Interpret FSL Basil Region Analysis

Hi All:

I get 4 perfusion measures once I run BASIL. Total GM, Total WM, Cortical GM, and Cerebral WM. I understand the difference between the Total GM and Cortical GM (the latter excludes subcortical structures), but I’m confused on the difference between Total WM and Cerebral WM. The readthedocs page just emphasizes that Cerebral WM is excluding subcortical WM based on the Harvard Oxford Atlas, but wouldn’t that exclude almost all of the WM?

-Dianne