Fig. 3

T2w images of an untreated animal from experimental group 2 at day 8 after tumor implantation. a Significant mass effect of the tumor (indicated by the #), which caused a midline shift (arrowhead in A; * indicates contralateral NABT). A T2w image of the same animal acquired 2 days later (b) revealed that the mass effect additionally led to an occlusive hydrocephalus with transependymal edema (arrows in B). Corresponding MRE-maps of viscoelasticity |G*| revealed a stiffening of the NABT on day 8 (c, NABT indicated by *), which regressed two days later (d, NABT indicated by *). The arrows in D indicate markedly soft areas, which correspond to the edema surrounding the enlarged lateral ventricle visible on the T2w image (B). The transient stiffening could be potentially related to an increased pressure due to the significant mass effect. The following softening could have been caused by an increased extracellular water content due to edema. NABT, normal appearing brain tissue