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Hi Anderson, Indeed I reduced my patients list because of quality of input images, and now I have 7 patients in one group with 2 up to 4 timepoints non regularly spaced in time : - patient1: 2 timepoints - patient2: 3 timepoints - patient3: 2 timepoints - patient4: 4 timepoints - patient5:4 timepoints - patient6: 3 timepoint - patient7: 3 timepoints Could you explain me how to use longitudinal TBSS with these data (define inputs, design matrix and contrasts) ? Best regards, Matthieu 2015-09-29 11:41 GMT+02:00 Matthieu Vanhoutte <[log in to unmask]>: > Hi Anderson, > > I would like to investigate for example FA reduction with time. The number > of timepoints is varied because of the clinical nature of the study: some > patients came one time whereas others came up to seven times. > Moreover, time between two timepoints aren't regular between patients. I > have 11 patients with the following timepoints: > > - patient1: 3 timepoints > - patient2: 3 timepoints > - patient3: 2 timepoints > - patient4: 3 timepoints > - patient5: 7 timepoints > - patient6: 1 timepoint > - patient7: 3 timepoints > - patient8: 2 timepoints > - patient9: 7 timepoints > - patient10: 3 timepoints > - patient11: 3 timepoints > > Do you think it is possible to make longitudinal TBSS on these irregular > timepoints subjects and in this case how define correctly input and model > for statistical analysis ? > > Thanks in advance for helping ! > > Best regards, > > Matthieu > > > 2015-09-29 11:02 GMT+02:00 Anderson M. Winkler <[log in to unmask]>: > >> Hi Matthieu, >> >> The "evolution" is too much a broad term. What exactly do you want to >> investigate? Could you explain the why the number of timepoints is varied? >> Is the missingness only towards the end, or are there gaps in the middle? >> Please, give as much detail as possible. >> >> All the best, >> >> Anderson >> >> >> On 29 September 2015 at 09:49, Matthieu Vanhoutte < >> [log in to unmask]> wrote: >> >>> Dear FSL's experts, >>> >>> I have one group and variable number of timepoints per subject (from 1 >>> up to 7) and would like to assess the evolution according time-points of >>> DTI parameters (FA, MD, ...). >>> >>> Concerning the statistical analysis, how should I proceed in terms of >>> inputs and models of the longitudinal variable number of timepoints ? >>> >>> Many thanks in advance for helping !! >>> >>> Best regards, >>> Matthieu >>> >> >> >