Excessive liver fat (steatosis) is now the most common cause of chronic liver disease worldwide and is an independent risk factor for cirrhosis and associated complications. Accurate and clinically useful diagnosis, risk stratification, prognostication, and therapy monitoring require accurate and reliable biomarker measurement at acceptable cost. This article describes a joint effort by the American Institute of Ultrasound in Medicine (AIUM) and the RSNA Quantitative Imaging Biomarkers Alliance (QIBA) to develop standards for clinical and technical validation of quantitative biomarkers for liver steatosis. The AIUM Liver Fat Quantification Task Force provides clinical guidance, while the RSNA QIBA Pulse-Echo Quantitative Ultrasound Biomarker Committee develops methods to measure biomarkers and reduce biomarker variability. In this article, the authors present the clinical need for quantitative imaging biomarkers of liver steatosis, review the current state of various imaging modalities, and describe the technical state of the art for three key liver steatosis pulse-echo quantitative US biomarkers: attenuation coefficient, backscatter coefficient, and speed of sound. Lastly, a perspective on current challenges and recommendations for clinical translation for each biomarker is offered.

© RSNA, 2022

过多的肝脂肪（脂肪变性）现在是全世界慢性肝病的最常见原因，并且是肝硬化和相关并发症的独立危险因素。准确和临床有用的诊断、风险分层、预后和治疗监测需要以可接受的成本进行准确可靠的生物标志物测量。本文介绍了美国医学超声研究所 (AIUM) 和 RSNA 定量成像生物标志物联盟 (QIBA) 为肝脂肪变性定量生物标志物的临床和技术验证制定标准的共同努力。AIUM 肝脂肪定量工作组提供临床指导，而 RSNA QIBA 脉冲-回波定量超声生物标志物委员会开发了测量生物标志物和减少生物标志物变异性的方法。在本文中，作者介绍了肝脏脂肪变性定量成像生物标志物的临床需求，回顾了各种成像模式的现状，并描述了三种关键的肝脏脂肪变性脉冲回波定量美国生物标志物的技术现状：衰减系数、反向散射系数和声音的速度。最后，就每种生物标志物的临床转化提出了当前挑战和建议的观点。

© 北美放射学会，2022