Hi April,
I assume you use 2DEPI, and not 3DEPI (given it is old data)? The below assumes you use 2DEPI, for 3DEPI the story is entirely different.
Try and find several scans (that is, single dynamics) during which the subject moved a lot, as determined by looking at the realignment parameters. When, in a cutting plane perpendicular to your slice (for axial recording this cutting plane could be coronal or saggital) you see a comb-like artifact with alternating brighter and darker lines coinciding with the plane of the slices, you are probably dealing with interleaved EPI.
This is not a guarantee though, but a strong indication.
When you don't see the comb artifact, you are back where you were. Then you have either non-interleaved data, or very fast readout and interleaved data after all. Or your subjects hardly moved and you have interleaved data. In that case, I do not know a way to find out other than asking your MR physicist.
I'd ask him or her anyway, the acquisition parameters from the scanning console are the only way to know for sure. Or have a look at the original dicoms or raw scanner format data.
Good luck,
Bas
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Dr. S.F.W. Neggers
Division of Brain Research
Rudolf Magnus Institute for Neuroscience
Utrecht University Medical Center
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________________________________________
From: SPM (Statistical Parametric Mapping) [[log in to unmask]] on behalf of April Fan [[log in to unmask]]
Sent: Friday, March 09, 2012 4:44 PM
To: [log in to unmask]
Subject: [SPM] interleaved EPI or not
Hi all,
I am doing some old fMRI data analysis collected many years ago. I lost the original infor. It might sound silly, but could any one tell me how to identify if the data is interleaved EPI or not? Many thanks.
April
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