Dear FSL experts,
How does randomise handle zeros in the parameter maps? I am analyzing DTI and NODDI data and there are instances where the parameter maps contain values which are non-physical (e.g. FA > 1). I would like to zero out these data points for this subject alone, rather than masking out the voxel for all subjects. Is this possible, or will randomise still calculate the statistics based on this subject with a value of zero?
Obviously, if it were possible to exclude individual subjects with zeroed-out data this will change the number of degrees of freedom across the image, but for a large enough sample (> 50 subjects per group), and assuming the zeros are occurring in random locations due to imperfections in the data, this should be a pretty small effect (alternatively, randomise may be able to handle the varying DOF's across the image).
Any advice you can give me on this would be much appreciated.
Thanks,
Mark Wagshul
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