The study consisted of three arms: A, B, and C (Figure 1). Arm A tested four ultrasound devices: the Siemens Acuson S3000, Toshiba Aplio 500 (software version 5.0), Philips Epiq 7, and GE Logiq E9. We chose the Siemens S3000 ultrasound scanner as the reference device because the largest number of studies exist for this ultrasound scanner or its predecessor, the Siemens S2000[27 (link)-29 (link)]. The Siemens S3000 and Philips Epiq 7 devices use p-SWE technology, and the Aplio 500 Toshiba and GE Logiq E9 devices use 2D-SWE technology. Study arm A showed that the Toshiba Aplio 500 device (software version 5.0) generated strongly deviating results compared to the other ultrasound devices tested. Due to the divergent results between Toshiba Aplio 500 (version 5.0) and the other tested devices, especially the reference device, the Toshiba Aplio 500 was tested using software version 6.0 against the Siemens Acuson S3000 in study arm B. In study arm C, the results of study arms A and B were compared to investigate the differences between the two different software versions of the Toshiba Aplio 500. Study arm A was conducted from May 2015 to September 2015 and study arm B from November 2016 to April 2017.