aerophagia, a collapsed left lung, and hyperinflation of the right lung due to suspected bronchial obstruction. The gecko was treated with conservative medical management, but was found dead 5 days after presentation. Necropsy findings showed intussusception of the proximal left lung into the left mainstem bronchus and trachea.