This option does require extra acquisitions (of fieldmaps) and these cannot be derived from other scans. That is why it is not on by default, as not all protocols acquire fieldmaps although we *strongly* recommend that people do acquire fieldmaps as they
really do improve registration considerably.
- "traditional" fieldmaps (e.g. two GE non-EPI scans with different TEs)
- PE-reversed spin-echo EPI pairs (such as is used often in DWI, and processed by the FSL tool topup)
You can find more details about fieldmaps and their use in FSL on the FSL wiki and in the FSL Course materials.
Dear FSL experts,
Is b0 unwrapping typically recommended? If yes, I find that it is unchecked by default and want to understand why.
Also, it looks like a fieldmap is required. Is that something I can generate from the structural or functional scan per se? If yes, can you please advise the typical procedure to obtain a fieldmap?
Much appreciated!
Daniel
--
Daniel Yang, Ph.D.
Yale Child Study Center
