1 and 2 performed similarly when we compared them. 3 is not a good idea, as GRE images have signal dropout that is asymmetric and will mess up the registration that underlies the reversed phase encoding direction method.
Matt. From: <hcp-users-boun...@humanconnectome.org<mailto:hcp-users-boun...@humanconnectome.org>> on behalf of Chris Filo Gorgolewski <krzysztof.gorgolew...@gmail.com<mailto:krzysztof.gorgolew...@gmail.com>> Date: Monday, October 5, 2015 at 6:25 PM To: "Harms, Michael" <mha...@wustl.edu<mailto:mha...@wustl.edu>> Cc: Hcp Users <hcp-users@humanconnectome.org<mailto:hcp-users@humanconnectome.org>> Subject: Re: [HCP-Users] Use of spin-echo EPI scans for distortion correction of fMRI data Thank you for the clarification! A quick follow up question. Do you know of any systematic comparison of: 1) standard fieldmap (two pairs of phase and magnitude images) 2) fieldmap derived from a pair of spin echo images with opposite phase encoding directions 3) fieldmap derived from a pair of gradient echo images with opposite phase encoding directions (for example the reference images - SBRef) ? Best regards, Chris On Mon, Oct 5, 2015 at 4:04 PM, Harms, Michael <mha...@wustl.edu<mailto:mha...@wustl.edu>> wrote: Yes, that is correct. (The SBRef for the BOLD scans are gradient-echo images). -- Michael Harms, Ph.D. ----------------------------------------------------------- Conte Center for the Neuroscience of Mental Disorders Washington University School of Medicine Department of Psychiatry, Box 8134 660 South Euclid Ave. Tel: 314-747-6173<tel:314-747-6173> St. Louis, MO 63110 Email: mha...@wustl.edu<mailto:mha...@wustl.edu> From: Chris Filo Gorgolewski <krzysztof.gorgolew...@gmail.com<mailto:krzysztof.gorgolew...@gmail.com>> Date: Monday, October 5, 2015 5:13 PM To: Hcp Users <hcp-users@humanconnectome.org<mailto:hcp-users@humanconnectome.org>> Subject: [HCP-Users] Use of spin-echo EPI scans for distortion correction of fMRI data Hi, After reading the preprocessing scripts (see https://github.com/Washington-University/Pipelines/blob/master/fMRIVolume/scripts/DistortionCorrectionAndEPIToT1wReg_FLIRTBBRAndFreeSurferBBRbased.sh#L271) and the paper (see http://www.sciencedirect.com/science/article/pii/S1053811913005053) I figured that HCP is using a pair of spin-echo EPI scans to estimate a fieldmap later used to correct fMRI data for distortions (in contrast to using a pair of SBRef images). We had a bit of a discussion in the lab about this and I just wanted someone from the HCP team to confirm this. Thanks in advance! Best, Chris _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org<mailto:HCP-Users@humanconnectome.org> http://lists.humanconnectome.org/mailman/listinfo/hcp-users ________________________________ The materials in this message are private and may contain Protected Healthcare Information or other information of a sensitive nature. If you are not the intended recipient, be advised that any unauthorized use, disclosure, copying or the taking of any action in reliance on the contents of this information is strictly prohibited. If you have received this email in error, please immediately notify the sender via telephone or return mail. _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org<mailto:HCP-Users@humanconnectome.org> http://lists.humanconnectome.org/mailman/listinfo/hcp-users _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users
