The image is the result of fiber tractography from diffusion-weighted magnetic resonance imaging. It illustrates the white matter of the brain, or in other words, its structural connections. The red smooth surface represents a glioblastoma tumor. We can see the effect of repulsion and infiltration of this mass on the white matter fiber pathways. A distance colormap is used for interpretation. Blue fibers mean that they are located within a safe distance of the tumor whereas red fibers are in a close perimeter to the tumor, and can cause severe post-operation deficits, if resected.