The aim of this study was to determine the normal value of radiographic attenuation on non-contrast computed tomography (CT) of the liver parenchyma in free-ranging blue and yellow macaws (Ara ararauna) under general anesthesia. Thirteen macaws from the Wildlife Triage and Rehabilitation Center of Pernambuco were evaluated through physical examinations, laboratory tests and CT prior to release into the wild and were considered healthy. The CT exam was performed using an imaging phantom to standardize the radiographic attenuation values obtained. The images were evaluated in multiplanar reconstructions and transverse slices. Hounsfield units of (HU) of tegions of interest within the right and left hepatic lobes were measured. The mean hepatic radiographic attenuation of the right and left lobes was 53.73 HU to 54.44 HU, respectively. Statistical analysis was performed using parametric tests (T-tests). Quantitative values of the normal liver radiographic attenuation of blue and yellow macaws were obtained, which can serve as a reference to aid in the diagnosis of diffuse liver diseases in this species.
