Diagnostic Sensitivity of Ultrasound, Radiography and Computed Tomography for Gender Determination in Four Species of Lizards

Abstract

Gender determination is frequently requested by reptile breeders, especially for species with poor or absent sexual dimorphism. The aims of the current study were to describe techniques and diagnostic sensitivities of ultrasound, radiography, and computed tomography for gender determination (identification of hemipenes) in four species of lizards. Nineteen lizards of known sex, belonging to four different species (Pogona vitticeps, Uromastyx aegyptia, Tiliqua scincoides, Gerrhosaurus major) were prospectively enrolled. With informed owner consent, ultrasound, noncontrast CT, contrast radiography, and contrast CT (with contrast medium administered into the cloaca) were performed in conscious animals. Imaging studies were reviewed by three different operators, each unaware of the gender of the animals and of the results of the other techniques. The lizard was classified as a male when hemipenes were identified. Nineteen lizards were included in the study, 10 females and nine males. The hemipenes were seen on ultrasound in only two male lizards, and appeared as oval hypoechoic structures. Radiographically, hemipenes filled with contrast medium appeared as spindle-shaped opacities. Noncontrast CT identified hemipenes in only two lizards, and these appeared as spindle-shaped kinked structures with hyperattenuating content consistent with smegma. Hemipenes were correctly identified in all nine males using contrast CT (accuracy of 100%). Accuracy of contrast radiography was excellent (94.7%). Accuracy of ultrasound and of noncontrast CT was poor (64.3% and 63.1%, respectively). Findings from the current study supported the use of contrast CT or contrast radiography for gender determination in lizards.

A comparison of two techniques to identify the sex of the eastern blue‐tongue skink (Tiliqua scincoides scincoides)

“…The female's hemiclitores is physically homologous to the hemepenes but is morphologically different in length, size and lumen shape 6 . Like the hemepenes, it is easily eversible, but its function is not fully understood, that is, it is unclear whether it is actively everted by the female during copulatory adjustment, and/or whether it stimulates the male's hemipenes during intromission 6, 7 …”

Sex Determination in Two Species of Anuran Amphibians by Magnetic Resonance Imaging and Ultrasound Techniques

“…In comparison with other imaging techniques, MRI constitutes a valuable tool that allows the easy visualization and differentiation of soft tissue structures. In addition, the possibility of an automatic self-adjustment of the equipment's main technical parameters and the lower cost of the new low-field benchtop-MRI equipment has contributed to its more generalized use in preclinical research and in a daily veterinary clinic routine [31][32][33][34][35]. The present study is the first report of the use of BT-MRI for the purpose of sex determination.…”

Morphological and structural differences between the hemipenes and hemiclitores of golden lancehead snakes, Bothrops insularis (Amaral, 1922), revealed by radiography

“…Hemiclitores were better visualized in elderly females because this age group had larger individuals. In lizards, hemipenes have been visualized with 100% accuracy using contrast computed tomography and 94.7% accuracy using contrast radiography (Di Ianni et al, 2014).…”