Hello all,
I´m having some problems with the dtifit analysis of images that were collected several years ago; many images have an apparent left/right diffusional hyperintensity on the FA color map that is due to a vibrational artifact, as in Gallichan D et al, 2010, Hum Brain Mapp, 31(2):193-202. I understand that I need to write a --cni co-regressor into my dtifit command, but as a newbie to FSL and Linux, I´m not sure how to go about it. Could anyone please tell me which values to include in a co-regressor like this one in a way that might be easier to understand than Gallichan? In Linux, do I need to write a C program for this? My data parameters are:
30 directions, Siemens TrioTrim.
Repetition time (ms)= 6700, echo time (ms)= 92
Flip angle= 90, number of averages= 1
Slice thickness and spacing both 3 mm
Image rows and columns both 128
Phase encoding direction= COL
Voxel size (mm) of both x and y= 1.79688
Number of slices and files both 48
Number of frames= 161914616
Slice duration (ms)= 45
For simplicity´s sake, I´m going to use one co-regressor for all images instead of creating one on a case-by-case basis.
Thanks so much in advance.
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