Fig. 1.

a) Individual transients pre- and post-fMRI PRESS (plotted in blue and red, respectively) from one of the highest drift datasets. The frequency offset derived from modeling the water signals is plotted (middle). Three hundred sixty averages correspond to 30 min total scan duration. Panel (b) shows water offset traces for all 95 scanners before and after fMRI for GE (green and light blue), Philips (orange and brown) and Siemens (blue and purple). Panel (c) shows the pre-fMRI PRESS traces and the same period (5:20 min) for post-fMRI traces.