Dear Darren & SPM community,
slice timing keeps stirring things up, apparently (although my recent
posting on the minor issue of time needed for the gradients did not
encounter any magnificant resonance).
Well, I think what you describe might be an example that interleaved
acquisitions may differ in their modus profoundly between different
scanner of different manufacturers. There is just one way for ascending
or descending: The worst that can happen is that they are defined the
other way around on your scanner than in SPM. But checking in the manual
of the scanner will tell you. However, as you have illustrated
implicitly, if you acquire more than 5 slices there are several ways to
adhere to a strictly interleaved acquisition in different orders. What
kind of scanner are you using? My hunch is that it is not a Siemens
scanner where interleaved usually proceeds from 1->3..., etc., but not
from 1->5. I guess the FIL folks have mostly used Siemens. In addition,
the scanner should allow for either anatomical OR chronological storings
upon output but that does not solve the issue.
> This looks as if it expected the slices in their original acquisition
> order. To get the same result as the old program one would have to enter a
> refslice of 8 and an acquisition order of [8 6 4 3 7 5 3 1]. Is this
> right???
IŽd believe so, except: [8 6 4 2 7 5 3 1]
And yes, we (we/a)re similarily confused.
Regards- andreas
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