Alle,
Of course, forgive me. The gradient echo T1 MRI was acquired as follows:
256 × 128 matrix, 124 slices, 1.2mm thickness, TE=8ms, TR=35ms, flip angle=
30, 24cm field of view
The images were converted to SPM/Analyze using "GE2Analyze" Matlab code,
written by Souheil Inati. In SPM, they are reported as having 256 x 256 x
124 dimensions, int16 datatype, voxel size = .938 x .938 x 1.2, origin= 129,
129, 62.5
The PET image was originally in ECAT 6.5 format, and converted using MRIcro.
Dimensions 128 x 128 x 31, int16 datatype, and voxel size 1.00 x 1.00 x
3.37, origin 62.1 63.7 3.91.
Any other information that would be helpful? Thanks for tackling the
problem.
-----Original Message-----
From: Alle Meije Wink [mailto:[log in to unmask]]
Sent: Wednesday, December 06, 2000 3:13 AM
To: Kareken, David A.
Cc: [log in to unmask]
Subject: Re: PET-MRI coregistration problems
Dear David,
Is it possible to send some more information about the specs of the
input/output images, like dimensions in voxels, voxel sizes in mm,
origin co-ordinates etc? This description is a little in the "black box"
style...
> The target is in my case a T1 MRI (SPGR), as I need the PET images (water)
> to be in the same space as the MRI. The PET images lack the dorsal part
of
> the brain due to field of view limitations. I specified the average water
> PET image as the object, and then tell it to apply the determined
> registration parameters to individual water images.
> The problem seems to be that the r*.img's (individual or mean) are not
even
> budged from their original orientation, let alone correctly registered on
Which options did you pass to the registration routine?
> the MRI. Am I doing something wrong? Is SPM? I did find something in
the
> mailbase about the origin of the images, and none of the origins are 0, if
> that's relevant.
They shouldn't. They should be somewhere in the middle...
> Another curious thing is that the supposedly co-registered MRI's are twice
> their original size-- that also seems funny.
Indeed. Once again, could you please provide (me/us) with some
additional info?
Best regards,
Alle Meije
--
Alle Meije Wink
Institute for Mathematics and Computing Science, room 105
University of Groningen P.O. Box 800
9700 AV Groningen
Telephone +31 50 363 71 27 The Netherlands
Fax: +31 20 875 48 00
E-mail: [log in to unmask]
WWW: http://www.cs.rug.nl/~wink
" I guess it comes down to a simple choice, really.
Get busy living, or get busy dying. "
(Andy Dufresne in The Shawshank Redemption)
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