Samsung S-Viscosity vs Canon Dispersion Slope in Steatotic Liver Disease (SAVID-SLD)

Background: Two-dimensional shear wave elastography (2D SWE) is widely used to quantify liver stiffness for fibrosis assessment, but stiffness can be confounded by inflammation, congestion, and other factors. Frequency-dependent shear-wave dispersion analysis yields viscosity-related parameters that may reflect tissue inflammation. Canon's Dispersion Slope Imaging (DS, \[m/s\]/kHz) has been validated against histology in the multicenter iLEAD study (Sugimoto et al., Radiology 2024) and shown to correlate with lobular inflammation in MASLD. Samsung Medison has recently introduced S-Viscosity within the S-Shearwave platform of the HERA W12 R30 system, providing dispersion-derived viscosity parameters from a single SWE acquisition; however, head-to-head comparison with Canon DS in SLD patients has not been reported. Hypothesis: Samsung S-Viscosity and Canon Dispersion Slope, both derived from frequency-dependent shear-wave analysis, will demonstrate moderate-to-strong correlation and clinically acceptable inter-vendor agreement in patients with steatotic liver disease. Study Design: Single-center, prospective, non-interventional observational study. Adult participants (≥18 years) will be enrolled into three cohorts: Cohort A (Healthy reference, n=15-20): living-donor candidates with confirmed steatosis \<5%, normal LFTs, and exclusion of chronic liver disease, recruited during routine donor evaluation. Cohort B+C (SLD, n≈80): adults with sonographically suspected or confirmed hepatic steatosis scheduled for clinical abdominal ultrasound, recruited consecutively. Post-hoc stratification of SLD participants uses LSM (2D S-SWE), DeepUSFF, and serum AST with institutionally-validated cutoffs (LSM 6.82 kPa for ≥F2 fibrosis; DeepUSFF asymmetric cutoffs of 7.86% for \<S1 rule-out and 15.05% for ≥S2 rule-in; AST 40 U/L institutional ULN) to define Low MASH risk (Cohort B), At-risk MASH (Cohort C), and an Indeterminate zone. Procedures: All participants undergo same-day ultrasound examinations on both Samsung HERA W12 (CA 1-7S probe) and Canon Aplio i800 (i8C1 probe) in randomized order, with operators blinded to LFT results at the time of scanning. From the right hepatic lobe via right intercostal approach after a minimum 4-hour fast: Samsung acquisitions include 2D S-Viscosity, 2D S-SWE, TAI, and DeepUSFF (5 measurements per parameter, 2 sessions); Canon acquisitions include Dispersion Slope Imaging and 2D SWE (5 measurements). Median values are used as representative. Statistical Analysis: Primary endpoints - Pearson or Spearman correlation between Samsung S-Viscosity and Canon Dispersion Slope (with 95% CI), and Bland-Altman analysis of inter-vendor agreement (mean bias and 95% limits of agreement). Sample size of approximately 80 SLD participants provides adequate precision for both correlation (r=0.4 to 0.6) and Bland-Altman limits-of-agreement estimation (±0.5 SD precision). Secondary endpoints include 95% reference interval derivation from Cohort A (n≥15 for nonparametric estimation), inter-cohort comparisons, Modified US-FAST score exploration, reproducibility (ICC and CV%), and technical success rate.