Computed tomographic features of presumed normal palatine tonsils in 140 dogs

OBJECTIVES: The purpose of this retrospective study was to describe the CT features of presumed normal canine palatine tonsils. MATERIALS AND METHODS: Pre- and post-contrast head CT studies of 140 dogs without tonsillar disease were included. Subjective evaluation of palatine tonsils included contrast enhancement pattern, differentiation from surrounding soft tissues and presence of gas or mineral within the tonsillar fossae. Quantitative measurements included pre- and post-contrast attenuation, width, height and length. Relationships between palatine tonsillar size and age, bodyweight, brachycephalic versus normocephalic conformation and concurrent regional disease were investigated. Bodyweight-based ranges (≤10.0 kg, 10.1 to 25.0 kg and >25.0 kg) for tonsillar sizes were established to assess differences in tonsillar size across weight categories. RESULTS: Palatine tonsils were identified on CT examination in all dogs. 52.9% palatine tonsils were poorly differentiated from adjacent soft tissues in post-contrast series, 86.1% tonsillar fossae contained gas and 7.9% contained mineral. Mean palatine tonsillar width was 6.9 mm (SD 2.2 mm), height 6.5 mm (SD 2.0 mm) and length 19.1 mm (SD 4.5 mm). Median attenuation pre-contrast was 50.8 HU (range 22.6 to 82.1 HU), significantly increasing to 89.4 HU post-contrast (range 49.7 to 128.0 HU). Tonsillar size was negatively correlated with age and positively correlated with bodyweight. There were statistically significant increases in tonsillar size with each ascending bodyweight range. No statistically significant size differences were found between brachycephalic and normocephalic breeds, nor between dogs with or without concurrent regional disease. CLINICAL SIGNIFICANCE: These findings may serve as informative references for evaluating palatine tonsils on CT examinations in healthy dogs and provide comparisons for assessing tonsillar pathology.