Ultrasonographic Measurement of the Renal Cortical Thickness-to-Abdominal Aortic Ratio in Healthy Rabbits.

Abstract

Background: Ultrasonography is a preferred diagnostic tool for renal disease in clinical practice. Kidney size is a commonly used morphological parameter in renal assessment; however, it lacks sensitivity for early disease detection. Cortical parameters, particularly cortical thickness, correlate more strongly with early renal disease, as the cortex plays a key role in filtration and is highly vulnerable to injury. Rabbits, widely kept as pets, have distinct renal anatomy and are prone to kidney diseases, making them a relevant model for renal studies. Previous studies have shown that ultrasonography can effectively measure kidney size in rabbits, correlating with body weight.

Objectives: This study aimed to establish a normative ratio of renal cortical thickness to the internal diameter of the abdominal aorta in healthy rabbits.

Methods: Sixty healthy adult male mixed-breed rabbits underwent ultrasonographic evaluation. Renal cortical thickness and abdominal aortic diameter were measured, ensuring that only rabbits without clinical or ultrasonographic signs of kidney disease were included.

Results: Pearson correlation analysis revealed a positive correlation between renal cortical thickness, aortic diameter and body weight. However, the ratio of renal cortical thickness to aortic diameter remained independent of body weight.

Conclusions: This study established a normative reference range for renal cortical thickness relative to aortic diameter in rabbits, providing a novel diagnostic parameter for renal assessment. The confidence intervals for the ratio were 0.82 (0.77-0.87) to 1.35 (1.30-1.40) for the left kidney and 0.79 (0.74-0.84) to 1.33 (1.27-1.38) for the right kidney, marking the first report of this method in the literature.