Thanks you for the reply. Martin, the scans are 0,14 and 21 days a part. I will run a few more subjects and check the results as you suggested.
On Fri, Apr 17, 2015 at 8:59 AM, Bruce Fischl <fis...@nmr.mgh.harvard.edu> wrote: > you should also plot them on the same axes (or at the very least with the > same limits) > > On Fri, 17 Apr 2015, Martin Reuter wrote: > > Hi Pradeep, >> >> is this the result of a single subject? In a single subject lot's of >> things >> can happen (e.g. motion artefacts can affect a single time point, other >> imaging or measurement noise will have effects). Also how far are the time >> points apart? Run the same thing with 20 subjects and you should see >> significantly reduced variablility in the longitudinal stream vs the cross >> sectional one. >> >> Best, Martin >> >> On 04/16/2015 01:12 PM, Pradeep wrote: >> Hello All, >> I have pre-processed a subject that has T1 scans at 3 time points >> using the freesurfer cross-sectional and longitudinal methods. The >> results show a lot of variability. I have attached the plots. Any >> advice would be much appreciated. >> Thanks, >> Pradeep >> >> On Wed, Apr 15, 2015 at 5:26 PM, Pradeep <tprad...@gmail.com> wrote: >> Hello All, >> I have pre-processed a subject that has T1 scans at 3 time using >> the freesurfer cross-sectional and longitudinal methods. The >> results show a lot of variability. I have attached the plots. >> Any advice would be much appreciated. >> Thanks, >> Pradeep >> >> On Wed, Jun 4, 2014 at 12:03 PM, Alexandru Hanganu >> <al.hang...@yahoo.ca> wrote: >> Thank you very much for your answer Bruce ! >> >> have a nice evening, >> >> Alex. >> >> >> Le 3 juin 14 7:6, Bruce Fischl a écrit : >> > Hi Alex >> > >> > I would think that longitudinal analysis is still >> the way to go as we try >> > to improve both reliability and sensitivity using >> the fact that we have >> > multiple scans/subject. >> > >> > cheers >> > Bruce >> > On Tue, 3 Jun 2014, Alexandru Hanganu wrote: >> > >> >> Hello Everyone, >> >> >> >> could someone please give us an advice about >> which method you consider is >> >> the best for our study ? >> >> >> >> we have two groups with MRI at Time 1. Each group >> received medication. After >> >> this we performed another MRI at Time 2 after 2 >> weeks. >> >> >> >> The best method for this study is a longitudinal >> one or a cross-sectional >> >> GLM ? >> >> >> >> We consider that the distance between the time >> points is too small, and the >> >> longitudinal method is not the best choice. >> Hence, this study should be >> >> treated as a cross-sectional one. In this case we >> think about performing a >> >> simple GLM with the contrasts: >> >> 0.5 0.5 0.5 0.5 >> >> or 1 -1 -1 1 >> >> >> >> for the groups: >> >> 1) grp 1 time 1 >> >> 2) grp 1 time 2 >> >> 3) grp 2 time 1 >> >> 4) grp 2 time 2 >> >> >> >> we are searching to see whether medication had >> any impact on the cortical >> >> morphology in each group and between the groups. >> >> >> >> Thank you ! >> >> Best regards, >> >> Alex. >> >> >> >> >> > _______________________________________________ >> > Freesurfer mailing list >> > Freesurfer@nmr.mgh.harvard.edu >> > >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer >> > >> > >> > 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. >> > >> > >> >> _______________________________________________ >> Freesurfer mailing list >> Freesurfer@nmr.mgh.harvard.edu >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer >> >> >> >> >> >> _______________________________________________ >> Freesurfer mailing list >> Freesurfer@nmr.mgh.harvard.edu >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer >> >> >> > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > 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. > >
_______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer 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.
