Figure 2.

Illustration of the same gamma mixture distribution with two different values of λ. m₁ and m₂ are the modes (most frequent values) of the low and high MWF components of the gamma mixture, respectively. λ is the gamma mixture mixing ratio and represents the proportion of low MWF to high MWF (when λ is equal to 0.5, the two components have the same contribution in the gamma mixture). To compare the relationship between lesion/NAWM masks and each gamma mixture component we defined ROI[m₁] and ROI[m₂] as all voxels with MWF value less than m₁ (in red) and greater than m₂ (in green), respectively. We assumed the lesion mask had more overlap with ROI[m₁] than ROI[m₂], and the NAWM mask more overlap with ROI[m₂] than ROI[m₁]. (Left) Distribution with a λ value less than 0.5 (exact parameters: m₁ = 0.06, m₂ = 0.17, λ = 0.25). (Right) Distribution with a λ value greater than 0.5 (exact parameters: m₁ = 0.06, m₂ = 0.17, λ = 0.75).