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Anatomy of the digestive tract of a bearded dragon illustrated by a digital image of the ventral view in situ after removal of all non digestive organs (1A), and radiograph of the tract dissected from the body and filled with barium (1B).
Source publication
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 a...
Contexts in source publication
Context 1
... radiographs obtained were of excellent quality, demonstrating each compartment of the gastrointesti- nal tract with complete filling and good distension. The bearded dragon gastrointestinal tract is composed of an esophagus, a stomach, a duodenal bulb, a short small intestine, a cecum, and a colon ( Fig. 1A and B). Most of the gastrointestinal tract organs were confined to the mid-coelomic region caudal to the heart and ...
Context 2
... the duodenum curved toward the left side of the coelomic cavity, then cranially. After this cranial curvature, the first intestinal loop following the duodenum (termed the jejunum in this study) began medially to the stomach and progressed cranially toward the right, before a dorsal turn cranio-dorsally to the cecum on the right of midline ( Fig. 1A and B). The following portion of the small intestine had a small diameter and remained dorsal to the duodenum and cecum. Following the jejunum, the ileum was the last transverse intestinal segment before reaching the cecum (Fig. 4A). The ileum began medially to the stom- ach and progressed toward the right side of the coelomic cavity, ...
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Citations
... Bearded dragons (Pogona vitticeps) are one of the few squamate species with published DI data [2,3]. Retrospective studies have highlighted the prevalence of intra-coelomic disease in bearded dragons [4,5]. ...
... Coelomic palpation is insensitive, and DI is often necessary for diagnosis of common disease processes, such as gastrointestinal (GI) obstruction, coelomic organ neoplasia, reproductive disease, etc [6,7,8]. Enteral positive contrast radiography is routinely utilized in reptiles, but has significant limitations, as it only provides indirect information about non-GI organs of the coelom [2,9]. Additionally, squamates generally have slow GI transit times, with reported barium GI transit times in healthy bearded dragons of 12 72 hours [2], which could delay diagnosis and require multiple radiographs, increasing cost and possible sedative or anesthetic events. ...
... Enteral positive contrast radiography is routinely utilized in reptiles, but has significant limitations, as it only provides indirect information about non-GI organs of the coelom [2,9]. Additionally, squamates generally have slow GI transit times, with reported barium GI transit times in healthy bearded dragons of 12 72 hours [2], which could delay diagnosis and require multiple radiographs, increasing cost and possible sedative or anesthetic events. Negative contrast radiography (use of room air, carbon dioxide (CO 2 ), nitrous oxide (N 2 O), or other gases) is another option to increase coelomic contrast. ...
Background
Contrast radiography is used to combat poor coelomic detail encountered in reptilian radiographs. This study describes pneumocoelomography, a novel negative contrast technique using room air in bearded dragons (Pogona vitticeps). The feasibility of this technique, its tolerance by the study subjects, and obtained images were evaluated.
Methods
Six clinically healthy, adult bearded dragons had standard and pneumocoelomogram radiographs performed under anesthesia. Pneumocoelom was induced by insufflating 0.2mL/mm coelomic length of room air via an over-the-needle catheter introduced into the coelom. Pre-, post-, and positive intravenous contrast-enhanced post-pneumocoelom computed tomography scans were also performed. Packed cell volume, total protein, and blood films were evaluated at time of imaging and two weeks post-procedure to assess potential systemic consequences of this technique.
Results
Procedures were well tolerated with no adverse anesthetic, recovery, post-procedural, hematologic, or behavioral declines in health status. The pneumocoelomogram consistently revealed the gonads (6/6 cases) in both sexes. There was an inconsistently improved characterization of other coelomic organs: the cardiac silhouette was improved in 4/6 cases, trachea in 2/6, lungs in 3/6, stomach in 3/6, cecum in 3/6, colon in 5/6, and kidneys in 2/6. The liver, spleen, and small intestines did not show improved characterization in any case.
Conclusion
Room air pneumocoelomography offers a well-tolerated, readily-available technique and provides additional coelomic organ characterization to that of standard radiographs. Future studies should evaluate if this technique provides diagnostic utility in pathological states.
... In dogs and cats, position and conspicuity of thoracic and abdominal structures have been well documented to vary between projection angles (Ruehl and Thrall, 1981;Armbrust et al., 2000;Avner and Kirberger, 2005;Marolf et al., 2008;Kirberger et al., 2009;Vander Hart and Berry, 2015;Thrall, 2017;Mavromatis et al., 2018). The normal radiographic gastrointestinal anatomy and barium sulfate contrast transit time have been described in the green iguana (Smith et al., 2001) and bearded dragon (Pogona vitticeps) (Grosset et al., 2014) by means of dorsoventral and horizontal beam right lateral views. Our group is unaware of published literature investigating the effect of horizontal vs. vertical radio-graphic beam orientation and the potential differences between right and left lateralities in lizards. ...
