Quantitative Hepatic Fat Quantification in NAFLD using Ultrasound-Based Techniques: A Review of Literature and their Diagnostic Performance Arinc Ozturk 1 , Joseph R. Grajo 2 , Michael S. Gee 4 , Alex Benjamin 3 , Rebecca E. Zubajlo 3 , Kai Thomenius 3 , Brian W. Anthony 3 , Anthony E. Samir 1 , and Manish Dhyani 1,5,* 1 Center for Ultrasound Research & Translation Department of Radiology Massachusetts General Hospital, Boston, MA 02140, USA 2 Department of Radiology, Division of Abdominal Imaging University of Florida College of Medicine, Gainesville, FL 32610, USA 3 Device Realization and Computational Instrumentation Laboratory Department of Mechanical Engineering Massachusetts Institute of Technology, Cambridge, MA 02139, USA 4 Department of Radiology, Division of Pediatric Imaging Massachusetts General Hospital, Boston, MA 02140, USA 5 Department of Internal Medicine, Carney Hospital, 2100 Dorchester Avenue, Boston, MA 02124, USA Abstract Non-alcoholic fatty liver disease (NAFLD) is a condition that is characterized by the presence of >5% fat in the liver and affects over one billion people worldwide. If adequate and early precautions are not taken, NAFLD can progress to cirrhosis and death. The current reference standard for detecting hepatic steatosis is a liver biopsy. However, due to the potential morbidity associated with liver biopsies, non-invasive imaging biomarkers have been extensively investigated. Magnetic resonance imaging (MRI)-based methods have proven accuracy in quantifying liver steatosis; however, these techniques are costly and have limited availability. Ultrasound-based quantitative imaging techniques are increasingly utilized because of their widespread availability, ease of use, and relative cost-effectiveness. Several ultrasound-based liver fat quantification techniques have been investigated, including techniques that measure changes in the acoustic properties of the liver due to the presence of fat. In this review, we will focus on quantitative ultrasound approaches and their diagnostic performance in the realm of NAFLD. Keywords NAFLD; quantitative; ultrasound; attenuation; backscatter; CAP; speed of sound * Corresponding Author: Manish Dhyani: Tel.: 617-852-8909 manishdhyani@icloud.com. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. HHS Public Access Author manuscript Ultrasound Med Biol. Author manuscript; available in PMC 2019 December 01. Published in final edited form as: Ultrasound Med Biol. 2018 December ; 44(12): 2461–2475. doi:10.1016/j.ultrasmedbio.2018.07.019. Author Manuscript Author Manuscript Author Manuscript Author Manuscript