yes, it's definitely not recommended. On Tue, 20 Oct 2009, Narly A Golestani wrote:
> > Hello all, > > I would like to know whether the T1 parameters such as TR, TE, TI, and > flip angle can systematically influence mean curvature values obtained by > recon-all -all. > > I have processed 2 data sets with the following T1 parameters, and am > noticing that the mean curvature values systematically bigger in the > former compared to the latter data set in 78% of the brain regions > segmented in the default (Desikan) atlas. > > data set 1: > TR=12.24, TE=3.56, TI=530.00, flip angle=23.00 > Original Data has (1, 1, 1) mm size and (240, 256, 176) voxels > > data set 2: > TR=20.66, TE=8.42, TI=640.00, flip angle=25.00 > Original Data has (1, 1, 1) mm size and (224, 256, 176) voxels > > More generally, I would like to confirm that it's not recommended to > combine data based on different scanning parameters in one study, due to > possible systematic differences in the segmentation output related to > scanning parameters. > > thanks in advance and all the best, > Narly. > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