A prospective study was performed in 12 green iguanas (Iguana iguana) to compare the radiographic appearance of coelomic viscera. Five radiographic projections (views) of the coelom were obtained: dorsoventral, right lateral vertical beam, left lateral vertical beam, right lateral horizontal beam, and left lateral horizontal beam. One week later, the same radiographic projections were obtained after oral administration of barium. In 4 of the 12 green iguanas, an additional vertical beam ventrodorsal view was obtained. In comparing lateral projections, lung, liver, and gonads were best imaged in horizontal beam lateral projections, before distention of the stomach with barium, whereas the gastrointestinal tract including the colon was best visualized in vertical beam lateral projections. The shape and size of the cardiac silhouette was considered equivalent between analogous lateral projections in most green iguanas (10 [83%] of 12). In comparing ventrodorsal and dorsoventral projections, the ventrodorsal projections improved visibility of the cardiac silhouette and lung in 4 (100%) of 4 green iguanas, while reducing cardiac length. Dorsoventral projections were preferred for the evaluation of the gastrointestinal tract. This study demonstrates that radiographic beam orientation and patient position result in obvious radiographic differences of the iguanid coelom and that projections are not interchangeable
... Only few studies about this topic had been published. A study with Pogona vitticeps demonstrated a median contrast transit time to the colon was 31 hours, and longest was 72 hours [16]. Another study, in the same species, demonstrated contrast transit time to the cloaca at >32 [17]. ...
Background
Alternatives to gross external anatomical sex determination are often required, peculiarly in species displaying poor or absent gross sexual dimorphism, such as the beaded lizard. This study evaluates results of hemipenile contrast radiography accuracy as compared to ultrasonography of the same beaded lizard (Heloderma alvarezi and Heloderma horridum).
Methods
Eleven captive adult beaded lizards (four Heloderma alvarezi and seven Heloderma horridum), underwent hemipenis contrast radiography, and results compared with coelomic ultrasound.
Results
By ultrasound, 2 lizards were females and 9 were males. By contrast hemipenis radiography, 2 animals were females and 9 were males. In this sample, there was a Kappa concordance of 1.
Conclusions and clinical relevance
In this species, contrast hemipenis radiography proved to be a reliable diagnostic tool for hemipenes identification, and sex determination with all test specimens. Further studies including a larger number of animals and different lizard species are warranted.
... Barium sulfate 30% weight per volume dilution was selected based on the findings of a study in red-eared sliders, a similarly sized chelonian species. 7 The volume of barium sulfate administered was selected based on recommendations for reptiles 22,23 and data from the pilot study in these individuals. It is notable that this volume dosage is almost double the volume dosage used in a similar study in red-eared sliders 7 concern, an enema administration of positive contrast media may be more appropriate to better visualize these structures. ...
Gastrointestinal disorders are an important cause of morbidity in box turtles (Terrapene carolina Carolina), however published information is currently lacking on the normal radiographic anatomy, transit, and emptying times of the gastrointestinal tract. A total of 15 healthy box turtles were recruited for this prospective, anatomic, reference interval study. Three‐view radiographic series (vertical beam dorsoventral, horizontal beam latero‐lateral, and horizontal beam rostrocaudal views) were acquired prior to contrast administration, and following contrast administration at 0, 20, 40, 60, and 90 min, 2, 4, 8, 12, and 24 h post administration, and every 24 h thereafter until all contrast was eliminated (15 mL/kg barium sulfate diluted to 30% weight per volume was administered via orogastric gavage). Vertical beam dorsoventral and horizontal beam latero‐lateral views were of excellent quality to identify gastrointestinal structures. The horizontal beam rostrocaudal view immediately postcontrast administration provided gastric and pyloric identification but had lesser diagnostic use at later time points due to anatomical superimposition. The gastrointestinal tract was composed of a tubular stomach, a pyloric sphincter near midline, a duodenum with a cranial flexure in the right cranial coelomic cavity, small intestines within the right coelom, a small cecal bulb, and a transverse and descending colon. Contrast media entered the large intestine by 24 h in all turtles, and a pyloro‐colic indentation was noted at the proximal descending colon. The large intestinal emptying was highly variable due to the interindividual variability of contrast sequestration within the cecal bulb. Findings from the current study serve as a reference on the gastrointestinal anatomy, transit, and emptying times in healthy eastern box turtles; and introduce a novel, horizontal beam, rostrocaudal view for gastrointestinal contrast studies in chelonians.
