Comparative Interpretation of Thoracic Radiography, Ultrasound and CT: A Multimodal Approach to Bottlenose Dolphin Lung Imaging
Marina Ivančić1,2*; Cynthia R. Smith1; Jennifer M. Meegan1; Forrest M. Gomez1; Michael S. Renner3; Michael J. Adkesson4; Jennifer N. Langan4,5; Natalie D. Mylniczenko6; Elizabeth C. Nolan6; Eric D. Jensen7
1National Marine Mammal Foundation, San Diego, CA, USA; 2AquaVetRad, San Diego, CA, USA; 3Marine Mammal Veterinary Consulting, Jupiter, FL, USA; 4Chicago Zoological Society, Brookfield Zoo, Brookfield, IL, USA; 5Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana IL, USA; 6Disney's Animals, Science, and Environment, Disney's Animal Kingdom, EPCOT's The Seas with Nemo and Friends, Walt Disney's Parks and Resorts, Bay Lake, FL, USA; 7U.S. Navy Marine Mammal Program, San Diego, CA, USA
Thoracic radiography and ultrasonography are routinely used to assess pulmonary health in small cetaceans. A growing number of marine mammal facilities are also obtaining thoracic computed tomography (CT) data. Lung pathology can be seen with all of these techniques, but the appearance of individual lesions across multiple modalities has not been described. Concurrent multimodal thoracic imaging performed in ten bottlenose dolphins (Tursiops truncatus) was evaluated retrospectively. Ultrasound and CT were performed in two animals, ultrasound and radiography in three, and all three imaging modalities were performed in five animals. All thoracic imaging data analyzed for a given animal was obtained within 50 days (range 0–50 days, mean 26 days, median 30 days). A side-by-side look at individual lesions on CT, radiography, and/or ultrasonography was explored. The relationship between lesion conspicuity (obviousness), location, and imaging modality was also detailed. CT-derived multiplanar reconstructions and MIPs (maximum intensity projections) similar in appearance to traditional thoracic radiographs were shown to enhance pattern recognition for clinical veterinarians. This comparison serves as a rare opportunity in marine mammal medicine to 'reverse interpret' a challenging dataset (i.e., thoracic radiographs, limited by superimposition artifact and animal size) with the aid of a gold-standard cross-sectional imaging test (CT).
The authors thank the veterinary technical and training staff of the U.S. Navy Marine Mammal Program; Theater of the Sea; Dolphin Connection; Brookfield Zoo; and Disney's Animals, Science, and Environment for their excellent technical support and animal handling during image acquisition.
* Presenting author