Jak2^V617F mice displayed more CVST–related hemorrhagic lesions at day 1. (A) Representative serial coronal T2-weighted images from Jak2^WT and Jak2^V617F mice, 1 day after CVST induction demonstrating localized ischemia (white asterisk) and/or ICH (black arrow) in cortical parenchyma. (B) Brain lesions volumes (ischemic and hemorrhagic) determined from coronal T2-weighted images from Jak2^WT and Jak2^V617F mice at day 1, n = 5 per group. (C) Quantification of hemoglobin brain content at day 1 after CVST; ∗P < .05 (t test), n = 6 per group. (D) Brain slices from Jak2^V617F and Jak2^WT mice showing different pattern of ICH severity after CVST (no ICH; type 1: localized ICH; type 2: diffuse ICH). (E) Incidence of severe ICH (i.e., type 2) was significantly increased in Jak2^V617F mice compared with Jak2^WT mice at day 1 after CVST (n = 17 and 12 per group, respectively). In Figure 2B,C, data were analyzed using Mann-Whitney U test. In Figure 2E, data were analyzed by χ² test; ∗P < .05.