Matthew:
Quick question I hope. Your name popped up in my email with your reply and I'm impulsively writing
back to you. The question is regarding percent signal change and marsbar.
I am analyzing perfusion MRI data. This analysis works out OK in spm but there is no convolution
with an HRF, no High pass filter and no AR model. I have 3 events
1) baseline - occurs both before and after a single block of stimulation
2) active - 120 seconds of stimulation
3) other- transisition times between baseline and active.
I want to look at percent signal change in active - baseline.
Can I just calculated percent change to active and then baseline events in marsbar and subtract?
thanks,
Darren
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Darren R. Gitelman, M.D.
Cognitive Neurology and the Alzheimer's Disease Center
Northwestern Univ., 320 E. Superior St., Searle 11-470, Chicago, IL 60611
Voice: (312) 908-9023 Fax: (312) 908-8789
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