Hello Stephen,
Thanks for your reply.
When a slice is thinker than 6mm, it is treated as a 2D slice.
Afterwards the results are unacceptable. We are using the Resample
function under Transformation, Toolbox to cut a thick slice into two 3mm
slices. Then the results are acceptable. We only use FLIRT for
co-registration.
Thanks again.
Yang
-----Original Message-----
From: FSL - FMRIB's Software Library [mailto:[log in to unmask]] On
Behalf Of Stephen Smith
Sent: Friday, April 15, 2005 1:08 AM
To: [log in to unmask]
Subject: Re: [FSL] questions 7mm thick slices
Hi, yes, 7mm is getting a little thick to expect accurate results out
of SIENA, though it should still work reasonably IF the image quality is
good in other respects. I'm slightly confused as to why upsampling the
7mm
data makes a difference to SIENA, as it's not as if there's any new
_information_ in the data - in what ways were the results improved? Did
you just use FLIRT to upsample the data?
Cheers, Steve.
On Thu, 14 Apr 2005, Yang Min wrote:
> Hello,
>
>
>
> We are using the siena package to analyze brain change on Multiple
>
> Sclerosis patients over time. We have some MR data from 1999-2001 and
>
> the scans were acquired at 7mm apart. Does siena require thinner
>
> slices? It appears that our current 3mm MR data is fine with siena,
>
> but our 7mm data gives very inconsistent results or without any value.
>
> We resliced the 7mm data into 3mm slices and it appears that the
siena
> package works fine.
>
> What would you suggest?
>
>
>
> Sincerely,
>
> Yang
>
>
>
>
--
Stephen M. Smith DPhil
Associate Director, FMRIB and Analysis Research Coordinator
Oxford University Centre for Functional MRI of the Brain
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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