Thanks for your help. Today, when we tried to run the new function of FS in DTI analysis, we got stuck again. The dt_recon command cannot run successfully, and always report us 'MRIresample(): error inverting matrix'.

The data is from Siemens Trio 3T system, and has 64 diffusion directions. Before running dt_recon, we have unpacked the DTI dicom data to a specific directory with unpacksdcmdir command.

To provide more details, I attach the dt_recon.log file and a DTI image (one direction) to this mail.

2008/3/12, Doug Greve <greve@nmr.mgh.harvard.edu>:

If you are using the 4-column par file, then just code them as separate, overlapping events, ie. If condition 1 is the block (lasting 10 sec) and condition 2 is the event (lasting 2 sec), then

0 1 10 1 ---> starts at t=0, lasts 10 sec
0 2    2   1 ----> starts att=0, lasts 2 sec
5 2    2   1 ----> starts at t=5, lasts 2 sec
7 2     2 1 ---> starts at t=7, lasts 2 sec

The last col of 1s just means that the event weight is one (probably what you want).

doug

Zhen Zonglei wrote:

Dear, Dr. Greve:

I hope I don't bother you too much. But I'm wondering about how to analyze mixed blocked/event related design with FSFAST. In our experiment, we have two blocked conditions and three event-related conditions in every block. We are not sure how to write the parfiles and construct the model to analyze these data in FSFAST.

Please give us some suggestions on this issue.

Thanks in advance.

Zonglei Zhen
-- 
Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu
Phone Number: 617-724-2358 
Fax: 617-726-7422

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