Howzabout this elegant combination of AFNI and shell commands:
3dROIstats -quiet -mask DSET_INT DSET_INT | tr '\t' '\n' | awk '{print int($1)}'
... which, in turn, get the mean value of each ROI region (which produces a line of floating point values of the ROI integers); which gets turned into a vertical column of those floating point values; when then get integerized?
--pt