AIF1 and Hydrocephalus: Examples of MRIs of rats with and without (w/o) hydrocephalus (HC) after SAH are shown in Figure 2A. In the rats w/o HC, there was an increase in the number of Iba‐1‐positive cells at 24 hours in SAH (9.3 ± 0.6%; n = 10) compared with sham‐operated rats (6.5 ± 0.4%; n = 12, P < .05, Figure 2B).