Dear FSL experts,

I have a couple of newbie questions for using fsl_motion_outliers:

1. When using DVARS as a metric, how exactly do I use the criteria of outlier = >0.3% BOLD signal change? I have DVARS values ranging between 18 and 120 for a particular subject. Should I somehow convert these values into percentages?

2. When providing a mask, should this be whole brain binarized, skull stripped mask (derived from anatomical images)?

3. Between refrms and dvars, the scales are vastly different:  max(refrms) = 0.066 and max(dvars)  = 33.70; I think they are both calculating the root mean squared BOLD signal change with only the difference in the reference volume (middle volume in refrms and n+1 volume in dvars). Is this difference expected or am I doing something majorly wrong?

Many thanks for your help and apologies for the really basic questions.

Thanks and Regards

PB