All entries for Sunday 28 October 2012
October 28, 2012
Writing about web page http://go.warwick.ac.uk/tenichols/scripts/fsl#DVARS
Multiple authors have found the spatial standard deviation of the temporal difference data useful for detecting anomalous or artifactual scans in fMRI. Called DVARS by Power et al. (NeuroImage, 59(3), 2142-54), this measure is useful but lacks interpretable units. In particular, the nominal value of DVARS reflects both the temporal standard deviation and the degree of temporal autocorrelation.
I’ve created a simple approach to standardize DVARS, attempting to remove the dependence on temporal standard deviation and autocorrelation. See my notes on Standardizing DVARS and a FSL script DVARS.sh to implement this new version of DVARS.