Objectives <p>Our objective was to provide further evidence regarding the diagnostic accuracy of ultrasound-guided attenuation parameter (UGAP) for detecting hepatic steatosis in a selected and homogeneous cohort of patients with impaired glucose tolerance using magnetic resonance imaging-proton density fat fraction (MRI-PDFF) as the standard reference method.</p> Materials and methods <p>From October 2023 to March 2024, individuals with impaired glucose tolerance and suspected metabolic dysfunction-associated steatotic liver disease (MASLD) who underwent abdominal ultrasound and MRI-PDFF were enrolled in this prospective study. Multivariable linear regression was performed to assess independent factors associated with UGAP. The correlation between UGAP, and MRI-PDFF was evaluated using the Pearson correlation coefficient. The diagnostic performance of the UGAP for hepatic steatosis was assessed using the area under the receiver operating characteristic curve (AUC).</p> Results <p>A total of 193 participants (median age, 35 years; IQR, 25–48 years; 98 male) were evaluated, including 90 participants (47%) with MASLD. Body mass index (BMI), waist circumference, and skin-liver capsule distance were independently associated with UGAP. UGAP was strongly and positively correlated with MRI-PDFF (<i>r</i> = 0.890, <i>p</i> &lt; 0.001). The AUCs of UGAP for diagnosing hepatic steatosis ≥ S1 (MRI-PDFF ≥ 6.4%), ≥ S2 (MRI-PDFF ≥ 17.4%), and ≥ S3 (MRI-PDFF ≥ 22.1%) were 0.980 (95% CI: 0.957–1.000), 0.955 (95% CI: 0.912–0.999), and 0.985 (95% CI: 0.970–1.000), respectively.</p> Conclusions <p>UGAP could accurately diagnose hepatic steatosis and estimate the hepatic fat fraction.</p> Critical relevance statement <p>UGAP has high diagnostic performance for hepatic steatosis. UGAP offers a method of quantifying liver fat content similar to MRI-PDFF, which is anticipated to be beneficial in the long-term monitoring of patients with impaired glucose tolerance.</p> Key Points <p><UnorderedList Mark="Bullet"> <ItemContent> <p>Hepatic steatosis is an early factor that causes liver damage in MASLD.</p> </ItemContent> <ItemContent> <p>UGAP has an accurate diagnostic performance for hepatic steatosis.</p> </ItemContent> <ItemContent> <p>UGAP was positively correlated with MRI- proton density fat fraction.</p> </ItemContent> <ItemContent> <p>Some clinical parameters may affect UGAP measurement.</p> </ItemContent> </UnorderedList></p> Graphical Abstract <p></p>