Hi Carolyn,
from you longitudinal qdec table you can create one that qdec can use by simply manually concatenating the first two collumns with a ".long." in the middle
tpid.long.baseid
and call that column "fsid" in the first row. This will instruct qdec to load the data from the longitudinal directories of this subject. However, Qdec will not understand that these data points come from the same subject. It will assume these are 6 different subjects. It is really only to load the data and investigate. All I am saying is that you cannot really do any longitudinal statistics with a single subject and only a few time points. If you want to use other statistical tools (note we also have Linear Mixed Effects Models in Matlab), you can use asegstats2table and aparcstats2table with the --qdec-long flag (passing the longitudinal qdec table). This will collect the stats values from your time points into a single csv table.
Best, Martin
On 06/08/2016 01:36 PM, Carolyn Drobak wrote:
So if these aren't useful for only 1 subject, what would be the best way to look at data over multiple scans for just the one subject?
On Mon, Jun 6, 2016 at 2:12 PM, Martin Reuter <mreuter@nmr.mgh.harvard.edu mailto:mreuter@nmr.mgh.harvard.edu> wrote:
Hi Carolyn, not sure what you are asking. You want to do statistics on N=1 subject ? Anyway, in order to use QDEC, you'd have to reduce the longitudinal data (thickness, measured at different time points) to a single number: the slope of a linear fit. This is called the 2-stage-approach. Or you skip Qdec and do a Linear Mixed Effects model directly. Either approach only makes sense if you have a bunch of subjects (per group). Best, Martin Ps info on longituidnal statistics: https://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalStatistics On 06/06/2016 09:45 AM, Carolyn Drobak wrote:Hello, I have six scans for a single subject. I have performed "group analysis," but wish to use longitudinal data analysis. In particular, I was able to get a base for the subjects, so can view in freeview and all of that. My issue arises when I try to use QDEC. Because QDEC can't use my long.qdec.table.dat file, nor does it like my cross.qdec.table.dat file. The problem seems to be that I only have one base, i.e. one subject. Is there some way to run analysis on this so I can still get all the statistics I want (mostly interested in cortical thickness) using just my one subject? I'm still fairly new to FS, but have done the large majority of the tutorials, so am pretty sure I'm not just messing up my files here. Thanks, CMD On Mon, Jun 6, 2016 at 9:40 AM, Carolyn Drobak <carolyn.drobak28@gmail.com <mailto:carolyn.drobak28@gmail.com>> wrote: Hello, I have six scans for a single subject. I have performed "group analysis," but wish to use longitudinal data analysis. In particular, I was able to get a base for the subjects, so can view in freeview and all of that. My issue arises when I try to use QDEC. Because QDEC can't use my long.qdec.table.dat file, nor does it like my cross.qdec.table.dat file. The problem seems to be that I only have one base, i.e. one subject. Is there some way to run analysis on this so I can still get all the statistics I want (mostly interested in cortical thickness) using just my one subject? I'm still fairly new to FS, but have done the large majority of the tutorials, so am pretty sure I'm not just messing up my files here. Thanks, CD _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer-- Martin Reuter, PhD Assistant Professor of Radiology, Harvard Medical School Assistant Professor of Neurology, Harvard Medical School A.A.Martinos Center for Biomedical Imaging Massachusetts General Hospital Research Affiliate, CSAIL, MIT Phone:+1-617-724-5652 <tel:%2B1-617-724-5652> Web :http://reuter.mit.edu _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu <mailto: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.
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