Vertebral heart size in chinchillas (Chinchilla lanigera) usingradiography and CT

OBJECTIVE: To determine the vertebral heart size in chinchillas using right and left lateral radiographic views and CT images. To evaluate the agreement between radiographic and CT modalities. METHODS: Twenty-one clinically healthy chinchillas and seven chinchillas with cardiovascular abnormalities underwent cardiovascular examination before thoracic radiographs and thoracic CT obtained under dexmedetomidine-ketamine anaesthesia. Two observers calculated vertebral heart size for radiographic and CT studies. Reference intervals were calculated with the robust method. Agreement between radiographic and CT-derived vertebral heart size was evaluated with Bland-Altman plots and Deming regression. RESULTS: Mean ±sd vertebral heart size for lateral radiographs was 8·9 ±0·62 (reference interval: 7·5 to 10·2) and for CT-derived vertebral heart size was 8·2 ±0·55 (reference interval: 7·1 to 9·4). CT significantly underestimated the radiographic vertebral heart size by 0·66 vertebrae. There was no significant difference between vertebral heart size for right and left lateral radiographic views, or between female and male chinchillas. CLINICAL SIGNIFICANCE: Radiographic vertebral heart size for chinchillas is larger than that reported for similar rodents. Vertebral heart size can be calculated using radiography or CT in chinchillas, but these techniques are not interchangeable.