Evaluation of Liver Stiffness in Obesity: A Comparison of Canon Aplio i800 2d-Shear Wave Elastography and Siemens Sequoia Point Shear Wave Elastography

Abstract

<i>Introduction:</i> Accurate assessment of liver fibrosis is essential for clinical management of patients with chronic liver disease. This study aimed to compare the diagnostic performance and agreement between two different ultrasound elastography systems, Canon Aplio i800 (2D-SWE) and Siemens Sequoia (pSWE), in an obese population with various liver pathologies and to identify factors influencing measurement discrepancies. <i>Methods:</i> In this prospective cross-sectional study, 89 adult patients with an increased risk of fatty liver disease underwent liver stiffness measurements using the Canon Aplio i800 (2D-SWE) and Siemens Sequoia (pSWE) systems. Patients were categorized into fibrosis stages (F0-F4) according to the established cut-off values. Agreement between systems was assessed using correlation coefficients, Bland-Altman analysis, and Cohen's kappa. Regression analysis was performed to identify the factors influencing measurement variability. <i>Results:</i> The study included 63 males and 25 females (mean age, 52 years; mean BMI: 29.5 kg/m²). The overall correlation between systems was moderate (r=0.68, 95% CI: 0.54-0.77), with a stronger correlation in F4 patients (r=0.575) than in non-F4 patients (r=0.237). For the F4 classification, both systems showed excellent sensitivity (97.5%), but Sequoia demonstrated superior specificity (100% vs. 79.6%) and overall accuracy (98.9% vs. 87.9%). The mean difference between measurements was -1.44 kPa overall, with larger discrepancies in F4 patients (-5.79 kPa) than in non-F4 patients (0.60 kPa). Multivariate analysis identified the skin-to-capsule distance and shear wave dispersion as the most significant factors affecting measurement variability, particularly for the Aplio system. <i>Conclusion:</i> Although both systems demonstrated high diagnostic performance for advanced fibrosis, the Sequoia system showed superior specificity and accuracy in the obese population. Measurements between systems are not directly interchangeable, particularly in patients with advanced fibrosis, increased subcutaneous fat, or liver inflammation. The Society of Radiologists in Ultrasound "rule of four" remains appropriate for liver stiffness classification, but system-specific considerations are necessary for accurate clinical interpretation.