Hi Ninad,
> We're interested in doing some voxel based morphometry on the structural
> scans. We scan subjects
> twice, separated by several hours, and were wondering if you can get
> better quality structural analysis by having two structural scans from
> the same subject - or is there little advantage of having a second?
I would agree with Cyril that in the setting you describe, the
disadvantages outweigh the advantages. You get better signal to noise if
you scan longer, and you can set your T1-sequence to collect two "nex"
in one scan. This will definitely increase SNR, but at the cost of much
longer (double :) scanner time.
You could conceivably scan twice, but in order to make use of this you
would have to combine the two images offline, which may or may not work
well (i.e., misregistration may dilute/destroy the advantages you have
from an increased SNR). Overall, I would think that with a solid,
high-resolution, isotropic, good GM/WM contrast and homogenous whole
brain T1 (nothing else, really ;) you are good to go without needing to
scan the same subject twice.
Best,
Marko
--
=====================================================================
Marko Wilke (Dr.med./M.D.)
[log in to unmask]
Universitäts-Kinderklinik University Children's Hospital
Abt. III (Neuropädiatrie) Dept. III (Pediatric neurology)
Hoppe-Seyler-Str. 1, D - 72076 Tübingen
Tel.: (+49) 07071 29-83416 Fax: (+49) 07071 29-5473
=====================================================================
|