Figure 6a. PCA in a 38-year-old woman who experienced a severe headache and a seizure 2 weeks after childbirth. (a) Axial unenhanced CT scan obtained at admission shows a cerebral hematoma in the left frontal lobe. (b) Axial T2-weighted MR image obtained after 2 days of evacuation shows a new hematoma in the right frontal lobe and residual hemorrhage in the left frontal lobe. (c, d) Right carotid angiogram (c) and magnified view with region-of-interest circles (d) show multifocal stenoses and a beaded appearance of the peripheral branches of the anterior and middle cerebral arteries. The findings are characteristic of the angiitis of PCA, which affects the small- and medium-caliber arteries beyond the proximal segments of the major cerebral arteries.