Figure 4.

(a) Unregistered pair and (b) registered pair in a slice of 3D Doppler color image volumes with grayscale portion blacked out. Dark gray (red) was the color of blood flow under moderate breast compression, medium gray (green) under relaxed compression, and light gray (yellow) was the overlap region. Notice the increase in flow with relaxation and also the increase in the light gray (yellow) region with registration. The registration was performed on the grayscale portion of the image volume with colored pixels zeroed. Refer to Figs. 56.