Use of Computed Tomography in the Clinical Diagnosis of Lower Respiratory Tract Diseases in Sheep

Lower airway diseases are a major health concern in sheep, often presenting with overlapping clinical signs that hinder accurate diagnosis. This study evaluated the diagnostic value of computed tomography (CT) in 58 adult sheep examined in northeastern Spain between 2017 and 2024. All animals underwent full clinical examination, CT under general anaesthesia, and post-mortem investigation. CT identified 82 pulmonary lesions, including interstitial pneumonia, respiratory complex, gangrenous pneumonia, caseous lymphadenitis, parasitic pneumonia, pulmonary adenocarcinoma, and pulmonary hydatidosis. Tissue density measurements provided additional information regarding disease stage and severity. The level of agreement between CT findings and definitive diagnoses consistently exceeded that of clinical evaluation, reaching almost perfect concordance for several conditions. Moreover, CT revealed concomitant respiratory pathologies within the same animal, many of which were not detected by conventional diagnostic methods. Although thorough individual clinical examination remains essential for the correct interpretation of imaging findings and the accurate diagnosis of respiratory disorders in the field, these results demonstrate that CT provides superior diagnostic accuracy compared with standard approaches and yields valuable insights for both clinical practice and research. Despite its practical limitations, CT could represent a major advance in improving health, welfare, and productivity in sheep farming.