Inter-sonographer reproducibility of quantitative ultrasound outcomes
and shear wave speed measured in the right lobe of the liver in adults
with known or suspected non-alcoholic fatty liver disease
Ethan Z. Sy
Andrew S. Boehringer
Michael P. Andre
John W. Erdman Jr
Claude B. Sirlin
William D. O’Brien Jr
Received: 20 March 2018 /Revised: 27 April 2018 / Accepted: 14 May 2018
European Society of Radiology 2018
Objectives To assess inter-sonographer reproducibility of ultrasound attenuation coefficient (AC), backscatter coefficient (BSC)
and shear wave speed (SWS) in adults with known/suspected non-alcoholic fatty liver disease (NAFLD).
Methods The institutional review board approved this HIPAA-compliant prospective study; informed consent was obtained.
Participants with known/suspected NAFLD were recruited and underwent same-day liver examinations with a clinical scanner.
Each participant was scanned by two of the six trained sonographers. Each sonographer performed multiple data acquisitions in
the right liver lobe using a lateral intercostal approach. A data acquisition was a single operator button press that recorded a B-
mode image, radio-frequency data, and the SWS value. AC and BSC were calculated from the radio-frequency data using the
reference phantom method. SWS was calculated automatically using product software. Intraclass correlation coefficient (ICC)
and within-subject coefficient of variation (wCV) were calculated for applicable metrics.
Results Sixty-one participants were recruited. Inter-sonographer ICC was 0.86 (95% confidence interval: 0.77–0.92) for AC and
0.87 (0.78–0.92) for log-transformed BSC (logBSC =10log
BSC) using one acquisition per sonographer. ICC was 0.88 (0.80–
0.93) for both AC and logBSC averaging 5 acquisitions. ICC for SWS was 0.57 (0.29–0.74) using one acquisition per sonog-
rapher, and 0.84 (0.66–0.93) using 10 acquisitions. The wCV was ~7% for AC, and 19–43% for SWS, depending on number of
Conclusions Hepatic AC, BSC and SWS measures on a clinical scanner have good inter-sonographer reproducibility in adults
with known or suspected NAFLD. Multiple acquisitions are required for SWS but not AC or BSC to achieve good inter-
• AC, BSC and SWS measurements are reproducible in adults with NAFLD.
• Inter-sonographer reproducibility of SWS measurement improves with more acquisitions being averaged.
• Multiple acquisitions are required for SWS but not AC or BSC.
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s00330-018-5541-9) contains supplementary
material, which is available to authorized users.
* William D. O’Brien, Jr
Bioacoustics Research Laboratory, Department of Electrical and
Computer Engineering, University of Illinois at Urbana-Champaign,
306 North Wright Street, Urbana, IL 61801, USA
Siemens Healthineers USA, 22010 South East 51st Street,
Issaquah, WA 98029, USA
Liver Imaging Group, Department of Radiology, University of
California at San Diego, 9452 Medical Center Drive, La
Jolla, CA 92037, USA
Department of Radiology, University of California at San Diego,
9500 Gilman Drive, San Diego, CA 92093, USA
San Diego VA Healthcare System, San Diego, CA, USA
Department of Food Science and Human Nutrition, University of
Illinois at Urbana-Champaign, 905 South Goodwin Avenue,
Urbana, IL 61801, USA
NAFLD Research Center, Division of Gastroenterology, Department
of Medicine, University of California at San Diego, 9500 Gilman
Drive, La Jolla, CA 92093, USA