> I did try doing just the EPIs, and was impressed how well it worked. My
> main concern here is the stretching of orbital signal. It seems to want
> take preserved signal in the orbital area and stretch it downward to fill
> the signal void. Maybe just apply fewer non-linear itterations?
The official solution would be to increase the amount of regularisation.
>
> By the way, our design required getting 4 MPRAGE scans on different days--
> even after registering/averaging the four image volumes (which markedly
> improved the inhommegeniety of which you spoke to barely detectable visual
> levels), it still committed the same sins.
The bias correction button of SPM2 may also help - although you may need to
tweak (decrease) the amount of regularisation in order to achieve better
results. The default settings probably work best for skull-stripped images.
Best regards,
-John
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