Quantitative ultrasonographic evaluation of chronic and acute renal disease in domestic cats: A new diagnostic marker

Kidney disease, whether in the acute kidney injury (AKI) or chronic kidney disease (CKD) form, is a pathology that affects a high percentage of the adult feline population.Complementary diagnostic methods, including serum measurement of renal biomarkers and abdominal ultrasounds, are used to diagnose and stage urinary tract conditions, as well as to monitor the progression of the clinical condition.Given the practical and frequent use of abdominal ultrasound in clinical settings, this study aimed to evaluate the renal cortical thickness to abdominal aorta ratio as a novel ultrasonographic parameter for detecting early structural changes in kidney disease and its potential to complement established biomarkers, such as creatinine, symmetric dimethylarginine (SDMA), and phosphorus.In this study, a total of 105 felines were included, divided into three groups: healthy felines (N=50), CKD felines (N=44), and AKI felines (N=11).Each feline underwent both ultrasonographic and biochemical evaluation.The results enabled us to establish a cutoff point for the ratio.Additionally, we highlight the potential role of FGF-23 as a biomarker and suggest that further research in this area is warranted.The analysis revealed that a renal cortical thickness to abdominal aorta ratio of 1.4 cm effectively distinguished healthy felines from those with kidney disease, with a sensitivity of 81.8% and a specificity of 86%.However, the ability of this ratio to differentiate CKD from AKI was limited, suggesting that the clinical features of these two conditions may overlap.Furthermore, the renal cortical thickness showed significant correlations with creatinine, highlighting its ability to reflect renal structural alterations in the early stages of CKD.We also observed that phosphorus levels remained stable in the early stages of CKD, likely due to compensatory mechanisms.This finding underscores the need for further validation of biomarkers in this context.In conclusion, this research highlights the importance of integrating ultrasonographic indices with traditional biomarkers, providing a quantitative, non-invasive ultrasonographic marker to distinguish healthy felines from those with kidney disease.