Adrian,
It seems you have use a few more variables than I do to collect your phase
images. Are these the variables GE service asked you to change? What version
is your scanner software? I imagine since you have an HDx your are running
some version of 14, ours is 14-M5.
Anyways, I change rhrcctrl to 19 (just acquire mag and phase), nograd=1, and
opphasset_factor=1. I do not change nofermi, rhimsize, or rhasset.
What is your rhimsize originally set to? I imagine if you are acquiring at
128 x 128 it should be reconstructing at 128x128.
I apply B0 correction to fMRI and DTI images. My fMRI images are at 64x64
and I don't have to apply any up/downsampling, FSL should take care of this.
As a word of caution, this is my first time (and our centers first time)
acquiring and applying fieldmap corrections. So the information that I have
put out (for example, what you read on the DTI B0 pipeline correction post)
is what I have learned from others, especially the FSL developers (which is
a good thing though). Additionally, you know how GE service can be at times.
Hopefully they have not provided either of us with incorrect information,
but it does seem we alter some different CV's.
Hope this helps.
Cheers,
Carlos Faraco
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