Hi Maryam, which version are you using? It should be fine to have different length runs (it was a problem in older versions). If you really need to make them the same length, using mri_convert with the --ndrop option to remove the last few time points. doug

Maryam Vaziri Pashkam wrote:

Hi Doug,

In one of my experiments I have 8 runs. 3 of these runs have 190 TRs and 5 of them have 192 TRs. The difference is only that there is a 4 sec fixation period in the end of the 5 longer runs which I dont really need. Otherwise the 8 runs could potentially be combined. Is there anyway that I could combine the runs in my experiment? The Selxavg3 does not let me analyze the 8 runs together as they have different lengths. Is there anyway to get rid of the last two TRs in the 5 longer runs and combine the runs in the analysis? I had an idea to import my .nii files to Matlab, cut off the last two TRs and then save them as .nii files again. Would that work? Is there a better way to do this?

Thanks, Maryam