Another problem we have been having is artifacts in myelin maps generated from the T1s and T2s acquired on our GE MR750D 3T magnet. Matt and I looked at this in December, and found that in our maps there tended to be an artifactual bias towards increasing T1/T2 ratio towards the center of the brain, leading to apparent dense myelination depp in sulci and light myelination at the tops of sulci that were not real. We've been trying to get to the bottom of this problem since then with no luck, so I'm turning to the list to see if anyone else has successfully created myelin maps on a GE scanner and would be willing to share their sequences (or at least parameters). We've traced the problem (we think) to the difference between the FSPGR that GE scanners use and the MPRAGE, specifically the inversion pulse that seems to make the FSPGR more sensitive to B1 receive field inhomogeneity than the MPRAGE (and the T2 sequence, hence the bias in the T1/T2 ratio). We've compared our seq uence to the one used in the NAMIC dataset obtained on an older GE scanner that Matt used in his original myelin mapping paper and haven't come up with any real differences so far. Any help or insight would be appreciated. Thanks!
__________________________ gaurav patel gauravpa...@gmail.com www.neurofreak.net _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users
