Hi Bruce,
I did that test some time ago (each sequence alone or averaged) but only with one control subject. I then checked the values of different measures and the cortical thickness maps for each situation and they were very similar indeed. I did it only with one subject because the point was to choose one of the MPRAGEs. But now that I need to drag conclusions I wasn't sure if the different sequences would be a major problem and would invalidate the conclusions.
I'll match the number of subjects for each sequence but bearing in mind that I have two different sequences anyway.
Thank you for the help!
Andreia
Quoting Bruce Fischl fischl@nmr.mgh.harvard.edu:
p.s. you would be better off if you had the same proportion of patients and controls with each sequence. Matching the numbers within one sequence and not the other doesn't really help
On Thu, 28 Mar 2013, _andreia_@sapo.pt wrote:
Hello list,
I have a group of subjects (4 patients and 8 controls) in which one MPRAGE sequence was used and another group of subjects (2 patients and 2 controls) where a diffent MPRAGE was used. Both groups were acquired in the same scanner. For each subject I have two anatomical sequences and I'm working with the average dataset. My question is can I put both groups together for comparision?
I've thought about this and I can't really be sure... I was thinking that since for group 2 the number of acquisitions is balanced maybe the overall impact of different sequences won't be significative... Patients and subjects are age-matched in both groups.
Please, any advice will be greatly appreciated!
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