... Among the most common causes of radiological and ultrasound consultations in reptiles, the literature mentions diseases of the cardiovascular, skeletal, gastrointestinal and genitourinary systems (1,7,12). The cases analyzed here partially confirm the literature data. ...
Reptiles are becoming increasingly popular animals in amateur husbandry in Poland and worldwide. The world literature, however, does not provide data on the actual causes of radiological and ultrasound consultations in certain groups of animals, including reptiles. The aim of the study was the analysis of causes and results of diagnostic imaging examinations. The study was based on the data of 75 lizards which were patients of the university diagnostic imaging service in the years 2006-2014. The most common clinical signs in those animals were visible body deformations (33.33%), loss of body weight (30.67%) and loss of appetite (26.67%). In cases in which a preliminary diagnosis had been made, the largest proportion of animals were referred with suspected post-traumatic changes (12%), dystocia (10.67%) and ileus (9.33%). In diagnostic imaging tests, musculoskeletal (29.33%) and coelomic abnormalities (40.33%) were most commonly confirmed. Coelomic changes affected mainly the liver, reproductive system and gastrointestinal tract. For the musculoskeletal system, the most frequently identified causes were the presence of post-traumatic changes, malformations of the vertebral column, as well as metabolic bone disease. Cardiorespiratory and urinary problems were observed only sporadically. In twenty-two animals (29.33%), radiographic and ultrasound examinations failed to establish a diagnosis. The results of this study provide valuable data on the cross-section of the most common problems leading to diagnostic imaging evaluation in lizards. This research demonstrates that, despite the growing popularity of exotic animals, most of the problems diagnosed in such animals still arise from inappropriate breeding and housing conditions. In most cases, diagnostic imaging provides valuable information, making it possible to implement further steps....
... The most recent of these publications proposes gastrointestinal nomenclature on the basis of the anatomic description and functional information acquired from contrast radiography. 13 In the present study, we used nomenclature provided in that report, 13 with the following gastrointestinal segments in order from orad to aborad: stomach (cardia, fundus, and pylorus), duodenal bulb, duodenum, jejunum, ileum, cecum, colon, and cloaca. ...
... The most recent of these publications proposes gastrointestinal nomenclature on the basis of the anatomic description and functional information acquired from contrast radiography. 13 In the present study, we used nomenclature provided in that report, 13 with the following gastrointestinal segments in order from orad to aborad: stomach (cardia, fundus, and pylorus), duodenal bulb, duodenum, jejunum, ileum, cecum, colon, and cloaca. ...
Objective:
To determine which organs can be reliably visualized ultrasonographically in bearded dragons (Pogona vitticeps), describe their normal ultrasonographic appearance, and describe an ultrasonographic technique for use with this species.
Design:
Cross-sectional study.
Animals:
14 healthy bearded dragons (6 females and 8 males).
Procedures:
Bearded dragons were manually restrained in dorsal and sternal recumbency, and coelomic organs were evaluated by use of linear 7- to 15-MHz and microconvex 5- to 8-MHz transducers. Visibility, size, echogenicity, and ultrasound transducer position were assessed for each organ.
Results:
Coelomic ultrasonography with both microconvex and linear ultrasound transducers allowed for visualization of the heart, pleural surface of the lungs, liver, caudal vena cava, aorta, ventral abdominal vein, gallbladder, fat bodies, gastric fundus, cecum, colon, cloaca, kidneys, and testes or ovaries in all animals. The pylorus was visualized in 12 of 14 animals. The small intestinal loops were visualized in 12 of 14 animals with the linear transducer, but could not be reliably identified with the microconvex transducer. The hemipenes were visualized in 7 of 8 males. The adrenal glands and spleen were not identified in any animal. Anechoic free coelomic fluid was present in 11 of 14 animals. Heart width, heart length, ventricular wall thickness, gastric fundus wall thickness, and height of the caudal poles of the kidneys were positively associated with body weight. Testis width was negatively associated with body weight in males.
Conclusions and clinical relevance:
Results indicated coelomic ultrasonography is a potentially valuable imaging modality for assessment of most organs in bearded dragons and can be performed in unsedated animals.
