Inter-observer agreement of ultrasound shear wave elastography measurements of renal cortical stiffness and morphometry in diabetic patients

Shear wave elastography (SWE) is increasingly used in renal imaging to assess cortical stiffness, potentially reflecting tissue alterations in conditions such as diabetic kidney disease. However, the reproducibility of SWE and traditional morphometric measurements remains a challenge. This is primarily due to factors such as operator dependency, variations in patient positioning, differences in breathing patterns during scanning, and the inherent technical limitations of ultrasound imaging. This pilot study aimed to assess the inter-observer agreement in ultrasound-based measurements of renal cortical stiffness, cortical thickness, length, and width in diabetic patients. In this prospective study, 30 adult diabetic patients underwent renal ultrasound performed by two independent observers. Parameters measured included cortical stiffness (kPa), cortical thickness (cm), kidney length (cm), and width (cm). Intraclass correlation coefficients (ICC), Bland-Altman plots, and Pearson's correlation were used to evaluate inter-observer variability and bias. Cortical stiffness measurements demonstrated good inter-observer agreement (ICC = 0.824 for left kidney, 0.762 for right kidney). Morphometric measurements such as renal length and width showed excellent agreement (ICC > 0.9), although systematic and proportional biases were present. Cortical thickness exhibited poor agreement (ICC < 0.5), despite the absence of systematic bias. SWE has potential role in detecting early changes in renal tissue stiffness. Cortical stiffness shows reproducible between observers and can be considered reliable in diabetic patient. Morphometric parameters show high variability in certain aspects, particularly cortical thickness.