Edema build-up and resolution phase characteristics. (A) Representative samples of Evans blue extravasation from rats sacrificed at 1, 3, 7, 14 and 20 dpi. Widespread leakage at 1 dpi (arrow) progressively decreased with a restriction to the lesion site (3 and 7 dpi, arrows) followed by a complete restoration of the BBB integrity at the later time points (14 and 20 dpi). (B) and (C) are representative illustrations of MRI and histological features for rats explored at 1 dpi (B) and 20 dpi (C). During the edema formation phase (1 dpi, B), the T2 signal increased along the internal capsule up to the midline with high ADC values (similar pattern as in Figure 1, day 3). The corresponding histology showed important BBB permeability (IgG) and massive infiltration of ED1 + cells around vessels (**) in MRI-defined edematous areas (dotted lines) while astrocytes were faintly stained (GFAP).During the edema resolution phase (20 dpi, C), T2 and ADC signals were mostly normalized, with the only persistence of a small cavitation at the site of injection due to necrosis (*, similar pattern as in Figure 1, day 14). The corresponding histology showed a large area with hypertrophic and entangled astrocytes i.e., gliosis (GFAP) around the point of injection (dotted lines) while BBB leakage (IgG) had mostly resolved with much lower presence of ED1+ cells.