Hello.

The toolbox was developed for native images i.e., no extra processing except bias correction is applied before segmenting the hyperintensities. 
A drawback of this is the aspect that for images with extra-bright layout (all voxels are somehow elevated more than in general), most of the regions on white matter will pop-up as detections in pmap.
Other users have also pointed out this issue with w2mhs. The only solution we suggest is adjusting the thresholds in WhyD_postproc. See the documentation.