QC field maps?

[pipitone]

Right now we don't have a way of including field maps in our QC pipeline. Is there something we could/should be doing with these field maps that would provide an indication of scan quality/integrity?

[josephdviviano]

We could make a visual print out of them, but I've never heard of this before.

[djrotenberg]

Phase maps are a bit tricky, not only because of phase-wrapping but due to the arbitrary phase values from the scanner (If not calculated directly from the raw complex data).

One method that I have seen before is to look at the phase derivative. Here's one example of that: http://www.tnw.tudelft.nl/fileadmin/Faculteit/TNW/Over_de_faculteit/Afdelingen/Imaging_Science_and_Technology/Research/Research_Groups/Quantitative_Imaging/Publications/List_Publications/doc/Supri_asci01.pdf

Generally, regardless of the absolute value, the rate of change should be more smoothly varying under less noisy conditions.

[josephdviviano]

Do we need to consider the derivative in all directions or just the phase-encoding direction?