Another (hopefully not too naive) question from a new user...
I'd like to create, for each individual subject, a subtraction image that
reflects %change in normalized rCBF. Thus, instead of t-values, the pixel
values of this image would be numbers reflecting change above or below
average whole brain. In my particular case, I have two baselines and two
activations, so I'd like to create the percent change subtraction image of:
(i1+i3)/2 - (i2+i4)/2.
Is there a way to easily accomplish this in SPM? As far as I can tell,
proportional scaling only comes as part of a process that produces a
statistical parametric map image, and I don't see anything in the image
calculator that would enable me to perform this step separately (i.e., take
an image, normalize each pixel by whole brain average, and then do the
subtractions).
Thanks much.
________________________________
David A. Kareken, Ph.D., ABPP
Board Certified Clinical Neuropsychologist
Assistant Professor & Director
Neuropsychology Section, Department of Neurology
RI 5999C
Indiana University School of Medicine
Indianapolis, IN 46202
(317) 274-7327 (voice)
(317) 274-1337 (fax)
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