FmExample - MRC CBU Imaging Wiki

Revision 1 as of 2006-07-04 15:01:25

Clear message
location: FmExample



First, get the [ Siemens example dataset (2MB)] (thanks to Michael Benharrosh and Marlene Richter at Princeton University for this). Unzip it and you should have three images in analyze format: an EPI, and the phase and magnitude from a gre_fieldmapping sequence. When you've installed the tool, at the matlab prompt type >> fieldmap_undistort_v3 Then, in the SPM window, choose the following options The EPI before and after undistortion should look like this: There's nothing that can be done about the dropout, but even the large distortion produced by this mis-shimming is mostly corrected. If you are going to collect your own data on a Siemens machine and your system doesn't allow you to reconstruct both mag and phase simultaneously, you'll need to change one line in your pulse sequence. Contact Stefan Thesen at Siemens [his surname] who'll probably be able to help.) First, get the [ Bruker example dataset (34MB)] Run by typing fieldmap_undistort at the SPM prompt, and choose the following options. Where requested, choose the directories and files from your copy of the data. The undistorted EPIs will be in the same directory as the raw EPIs, with the added suffix ‘u’.

[ ]

CBU Imaging Website. © Copyright MRC Cognition and Brain Sciences Unit 2006. Page maintained by: