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Bug 774 - Realtime motion monitoring in MRI fails

Reported 2011-06-22 14:08:00 +0200
Modified 2011-07-13 14:46:33 +0200
Product: FieldTrip
Component: realtime
Version: unspecified
Hardware: PC
Operating System: Windows
Importance: P1 normal
Assigned to: Arjen Stolk
Depends on:
See also:

Arjen Stolk - 2011-06-22 14:08:50 +0200

This error pops up recently whereas the functionality was fine before. Paul suggests it may be related to a recent change in fMRI sequencing, see message below. Paul will first try to use the old sequence and check whether the motion monitoring still works fine. If so, it is related to the new sequence protocol and adapatations to this sequence need to be made in FT. Dear all (scanning on the Trio), some time ago we informed you about instabilities in single slices on the Trio which occured regularly when using the 32 channel coil. After a lengthy process and discussion with Siemens, it became clear that this is not a site specific problem. Siemens proposes to use a more stable phase correction scheme. We have implemented this in the home made (ME)EPI sequence(BP_ep2d_multipurpose) on the Trio, which should now reduce this fluctuating ghosts. You don't have to do anything, all your protocols still work as before. If you have very long scans, you might still experience slowly increasing ghosts, there is currently no solution on the sequence side for this (except to keep your run length reasonably short). However, the influence of these will be reduced by the (standard) high-pass temporal filtering in the pre-processing steps. If you have any further questions, please contact Paul or me. Success with the scanning, Markus & Paul

Arjen Stolk - 2011-06-22 16:32:46 +0200

Paul tested with the old sequence and the function worked again. Intriguingly, when using the new sequence again, the realtime monitoring also still works fine.. * closed for now *

Robert Oostenveld - 2011-07-13 14:46:33 +0200

changed the status for a whole bunch of resolved bugs to CLOSED