RADIOGRAPHIC LIVER SIZE IN PEKINGESE DOGS VERSUS OTHER DOG BREEDS

Differential diagnoses for canine liver disease are commonly based on radiographic estimates of liver size, however little has been published on breed variations. Aims of this study were to describe normal radiographic liver size in Pekingese dogs and to compare normal measurements for this breed with other dog breeds and Pekingese dogs with liver disease. Liver measurements were compared for clinically normal Pekingese (n=61), normal non-Pekingese brachycephalic (n=45), normal nonbrachycephalic (n=71), and Pekingese breed dogs with liver disease (n=22). For each dog, body weight, liver length, T11 vertebral length, thoracic depth, and thoracic width were measured on right lateral and ventrodorsal abdominal radiographs. Liver volume was calculated using a formula and ratios of liver length/T11 vertebral length and liver volume/body weight ratio were determined. Normal Pekingese dogs had a significantly smaller liver volume/body weight ratio (16.73 +/- 5.67, P < 0.05) than normal non-Pekingese brachycephalic breed dogs (19.54 +/- 5.03) and normal nonbrachycephalic breed dogs (18.72 +/- 6.52). The liver length/T11 vertebral length ratio in normal Pekingese (4.64 +/- 0.65) was significantly smaller than normal non-Pekingese brachycephalic breed dogs (5.16 +/- 0.74) and normal nonbrachycephalic breed dogs (5.40 +/- 0.74). Ratios of liver volume/body weight and liver length/T11 vertebral length in normal Pekingese were significantly different from Pekingese with liver diseases (P < 0.05). Findings supported our hypothesis that Pekingese dogs have a smaller normal radiographic liver size than other breeds. We recommend using 4.64x the length of the T11 vertebra as a radiographic criterion for normal liver length in Pekingese dogs. (C) 2012 Veterinary Radiology & Ultrasound.