Abstract

Foot disease is one of the most important health conditions of captive elephants, but treatment is hindered by the limitations of diagnostic imaging. Despite the high value of individual animals, advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) are currently not possible in live elephant feet. A pilot study was performed to initially assess the potential value of a simple inexpensive standardised 3D radiographic representation of elephant feet by stereoradiography, in enhancing visualisation of osseous foot pathology and its recognition by inexperienced observers. Thirty (30) 4th year veterinary students, with no experience or training in elephant radiography assessed 6 post-mortem elephants joint radiographs via standard 2D and 3D images in a blind cross-over study, to assess pathology severity. Pathology grading was compared to an expert who graded the actual bone specimens after clearing from the feet, blinded. When assessing standard 2D radiographs veterinary undergraduate students were no better than chance in detecting more from less severe pathology. In contrast, 83.3% were able to differentiate more from less severe radiographic bone pathology on 3D stereoradiography correlated to expert assessment of the cleared bones; an absolute improvement (difference) of 30% in assessment (95% confidence intervals being 6.4–49.6%).

After the pilot, further studies were conducted to analyse the applications of stereoradiography in post-graduate veterinarians (n=22) and other veterinary students with varying levels of experience (n=43). The postgraduate group were more successful in differentiating between more and less severe pathology on the 2D radiographs, with 68.1% able to differentiate in accordance to the expert assessment. However, even they showed an absolute improvement of 18.6% when assessing the 3D radiographs (95% confidence intervals being 6.7–39.2%).

Data obtained from all participants demonstrated that on self-assessment, 70.5% (95% confidence interval 60.7–78.8%) of students believed 3D radiography to improve their diagnosis of bone pathology in elephant foot radiographs. Furthermore, participants reported superior visualisation of images when the stereoradiographs were inverted and displayed on a monitor opposed to a projector. Initial results suggest a standardised method of 3D stereoradiography may hold potential for the improvement radiographic diagnosis of elephant pathology by veterinarians.