Steatotic liver disease (SLD) is one of the most common chronic liver diseases worldwide. Distinguishing simple steatosis from metabolic dysfunction-associated steatohepatitis (MASH) with significant fibrosis is clinically important, but liver biopsy - the current standard - is invasive. Recent ultrasound technology allows noninvasive measurement of tissue viscoelasticity, which has been linked to liver inflammation. Samsung Medison's HERA W12 system (S-Viscosity) and Canon Aplio i800 (Dispersion Slope Imaging) both provide vendor-specific viscoelasticity parameters derived from shear-wave dispersion analysis, but their relationship and agreement have not been compared in SLD patients.

This prospective single-center observational study will enroll approximately 95-100 participants in three cohorts: (A) 15-20 living-donor candidates as a healthy reference, (B+C) approximately 80 adults with sonographically suspected or confirmed SLD recruited consecutively. SLD participants will be classified post-hoc into low-MASH-risk (Cohort B) and at-risk MASH (Cohort C) subgroups using a multi-parametric stratification combining liver stiffness (LSM), DeepUSFF (deep-learning-based ultrasound fat fraction), and serum AST. All participants will undergo same-day ultrasound examination with both Samsung HERA W12 and Canon Aplio i800. The primary objective is to evaluate the correlation and agreement between Samsung S-Viscosity and Canon Dispersion Slope. Secondary objectives include deriving a normal reference range from the healthy cohort, comparing viscoelasticity parameters across cohorts, and exploring a Modified US-FAST score.

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 \

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

Adults aged 18 years or older recruited from Seoul National University Hospital, including (1) living-donor candidates undergoing donor evaluation as a healthy reference cohort, and (2) outpatients with sonographically suspected or confirmed hepatic steatosis scheduled for clinical abdominal ultrasound.