French Bulldog study refines kidney-to-aorta ultrasound norms
Bottom line
French Bulldogs may need their own ultrasound reference values when clinicians assess kidney size. A new study in Veterinary Radiology & Ultrasound established breed-specific ultrasonographic kidney-to-aorta parameters for French Bulldogs and found that sex and scanning technique can affect the result. According to the study abstract, the authors reported excellent measurement reliability, with intraclass correlation coefficients ranging from 0.88 to 0.96, and concluded that breed, sex, and the aortic scanning plane should be considered when interpreting the kidney length-to-aortic diameter ratio in this breed. The work builds on earlier canine research that proposed the kidney-to-aorta ratio as a more objective way to assess renal size than absolute kidney measurements alone. (onlinelibrary.wiley.com)
Why it matters: For veterinary professionals, this is a practical reminder that “normal” renal ultrasound measurements may not translate cleanly across breeds, especially in chondrodystrophic, brachycephalic dogs with distinctive body conformation. Earlier studies have shown the kidney-to-aorta ratio can help standardize renal assessment in dogs, while more recent work suggests the metric may also have clinical value in chronic kidney disease evaluation. This French Bulldog-specific paper adds to that literature by suggesting clinicians should be cautious about applying generic cutoffs in a breed that is already overrepresented in primary care and referral imaging caseloads. (pubmed.ncbi.nlm.nih.gov)
What to watch: Whether future studies validate diagnostic cutoffs in French Bulldogs with confirmed renal disease, rather than only establishing reference values in apparently healthy dogs. (onlinelibrary.wiley.com)
Key facts
- Study
- Ultrasonographic Measurement of Kidney-to-Aorta Parameters in French Bulldogs
- Journal
- Veterinary Radiology & Ultrasound
- Breed
- French Bulldogs
- Finding
- Breed-specific ultrasonographic kidney-to-aorta reference values were established
- Factors affecting results
- Sex and aortic scanning plane influenced the measurements
- Reliability
- Intraclass correlation coefficients ranged from 0.88 to 0.96
- Interpretation
- Breed, sex, and the aortic scanning plane should be considered when interpreting the kidney length-to-aortic diameter ratio
A new imaging study suggests French Bulldogs may need their own ultrasonographic reference values for kidney size assessment, rather than relying on generalized canine benchmarks. In Veterinary Radiology & Ultrasound, Elsa Penel, Maxime Cambournac, and Eymeric Gomes reported breed-specific kidney-to-aorta parameters for French Bulldogs, with strong repeatability across measurements and evidence that sex and aortic scanning plane influence the results. (onlinelibrary.wiley.com)
That matters because the kidney length-to-aortic diameter ratio was originally developed to reduce the limitations of absolute renal measurements, which can vary with body size and conformation. A 2007 study in dogs proposed the ratio as an objective ultrasonographic method for estimating renal size, and later work in young dogs found previously described KL:Ao values were generally applicable after 6 months of age. More recently, investigators studying dogs with chronic kidney disease have examined whether the ratio has diagnostic value beyond simple morphometrics. (pubmed.ncbi.nlm.nih.gov)
Against that backdrop, the French Bulldog paper pushes the field toward more breed-specific interpretation. From the abstract, the study established reference values for the kidney-to-aorta diameter ratio in French Bulldogs, accounted for sex differences, and found excellent reliability, with intraclass correlations from 0.88 to 0.96. The authors also emphasized that the aortic scanning plane matters, a notable operational detail for clinicians trying to compare serial studies or align measurements across operators. (onlinelibrary.wiley.com)
While no separate press release or formal outside commentary was readily available in indexed sources, the broader imaging literature supports the study’s premise. The ACVR and ECVDI abdominal ultrasound consensus statement stresses standardized technique, written interpretation, and integration of imaging findings with history and clinicopathologic data. General ultrasound guidance has also long noted that organ orientation and imaging plane can materially alter renal appearance and measurements, which is consistent with this study’s warning about aortic plane effects. (onlinelibrary.wiley.com)
Why it matters: For general practitioners, internists, and radiologists, the study is less about a niche ratio and more about measurement discipline. French Bulldogs are common patients, and they often present with conformational traits that can complicate one-size-fits-all interpretation. If breed and sex shift expected values, and if scanning plane changes the denominator used in the ratio, then a renal measurement that appears borderline on paper may be less meaningful without breed-aware context and consistent technique. That’s especially relevant when monitoring suspected chronic kidney disease, screening incidental findings, or deciding whether mild renomegaly or small kidneys are truly abnormal. (onlinelibrary.wiley.com)
The paper also fits a wider trend in veterinary imaging toward reference intervals tailored to signalment and anatomy, rather than broad canine averages. Similar ratio-based approaches are used elsewhere in ultrasound, including vena cava-to-aorta assessments, and recent canine studies continue to refine where those tools work best and where population-specific norms may be needed. In that sense, the French Bulldog study is incremental, but clinically useful, because it sharpens how a familiar metric should be applied in a very familiar breed. (pubmed.ncbi.nlm.nih.gov)
What to watch: The next step is clinical validation: whether these French Bulldog-specific reference values improve detection of renal disease in real-world patients, and whether future papers translate the findings into practical cutoffs or reporting recommendations for first-opinion and specialty practice. (onlinelibrary.wiley.com)