Dear Sophie,
I would not expect a significant difference in terms of tractography results when going from half to full sphere sampling.
Your tractography will be influenced by other factors, such as number of acquired orientations, b-value, signal- and contrast-to-noise-ratios. If these values are too low, bedpostX might struggle to estimate complex voxel-wise fibre configurations
such as 2 or 3 fibre crossings, leading to incorrect structural connectivity estimates. You could try to lower the ARD weight (-w option in bedpostX) to get more 2 and 3 fibre configurations, but you should carefully inspect the data to ensure that they look
anatomically plausible (i.e., check for spatial continuity/coherence).
Hope this helps, cheers,
Matteo
Dear FSL users,
I have a 64 Direction DTI dataset where diffusion was only sampled on the half sphere instead of the whole sphere. I noticed my tractography results showed very low connectivity between my language ROIs (pars opercularis and posterior superior temporal gyrus).
I'm presuming it's due to the half sphere scheme. Do half sphere and whole sphere DTI schemes change the results substantially?
I would like to acquire diffusion on the whole sphere in the future. Do you know what parameter/setting on a Siemens Verio 3T would need to be changed to allow for that?
Thanks,
SH
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