Ultrasonographic Measurement of Kidney-to-Aorta Parameters in French Bulldogs.

Ultrasonographic kidney size assessment requires normalization to body size; the kidney length-to-aorta diameter (KL/AoD) ratio improves diagnostic accuracy, yet reference ranges vary across breeds. This study aimed to establish KL/AoD reference values in French Bulldogs and assess the effects of sex, age, body weight, kidney side, and aortic scanning plane. Fifty healthy French Bulldogs were examined. KLs were measured in the sagittal plane, and aortic diameters were recorded just caudal to the left renal artery in longitudinal (AoDL) and transverse (AoDT) planes. Each measurement was taken thrice by a single operator. Intraclass correlation coefficients (ICCs) assessed reproducibility; statistical analyses evaluated potential influencing factors (p < 0.05). ICC values ranged from 0.88 to 0.96, indicating excellent reliability. Mean LKL was 5.06 ± 0.44 cm, and RKL was 5.05 ± 0.44 cm. Mean AoDL was 0.70 ± 0.08 cm, significantly different from AoDT (0.75 ± 0.10 cm). No significant side difference was observed (p > 0.61); data from both kidneys were pooled. Sex significantly influenced all parameters (p < 0.001). Reference intervals, established using the American Society for Veterinary Clinical Pathology (ASVCP) robust method, were KL/AoDL 6.30-8.33 (males: 6.43-8.38; females: 5.97-7.91) and KL/AoDT 5.59-7.92 (males: 5.75-7.97; females: 4.96-7.65). Breed-specific reference intervals were established using the ASVCP robust method, with sex-specific values for KL/AoDL (males: 6.43-8.38; females: 5.97-7.91) and KL/AoDT (males: 5.75-7.97; females: 4.96-7.65), emphasizing the need to account for breed, sex, and aortic scanning plane in ultrasonographic assessment.