asl_file: command line manipulation of ASL data
asl_file is a command line tool designed for the convenient manipulation of ASL data within FSL. It is part of the BASIL toolset (and is used extensively within the oxford_asl and Asl_gui tools). ASL data has the relatively unique feature compared to other MRI datasets that it is comprised of an interleaved series of tag and control images. Common manipulations of ASL data require either the pairwise subtraction of the volumes of extraction of only control (or tag) images, this can be quite tedious with existing tools. This gets even more complicated with multi inflow-time ASL that contains tag-control pairs at a range of inflow-times. asl-file was thus designed to know about the common structures of ASL data and permits direct operations without the need to separate out the individual volumes.