Hello,
My question relates to the realignment procedure.
I analysed a data set (lets call it CB) of 209 volumes (without realigning)
and got activation maps which were o.k. and roughly in the right brain
areas.
I then normalised the data set (again without realigning) and carried out
the same statistical analysis on this normalised data set (NCB) and again
the activation maps appeared fine.
Finally, I realigned the data (CB) and carried out the same ststistical
analysis on this data set (RCB) but and all I got was the ominous x and
axes display. I understand from previous postings that this means there
was nothing of interest found.
The realignment options I used were:
1. Coregister and reslice
2. Sinc Interp.
3. All images and mean image
4. 1st order and spin history (I have 209 volumes and TR =2.5 seconds).
In an effort to get at the source of this I have changed the default
settings (for realignment) to 'no mask ' and 'bilinear interpolation', but
this still gives me the dreaded axes display. I have not changed the
adjustment for movement option as as the 1st order and spin history
appears most appropriate (i.e. TR < 4s, n > 40).
Does anyone know what is happening here ?
Many thanks in advance
Frank Graydon
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