[Mrtrix-discussion] empty FA images and streamtrack questions

[Kerstin Pannek]

Hello again everyone,

Donald, thank you for fixing find_SH_peaks. Unfortunately I did not 
quite get around to really playing with it yet.

I was just trying to analyze some DTI data that had not been optimized 
for CSD and tractography (b value 1200; slice gap...). When running 
tensor2FA, I get only an empty image. Image conversion from DICOM works, 
i.e. I get a non-empty dwi.mif and encoding - just a warning about the 
slice gap, no error message. What might be causing this problem?

Some more question about streamtrack:
1) When I want to use the option -initdirection <dir>, what format 
should <dir> be?
2) I do get segmentation faults fairly frequently using streamtrack 
SD_PROB. I did get segmentation faults using fslview in the past, making 
me think that this was a hardware problem at my end. With the new 
version of FSL and a different video card, the fslview segmentation 
fault issue has been resolved, but the streamtrack segmentation fault 
remains. Any thoughts on what this problem might be related to? I case 
it is important, I get some "failed to converge" messages from csdeconv.

Thanks for your help.
Kerstin