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.

Inclusion criteria

• [Cohort A - Healthy reference]

• Adults ≥18 years old
• Currently undergoing living-donor evaluation at SNUH
• Donor evaluation confirms (a) hepatic steatosis <5% by imaging or biopsy, (b) normal AST/ALT, and (c) absence of chronic liver disease (HBV, HCV, autoimmune, cholestatic, etc.)
• Provided written informed consent [Cohort B + C - Steatotic liver disease]
• Adults ≥18 years old
• Sonographically suspected or confirmed hepatic steatosis on B-mode ultrasound, scheduled for clinical abdominal ultrasound
• Serum AST/ALT results available within 6 weeks of ultrasound, or scheduled
• Provided written informed consent

Exclusion criteria

• • Significant alcohol intake within the past 2 years (>30-60 g/day for males, >20-50 g/day for females)

• Diagnosed or strongly suspected chronic liver disease (active HBV/HCV, autoimmune liver disease, cholestatic liver disease, Wilson's disease, hemochromatosis, etc.)
• Suspected hepatic failure or decompensated cirrhosis (albumin <3.2 g/dL, INR >1.3, direct bilirubin >1.3 mg/dL)
• Ascites, history of variceal bleeding, or acute biliary obstruction rendering stable measurements unfeasible
• History of liver malignancy or treatment for liver malignancy
• History of liver surgery
• Pregnancy or lactation
• Inadequate ultrasound image quality due to obesity, bowel gas, or patient inability to cooperate