An image registration strategy for multi‐echo fMRI

Functional magnetic resonance imaging (fMRI) based on multiple‐echo T2* mapping has attracted much attention recently. The contrasts in the parametric T2* maps are usually too low to allow direct image registration. In this study, an image registration strategy has been proposed for single‐shot multi‐echo data sets acquired for dynamic T2* mapping. We performed image registration of the T2*‐weighted images before the calculation of the T2* parameter maps using two different strategies. One is to perform separate image registration on each echo and the other is to use the same motion correction parameters extracted from the second echo for all the data. Both strategies increase the number of activated voxels and reduce the effective noise level. The results also indicate that, for a single‐shot dual‐echo image data set, it is slightly preferable to use the second echo for direct image registration and then apply the same motion correction parameters to the first echo images. J. Magn. Reson Imaging 1999;10:154–158. © 1999 Wiley‐Liss, Inc.