Dear Emily,
There are several ways to proceed but the simplest would be to create a
new 4D file where you would have removed the first 8 volumes.
This is something you can do with the "3D to 4D file conversion" module
where, for the "3D Volumes" entry, you would select frames 9:480 of your
original 4D file.
As usual, be careful to adjust your onset timings according to the
number of scans you are removing.
Best regards,
Guillaume.
On 08/10/2019 22:19, Emily Belleau wrote:
> Hello SPM experts,
>
> I realize that this is likely a very basic question.
>
> I was wondering how I could specify in my SPM script that I want to drop
> the first 8 volumes of data, to allow for scanner stablization.
>
> I thought I would just need to specify the frames I wanted to select in
> my script when I expand the frames as I am working with 4D data. So I
> would simply specify that I want to select volumes 9 through 480.
> However, this does not seem to work and it seems like there is something
> more I need to do.
>
> For example in this bit of my script, I thought this was the only bit I
> would need to specify but perhaps I need to change my dependencies as
> well throughout the script?
>
> matlabbatch{7}.spm.util.exp_frames.files(1) = cfg_dep('File Selector
> (Batch Mode): Selected Files (.*)', substruct('.','val', '{}',{2},
> '.','val', '{}',{1}, '.','val', '{}',{1}, '.','val', '{}',{1}),
> substruct('.','files'));
> matlabbatch{7}.spm.util.exp_frames.frames = [9, 10, 11, 12 ...480]
>
> In the past I had always taken them off prior to analysis via the dcm to
> nii 3d to 4d conversion but the newer dcm to niix has gotten rid of the
> 3D to 4D functionality.
>
>
> I would appreciate any guidance!
>
> Emily
--
Guillaume Flandin, PhD
Wellcome Centre for Human Neuroimaging
UCL Queen Square Institute of Neurology
London WC1N 3BG
