May 29, 2024

Comparison Between Digital Radiography and Computed Tomography for the Detection of Metal Fragments in Postmortem Examined Pinniped Skulls


Victoria Sorriba, Lia Lujan, Viviana De los Santos, Adam W. Stern, Federico R. Vilaplana Grosso, and Juan Pablo Damián


Document: Article
Abstract: The conservation of marine animals, such as pinnipeds, is very difficult when their feeding areas overlap with fishing activity. During these interactions, they are often victims of firearm injuries that result in their death. For veterinarians and biologists investigating crimes against wildlife, the use of diagnostic imaging techniques is essential. Although computed tomography (CT) can be used to evaluate animals with skeletal trauma, digital radiography (DR) is a cheaper and more widely available diagnostic imaging technique. The objective of this study was to determine whether the presence and number of metal fragments in the skull of pinnipeds differed between DR and CT. Thirty pinniped skulls—19 South American sea lions (Otaria byronia) and 11 South American fur seals (Arctocephalus australis)—with evidence of trauma and available DR and CT examinations were included in the study. The DR and CT images were evaluated by three independent observers—a veterinarian, a board-certified veterinary pathologist, and a board-certified veterinary radiologist. The detection of metal fragments in pinniped skulls with both imaging techniques was not different between the observers (p = 1.0), and it was not significantly different between DR (13/30) and CT (16/30) (p = 0.71). The number of metal fragments in pinniped skulls was also not significantly different between DR (6.6 ± 1.9) and CT (7.9 ± 1.7) (p = 0.37). Furthermore, there was excellent agreement between the three observers in the detection and number of fragments both for DR (kappa = 1.0; p < 0.0001) and for CT (kappa = 1.0; p < 0.0001), as well as between the two techniques (DR and CT: kappa = 0.802; p < 0.0001). This study showed that CT identified more skulls with metal fragments and an increased number of metal fragments as compared to DR; however, there were no significant statistical differences noted, suggesting that DR is just as useful as CT for the detection of metal fragments in pinniped skulls. Therefore, DR is a valid tool that can be used to investigate cases of projectile injuries against wildlife.
Key Words: gunshot injuries, projectile injuries, sea lion, seal, metal fragment, diagnostic imaging, head trauma
DOI: https://doi.org/10.1578/AM.47.4.2021.321
Page Numbers: 321-329

Info SKU: Vol__47__Iss__4__Sorriba Category: