Hi, Stephen,
I understand that the bvecs need to be relative to the image space. My
question is how do you set up your rule for your software which is not
clear in your original document: should x_1 be the first value of G_read
or G_x of the diffusion weighting gradient direction vector?
Li
-----Original Message-----
From: FSL - FMRIB's Software Library [mailto:[log in to unmask]] On
Behalf Of Steve Smith
Sent: 26 June 2007 09:19
To: [log in to unmask]
Subject: Re: [FSL] bvecs
Hi - the bvecs need to be relative to the image space - otherwise
they don't mean anything to the processing software!
Cheers.
On 25 Jun 2007, at 15:32, Li Sun wrote:
> HI,
> From FSL document, bvecs contains x_1 ..., it seems gradient
> directions
> in the real world, ie, Gx, Gy and Gz but I am not sure if it is
> true. If
> it is, as what I got from my scanner is DWG-read, DWG-phase and
> DWG-slice, I can find out and convert them to corresponding
> orientations
> in the real world. For example, G-read is -Gx, G-phase is -Gz, and
> G-slice is +Gy, and how do I deal with negtive, ie, -Gx and -Gz? Is it
> also related to display the results with FSLView?
> Li
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR 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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