Diagnostic performance of ultrasound attenuation imaging for assessing low-grade hepatic steatosis

To investigate the diagnostic performance of attenuation imaging (ATI) for the assessment of low-grade hepatic steatosis using liver biopsy as the reference standard. The study included 57 potential donor candidates for living liver transplantation who underwent ATI, transient elastography (TE), and liver biopsy for evaluation of hepatic steatosis between February 2020 and April 2020. The attenuation coefficient (AC) from ATI and the controlled attenuation parameter (CAP) from TE were measured for each participant in a random and blind manner. The histologic hepatic fat fraction (HFF) was graded (S0,   66%). The accuracy of ATI for diagnosing hepatic steatosis was compared with that of CAP using ROC analysis. Correlations between AC and HFF were evaluated, and factors affecting AC were determined by linear regression analysis. The median HFF was 3% (range: 0–35%), with 31 (54.4%), 24 (42.0%), and 2 (3.5%) participants being graded as S0, S1, and S2, respectively. The AUCs for the ROCs of AC and CAP for the detection of hepatic steatosis were 0.808 (95% CI: 0.682–0.900) and 0.829 (95% CI: 0.706–0.916), respectively, with the difference not being statistically significant (p = 0.762). AC showed 61.5% of sensitivity and 90.3% of specificity. AC was positively correlated with HFF (p < 0.001). HFF was the only factor significantly affecting AC. ATI showed moderate sensitivity and high specificity in the diagnosis and quantification of hepatic steatosis in low-grade steatosis without fibrosis. Only HFF significantly affected AC. • Attenuation imaging showed moderate sensitivity and high specificity performance in the diagnosis and quantification of hepatic steatosis in low-grade steatosis without fibrosis. • The diagnostic performance of the attenuation coefficient by attenuation imaging did not significantly differ from that of the controlled attenuation parameter by transient elastography in quantifying low-grade steatosis. • The histopathologically determined hepatic fat fraction was the only factor significantly affecting the attenuation coefficient.