SCANNING CETACEANS! FACILITATING SERIAL COMPUTERIZED TOMOGRAPHY (CT) SCANS OF ATLANTIC BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)

Since its inception in 1972, computerized tomography revolutionized the ability to diagnose, treat, and monitor injuries and pathology in humans. Computerized tomography (CT) involves serial, radiological, cross-sectional scans, resulting in detailed, three-dimensional images of internal anatomy (Wellington & Vinegar, 1987). This tool was adopted for use in domestic veterinary medicine in 1989 and later utilized in post-mortem assessments of wild, stranded cetaceans (Schwarz & Saunders, 2011). In 2004, the U.S. Navy Marine Mammal Program conducted the first live dolphin CT scans to provide insight into cranial anatomy (Houser et al., 2004). Recently, other marine mammal facilities have utilized computerized tomography for acute diagnostics, but few use this tool to document the progression and treatment of chronic diseases.

As part of a strategic and collaborative effort among training and veterinary teams, three facilities in Key Largo, Florida (Dolphins Plus Oceanside, Dolphins Plus Bayside, and Island Dolphin Care) successfully conducted 16 CT scans of 8 Atlantic bottlenose dolphins (Tursiops truncatus) over a three-year period to diagnose chronic respiratory disease and systematically assess responses to treatment. The goal of this report is to share information concerning the training, protocols, logistics, risks and benefits, and results of thoracic serial CT scans in T. truncatus.

Training for repeated CT scans was largely focused on a voluntary beach behavior, due to the absence of shallow areas within the enclosures, and elaborate desensitization plans for minimizing reactions to a mechanical lift, pads, the stretcher, trainers positioned for restraint, transport, and the CT machine. Additionally, subjects were trained to respond to SDs while out of the water and restrained, including voluntary apnea to facilitate specific diagnostic scans. The detailed CT scan images revealed pertinent information regarding the thoracic cavity, which enabled strategic, and ultimately successful, treatment plans. Thus, although there are risks associated with the transport and CT procedure, these risks can be minimized by strategic and elaborate training plans.

This report exemplifies the extensive, state of the art care provided to marine mammals in a zoological setting as part of a larger, collaborative effort to ensure the health and well-being of each individual animal. Utilization of the CT scan as a routine diagnostic tool could prevent or mitigate thoracic disease and contribute to an improved understanding of these conditions among wild and stranded bottlenose dolphins.