Dear Christophe,
There have been a number of messages on this subject recently, and you may
want to check the archive for a more detailed answer from John Ashburner.
SPM works with images in neurological orientation. When you give it an
image to normalise, it assumes that the image is in radiological
orientation (as used in analyze). Therefore one of the early steps in the
normalisation is to flip the images from radiological to neurological
orientation.
If your images are not in radiological orientation, it is possible to
change this feature via the <defaults> button so that SPM assumes your
images are in neurological format (for example).
Best Wishes
Xavier
At 13:46 28/06/00 +0200, you wrote:
> Dear SPMers, I just want to ask you for some advice about a strange
>result I got after spatial normalization. First, I have made a converter
>from our own data file to spm-compatible Analyze file. To check it I tried
>to convert and to display a 3D T1 MRI presenting an easy identifiable
>anomaly on the right temporal lobe. Result was OK (the anomaly was on the
>left on the images in neuroradiological convention) Then I performed a
>spatial normalization with the T1 template on such data (I know this does
>not make sense but it was just to check). But I realized that the
>normalized data were Left-Right flipped. In fact the anomaly appeared now
>on the left temporal lobe (on the right on the images in neuroradiological
>convention). Can anyone give me an explanation of such Left-Right
>inversion ??? Thanks in advance, Best Regards
>Christophe GROVA *************************************************
>Christophe GROVA
>Laboratoire SIM, faculte de Medecine,
>Université de Rennes 1 tel : 02 99 33 68 63
>fax : 02 99 33 68 64
>e-mail : [log in to unmask]
>site : http://sim3.univ-rennes1.fr
>*************************************************
>
Xavier Chitnis
Section of Cognitive Psychopharmacology
Dept. of Psychological Medicine
Institute of Psychiatry
De Crespigny Park
London, SE5 8AF.
Tel: 0171 919 3977
Pager: 07669 028 121
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