Hi Gergely, Was this collected on a Siemens scanner? If so, the Siemen's MPRAGE sequence is such that the "slices" form the "inner loop" of the acquisition -- that is "Number of slices" lines in k-space are acquired for each TR period. So, having a differing number of slices theoretically has an impact on the spatial filtering properties of the acquisition. My intuition suggests to me that this would be a minor effect that would be washed out by other noise and inter-subject differences. But perhaps others have quantitative results in this regard...? (e.g., collecting both sequences on a set of subjects and then looking for differences using an intra-subject design).
cheers, -MH
Hi Freesurfers,
I have a quick question:
I have two groups, both measured on the same scanner, with the same sequence (3D MPRAGE), and with almost the same parameters.
TR/TE/TI/BW/MATRIX/FOV/FOV-phase/Flip angle/Slice thickness/in-plane resolution... everything is the same, but the number of slices. Total measurement time was also the same.
One group was measured with 160 slices, the other with 176.
Can I compare the two groups in freesurfer?
Thanx,
-- Gergely Orsi biologist - research associate Diagnostic Center of Pécs H-7623 Pécs, Rét str. 2. Tel.: 0036-70-3174676 E-mail: gergo.orsi@gmail.com _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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