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Ella,

You can use FEAT for a ‘higher-level analysis’ using your perfusion_calib images as the input for each subject at each ‘time point’. You need to select the option that says ‘Inputs are 3D cope images from FEAT directories’. The you should be able to setup your design as you would a BOLD experiment and you can use the guidance for higher level analysis in FEAT to create a design specifically for your problem.
Some thing to watch out for with perfusion data is the intra-subject variability in global perfusion. However, as you have a baseline in each subject you can do a paired test which means this should be less of an issue for you.

Michael


On 11 Sep 2014, at 12:47, Ella Hinton <[log in to unmask]<mailto:[log in to unmask]>> wrote:

Dear FSLers,

I have been using the ASL GUI to process my pulsed ASL data, and now have calibrated perfusion images.

I am uncertain however as to how to run my statistical analyses on these data - that is how can I input these perfusion_calib.nii.gz images into Feat in order to compare scans within sessions and between sessions?

I believe I should compare the absolute quantified perfusion images as within my cross over design I need to compare data collected on different days - is this correct?  I have 10 subjects, scanned in two sessions in a crossover design. One session they drink an amino acid drink and the other a placebo for us to compare the resulting activity and predicted changes in fullness following a liquid meal. There are three scans per session: baseline, post drink and post milkshake meal. I would like to compare both scans to baseline within a session and then look for differences between amino acid treatments/sessions.

I would be grateful for your advice,
With thanks
Ella

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Michael Chappell MEng DPhil
    W: http://www.ibme.ox.ac.uk/qubic
    T: +44 1865 617657
Associate Professor, Institute of Biomedical Engineering, University of Oxford.
    http://www.ibme.ox.ac.uk
Director of Training, EPSRC-MRC CDT in Biomedical Imaging
      http://www.onbi.ox.ac.uk
Governing Body Fellow, Wolfson College, Oxford.
    http://www.wolfson.ox.ac.uk
Research Fellow, FMRIB Centre
    http://www.fmrib.ox.ac.uk