A review of diagnostic imaging of snakes and lizards

Abstract

Snakes and lizards are considered 'stoic' animals and often show only non-specific signs of illness. Consequently, diagnostic imaging--along with clinical examination and laboratory tests--is gaining importance in making a final diagnosis and establishing a correct therapy. The large number of captive snake and lizard species commonly kept as pets, together with the high inter- and intraspecific morphological variability that is innate in these animals, make the analysis of diagnostic images challenging for the veterinary practitioner. Moreover, a thorough knowledge of the anatomy, physiology and pathology of the species that are the object of clinical investigation is mandatory for the correct interpretation of diagnostic images. Despite the large amount of clinical and scientific work carried out in the past two decades, the radiographic features of snakes and lizards have not undergone systematic description, and therefore veterinarians often have to rely mostly on anatomical studies rather than radiological literature. The aim of this paper is to review the most commonly used diagnostic imaging modalities, as well as to provide an overview of the available international original studies and scientific reviews describing the normal and pathological imaging features in snakes and lizards.

Causes of consultations and results of radiological and ultrasound methods in lizard diseases (2006-2014)

“…The ultrasound provided much more information in cases of abnormalities of the bile duct, liver, and reproductive system. It also made it easy to determine the sexual status of animals, which is consistent with conclusions drawn by other authors (1,4,6,10,17). These results indicate greater usefulness of ultrasound examination compared with radiographic examination, which may yield low-contrast images due to the anatomic characteristics of reptiles, especially close anatomic proximity of internal organs, a small amount of internal adipose tissue, the lack of a clearly demarcated thorax and abdomen, as well as image degradation from the superimposed exoskeleton and cutaneous scales (17).…”

“…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.…”

“…Growing attention is being focused on their health problems, as well as on diagnostic capabilities (3,19). However, diagnostic imaging of these animals can be problematic, as reptiles are characterized by large anatomic variability (1,16,17). The lack of a diaphragm, the peculiar topography of internal organs, and the small amount of intraperitoneal adipose tissue between parenchymal organs negatively affect image clarity in radiological examinations (17).…”

“…The lack of a diaphragm, the peculiar topography of internal organs, and the small amount of intraperitoneal adipose tissue between parenchymal organs negatively affect image clarity in radiological examinations (17). In addition, there are no objective criteria for image evaluation with respect to the normal organ size (1,13,16,17).…”

“…The world literature, however, does include publications on correct tomographic, radiological and ultrasound images for particular groups of reptiles (1)(2)(3). The majority of publications are based on case studies of individual animals, selected groups of animals or suborders of snakes and lizards and orders of turtles.…”