Dear experts,
First off, I apologize for asking this question that has been asked many times already. I still have to re-post it because there is some twist in the situation.
I am getting DTI data from my scanner in the following form:
1 zero b-value, 12 non-zero b values and the entire set repeated 4 times. Therefore, each 4D image has 4 sets of these 13 images.
The twist (or may be not so much of a twist): The b-value and b-vec files also have the repeated values. Hence, 4 sets of 13 values for b-value file and 4 matrices of 3 by 13 size each.
dtifit doesn't have any problem with it because the files are matching.
I guess that dtifit is considering all the repeated values as more directions. Is that true?
And in that case the answer must be close to what one would obtain by averaging before feeding the data to dtifit.
Is one approach better than the other? I tried both and I do see some difference but it is hard to quantify.
Many thanks.
Eyesha
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