In this study, displacements of brain tissue in six human subjects and one gelatin “phantom” were measured by MR elastography on two MR scanners. Both were Siemens Trio 3T MRI scanners. One Trio scanner was located at the Beckman Institute at University of Illinois in Urbana-Champaign (UIUC; four subjects) and the other Trio scanner was at the Center for Clinical Imaging Research at Washington University in St. Louis (WU; two subjects and gel phantom). After publication, we discovered that the default motion-encoding gradient strength was not identical on the two scanners, but was lower on the WU scanner than on the UIUC scanner (20 mT/m versus 26 mT/m on the UIUC scanner). Thus, in two subjects and the gel phantom, the estimated displacement amplitudes should be higher by a factor equal to $26/20$ (1.3).

Correcting this error changes estimates of mean and standard...