Dear all SPM experts
I have a longitudinal T1 dataset for group of patients and normal controls (3 time-point for each subjects, the time interval for each time-point isn't identical) and want to use SPM12 longitudinal toolbox to perform longitudinal VBM analysis for this dataset. The following points are my goal in this study:
1. Calculate GM tissue volume of each time-point for each participants in voxel wised manner
2. Calculate the GM atrophy rate of each participants in voxel wised manner
After reading the related information in the mail-list and the manual of SPM12b, I design the following pipeline for this study, could some experts verify this pipeline is ok for my research goal ?
1. Using SPM12b longitudinal toolbox for 3 time-point registration. I have a question about how to setup the option of "time". In order to calculate GM tissue volume of each time-point, I think I need to setup this option with identical value (use 0,0,0). Is it right to set 0,0,0 for this three time-points data or i should set the real time interval for this option?
2. Segment each subject's mid-point average image (default segment in spm12).
3. Multiply the Jacobian maps from (1) by the grey matter from (2) (ImCalc).
4. Dartel to estimate how to warp all the subjects together using mid-point average images
5. Dartel's normalise to MNI space using the output from (3) with "tissue modulation" option. The output of this step is the GM tissue volume of corresponded time-point.
6. Using the output of step 5 and perform the regression analysis to calculate the atrophy rate for each participants. In this step the real time interval of each data-point were used to calculate the annual atrophy rate for each participants
Is the above pipeline reasonable for my research goal ?
Thank you
Best
Paul
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