Dear John,
we deleted the first five scans, which in this case gives a time of
25 seconds to reach equilibrium.
Regards
Thomas Stephan
John Ashburner wrote:
>
> Can I just add a comment on the CSF activation issue. Are you analysing
> all your scans, or excluding the first few seconds worth from the analysis?
> It is possible that you may need to leave out more of your early scans.
>
> The problem may be something to do with what I believe are called T1 effects.
> In the first few scans, the brain has not experienced as much magnetisation
> as in the later scans, so you get a different contrast in the early images.
> Things start to reach an equilibrium after the first few scans.
>
> Regards,
> -John
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Thomas Stephan Email: [log in to unmask]
Klinikum Grosshadern
Neurologisches Forschungshaus
Marchioninistr. 23 Fon: +49 089 / 7095-4819 *NEU*
81377 Muenchen Fax: +49 089 / 7095-4801
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