12 DOF is probably not going to help much. I vaguely remember that there were some tools out there that would attempt to fit the non-linear parts of the B0 map. Maybe in fmriprep? Sorry, can't give you more guidance than that.

On 10/26/19 10:56 AM, Daniel Callow wrote:

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Hello,

I am trying to do a within-subject co-registration between b0 volumes and T1's for my subjects. This is an old dataset that does not have anything for correcting b0 inhomogeneities. The registration using --dti and normal parameters for bbregister led to "okay" within-subject registration. I am wondering if modifying the --dof (like 12) option for bbregister or applying some type of linear/nonlinear registration might improve the registration?

Best, 
--
Daniel Callow
PhD Student, Neuroscience and Cognitive Science
Exercise for Brain Health Lab
University of Maryland, College Park
ddcc2442@gmail.com
443-254-6298

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