||<100% bgcolor="#FFFF99">'''Using a field-map to undistort EPIs'''[[BR]][wiki:FmBackground Background][[BR]][wiki:FmPower Improvement in power!][[BR]][wiki:FmFieldmaps Acquiring fieldmaps][[BR]][wiki:FmDownload Download][[BR]][wiki:FmRequirements What you'll need to undistort an EPI data series][[BR]][wiki:FmReference Guide and reference][[BR]][wiki:FmExample Step-by-step example][[BR]][wiki:FmBatch Batch mode]|| = Improvement in power in RFX analysis = What you really care about is probably power to detect functional activation. Here are the results of a random effects analysis (N=12) of a motor cortex localiser task. Subjects were asked to press a button either with a finger of their left hand (left column) or their right (right column). The data were analysed with or without undistortion. http://imaging.mrc-cbu.cam.ac.uk/images/motortask.gif Functional images (thresholded at 0.001 uncorrected) are shown superimposed on the SPM T1 template. The numbers in the top left of each image indicate peak t values over the whole volume. After the application of undistortion, clear activation can be seen in motor cortex (BA 4) on each side.