Computed tomographic bronchioarterial ratio for brachycephalic dogs without pulmonary disease

The bronchoarterial (BA) ratio measured with computed tomography is widely used in human medicine to diagnose bronchial dilation or collapse. Although use of the BA ratio in veterinary medicine has been recently studied, this has not been evaluated in brachycephalic dogs predisposed to bronchial diseases including bronchial collapse. The purpose of this study was to establish BA ratios for brachycephalic dogs and compare the values with those of non-brachycephalic dogs. Twenty-three brachycephalic dogs and 15 non-brachycephalic dogs without clinical pulmonary disease were evaluated. The BA ratio of the lobar bronchi in the left and right cranial as well as the right middle, left, and right caudal lung lobes was measured. No significant difference in mean BA ratio was observed between lung lobes or the individual animals (p = 0.148). The mean BA ratio was 1.08 ± 0.10 (99% CI = 0.98~1.18) for brachycephalic dogs and 1.51 ± 0.05 (99% CI = 1.46~1.56) for the non-brachycephalic group. There was a significant difference between the mean BA ratios of the brachycephalic and non-brachycephalic groups (p = 0.00). Defining the normal limit of the BA ratio for brachycephalic breeds may be helpful for diagnosing bronchial disease in brachycephalic dogs.