How do I generate the perfusion data from the raw image series? What is the difference between the preprocessing of perfusion and BOLD data?
Perfusion image time series are generally produced by pair-wise subtraction between interleaved label and control acquisitions. The simplest way is to do direct pair-wise subtraction between temporally adjacent label and control acquisitions. Artifacts can be reduced by first performing a sinc interpolation to shift the series of label (or control) images by one TR, followed by pair-wise subtraction between time-matched label and control images. “Surround subtraction” has also been proposed through linear interpolation to shift the series of label (or control) images by one TR, followed by pair-wise subtraction. However, the “surround subtraction” method will slightly inflate the false-positive rate in statistical analysis through temporal smoothing. The preprocessing of perfusion and BOLD data is similar, although motion correction may be performed separately on the label and control images in the raw image data. Also, perfusion fMRI data tend to benefit from spatial smoothing to a gr
