If you copy parameters on the scanner and the Phase encoding direction is different, the scanner will pop up a warning that it is reverting the phase encoding direction (you then need to change the phase encoding direction back). What I have done in the past to deal with this is do it carefully the first time, but then on subsequent direction sets to copy parameters between the scans with the same phase encode direction.
hth d On Wed, Nov 9, 2016 at 6:59 PM, Glasser, Matthew <[email protected]> wrote: > I believe there is another variable in the sequence that causes the flip. > > Peace, > > Matt. > > From: <[email protected]> on behalf of Thomas DeRamus > <[email protected]> > Date: Wednesday, November 9, 2016 at 5:57 PM > To: "[email protected]" <[email protected]> > Subject: [HCP-Users] Question about UMinn 3T PRISMA dMRI_98_AP & PA Sequence > > Hi HCP Users, > > > Our center recently began using the UMinn 3T PRISMA protocols and I noticed > some minor distortion in the vmPFC region. I was planning on applying FSL's > topup to try and correct for this but when I was making the phase encoding > text file I noticed in the protocol that both the DWI_dir98_AP and > DWI_dir98_PA seem to use A >> P phase encoding. > > > http://lifespan.humanconnectome.org/data/LSCMRR_3T_printout_2014.08.15.pdf > > Does that mean that both are AP? I remember seeing the same when we first > started the AP sequence on the scanner and that doesn't seem correct. > > > > I also noticed the only differences in the the b-tables were for the vector > values for b0's in AP vs PA, with the rest the same. May I ask why this is > or if it has anything to do with the phase encoding? > > > -- > Thomas DeRamus > UAB Department of Psychology, Behavioral Neuroscience > Graduate Research Trainee > Civitan International Research Center > 1719 6th Ave S, Suite 235J, Birmingham, AL 35233 > Phone: 205-934-0971 Email: [email protected], [email protected] > > _______________________________________________ > HCP-Users mailing list > [email protected] > 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 > [email protected] > http://lists.humanconnectome.org/mailman/listinfo/hcp-users _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
