Associations between respiratory signs and abnormalities reported in thoracic CT scans of cats

To estimate the prevalence of subclinical abnormalities reported in thoracic (CT) scans of cats and to investigate associations between respiratory signs and CT signs.

Retrospective review of signalment, indications, respiratory signs and reported CT findings in a series of cats. Associations between patient variables, respiratory signs and CT signs were analysed using multi-variable regression methods.

Records of 352 consecutive cats were reviewed. Abnormalities affecting thoracic structures were reported in CT scans of 138/179 (77%) cats that did not have respiratory signs; the most prevalent CT findings were pulmonary collapse (41%), evidence of bronchial disease (24%) and space-occupying lesions (21%). Dyspnoea, cough and tachypnoea were associated with space-occupying lesions. Dyspnoea was also associated with pulmonary consolidation and atelectasis. Increasing body weight was associated with pulmonary atelectasis and increasing age was associated with evidence of bronchial disease.

Abnormalities were commonly detected in thoracic CT scans of cats that did not show respiratory signs. The most prevalent abnormality - pulmonary atelectasis - is probably a temporary effect of sedation or anaesthesia. A high prevalence of subclinical abnormalities and limited correlations between clinical signs and CT findings will complicate diagnosis.