Here's a way to test ASL scans (snapshots for each step on right):

Convert images with CSPM
Check for multiple nifti images; should have a minimum of 2, usually more
Run a global timetrend; from CSPM fMRI menu, select Global Timetrend, select the images, and choose Raw
Check that the images are high/low or low/high (unlabeled/labelled or labeled/unlabeled)
Create CBF maps from ASL menu; select the images, and ignore the mask (click "Done" with nothing selected
Review the mean CBF image; if the values are negative, the order is flipped. If the values are super high or super low, the default parameters are off; However, the relative intensities won't change with the correct parameters, only the scaling.
To change settings, edit the cspm_asl.m file - click the link in the command window to open.

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