Dear Doug and Martin, Thanks a lot. I just have one group including 20 subjects. The scans have been done in a range of 0.9 to 1.5 years difference (tp2-tp1). Is ooh if I use the instructions from Paired Analysis : https://surfer.nmr.mgh.harvard.edu/fswiki/PairedAnalysis ? Regards,
Best regards, Amirhossein Manzouri On Thu, Jan 30, 2014 at 10:31 PM, Martin Reuter <mreu...@nmr.mgh.harvard.edu > wrote: > Hi, > > with one group you want to check if atrophy is significantly different > from zero? That is probably the case for any group (e.g. aging), so it > won't tell you anything really. Also, if you don't find atrophy in a region > it doesn't mean it's not there (only your group size is too small to detect > it). > So the only real use I can think of, would be a test-retest study, where > the assumption is that there is no change? > > Sadly Qdec cannot do 'one sample group mean', otherwise you could do that > in qdec. If only you had a second 'control' group, then it could be done. > You can use long_mris_slopes to compute rate or percent change maps (one > for each subjects) and then you can use qdec to analyze those rate maps > across groups. > If you don't have a control group, you could still use long_mris_slopes > (it can also map and stack the rate maps on fsaverage) and then simply run > the one sample group mean in mri_glmfit. > > some info is also here: > > https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/LongitudinalTutorial_freeview > and > https://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalTwoStageModel > > > Best, Martin > > > On 01/30/2014 09:18 AM, amirhossein manzouri wrote: > > Hi, > Would you please advise if it is possible to do longitudinal statistical > analysis within a group with two time points in Qdec. And if it is not > possible in Qdec how I suppose to do it? > > Best regards, > Amirhossein Manzouri > > > > > > _______________________________________________ > Freesurfer mailing > listfreesur...@nmr.mgh.harvard.eduhttps://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > -- > Martin Reuter, Ph.D. > Assistant in Neuroscience - Massachusetts General Hospital > Instructor in Neurology - Harvard Medical School > MGH / HMS / MIT > > A.A.Martinos Center for Biomedical Imaging > 149 Thirteenth Street, Suite 2301 > Charlestown, MA 02129 > > Phone: +1-617-724-5652 > Email: > mreu...@nmr.mgh.harvard.edu > reu...@mit.edu > Web : http://reuter.mit.edu > > The information in this e-mail is intended only for the person to whom > it is > addressed. If you believe this e-mail was sent to you in error and the > e-mail > contains patient information, please contact the Partners Compliance > HelpLine at > http://www.partners.org/complianceline . If the e-mail was sent to you in > error > but does not contain patient information, please contact the sender and > properly > dispose of the e-mail. >
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