This multicenter prospective study aims to evaluate the correlation between quantitative ultrasound fat fraction (USFF) and MRI-PDFF (Proton Density Fat Fraction) for liver fat quantification in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). The study will compare the diagnostic accuracy of quantitative ultrasound imaging against MRI-PDFF as the reference standard.

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a common liver disease requiring accurate assessment for treatment planning and monitoring. While liver biopsy remains the gold standard, it is invasive with potential complications. MRI-PDFF has emerged as an accurate non-invasive method, but it is expensive and has limited accessibility. Quantitative ultrasound techniques using RF data have been developed to provide objective liver fat assessment.

Objective: To prospectively evaluate the correlation between quantitative ultrasound-derived fat fraction (DeepUSFF) and MRI-PDFF in patients with suspected MASLD across different ethnicities and varying degrees of hepatic steatosis.

Methods: This prospective multicenter study will recruit 62 patients (31 from each participating center) suspected of having MASLD. All participants will undergo both quantitative ultrasound examination and non-contrast liver MRI within one week. The primary endpoint is the correlation coefficient between ultrasound fat fraction and MRI-PDFF. Secondary endpoints include diagnostic accuracy metrics and inter-observer reproducibility.

Inclusion Criteria:

• Patients with clinically suspected MASLD based on abnormal ultrasound or liver function tests requiring liver ultrasound or MRI examination
• BMI ≥25 kg/m² or waist circumference >90 cm (male) or >80 cm (female), suggesting high likelihood of fatty liver disease
• Living liver transplant donors requiring preoperative liver ultrasound or MRI examination
• Age ≥18 years
• Understanding and signing informed consent

Exclusion Criteria:

• Significant alcohol consumption in the past 2 years:

Male: ≥30-60g/day average alcohol intake Female: ≥20-50g/day average alcohol intake

-Chronic liver disease:

Histological diagnosis of chronic liver disease HBsAg positive Anti-HCV positive Other suspected chronic liver diseases

-Liver failure:

Serum albumin <3.2 g/dL INR >1.3 Direct bilirubin >1.3 mg/dL

• History of esophageal varices, ascites, hepatic encephalopathy, or acute biliary obstruction
• History of liver cancer diagnosis or treatment
• History of liver surgery
• Pregnancy
• Inability to obtain adequate liver ultrasound imaging:

Patient cooperation impossible Inadequate image acquisition as determined by investigator

-Inability to obtain adequate liver MRI imaging: Patient cooperation impossible Severe obesity preventing MRI examination MRI contraindications (cardiac pacemaker, etc.) Other factors preventing adequate imaging as determined by investigator

De-identified quantitative ultrasound measurements (USFF values) De-identified MRI-PDFF measurements Anonymized clinical variables (age, BMI, laboratory values) Statistical analysis datasets without patient identifiers

Beginning 12 months following article publication

Requests should be directed to the corresponding author with a detailed research proposal Data sharing agreements will be required Institutional review board approval may be required for secondary analyses