Ultrasonographic renal cortical thickness to abdominal aorta internal diameterin healthy cats and chronic kidney disease cats

Chronic kidney disease (CKD) is a one of the most common disorder in cats, particularly in aging populations. Early detection and accurate monitoring are crucial for effective disease management. This study aims, first, to evaluate the ultrasonographic parameters, including renal cortical thickness (RCT), medullary thickness (MT), renal length (RL), abdominal aorta diameter (Ao) and ratios, including RCT/Ao, RCT/MT, RCT/RL, MT/Ao and RL/Ao compared between clinically healthy and CKD cats. Second, to evaluate the correlations of ultrasonographic parameters with blood renal functions including blood urea nitrogen (BUN), creatinine (Cr) and symmetric dimethylarginine (SDMA) and also correlation with age, body weight (BW) and sex. Finally, to establish the cut-off values of ultrasonographic parameters for clinical evaluation CKD in cats. A total 60 cats, including 30 clinically healthy cats and 30 CKD cats were enrolled in this study. All ultrasonographic parameters were performed in sagittal, dorsal and transverse planes (only RL and Ao were performed in sagittal plane). We found that RCT, RCT/Ao, RCT/MT and RCT/RL values were significantly lower in CKD cats than those of clinical healthy cats, especially in transverse plane (P < 0.001; P < 0.0001; P < 0.001; P < 0.0001, respectively). MT and MT/Ao were lower values in CKD than those of clinically healthy. But the significant difference was observed only in dorsal plane (P = 0.0009; P = 0.022, respectively). RL and RL/Ao were lower in CKD cats but only RL was found significant difference between groups (P = 0.03). Additionally, RCT and its ratio parameters had strongest and significant negative correlation with BUN, Cr and SDMA than those MT and RL parameters. Age, BW and sex did not affect to all RCT parameters in this study. Moreover, we found that RCT and its ratio including RCT/Ao, RCT/MT and RCT/RL, especially on transverse plane, had higher sensitivity and specificity of cut-off values than others. The cut-off values, sensitivity and specificity of RCT parameters were RCT (0.673 cm, 80%, 73.33%), RCT/Ao (1.757, 73.33, 83.33%), RCT/MT (0.626, 76.67%, 93.33%) and RCT/RL (0.172, 86.67%, 73.33%). In conclusion, the findings suggested that RCT and its ratio parameters are recommended in clinical evaluation and monitoring of feline CKD.