Here, we report the synthesis of robust hybrid iodinated silica-lipid nanoemulsions (HSLNEs) for use as a contrast agent for ultrasound and X-ray applications. We engineered iodinated silica nanoparticles (SNPs), lipid nanoemulsions, and a series of HSLNEs by a low-energy spontaneous nanoemulsification process. The formation of a silica shell requires sonication to hydrolyze and polymerize/condensate the iodomethyltrimethoxysilane at the oil/water interface of the nanoemulsion droplets. The resulting nanoemulsions (NEs) exhibited a homogeneous spherical morphology under transmission electron microscopy. The particles had diameters ranging from 20 to 120 nm with both negative and positive surface charges in the absence and presence of cetyltrimethylammonium bromide (CTAB), respectively. Unlike CTAB-coated nanoformulations, the CTAB-free NEs showed excellent biocompatibility in murine RAW macrophages and human U87-MG cell lines in vitro. The maximum tolerated dose assessment was evaluated to verify their safety profiles in vivo. In vitro X-ray and ultrasound imaging and in vivo computed tomography were used to monitor both iodinated SNPs and HSLNEs, validating their significant contrast-enhancing properties and suggesting their potential as dual-modality clinical agents in the future.
A 5-year-old, female red-tailed boa constrictor ( Boa constrictor constrictor ) was presented with hyporexia, regurgitation and progressive focal distention of the caudal coelom since two months. During physical examination a firm, well-demarcated and movable intracoelomic mass was detected halfway down the caudal coelom but no other abnormalities were noticed. Ultrasonographic examination showed the mass to consist of an intestinal intussusception. A complete blood cell count and serum biochemistry blood test results revealed mild anemia and leukocytosis as well as hyperuricemia and hyperphosphatemia with inversion of the calcium/phospohorus ratio. Explorative coeliotomy was performed and revealed anterograde invagination of the ileum into the colon through the ileocolic junction. Although the intussusception was surgically repositioned, the snake died three weeks post-operatively despite showing a good general condition and defecation following assisted feeding. During necropsy, a thickened wall of the caudal segment of the ileum that was previously involved in the intussusception was observed as well as the presence of multifocal, white nodules throughout the parenchyma of the liver, spleen and kidneys. Histopathological examination demonstrated a malignant round cell tumor of the ileum with infiltration of neoplastic round cells in the liver, spleen and kidneys. Immunohistochemical staining (CD3, CD20, MAC387, S100 and NSE) could not confirm the cell origin of the round cell tumor. The present case highlights the need to include round cell tumors as a differential diagnosis in the development of ileocolic intussusception in red-tailed boa constrictors.
Reptiles and amphibians represent a broad range of body conformations and sizes, along with several unique anatomical variations. This diversity amongst lizards, turtles, tortoises, snakes, and amphibians creates unique challenges for diagnostic imaging. While radiography remains the most common imaging modality, ultrasound, computed tomography, and even magnetic resonance imaging are being utilized frequently. When acquiring and interpreting images with any modality, it is essential to keep species-specific considerations in mind.
Imaging techniques have proved to be crucial for diagnosis in reptile species. The topography of the internal organs of bearded dragons has been described in recent studies as meeting the small animal practitioners´ demand for knowledge concerning their anatomy. However, the nomenclature in the respective literature is not uniform, which could lead to misunderstandings concerning the respective and/or affected parts of the alimentary canal. Therefore, the aim of this study was to provide clear information on anatomy and histology of the alimentary canal of bearded dragons including supplying blood vessels. For the dissection of the alimentary canal, 11 Inland Bearded Dragons (Pogona vitticeps) were used (five males, six females), which had been euthanised for clinical reasons other than those concerning the digestive tract or had died spontaneously. The supplying arteries were demonstrated by injecting red latex into the aorta, while the intestinal veins were filled with blue latex via the portal vein. Microscopic examination was carried out on specimens of seven additional bearded dragons using routine histologic procedures. Macroscopically, the sections of the alimentary canal from oral to aboral were distinguished into oesophagus, stomach, small intestine, colic ampulla, colic isthmus, rectum and cloaca. Differentiation of the duodenum, jejunum and ileum was only possible when considering the bile duct, the vasculature and the histology of the organ wall. Arteries supplying the oesophagus and the final straight part of the large intestine originated from the aorta in a segmental manner. Between these, three unpaired arteries arose from the aorta. Their branches supplied stomach and intestine excluding its last part. Based on the findings of the present study, a nomenclature for the different parts of the alimentary canal and the supplying blood vessels of bearded dragons is suggested which is well understandable for veterinary practitioners and is based on zoological knowledge of reptiles.
