Hi All, We've collected 2 MPRAGEs per subject for a study. This is on a Siemens Tim Trio 3T with a 32-channel head coil, 1mm isotropic data. The SNR looks pretty good as expected. I've read in the freesurfer archive that it is not necessary to use two MPRAGEs with this high quality data, but I'm wondering if there is a drawback to using two since we've already got the data on everyone. I've compared the surface reconstruction and segmentation for a few subjects comparing one vs. two MPRAGEs and there is very little difference that I can see with my naked eye, except that for one subject there were more surface corrections needed for the subject without the two averaged together as opposed to just using the first image series.
So, I guess what I'm asking is given this quality of data, would one recommend systematically using both MPRAGEs since I already have the data, using the first MPRAGE alone to decrease chances of blurring, or taking an extra step and trying to figure out for each individual which has less motion and using that one? Honestly, the last option does not seem to be totally realistic because there is very little motion in any of these images that appears subjectively.
Thanks for your help. Ariel
--------------- Ariel Brown, PhD
Research Fellow Department of Psychiatry Mass General Hospital & Harvard Medical School
Visiting Scientist Department of Brain & Cognitive Sciences Massachusetts Institute of Technology